Service mode › Ideal

Ideal boiler service mode

How to put an Ideal boiler into service mode, so it holds maximum or minimum rate while you take combustion readings. 182 models from 66 Ideal installation and servicing manuals, each step with the page it came from.

Grouped by manual: one manual usually covers a range of outputs. The CO₂ figures are the manual's own. Set and check them with a calibrated analyser, never by eye.

Atlantic Combi 24, 30, 35

Covers: Atlantic Combi 24, Atlantic Combi 30

GC 47-349-81, 47-349-82

Setting Maximum Rate (DHW max. gas rate, operating in CH mode)

Hold “preheat” & “restart” buttons together for more than 5s
Last 3 faults will be shown
SH shown, press “restart”
Burner will run for 10 minutes at maximum rate.
Press “restart” to exit Maximum Rate mode.

From manual UIN 223483 A03, page 69.

Setting Minimum Rate

Hold “PREHEAT” & “restart” buttons together for more than 5s
Last 3 faults will be shown
SH shown, press “preheat”
SL shown, press “restart”
Burner will run for 10 minutes at minimum rate.
Press “restart” to exit Minimum Rate mode.

From manual UIN 223483 A03, page 69.

Gas	CO₂ max rate	CO₂ min rate	CO max
Natural gas	9.5% ± 0.7	8.8% ± 0.7	350 ppm

CO₂ and CO from manual UIN 223483 A03, page 8. Check against the data badge.

Please Note: The combustion for this appliance has been checked, adjusted and preset at the factory for operation on the gas type defined on the appliance data plate. DO NOT adjust the air/gas ratio valve. (page )

Esprit eco

Covers: Esprit Eco 24, Esprit Eco 30

GC 47-348-91, 47-348-92

Setting Boiler to Minimum Rate

Turn the CH temperature control knob into the 10 O’clock position.
Create a CH demand by ensuring that the system controls are requesting heat and the boiler Mode Knob is in the Winter Position.
Within an overall time of 3 seconds, turn the CH temperature control knob fully clockwise, back to 10 O’clock and then fully clockwise again.
“S” will be shown on the display and the boiler output will be reduced to minimum.
The boiler will remain at minimum rate for 5 minutes before reverting to normal operation.

From manual 207493, page 62.

The air gas ratio valve is factory-set and must not be adjusted DURING COMMISSIONING. (page 62)

ESPRIT ECO2 24 30 35

Covers: Esprit ECO2 24, Esprit ECO2 35

GC 47-349-65, 47-349-67

Setting to Maximum Rate (DHW max. gas rate, operating in CH mode)

Hold "preheat" & "restart" buttons together for more than 5s
Last 3 faults will be shown
SH shown, press "restart"
Burner will run for 10 minutes at maximum rate.
Press "restart" to exit Maximum Rate mode.

From manual UIN 220218 A07, page 68.

Setting to Minimum Rate

Hold "RESTART" & Function buttons together for more than 5s
Last 3 faults will be shown
SL shown, press "RESTART"
If the return temperature is under 40 °C the fan will run for 90 seconds starting at maximum.
The boiler will reduce to minimum rate for 10 minutes unless manually overridden.
Press "RESTART" to exit Minimum Rate mode.

From manual UIN 220218 A07, page 68.

Model	Gas	CO₂ max rate	CO₂ min rate	CO max
Esprit ECO2 24	Natural gas	9.5% ± 0.7	8.8% ± 0.7	350 ppm
Esprit ECO2 35	Natural gas	9.5% ± 0.7	8.9% ± 0.7	350 ppm

CO₂ and CO from manual UIN 220218 A07, page 8. Check against the data badge.

The combustion for this appliance has been checked, adjusted and preset at the factory for operation on the gas type defined on the appliance data plate. DO NOT adjust the air/gas ratio valve. (page 33)

EVOMAX

Covers: Evomax 30P, Evomax 40P, Evomax 60

GC 41-750-35, 41-750-40, 41-750-41

Entering Installer Mode

Press SELECT and then hold + and - down together for more than 5s.
Installer Mode menu will be displayed.

From manual 206210 A03, page 32.

Setting Boiler to Maximum Rate (Servicing)

Ensure that there is a current CH demand to the boiler (e.g. the CH Switched Live is on).
Press SELECT.
Rotate KNOB clockwise until Set Off/Sum/Win is displayed and press SELECT.
Press + and - until Minimum / Maximum screen is displayed.
Highlight Maximum and press ENTER.
The boiler will go to Maximum Rate for 5 minutes. Operation will be automatically reset at the end of 5 minutes.

From manual 206210 A03, page 43.

Gas	CO₂ max rate	CO₂ min rate	CO max
Natural gas	9.7% ± 0.5%	8.7% ± 0.5%	–
LPG	11.4% ± 0.5%	10.2% ± 0.5%	–

CO₂ and CO from manual 206210 A03, page 41. Check against the data badge.

i 24, i 30, i 35 combination boilers (manual UIN 207496 A03)

Covers: Combi i 24, Combi i 30, Combi i 35

GC 47-348-82, 47-348-83, 47-348-84

Setting to Minimum Rate (Commissioning Flowchart)

Turn the CH temperature control knob into the 10 O’clock position.
Create a CH demand by ensuring that the system controls are requesting heat and the boiler Mode Knob is in the Winter Position.
Within an overall time of 3 seconds, turn the CH temperature control knob fully clockwise, back to 10 O’clock and then fully clockwise again.
“S” will be shown on the display and the boiler output will be reduced to minimum
The boiler will remain at minimum rate for 5 minutes before reverting to normal operation

From manual UIN 207496 A03, page 62.

Please Note: The combustion for this appliance has been checked, adjusted and preset at the factory for operation on the gas type defined on the appliance data plate. No measurement of the combustion is necessary. Do not adjust the air/gas ratio valve. (page 29)

i 24, i 30, i 35 combination boilers (manual UIN 220220 A05)

Covers: I2 Combi 24, I2 Combi 35

GC 47-349-74, 47-349-76

Setting to Maximum Rate (DHW max. gas rate, operating in CH mode)

Hold “preheat” & “restart” buttons together for more than 5s
Last 3 faults will be shown
SH shown, press “restart”
Burner will run for 10 minutes at maximum rate.
Press “restart” to exit Maximum Rate mode.

From manual UIN 220220 A05, page 68.

Setting to Minimum Rate

Hold “PREHEAT” & “restart” buttons together for more than 5s
Last 3 faults will be shown
SH shown, press “preheat”
SL shown, press “restart”
Burner will run for 10 minutes at minimum rate.
Press “restart” to exit Minimum Rate mode.

From manual UIN 220220 A05, page 68.

Gas	CO₂ max rate	CO₂ min rate	CO max
Natural gas	9.5% ± 0.7	8.8% ± 0.7	350 ppm

CO₂ and CO from manual UIN 220220 A05, page 8. Check against the data badge.

i-mini

Covers: i-mini 24, i-mini 30

GC 47-348-77, 47-348-78

Setting Boiler to Minimum Rate

Turn the CH temperature control knob into the 10 O’clock position.
Create a CH demand by ensuring that the system controls are requesting heat and the boiler Mode Knob is in the Winter Position.
Within an overall time of 3 seconds, turn the CH temperature control knob fully clockwise, back to 10 O’clock and then fully clockwise again.
“S” will be shown on the display and the boiler output will be reduced to minimum.
The boiler will remain at minimum rate for 5 minutes before reverting to normal operation.

From manual UIN 206743 A07, page 62.

The gas input to the burner is regulated by the gas valve according to the air flow produced by the fan. It is not user-adjustable. Any interference to sealed settings on the gas valve will adversely affect operation and render our warranty void. (page 30)

The air gas ratio valve is factory-set and must not be adjusted DURING COMMISSIONING. (page 62)

i-mini C24, C30

Covers: i-mini C24, i-mini C30

GC 47-349-30, 47-349-31

Accessing the Installer Mode

Press the 'PREHEAT' and 'RESTART' Buttons together for more than 5s.
The last 3 faults will be shown.
'SL' will be shown. To run the burner at minimum rate press 'RESTART', otherwise press 'PREHEAT'.
'SH' will be shown. To run the burner at maximum rate press 'RESTART', otherwise press 'PREHEAT'.
'VF' will be shown. To activate the venting function press 'RESTART', otherwise press 'PREHEAT'.
'dU' will be shown. To move the diverter valve to mid-position for replacement press 'RESTART', otherwise press 'PREHEAT'.
'P1' will be shown. To set the minimum CH pump speed to 100% press 'RESTART', otherwise press 'PREHEAT'.
'P7' will be shown. To set the minimum CH pump speed to 70% (default) press 'RESTART', otherwise press 'PREHEAT'.
'FL' will be shown. Press 'PREHEAT'.
'SE' will be shown. Press 'PREHEAT' to exit.

From manual 222352, page 37.

Gas	CO₂ max rate	CO₂ min rate	CO max
Natural gas	9.5% ± 0.7	8.8% ± 0.7	350 ppm

CO₂ and CO from manual 222352, page 8. Check against the data badge.

Please Note: The combustion for this appliance has been checked, adjusted and set at the factory for operation on the gas type defined on the appliance data plate. DO NOT adjust the air/gas ratio valve. (page )

i-mini2 C24 (Combi)

Covers: i-mini2 C24, i-mini2 C30, i-mini2 C35

GC 47-387-15, 47-387-16, 47-387-17

Accessing Installer Mode

Press the MODE and RESTART buttons together for more than 5s.
The last 3 faults will be shown.
PH will be shown: to change the preheat setting press the RESTART button, press the MODE button, then press the RESTART button again, otherwise press the MODE button.
SH will be shown: to run the burner at maximum rate press the RESTART button, otherwise press the MODE button.
SL will be shown: to run the burner at minimum rate press the RESTART button, otherwise press the MODE button.
UF will be shown: to activate the Venting function press the RESTART button, otherwise press the MODE button.
dU will be shown: to move the diverter valve to mid-position press the RESTART button, otherwise press the MODE button.
P1 will be shown: to set the minimum CH pump speed to 100% press the RESTART button, otherwise press the MODE button.
P7 will be shown: to set the minimum CH pump speed to 70% press the RESTART button, otherwise press the MODE button.
SE will be shown: for service timer function refer to separate instructions.
Press the MODE button to exit.

From manual 236471 A02, page 33.

Model	Gas	CO₂ max rate	CO₂ min rate	CO max
i-mini2 C24, i-mini2 C30	Natural gas	9.2% ± 0.7	8.5% ± 0.7	350 ppm
i-mini2 C35	Natural gas	9.7% ± 0.7	8.8% ± 0.7	–

CO₂ and CO from manual 236471 A02, page 6. Check against the data badge.

IDEAL CLASSIC 24 30 35

Covers: Classic 24, Classic 30

GC 47-349-07, 47-349-08

Setting Boiler to Minimum Rate

Turn the CH temperature control knob into the 10 O’clock position.
Create a CH demand by ensuring that the system controls are requesting heat and the boiler Mode Knob is in the Winter Position.
Within an overall time of 3 seconds, turn the CH temperature control knob fully clockwise, back to 10 O’clock and then fully clockwise again.
“S” will be shown on the display and the boiler output will be reduced to minimum.
The boiler will remain at minimum rate for 5 minutes before reverting to normal operation.

From manual UIN 212135 A06, page 64.

The air gas ratio valve is factory-set and must not be adjusted DURING COMMISSIONING. (page 64)

IDEAL CLASSIC2 24 30 35

Covers: CLASSIC2 24, CLASSIC2 30, CLASSIC2 35

GC 47-349-71, 47-349-72, 47-349-73

Setting Boiler to Maximum Rate (DHW max. gas rate, operating in CH mode)

Hold “preheat” & “restart” buttons together for more than 5s
Last 3 faults will be shown
SH shown, press “restart”
Burner will run for 10 minutes at maximum rate.
Press “restart” to exit Maximum Rate mode.

From manual UIN 220219 A07, page 68.

Setting Boiler to Minimum Rate

Hold “preheat” & “restart” buttons together for more than 5s
Last 3 faults will be shown
SH shown, press “preheat”
SL shown, press “restart”
Burner will run for 10 minutes at minimum rate.
Press “restart” to exit Minimum Rate mode.

From manual UIN 220219 A07, page 68.

Diverter Valve Manual Positioning (Service Mode)

Ensure that the switched live to the boiler is off and that all DHW taps are shut and that pre-heat is switched off.
Press and hold the “PREHEAT” and “RESTART” buttons together for more than 5s, the last 3 faults will then be shown in sequence before “SL” is shown
Press “PREHEAT”, “SH” will be shown
Press “PREHEAT”, “UF” will be shown
Press “PREHEAT”, “DU” will be shown
Press “RESTART” and the diverter valve will move to the mid-position

From manual UIN 220219 A07, page 45.

Model	Gas	CO₂ max rate	CO₂ min rate	CO max
CLASSIC2 24, CLASSIC2 30	Natural gas	9.5% ± 0.7	8.8% ± 0.7	350 ppm
CLASSIC2 35	Natural gas	9.5% ± 0.7	8.9% ± 0.7	350 ppm

CO₂ and CO from manual UIN 220219 A07, page 8. Check against the data badge.

IDEAL COMPACT EXTRA Wall mounted, Balanced Flue Gas Boiler

Covers: Compact

Service Mode & Commissioning

To light pilot: Turn gas control knob to PILOT position, press in, press ignitor button (C) repeatedly, hold for 15 seconds after ignition (Frame 27/29).
Pressure adjustment: Turn clockwise to decrease, anticlockwise to increase pressure using adjusting screw (G) (Frame 29).
Setting Pilot Length: If incorrect, turn adjuster screw (L) clockwise to close, then 4 full turns anticlockwise (Frame 7).
System Flushing: Set and lock diverter valve manual lever to OPEN position when filling (Frame 14).
Pump Venting: Remove vent plug, use screwdriver in shaft slot to rotate (Frame 14).

From the installation and servicing manual, page 40.

IDEAL EXCLUSIVE 24 30 35

Covers: Exclusive 24, Exclusive 30, Exclusive 35

GC 47-349-41, 47-349-42, 47-349-43

Setting Boiler to Minimum Rate (Service Mode)

Turn the CH temperature control knob into the 10 O’clock position.
Create a CH demand by ensuring that the system controls are requesting heat and the boiler Mode Knob is in the Winter Position.
Within an overall time of 3 seconds, turn the CH temperature control knob fully clockwise, back to 10 O’clock and then fully clockwise again.
“S” will be shown on the display and the boiler output will be reduced to minimum.
The boiler will remain at minimum rate for 5 minutes before reverting to normal operation.

From manual UIN 217746 A03, page 66.

IDEAL EXCLUSIVE2 24 30 35

Covers: EXCLUSIVE2 24, EXCLUSIVE2 30, EXCLUSIVE2 35

GC 47-349-62, 47-349-63, 47-349-64

Setting Boiler to Maximum Rate (DHW max. gas rate, operating in CH mode)

Hold 'preheat' & 'restart' buttons together for more than 5s
Last 3 faults will be shown
SH shown, press 'restart'
Burner will run for 10 minutes at maximum rate.
Press 'restart' to exit Maximum Rate mode.

From manual UIN 220221 A07, page 68.

Setting Boiler to Minimum Rate

Hold 'RESTART' & Function buttons together for more than 5s
Last 3 faults will be shown
SL shown, press 'RESTART'
If the return temperature is under 40 °C the fan will run for 90 seconds starting at maximum.
The boiler will reduce to minimum rate for 10 minutes unless manually overridden.
Press 'RESTART' to exit Minimum Rate mode.

From manual UIN 220221 A07, page 68.

Model	Gas	CO₂ max rate	CO₂ min rate	CO max
EXCLUSIVE2 24	Natural gas	9.5% ± 0.7	8.8% ± 0.7	350 ppm
EXCLUSIVE2 30	Natural gas	9.3% ± 0.7	8.8% ± 0.7	350 ppm
EXCLUSIVE2 35	Natural gas	9.5% ± 0.7	8.9% ± 0.7	350 ppm

CO₂ and CO from manual UIN 220221 A07, page 8. Check against the data badge.

The air/gas ratio valve is factory-set and must not be adjusted DURING COMMISSIONING. Any interference to sealed settings on the gas valve will adversely affect operation and render our warranty void. (page )

Ideal GB24 & GB30 Series III Combination Boiler

Covers: GB24 / GB30

Enter Service Mode (Maximum Rate)

Hold 'restart' & 'function' buttons together for more than 5s.
Last 3 faults will be shown.
SH shown, press 'restart'.
Burner will run for 10 minutes at maximum rate.
Press 'restart' to exit Maximum Rate mode.

From manual UIN 220217 A04, page 39.

Enter Service Mode (Minimum Rate)

Hold 'restart' & 'function' buttons together for more than 5s.
Last 3 faults will be shown.
SH shown, press 'function' button.
SL shown, press 'restart'.
Burner will run for 10 minutes at minimum rate.
Press 'restart' to exit Minimum Rate mode.

From manual UIN 220217 A04, page 39.

The air gas ratio valve is factory-set and must not be adjusted DURING COMMISSIONING. (page 39)

Ideal INSTINCT

Covers: Instinct 24, Instinct 30, Instinct 35

GC 47-349-09, 47-349-10, 47-349-11

Setting to Minimum Rate

Turn the CH temperature control knob into the 10 O’clock position.
Create a CH demand by ensuring that the system controls are requesting heat and the boiler Mode Knob is in the Winter Position.
Within an overall time of 3 seconds, turn the CH temperature control knob fully clockwise, back to 10 O’clock and then fully clockwise again.
“S” will be shown on the display and the boiler output will be reduced to minimum
The boiler will remain at minimum rate for 5 minutes before reverting to normal operation

From manual UIN 212456 A03, page 64.

IDEAL INSTINCT2 24 30 35

Covers: Instinct2 24, Instinct2 30, Instinct2 35

GC 47-349-68, 47-349-69, 47-349-70

Setting to Maximum Rate (DHW max. gas rate, operating in CH mode)

Hold “preheat” & “restart” buttons together for more than 5s
Last 3 faults will be shown
SH shown, press “restart”
Burner will run for 10 minutes at maximum rate.
Press “restart” to exit Maximum Rate mode.

From manual UIN 220222 A07, page 68.

Setting to Minimum Rate

Hold “RESTART” & Function buttons together for more than 5s
Last 3 faults will be shown
SL shown, press “RESTART”
If the return temperature is under 40 °C the fan will run for 90 seconds starting at maximum.
The boiler will reduce to minimum rate for 10 minutes unless manually overridden.
Press “RESTART” to exit Minimum Rate mode.

From manual UIN 220222 A07, page 68.

Model	Gas	CO₂ max rate	CO₂ min rate	CO max
Instinct2 24, Instinct2 30	Natural gas	9.5% ± 0.7	8.8% ± 0.7	350 ppm
Instinct2 35	Natural gas	9.5% ± 0.7	8.9%	350 ppm

CO₂ and CO from manual UIN 220222 A07, page 8. Check against the data badge.

Ideal Logic + System

Covers: Logic + System 15, Logic + System 18, Logic + System 24, Logic + System 30

GC 41-750-29, 41-750-30, 41-750-31, 41-750-32

Setting Boiler to Minimum Gas Rate

Turn the CH temperature control knob into the 10 O’clock position.
Create a heat demand by ensuring that the system controls are requesting heat and the boiler Mode Knob is in the On Position.
Within an overall time of 3 seconds, turn the CH temperature control knob fully clockwise, back to 10 O’clock and then fully clockwise again.
“S” will be shown on the display and the boiler output will be reduced to minimum.
The boiler will remain at minimum rate for 5 minutes before reverting to normal operation.

From manual 206025, page 58.

The combustion for this appliance has been checked, adjusted and preset at the factory for operation on the gas type defined on the appliance data plate. Do not adjust the air/gas ratio valve. (page 30)

Ideal Logic Code Combi 26, 33, 38

Covers: Logic Code Combi 33

GC 47-348-75

Setting boiler to operate at maximum rate

Open hot tap to maximum flow.

From manual 206279, page 32.

The combustion for this appliance has been checked, adjusted and preset at the factory for operation on the gas type defined on the appliance data plate. No measurement of the combustion is necessary. Do not adjust the air/gas ratio valve. (page 32)

Ideal Logic Combi 24, 30, 35

Covers: Logic Combi 24, Logic Combi 30, Logic Combi 35

GC 47-348-56, 47-348-57, 47-348-58

Setting Boiler to Minimum Rate (Combustion / Service Check)

Turn the CH temperature control knob into the 10 O'clock position.
Create a CH demand by ensuring that the system controls are requesting heat and the boiler Mode Knob is in the Winter Position.
Within an overall time of 3 seconds, turn the CH temperature control knob fully clockwise, back to 10 O'clock and then fully clockwise again.
"S" will be shown on the display and the boiler output will be reduced to minimum.
The boiler will remain at minimum rate for 5 minutes before reverting to normal operation.

From manual 204626 A12, page 62.

Ideal Mini C24/C28/C32 S24/S28

Covers: Mini C24, Mini C32

GC 47-348-18, 47-348-25, 47-348-41

Entering Service Mode

With the boiler switched ON (heating or hot water mode), move and re-set to its original position any of the function selectors to activate service operation mode and illuminate all the lamps.
To reset the main control p.c.b. to normal operation, turn the knob to the stand-by position or switch off the boiler for a short while at the fused spur isolation switch.

From manual 3603 56A4 GB, page 46.

The boiler is factory pre-set and should not need adjustment. However if adjustment is required refer to frame 29. (page 25)

Ideal mini HE

Covers: Mini

GC 47-348-38

Enter Service / Ignition Rate Adjustment Mode

Open the gas valve outlet pressure test point E and connect the gauge.
Loosen the screws F and remove the service panel.
Set dip-switch "3" to the OFF position and adjust potentiometer marked "ACC" with a screwdriver until correct ignition gas pressure is obtained.
Alternatively, for the updated model variant, rotate the radiator temperature control C as indicated and ensure the room thermostat is set to heat demand, run the boiler in c.h. mode without opening any d.h.w. tap.
Press and hold the reset button D for about 10 seconds until the lock-out signal light E blinks.

From manual 17962.1138.0, page 25.

The boiler is factory pre-set and should not need adjustment. However if adjustment is required refer to frame 27. (page 24)

Ideal Systemiser SE

Covers: Systemiser

GC 41-349-70

Force Max Rate (Test Mode)

Remove the controls button cover plate.
Select TEST mode by pressing MODE and '+' buttons simultaneously (to simulate a call for maximum heat).

From manual 151415, page 35.

Force Min Rate (Test Mode)

Remove the controls button cover plate.
Select TEST mode by pressing MODE and '-' buttons simultaneously (to simulate a call for minimum heat).

From manual 151415, page 35.

The valve is factory set and sealed. No adjustment is necessary. (page 45)

IDEAL Turbo 2

Covers: Turbo2 24

Service and Commissioning Procedure

Isolate the boiler from the mains supply.
Remove the outer casing.
Clean the burner box, heat exchanger, and check main/pilot injectors.
Check that water ways are not scaled and condensate drain is unobstructed.
Burner pressure is preset at the factory and should not require adjustment.
Check for gas soundness.

From the installation and servicing manual, page 17.

The burner pressure is pre-set at the factory and should not require adjustment. (page 15)

Imax W (System)

Covers: Imax W

Force Max & Min Rate

To set the fan speed to maximum: Press and hold in the 'mode' and '+' buttons simultaneously. Display will show H as first digit.
To set the fan speed to minimum: Press and hold in the 'mode' and '-' buttons simultaneously. Display will show L as first digit.
Press the 'reset' button to return to normal operating mode.

From manual 158 334 A02, page 38.

Gas	CO₂ max rate	CO₂ min rate	CO max
Natural gas	8.9%	8.7%	–
LPG	10.6%	10.3%	–

CO₂ and CO from manual 158 334 A02, page 2. Check against the data badge.

Only valves supplied by Caradon Ideal Limited should be used, as these are factory preset and require no adjustment. (page 43)

INDEPENDENT + COMBI 24 30 35

Covers: Independent + Combi 24, INDEPENDENT + Combi 30, INDEPENDENT + Combi 35

GC 47-349-27, 47-349-28, 47-349-29

Accessing the Installer Mode

Press the PREHEAT and RESTART Buttons together for more than 5s.
The last 3 faults will be shown.
SL will be shown. To run the burner at minimum rate press RESTART, otherwise press PREHEAT.
SH will be shown. To run the burner at maximum rate press RESTART, otherwise press PREHEAT.
VF will be shown. To activate the venting function press RESTART, otherwise press PREHEAT.
dU will be shown. To move the diverter valve to mid-position for replacement press RESTART, otherwise press Preheat.
P1 will be shown. To set the minimum CH pump speed to 100% press RESTART, otherwise press PREHEAT.
P7 will be shown. To set the minimum CH pump speed to 70% (default) press RESTART, otherwise press PREHEAT to Exit.

From manual UIN 215343 A06, page 37.

Gas	CO₂ max rate	CO₂ min rate	CO max
Natural gas	9.5% ± 0.7	8.8% ± 0.7	350 ppm

CO₂ and CO from manual UIN 215343 A06, page 8. Check against the data badge.

Independent + Combi C24, C30, C35

Covers: Independent + C24, INDEPENDENT + C30, INDEPENDENT + C35

GC 47-348-85, 47-348-86, 47-348-87

Setting to Minimum Rate (Flowchart procedure)

Turn the CH temperature control knob into the 10 O’clock position.
Create a CH demand by ensuring that the system controls are requesting heat and the boiler Mode Knob is in the Winter Position.
Within an overall time of 3 seconds, turn the CH temperature control knob fully clockwise, back to 10 O’clock and then fully clockwise again.
“S” will be shown on the display and the boiler output will be reduced to minimum.
The boiler will remain at minimum rate for 5 minutes before reverting to normal operation.

From manual 207607, page 62.

Independent C24, C30, C35

Covers: INDEPENDENT C24 (2010-2016), INDEPENDENT C30

GC 47-348-68, 47-348-69

Setting Boiler to Minimum Rate

Turn the CH temperature control knob into the 10 O’clock position.
Create a CH demand by ensuring that the system controls are requesting heat and the boiler Mode Knob is in the Winter Position.
Within an overall time of 3 seconds, turn the CH temperature control knob fully clockwise, back to 10 O’clock and then fully clockwise again.
“S” will be shown on the display and the boiler output will be reduced to minimum
The boiler will remain at minimum rate for 5 minutes before reverting to normal operation

From manual 205367, page 62.

INDEPENDENT COMBI 24 30 35

Covers: INDEPENDENT Combi 30

GC 47-349-25

Accessing the Installer Mode

To access Installer Mode press the 'PREHEAT' and 'RESTART' Buttons together for more than 5s.
The last 3 faults will be shown.
'SL' will be shown. To run the burner at minimum rate press 'RESTART', otherwise press 'PREHEAT'.
'SH' will be shown. To run the burner at maximum rate press 'RESTART', otherwise press 'PREHEAT'.
'VF' will be shown. To activate the venting function press 'RESTART', otherwise press 'PREHEAT'.
'dU' will be shown. To move the diverter valve to mid-position for replacement press 'RESTART', otherwise press Preheat.
'P1' will be shown. To set the minimum CH pump speed to 100% press 'RESTART', otherwise press 'PREHEAT'.
'P7' will be shown. To set the minimum CH pump speed to 70% (default) press 'RESTART', otherwise press 'PREHEAT' to Exit.

From manual UIN 215344 A06, page 37.

Gas	CO₂ max rate	CO₂ min rate	CO max
Natural gas	9.5% ± 0.7	8.8% ± 0.7	350 ppm

CO₂ and CO from manual UIN 215344 A06, page 8. Check against the data badge.

INDEPENDENT COMBI2 C24 C30 C35

Covers: Independent COMBI2 C24

GC 47-387-09

Accessing the Installer Mode

Press the MODE and RESTART buttons together for more than 5s.
The last 3 faults will be shown.
'PH' will be shown. To change the preheat setting press Restart, press Mode, then press Restart again, otherwise press Mode.
'SH' will be shown. To run the burner at maximum rate press 'RESTART', otherwise press 'MODE'.
'SL' will be shown. To run the burner at minimum rate press 'RESTART', otherwise press 'MODE'.
'UF' will be shown. To activate the Venting function press 'RESTART', otherwise press 'MODE'.
'dU' will be shown. To move the diverter valve to mid-position for replacement press 'RESTART', otherwise press 'MODE'.
'P1' will be shown. To set the minimum CH pump speed to 100% press 'RESTART', otherwise press 'MODE'.
'P7' will be shown. To set the minimum CH pump speed to 70% press 'RESTART', otherwise press 'MODE'.
'SE' will be shown. For service timer function refer to separate instructions. Press 'MODE' to exit.

From manual UIN 236469 A02, page 33.

Gas	CO₂ max rate	CO₂ min rate	CO max
Natural gas	9.2% ± 0.7	8.5% ± 0.7	350 ppm

CO₂ and CO from manual UIN 236469 A02, page 6. Check against the data badge.

INDEPENDENT SYSTEM s15 s18 s24 s30

Covers: Independent System S15, INDEPENDENT System s24, INDEPENDENT System s30

GC 41-750-69, 41-750-71, 41-750-72

Accessing the Installer Mode

To access Installer Mode press the function button and RESTART Buttons together for more than 5s.
The last 3 faults will be shown
SL will be shown. To run the burner at minimum rate press RESTART, otherwise press the function button.
SH will be shown. To run the burner at maximum rate press RESTART, otherwise press the function button.
VF will be shown. To activate the venting function press RESTART, otherwise press the function button.

From manual 215351, page 38.

Gas	CO₂ max rate	CO₂ min rate	CO max
Natural gas	9.3% ± 0.7	8.8% ± 0.7	–

CO₂ and CO from manual 215351, page 8. Check against the data badge.

INDEPENDENT SYSTEM2 S15 S18 S24 S30

Covers: Independent SYSTEM2 S18, Independent SYSTEM2 S24, Independent SYSTEM2 S30

GC 41-860-07, 41-860-08, 41-860-09

Accessing the Installer Mode

To access Installer Mode, press the “MODE” and “RESTART” buttons together for more than 5s.
The last 3 faults will be shown.
“SH” will be shown. To run the burner at maximum rate press “RESTART”, otherwise press “MODE”.
“SL” will be shown. To run the burner at minimum rate press “RESTART”, otherwise press “MODE”.
“UF” will be shown. To activate the Venting function press “RESTART”, otherwise press “MODE”.
“P1” will be shown. To set the minimum CH pump speed to 100% press “RESTART”, otherwise press “MODE”.
“P7” will be shown. To set the minimum CH pump speed to 70% press “RESTART”, otherwise press “MODE”.
“SE” will be shown. For service timer function refer to separate instructions. Press “MODE” to exit.
“SE” will be shown. For service timer function refer to separate instructions. Press “MODE” to exit.

From manual 236470, page 34.

Model	Gas	CO₂ max rate	CO₂ min rate	CO max
Independent SYSTEM2 S18	Natural gas	9.3% ± 0.7	8.3% ± 0.7	350 ppm
Independent SYSTEM2 S24, Independent SYSTEM2 S30	Natural gas	9.5% ± 0.7	8.9% ± 0.7	350 ppm

CO₂ and CO from manual 236470, page 6. Check against the data badge.

The air gas ratio valve is factory-set and must not be adjusted DURING COMMISSIONING. (page 60)

Logic + Combi 24, 30, 35

Covers: Logic+ Combi 30, Logic+ Combi 35

GC 47-348-66, 47-348-67

Entering Installer Mode

Turn the DHW temperature control knob full anti-clockwise.
Turn the CH flow temperature control knob full anti-clockwise.
Turn and hold the mode knob in the reset position for more than 5 secs and then turn it to the Winter or Summer position.

From manual 204978, page 36.

Logic + System s15 s18 s24 s30

Covers: 15, Logic+ System S18, Logic+ System s24, Logic+ System s30

GC 41-750-65, 41-750-66, 41-750-67, 41-750-68

Accessing the Installer Mode

To access Installer Mode press the function button and RESTART buttons together for more than 5s.
The last 3 faults will be shown.
SL will be shown: To run the burner at minimum rate press RESTART, otherwise press the function button.
SH will be shown: To run the burner at maximum rate press RESTART, otherwise press the function button.
VF will be shown: To activate the venting function press RESTART, otherwise press the function button. (The venting function runs for 5 minutes before automatically returning to normal operation; the Pump alternates between being on for 50s and then off for 10s).
dU will be shown: press the Function button.
P1 will be shown: To set the minimum CH pump speed to 100% press RESTART, otherwise press the function button.
P7 will be shown: To set the minimum CH pump speed to 70% (default) press RESTART, otherwise press the function button to Exit.

From manual UIN 215353 A01, page 38.

The air gas ratio valve is factory-set and must not be adjusted DURING COMMISSIONING. (page 35)

Logic Code Combi ES (ES26, ES33, ES38)

Covers: Logic Code Combi ES26, Logic Code Combi ES33

GC 47-349-04, 47-349-05

Setting Boiler to Minimum Rate (Combustion / Service Check)

Turn the CH temperature control knob into the 10 O'clock position.
Create a CH demand by ensuring that the system controls are requesting heat and the boiler Mode Knob is in the Winter Position.
Within an overall time of 3 seconds, turn the CH temperature control knob fully clockwise, back to 10 O'clock and then fully clockwise again.
"S" will be shown on the display and the boiler output will be reduced to minimum.
The boiler will remain at minimum rate for 5 minutes before reverting to normal operation.

From manual 210927 A03, page 66.

The air gas ratio valve is factory-set and must not be adjusted DURING COMMISSIONING. The gas input to the burner is regulated by the gas valve according to the air flow produced by the fan. It is NOT user-adjustable. Any interference to sealed settings on the gas valve will adversely affect operation and render our warranty void. (page 33)

Logic Code Combi ESP1 26 33 38

Covers: Logic Code Combi ESP1 26, Logic Code Combi ESP1 33, Logic Code Combi ESP1 38

GC 47-349-35, 47-349-36, 47-349-37

Accessing the Installer Mode

To access Installer Mode press the Function and RESTART Buttons together for more than 5s.
The last 3 faults will be shown.
SL will be shown: To run the burner at minimum rate press RESTART, otherwise press the Function button.
SH will be shown: To run the burner at maximum rate press RESTART, otherwise press the Function button.
VF will be shown: To activate the venting function press RESTART, otherwise press the Function button.
dU will be shown: To move the diverter valve to mid-position for replacement press RESTART, otherwise press Function button.
P1 will be shown: To set the minimum CH pump speed to 100% press RESTART, otherwise press the Function button.
P7 will be shown: To set the minimum CH pump speed to 70% (default) press RESTART, otherwise press the Function button.
FL will be shown: This feature is not required on this appliance. Press the function button.
SE will be shown: For service timer function refer to separate instructions. Press the function button to exit.

From manual UIN 222364 A04, page 38.

Setting to Maximum Rate (Combustion / Commissioning Check)

Hold RESTART & Function buttons together for more than 5s
Last 3 faults will be shown
SL shown, press the Function button
SH shown, press RESTART
Burner will run for 10 minutes at maximum rate.
Press RESTART to exit Maximum rate mode.

From manual UIN 222364 A04, page 68.

Setting to Minimum Rate (Combustion / Commissioning Check)

Hold RESTART & Function buttons together for more than 5s
Last 3 faults will be shown
SL shown, press RESTART
If the return temperature is under 40 °C the fan will run for 90 seconds starting at maximum.
The boiler will reduce to minimum rate for 10 minutes unless manually overridden.
Press RESTART to exit Minimum Rate mode.

From manual UIN 222364 A04, page 68.

Model	Gas	CO₂ max rate	CO₂ min rate	CO max
Logic Code Combi ESP1 26, Logic Code Combi ESP1 33	Natural gas	9.2% ± 0.7	8.7%	350 ppm
Logic Code Combi ESP1 38	Natural gas	10.1% ± 0.7	8.8% ± 0.7	350 ppm

CO₂ and CO from manual UIN 222364 A04, page 8. Check against the data badge.

The gas input to the burner is regulated by the gas valve according to the air flow produced by the fan. It is NOT user-adjustable. Any interference to sealed settings on the gas valve will adversely affect operation and render our warranty void. (page 36)

Logic Combi C24 C30 C35

Covers: Logic Combi C24, Logic Combi C30, Logic Combi C35

GC 47-349-18, 47-349-19, 47-349-20

Accessing the Installer Mode

To access Installer Mode press the 'PREHEAT' and 'RESTART' Buttons together for more than 5s.
The last 3 faults will be shown.
'SL' will be shown. To run the burner at minimum rate press 'RESTART', otherwise press 'PREHEAT'.
'SH' will be shown. To run the burner at maximum rate press 'RESTART', otherwise press 'PREHEAT'.
'VF' will be shown. To activate the venting function press 'RESTART', otherwise press 'PREHEAT'.
'dU' will be shown. To move the diverter valve to mid-position for replacement press 'RESTART', otherwise press 'PREHEAT'.
'P1' will be shown. To set the minimum CH pump speed to 100% press 'RESTART', otherwise press 'PREHEAT'.
'P7' will be shown. To set the minimum CH pump speed to 70% (default) press 'RESTART', otherwise press 'PREHEAT'.

From manual UIN 213972 A09, page 38.

Model	Gas	CO₂ max rate	CO₂ min rate	CO max
Logic Combi C24, Logic Combi C35	Natural gas	9.5% ± 0.7	8.8% ± 0.7	350 ppm
Logic Combi C30	Natural gas	9.3% ± 0.7	–	350 ppm

CO₂ and CO from manual UIN 213972 A09, page 8. Check against the data badge.

Logic Combi ES ES24, ES30, ES35

Covers: Logic Combi ES24, Logic Combi ES30, Logic Combi ES35

GC 47-349-01, 47-349-02, 47-349-03

Setting Boiler to Minimum Rate

Turn the CH temperature control knob into the 10 O’clock position.
Create a CH demand by ensuring that the system controls are requesting heat and the boiler Mode Knob is in the Winter Position.
Within an overall time of 3 seconds, turn the CH temperature control knob fully clockwise, back to 10 O’clock and then fully clockwise again.
“S” will be shown on the display and the boiler output will be reduced to minimum
The boiler will remain at minimum rate for 5 minutes before reverting to normal operation

From manual 208383, page 62.

Please Note: The combustion for this appliance has been checked, adjusted and preset at the factory for operation on the gas type defined on the appliance data plate. Do not adjust the air/gas ratio valve. (page )

Logic Combi ESP

Covers: Logic Combi ESP24, Logic Combi ESP30, Logic Combi ESP35

GC 47-349-12, 47-349-13, 47-349-14

Setting Boiler to Minimum Rate

Turn the CH temperature control knob into the 10 O’clock position.
Create a CH demand by ensuring that the system controls are requesting heat and the boiler Mode Knob is in the Winter Position.
Within an overall time of 3 seconds, turn the CH temperature control knob fully clockwise, back to 10 O’clock and then fully clockwise again.
“S” will be shown on the display and the boiler output will be reduced to minimum.
The boiler will remain at minimum rate for 5 minutes before reverting to normal operation.

From manual 213936, page 66.

The air gas ratio valve is factory-set and must not be adjusted DURING COMMISSIONING. (page 34)

Logic Combi ESP1 24 30 35

Covers: Logic Combi ESP1 24, Logic Combi ESP1 30, Logic Combi ESP1 35

GC 47-349-21, 47-349-22, 47-349-23

Accessing the Installer Mode

To access Installer Mode press the PREHEAT and RESTART Buttons together for more than 5s.
The last 3 faults will be shown
SL will be shown. To run the burner at minimum rate press RESTART, otherwise press the FUNCTION button.
SH will be shown. To run the burner at maximum rate press RESTART, otherwise press the FUNCTION button.
VF will be shown. To activate the venting function press RESTART, otherwise press the FUNCTION button.
dU will be shown. To move the diverter valve to mid-position for replacement press RESTART, otherwise press the FUNCTION button.
P1 will be shown. To set the minimum CH pump speed to 100% press RESTART, otherwise press the FUNCTION button.
P7 will be shown. To set the minimum CH pump speed to 70% (default) press RESTART, otherwise press the FUNCTION button.
FL will be shown. This feature is not required on this appliance. Press the FUNCTION button.
SE will be shown. For service timer function refer to separate instructions. Press the FUNCTION button to exit.

From manual UIN 222353 A04, page 38.

Setting to Maximum Rate (Commissioning)

Hold RESTART & Function buttons together for more than 5s
Last 3 faults will be shown
SL shown, press the Function button
SH shown, press RESTART
Burner will run for 10 minutes at maximum rate.
Press RESTART to exit Maximum rate mode.

From manual UIN 222353 A04, page 68.

Setting to Minimum Rate (Commissioning)

Hold RESTART & Function buttons together for more than 5s
Last 3 faults will be shown
SL shown, press RESTART
Burner will run for 10 minutes at minimum rate.
Press RESTART to exit Minimum rate mode.

From manual UIN 222353 A04, page 68.

Gas	CO₂ max rate	CO₂ min rate	CO max
Natural gas	9.5% ± 0.7	8.8% ± 0.7	–

CO₂ and CO from manual UIN 222353 A04, page 8. Check against the data badge.

LOGIC COMBI2 C24 C30 C35

Covers: Logic COMBI2 C24, Logic COMBI2 C30, Logic COMBI2 C35

GC 47-349-93, 47-349-94, 47-349-95

Accessing the Installer Mode

Press the MODE and RESTART buttons together for more than 5s.
The last 3 faults will be shown.
PH will be shown. To change the preheat setting press Restart, press Mode, then press Restart again, otherwise press Mode.
SH will be shown. To run the burner at maximum rate press RESTART, otherwise press MODE.
SL will be shown. To run the burner at minimum rate press RESTART, otherwise press MODE.
UF will be shown. To activate the Venting function press RESTART, otherwise press MODE.
dU will be shown. To move the diverter valve to mid-position for replacement press RESTART, otherwise press MODE.
P1 will be shown. To set the minimum CH pump speed to 100% press RESTART, otherwise press MODE.
P7 will be shown. To set the minimum CH pump speed to 70% press RESTART, otherwise press MODE.
SE will be shown. For service timer function refer to separate instructions. Press MODE to exit.

From manual UIN 228296 A05, page 34.

Model	Gas	CO₂ max rate	CO₂ min rate	CO max
Logic COMBI2 C24	Natural gas	9.2% ± 0.7	8.5% ± 0.7	350 ppm
Logic COMBI2 C30	Natural gas	9.3% ± 0.7	8.5% ± 0.7	350 ppm
Logic COMBI2 C35	Natural gas	9.7% ± 0.7	8.8% ± 0.7	350 ppm

CO₂ and CO from manual UIN 228296 A05, page 6. Check against the data badge.

LOGIC Heat 12, 15, 18, 24, 30

Covers: Logic Heat 12, Logic Heat 15, Logic Heat 18, Logic Heat 24, Logic Heat 30

GC 41-399-99, 41-409-93, 41-409-94, 41-409-95, 41-409-96

Setting Boiler to Minimum Rate (Service / Combustion Test Mode)

Turn the CH temperature control knob into the 10 O’clock position.
Create a heat demand by ensuring that the system controls are requesting heat and the boiler Mode Knob is in the On Position.
Within an overall time of 3 seconds, turn the CH temperature control knob fully clockwise, back to 10 O’clock and then fully clockwise again.
"S" will be shown on the display and the boiler output will be reduced to minimum.
The boiler will remain at minimum rate for 5 minutes before reverting to normal operation.

From manual 205862, page 60.

Logic Heat H

Covers: Logic Heat H12, Logic Heat H15, Logic Heat H18, Logic Heat H24, Logic Heat H30

GC 41-750-77, 41-750-78, 41-750-79, 41-750-80, 41-750-81

Accessing The Installer Mode and Forcing Rate

To access Installer Mode press the function button and RESTART buttons together for more than 5s.
The last 3 faults will be shown.
‘SL’ will be shown. To run the burner at minimum rate press ‘RESTART’, otherwise press the function button.
‘SH’ will be shown. To run the burner at maximum rate press ‘RESTART’, otherwise press the function button.
‘VF’ will be shown. Press the Function button.
‘dU’ will be shown. Press the Function button.
‘P1’ will be shown. Press the function button.
‘P7’ will be shown. Press the function button to Exit.

From manual UIN 215354 A07, page 42.

Model	Gas	CO₂ max rate	CO₂ min rate	CO max
Logic Heat H12, Logic Heat H30	Natural gas	9.1% ± 0.7	8.5% ± 0.7	350 ppm
Logic Heat H15	Natural gas	9.5% ± 0.7	8.8% ± 0.7	350 ppm
Logic Heat H18	Natural gas	9.5% ± 0.7	8.9% ± 0.7	–
Logic Heat H24	Natural gas	9.3% ± 0.7	8.8% ± 0.7	350 ppm

CO₂ and CO from manual UIN 215354 A07, page 8. Check against the data badge.

Logic Heat2 H

Covers: Logic HEAT2 H15, Logic HEAT2 H18, Logic HEAT2 H24, Logic HEAT2 H30

GC 41-860-11, 41-860-12, 41-860-13, 41-860-14

Accessing the Installer Mode

Press the MODE and RESTART buttons together for more than 5 seconds.
The last 3 faults will be shown.
PH will be shown. Press MODE.
SH will be shown. To run the burner at maximum rate press RESTART, otherwise press MODE.
SL will be shown. To run the burner at minimum rate press RESTART, otherwise press MODE. Note that the burner will initially run at maximum rate for 30s before ramping down to minimum over 1 minute.
UF will be shown. Press MODE.
dU will be shown. Press MODE.
P1 will be shown. To set the minimum CH pump speed to 100% press RESTART, otherwise press MODE.
P7 will be shown. Press MODE.
SE will be shown. For service timer function refer to separate instructions. Press MODE to exit.

From manual 228298 A04, page 37.

Setting to Maximum Rate (Commissioning/Servicing)

Hold MODE & RESTART buttons together for more than 5s.
Last 3 faults will be shown.
SH shown, press RESTART button.
Burner will run for 10 minutes at maximum rate.
Press RESTART to exit Maximum Rate mode.

From manual 228298 A04, page 60.

Setting to Minimum Rate (Commissioning/Servicing)

Hold MODE & RESTART buttons together for more than 5s.
Last 3 faults will be shown.
SH shown, press MODE button.
SL shown, press RESTART.
If the Return Temperature is under 40°C then the burner will run at maximum rate for 30s before ramping down to minimum rate over 60s.
If the Return Temperature is over 40°C then the burner will ramp down to minimum rate over 60s.
Burner will run for 10 minutes at minimum rate.
Press RESTART to exit Minimum Rate mode.

From manual 228298 A04, page 60.

Gas	CO₂ max rate	CO₂ min rate	CO max
Natural gas	9.1% ± 0.7	8.5% ± 0.7	350 ppm

CO₂ and CO from manual 228298 A04, page 6. Check against the data badge.

Logic Max Combi C 24 30 35

Covers: Logic Max Combi C24, Logic Max Combi C30, Logic Max Combi C35

GC 47-349-56, 47-349-57, 47-349-58

Accessing Service Mode Maximum DHW Rate

Ensure a CH demand is already present.
Press Menu.
Press Next until the Service Mode Maximum DHW Rate screen is displayed.
Press Enter.
Press Exit to return to normal operation.

From manual UIN 222362 A01, page 39.

Accessing Service Mode Maximum CH Rate

Ensure a CH demand is already present.
Press Menu.
Press Next until the Service Mode Maximum CH Rate screen is displayed.
Press Enter.
Press Exit to return to normal operation.

From manual UIN 222362 A01, page 39.

Accessing Service Mode Minimum Rate

Ensure a CH demand is already present.
Press Menu.
Press Next until the Service Mode Minimum Rate screen is displayed.
Press Enter.
Press Exit to return to normal operation.

From manual UIN 222362 A01, page 39.

Gas	CO₂ max rate	CO₂ min rate	CO max
Natural gas	9.5% ± 0.7	8.8% ± 0.7	–

CO₂ and CO from manual UIN 222362 A01, page 8. Check against the data badge.

Logic Max Combi2 C24 C30 C35

Covers: Logic Max COMBI2 C24, Logic Max COMBI2 C30, Logic Max COMBI2 C35

GC 47-387-03, 47-387-04, 47-387-05

Setting Maximum and Minimum Rates

Maximum DHW and Minimum Rate can be accessed through the menu option.
On the Maximum DHW Rate screen, press the Exit button.
The boiler will run at Maximum DHW Rate for 10 mins as long as there is sufficient cooling load.
On the Minimum Rate screen, press the Exit button.
The boiler will run at Minimum Rate for 10 mins. If the return temperature is under 40°C then the fan will run for 30s at maximum rate before ramping down over 60s to minimum rate.
If the return temperature is above 40°C then the fan will ramp down over 60s to minimum rate.

From manual 237660, page 34.

Model	Gas	CO₂ max rate	CO₂ min rate	CO max
Logic Max COMBI2 C24	Natural gas	9.2% ± 0.7	8.5% ± 0.7	350 ppm
Logic Max COMBI2 C30	Natural gas	9.3% ± 0.7	8.5% ± 0.7	–
Logic Max COMBI2 C35	Natural gas	9.7% ± 0.7	8.8% ± 0.7	350 ppm

CO₂ and CO from manual 237660, page 6. Check against the data badge.

Logic Max Heat H 12 15 18 24 30

Covers: Logic Max Heat H12, Logic Max Heat H15, Logic Max Heat H18, Logic Max Heat H24, Logic Max Heat H30

GC 41-796-17, 41-796-18, 41-796-19, 41-796-20, 41-796-21

Accessing The Installer Mode

To access Installer Mode press the function button and RESTART Buttons together for more than 5s.
The last 3 faults will be shown
SL will be shown: To run the burner at minimum rate press RESTART, otherwise press the function button.
SH will be shown: To run the burner at maximum rate press RESTART, otherwise press the function button.
VF will be shown: press the function button.
dU will be shown: press the function button.
P1 will be shown: Press the function button.
P7 will be shown: Press the function button.
FL will be shown: This feature is not required on this appliance. Press the function button.
SE will be shown: This feature is not required on this appliance. Press the function button to exit.

From manual UIN 219010 A04, page 42.

Setting to Maximum and Minimum Rate (from commissioning / flowchart instructions)

Setting to Maximum Rate: 1. Hold RESTART & Function buttons together for more than 5s. 2. Last 3 faults will be shown. 3. SL shown, press the Function button. 4. SH shown, press RESTART. 5. Burner will run for 10 minutes at maximum rate. 6. Press RESTART to exit Maximum rate mode.
Setting to Minimum Rate: 1. Hold RESTART & Function buttons together for more than 5s. 2. Last 3 faults will be shown. 3. SL shown, press RESTART. 4. Burner will run for 10 minutes at minimum rate. 5. Press RESTART to exit Minimum rate mode.

From manual UIN 219010 A04, page 66.

Model	Gas	CO₂ max rate	CO₂ min rate	CO max
Logic Max Heat H12	Natural gas	9.1% ± 0.7	8.5% ± 0.7	350 ppm
Logic Max Heat H15, Logic Max Heat H30	Natural gas	9.3% ± 0.7	8.8% ± 0.7	350 ppm
Logic Max Heat H18	Natural gas	9.5% ± 0.7	8.9% ± 0.7	350 ppm
Logic Max Heat H24	Natural gas	9.5% ± 0.7	8.8% ± 0.7	350 ppm

CO₂ and CO from manual UIN 219010 A04, page 8. Check against the data badge.

LOGIC MAX HEAT2 H12 H15 H18 H24 H30

Covers: Logic Max HEAT2 H12, Logic Max HEAT2 H18, Logic Max HEAT2 H24, Logic Max HEAT2 H30

GC 41-860-25, 41-860-27, 41-860-28, 41-860-29

Maximum and Minimum Rates

Maximum and Minimum Rate can be accessed through the menu option.
In the Menu screen, press the Down button to scroll to the desired option, then press the Enter button to select it.
On the Maximum Rate screen, press the 'Press' button; the boiler will run at Maximum Rate for 10 mins as long as there is sufficient cooling load (with Outside Sensor); press Exit to leave.
On the Minimum Rate screen, press the 'Press' button; the boiler will run at Minimum Rate for 10mins; press Exit to leave.

From manual 228292, page 40.

Model	Gas	CO₂ max rate	CO₂ min rate	CO max
Logic Max HEAT2 H12, Logic Max HEAT2 H24	Natural gas	9.1% ± 0.7	8.5% ± 0.7	–
Logic Max HEAT2 H18	Natural gas	9.3% ± 0.7	8.7% ± 0.7	–
Logic Max HEAT2 H30	Natural gas	9.7% ± 0.7	8.8% ± 0.7	350 ppm

CO₂ and CO from manual 228292, page 6. Check against the data badge.

Logic Max System S 15 18 24 30

Covers: Logic Max System S15, Logic Max System S18, Logic Max System S24, Logic Max System S30

GC 41-796-13, 41-796-14, 41-796-15, 41-796-16

Accessing the Installer Mode

To access Installer Mode press the function button and RESTART buttons together for more than 5s.
The last 3 faults will be shown.
SL will be shown. To run the burner at minimum rate press RESTART, otherwise press the function button.
SH will be shown. To run the burner at maximum rate press RESTART, otherwise press the function button.
VF will be shown. To activate the venting function press RESTART, otherwise press the function button.

From manual 219009, page 38.

Setting to Maximum Rate (Commissioning / Combustion)

Hold RESTART & Function buttons together for more than 5s
Last 3 faults will be shown
SL shown, press the Function button
SH shown, press RESTART
Burner will run for 10 minutes at maximum rate.
Press RESTART to exit Maximum rate mode.

From manual 219009, page 64.

Setting to Minimum Rate (Commissioning / Combustion)

Hold RESTART & Function buttons together for more than 5s
Last 3 faults will be shown
SL shown, press RESTART
Burner will run for 10 minutes at minimum rate.
Press RESTART to exit Minimum rate mode.

From manual 219009, page 64.

Model	Gas	CO₂ max rate	CO₂ min rate	CO max
Logic Max System S15, Logic Max System S30	Natural gas	9.3% ± 0.7	8.8% ± 0.7	350 ppm
Logic Max System S18	Natural gas	9.5% ± 0.7	8.9% ± 0.7	350 ppm
Logic Max System S24	Natural gas	9.5% ± 0.7	8.8% ± 0.7	350 ppm

CO₂ and CO from manual 219009, page 8. Check against the data badge.

The air/gas ratio valve is factory-set and must not be adjusted during commissioning. (page )

LOGIC MAX SYSTEM2 S15 S18 S24 S30

Covers: Logic Max SYSTEM2 S15, Logic Max SYSTEM2 S18, Logic Max SYSTEM2 S24, Logic Max SYSTEM2 S30

GC 41-796-97, 41-796-98, 41-796-99, 41-860-01

Accessing Maximum and Minimum Rates

Maximum and Minimum Rate can be accessed through the menu option.
The boiler will run at Maximum Rate for 10 mins as long as there is sufficient cooling load.
The boiler will run at Minimum Rate for 10 mins. If the return temperature is under 40°C then the fan will run for 30s at maximum rate before ramping down over 60s to minimum rate.
If the return temperature is above 40°C then the fan will ramp down over 60s to minimum rate.

From manual 237661, page 34.

Model	Gas	CO₂ max rate	CO₂ min rate	CO max
Logic Max SYSTEM2 S15	Natural gas	9.5% ± 0.7	8.9% ± 0.7	–
Logic Max SYSTEM2 S18	Natural gas	9.3% ± 0.7	8.3% ± 0.7	–
Logic Max SYSTEM2 S24	Natural gas	9.2% ± 0.7	8.5% ± 0.7	350 ppm
Logic Max SYSTEM2 S30	Natural gas	9.6% ± 0.7	8.7% ± 0.7	350 ppm

CO₂ and CO from manual 237661, page 6. Check against the data badge.

Logic System 15, 18, 24, 30

Covers: Logic System 15, Logic System 18, Logic System 24

GC 41-750-24, 41-750-25, 41-750-26

Setting to Minimum Rate for Combustion Test

Turn the CH temperature control knob into the 10 O’clock position.
Create a heat demand by ensuring that the system controls are requesting heat and the boiler Mode Knob is in the On Position.
Within an overall time of 3 seconds, turn the CH temperature control knob fully clockwise, back to 10 O’clock and then fully clockwise again.
“S” will be shown on the display and the boiler output will be reduced to minimum.
The boiler will remain at minimum rate for 5 minutes before reverting to normal operation.

From manual 205552, page 58.

Logic System s15 s18 s24 s30

Covers: Logic System S15, Logic System S18, Logic System s24, Logic System s30

GC 41-750-61, 41-750-62, 41-750-63, 41-750-64

Accessing the Installer Mode

To access Installer Mode press the function button and RESTART buttons together for more than 5s.
The last 3 faults will be shown
‘SL’ will be shown. To run the burner at minimum rate press ‘RESTART’, otherwise press the function button.
‘SH’ will be shown. To run the burner at maximum rate press ‘RESTART’, otherwise press the function button.
‘VF’ will be shown. To activate the venting function press ‘RESTART’, otherwise press the function button. The venting function runs for 5 minutes before automatically returning to normal operation. The Pump alternates between being on for 50s and then off for 10s.
‘dU’ will be shown. Press the Function button.
‘P1’ will be shown. To set the minimum CH pump speed to 100% press ‘RESTART’, otherwise press the function button.
‘P7’ will be shown. To set the minimum CH pump speed to 70% (default) press ‘RESTART’, otherwise press the function button to Exit.

From manual 215349, page 38.

Model	Gas	CO₂ max rate	CO₂ min rate	CO max
Logic System S15, Logic System s24, Logic System s30	Natural gas	9.3% ± 0.7	8.8% ± 0.7	350 ppm
Logic System S18	Natural gas	9.5% ± 0.7	8.9% ± 0.7	350 ppm

CO₂ and CO from manual 215349, page 8. Check against the data badge.

Logic System2 S15 S18 S24 S30

Covers: Logic SYSTEM2 S15, Logic SYSTEM2 S18, Logic SYSTEM2 S24, Logic SYSTEM2 S30

GC 41-796-85, 41-796-86, 41-796-87, 41-796-88

Accessing the Installer Mode

To access Installer Mode, press the mode button and the restart button together for more than 5s.
The last 3 faults will be shown.
"PH" will be shown. Press the mode button.
"SH" will be shown. To run the burner at maximum rate press the restart button, otherwise press the mode button.
"SL" will be shown. To run the burner at minimum rate press the restart button, otherwise press the mode button. Note that the burner will initially run at maximum rate for 30s before ramping down to minimum over 1 minute.
"UF" will be shown. Press the mode button.
"dU" will be shown. Press the mode button.
"P1" will be shown. To set the minimum CH pump speed to 100% press the restart button, otherwise press the mode button.
"P7" will be shown. To set the minimum CH pump speed to 70% press the restart button, otherwise press the mode button.
"SE" will be shown. For service timer function refer to separate instructions. Press the mode button to exit.
"SE" will be shown. For service timer function refer to separate instructions. Press the mode button to exit.

From manual UIN 228297 A05, page 34.

Model	Gas	CO₂ max rate	CO₂ min rate	CO max
Logic SYSTEM2 S15, Logic SYSTEM2 S24, Logic SYSTEM2 S30	Natural gas	9.5% ± 0.7	8.9% ± 0.7	–
Logic SYSTEM2 S18	Natural gas	9.3% ± 0.7	8.3% ± 0.7	350 ppm

CO₂ and CO from manual UIN 228297 A05, page 6. Check against the data badge.

The air gas ratio valve is factory-set and must not be adjusted DURING COMMISSIONING. (page 60)

Logic+ Combi C 24 30 35

Covers: Logic + Combi C24, Logic + Combi C30, Logic + Combi C35

GC 47-349-15, 47-349-16, 47-349-17

Enter Service Mode (Maximum DHW Rate)

Press Menu.
Press Next until the Service Mode Maximum DHW Rate screen is displayed.
Press Enter to activate.

From manual UIN 215346 A01, page 39.

Enter Service Mode (Maximum CH Rate)

Press Menu.
Press Next until the Service Mode Maximum CH Rate screen is displayed.
Press Enter to activate. Note that a CH demand has to already be present for this feature to be active.

From manual UIN 215346 A01, page 39.

Enter Service Mode (Minimum Rate)

Press Menu.
Press Next until the Service Mode Minimum Rate screen is displayed.
Press Enter to activate. Note that a CH demand has to already be present for this feature to be active.

From manual UIN 215346 A01, page 39.

Logic+ Combi2 C24 C30 C35

Covers: Logic+ COMBI2 C24, Logic+ COMBI2 C30

GC 47-349-99, 47-387-01

Setting Maximum and Minimum Rates

Maximum DHW and Minimum Rate can be accessed through the menu option.
The boiler will run at Maximum DHW Rate for 10 mins as long as there is sufficient cooling load.
The boiler will run at Minimum Rate for 10 mins. If the return temperature is under 40°C then the fan will run for 30s at maximum rate before ramping down over 60s to minimum rate.
If the return temperature is above 40°C then the fan will ramp down over 60s to minimum rate.

From manual UIN 237662 A05, page 36.

Model	Gas	CO₂ max rate	CO₂ min rate	CO max
Logic+ COMBI2 C24	Natural gas	9.2% ± 0.7	8.5% ± 0.7	350 ppm
Logic+ COMBI2 C30	Natural gas	9.3% ± 0.7	8.5% ± 0.7	–

CO₂ and CO from manual UIN 237662 A05, page 6. Check against the data badge.

Logic+ Heat H12 H15 H18 H24 H30

Covers: Logic+ Heat H12, Logic+ Heat H15, Logic+ Heat H18, Logic+ Heat H24, Logic+ Heat H30

GC 41-750-82, 41-750-83, 41-750-84, 41-750-85, 41-750-86

Accessing The Installer Mode

To access Installer Mode press the function button and RESTART Buttons together for more than 5s.
The last 3 faults will be shown
‘SL’ will be shown. To run the burner at minimum rate press ‘RESTART’, otherwise press the function button.
‘SH’ will be shown. To run the burner at maximum rate press ‘RESTART’, otherwise press the function button.
‘VF’ will be shown, press the function button.
‘dU’ will be shown, press the function button.
‘P1’ will be shown, press the function button.
‘P7’ will be shown, press the function button.
‘FL’ will be shown. This feature is not required on this appliance. Press the function button.
‘SE’ will be shown. This feature is not required on this appliance. Press the function button to exit.

From manual UIN 215355 A10, page 42.

Setting to Maximum Rate (Commissioning/Servicing)

Hold ‘RESTART’ & Function buttons together for more than 5s
Last 3 faults will be shown
SL shown, press the Function button
SH shown, press ‘RESTART’
Burner will run for 10 minutes at maximum rate.
Press ‘RESTART’ to exit Maximum rate mode.

From manual UIN 215355 A10, page 64.

Setting to Minimum Rate (Commissioning/Servicing)

Hold ‘RESTART’ & Function buttons together for more than 5s
Last 3 faults will be shown
SL shown, press ‘RESTART’
Burner will run for 10 minutes at minimum rate.
Press ‘RESTART’ to exit Minimum rate mode.

From manual UIN 215355 A10, page 64.

Model	Gas	CO₂ max rate	CO₂ min rate	CO max
Logic+ Heat H12	Natural gas	9.1% ± 0.7	8.5% ± 0.7	350 ppm
Logic+ Heat H15, Logic+ Heat H30	Natural gas	9.3% ± 0.7	8.8% ± 0.7	350 ppm
Logic+ Heat H18	Natural gas	9.5% ± 0.7	8.9% ± 0.7	350 ppm
Logic+ Heat H24	Natural gas	9.5% ± 0.7	8.8% ± 0.7	350 ppm

CO₂ and CO from manual UIN 215355 A10, page 8. Check against the data badge.

Logic+ HEAT2 H12 H15 H18 H24 H30

Covers: Logic+ HEAT2 H12, Logic+ HEAT2 H24, Logic+ HEAT2 H30

GC 41-860-20, 41-860-23, 41-860-24

Accessing Maximum and Minimum Rates

The menu option contains a list of attributes that informs the user about the operating state of the boiler.
Scroll down the menu using the Down button and press the Enter button to select the desired option (Maximum Rate or Minimum Rate).
On the Maximum Rate screen, press the Exit button to leave; the boiler will run at Maximum Rate for 10 mins as long as there is sufficient cooling load (with Outside Sensor).
On the Minimum Rate screen, press the Exit button to leave; the boiler will run at Minimum Rate for 10mins. If the return temperature is under 40°C the fan will run for 30s at maximum rate before ramping down over 60s to minimum rate. If the return temperature is above 40°C the fan will ramp down over 60s to minimum rate.

From manual UIN 228295 A08, page 40.

Model	Gas	CO₂ max rate	CO₂ min rate	CO max
Logic+ HEAT2 H12, Logic+ HEAT2 H30	Natural gas	9.1% ± 0.7	8.5% ± 0.7	350 ppm
Logic+ HEAT2 H24	Natural gas	9.3% ± 0.7	8.4% ± 0.7	350 ppm

CO₂ and CO from manual UIN 228295 A08, page 6. Check against the data badge.

The air gas ratio valve is factory-set and must not be adjusted DURING COMMISSIONING. (page )

LOGIC+ SYSTEM2 S15 S18 S24 S30

Covers: Logic+ SYSTEM2 S15, Logic+ SYSTEM2 S24, Logic+ SYSTEM2 S30

GC 41-796-93, 41-796-95, 41-796-96

Accessing Maximum and Minimum Rates

From the Menu screen, press the Down button to scroll through the list of options.
Press the Enter button to select the desired option.
On the Maximum Rate screen, press the Press button to run the boiler at Maximum Rate for 10 minutes (as long as there is sufficient cooling load).
Press the Exit button to leave the Maximum Rate screen.
On the Minimum Rate screen, press the Press button to run the boiler at Minimum Rate for 10 minutes.
Press the Exit button to leave the Minimum Rate screen.

From manual UIN 237663 A05, page 34.

Gas	CO₂ max rate	CO₂ min rate	CO max
Natural gas	9.5% ± 0.7	8.9% ± 0.7	–

CO₂ and CO from manual UIN 237663 A05, page 6. Check against the data badge.

Maximiser SE 42 & SE 65

Covers: Maximiser SE 42, Maximiser SE 65

GC 41-349-85, 41-349-86

Entering Service / Test Mode

Remove the cover from the control panel.
Move the service switch to the upper position (chimney sweep symbol).
Re-connect the electricity supply. The boiler will now light.
When the boiler is firing, press the service button for 5 seconds until the letter Y shows on the display.
Turn the middle potentiometer to position 1 (low load = 30% constant) or use the test switch for maximum power.

From manual 152556, page 21.

The boiler is preset at the factory, therefore no adjustments should be necessary. However, if problems are experienced refer to Frame 31. The adjustment screw is protected by a star-shaped cover on the Honeywell gas valve. This cover has to be removed, before an adjustment can be made. The adjustment screw can be turned by means of a Torx-bit T40H. (page 20)

Response 80 / 100 / 120

Covers: Response 120, Response 80

GC 47-348-01, 47-348-02

Entering service / checking burner pressure

Turn the heating controls to maximum so that the boiler lights and remains running.
Check that no other gas appliances in the house are in use or likely to be used.
Fully open a hot water tap. The pump should stop as the boiler switches to HW mode.
Remove the screw in the burner pressure test point and connect a gas pressure gauge via a flexible tube.
Operate the boiler for 10 minutes to stabilise the burner temperature and check pressures against Tables 2 and 3.

From manual UIN 152 318 A12, page 31.

The burner pressure is regulated by the gas valve according to the air flow produced by the fan. It is NOT user-adjustable. Any interference to sealed settings on the gas valve will adversely affect operation and render our warranty void. (page 31)

Response SE Combi - Installation

Covers: Response SE

GC 47-348-03

Service Mode / Test Mode Operation

Remove controls button cover plate (O).
For Maximum Heat: Select TEST mode by pressing MODE and '+' buttons simultaneously.
For Minimum Heat: Select TEST mode by pressing MODE and '-' buttons simultaneously.
To return to STANDBY mode: Press '+' and '-' buttons simultaneously.

From the installation and servicing manual, page 34.

The gas valve is factory set and sealed. No adjustment is required. (page 44)

Vogue combination boiler

Covers: Vogue c26, Vogue C32, Vogue c40

GC 47-348-97, 47-348-98, 47-348-99

Service Mode Maximum Rate

Press ENTER to access the MENU.
Press “-“ until Service Mode Maximum Rate is displayed.
Press ENTER to activate the feature. Note that a CH demand has to already be present for the feature to be active.

From manual 208548, page 38.

Service Mode Minimum Rate

Press ENTER to access the MENU.
Press “-“ until Service Mode Minimum Rate is displayed.
Press ENTER to activate the feature. Note that a CH demand has to already be present for the feature to be active.

From manual 208548, page 38.

Vogue Max Combi 26 32 40

Covers: Vogue Max Combi 26, Vogue Max Combi 32, Vogue Max Combi 40

GC 47-349-59, 47-349-60, 47-349-61

Enter Service Mode Minimum CH Rate

Press MENU
Press ∨ until the screen showing SERVICE MODE is displayed
Press SELECT to enter SERVICE MODE
Press SELECT to select MINIMUM CH RATE
Note that a CH demand has to already be present for this feature to be active

From manual UIN 222378 A08, page 45.

Enter Service Mode Maximum CH Rate

Press MENU
Press ∨ until SERVICE MODE is highlighted
Press SELECT
Press ∨ until MAXIMUM CH RATE is highlighted
Press SELECT
Note that a CH demand has to already be present for this feature to be active

From manual UIN 222378 A08, page 45.

Enter Service Mode Maximum DHW Rate

Press MENU
Press the down arrow (∨) until SERVICE MODE is highlighted
Press SELECT
Press the down arrow (∨) until MAXIMUM DHW RATE is highlighted
Press SELECT
Note that a CH demand has to be present for this feature to be active

From manual UIN 222378 A08, page 46.

Model	Gas	CO₂ max rate	CO₂ min rate	CO max
Vogue Max Combi 26, Vogue Max Combi 32	Natural gas	9.4% ± 0.7	8.0% ± 0.7	–
Vogue Max Combi 40	Natural gas	9.6% ± 0.7	8.1% ± 0.7	–

CO₂ and CO from manual UIN 222378 A08, page 8. Check against the data badge.

Vogue Max System

Covers: Vogue Max System 15, Vogue Max System 18, Vogue Max System 26, Vogue Max System 32

GC 41-796-22, 41-796-23, 41-796-24, 41-796-25

Enter Service Mode Maximum Rate

Press MENU
Press the down arrow (∨) until SERVICE MODE is highlighted
Press SELECT
Press the down arrow (∨) until MAXIMUM CH RATE is highlighted
Press SELECT

From manual UIN 219005 A08, page 43.

Enter Service Mode Minimum Rate

Press MENU
Press the down arrow until SERVICE MODE is highlighted
Press SELECT
Press SELECT again to activate MINIMUM CH RATE

From manual UIN 219005 A08, page 43.

Model	Gas	CO₂ max rate	CO₂ min rate	CO max
Vogue Max System 15	Natural gas	9.4% ± 0.7	8.3% ± 0.7	350 ppm
Vogue Max System 18	Natural gas	9.5% ± 0.7	8.5% ± 0.7	350 ppm
Vogue Max System 26	Natural gas	9.5% ± 0.7	8.4% ± 0.7	350 ppm
Vogue Max System 32	Natural gas	9.5% ± 0.7	8.2% ± 0.7	350 ppm

CO₂ and CO from manual UIN 219005 A08, page 8. Check against the data badge.

Vogue System Boiler

Covers: Vogue S15, Vogue S18, Vogue s26, Vogue s32

GC 41-750-53, 41-750-54, 41-750-55, 41-750-56

Service Mode Maximum Rate

Ensure a CH demand is already present.
Press ENTER to access the MENU.
Press '-' until 'Service Mode Maximum Rate' is displayed.
Press ENTER to activate the maximum rate feature.
Press EXIT twice to return to normal operation.

From manual 208549, page 39.

Service Mode Minimum Rate

Ensure a CH demand is already present.
Press ENTER to access the MENU.
Press '-' until 'Service Mode Minimum Rate' is displayed.
Press ENTER to activate the minimum rate feature.
Press EXIT twice to return to normal operation.

From manual 208549, page 39.

Vogue System Gen2 (S15, S18, S26, S32)

Covers: Vogue S15P Gen2 System, Vogue S18 Gen2 System, Vogue s32 Gen2 System

GC 41-750-88, 41-750-89, 41-750-91

Entering Service Mode Maximum Rate

Press the MENU button
Press the down arrow (∨) button until SERVICE MODE is highlighted
Press the SELECT button
Press the down arrow (∨) button until MAXIMUM CH RATE is highlighted
Press the SELECT button
Operation will end automatically after 10 mins or press the EXIT button to end manually

From manual 216172, page 43.

Entering Service Mode Minimum Rate

Press MENU
Press the down arrow (∨) until the SERVICE MODE option is highlighted
Press SELECT to open the SERVICE MODE menu (MINIMUM CH RATE highlighted)
Press SELECT again to activate MINIMUM CH RATE
Operation will end automatically after 10 mins or press EXIT to end manually

From manual 216172, page 43.

Model	Gas	CO₂ max rate	CO₂ min rate	CO max
Vogue S15P Gen2 System, Vogue s32 Gen2 System	Natural gas	9.4% ± 0.7	8.3% ± 0.7	–
Vogue S18 Gen2 System	Natural gas	9.5% ± 0.7	8.5% ± 0.7	350 ppm

CO₂ and CO from manual 216172, page 8. Check against the data badge.

The app

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Service mode, gas valve and combustion figures, fault codes and the full manual for the boiler in front of you, plus Ask Flint for anything the manual covers.

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Common questions

Is service mode the same as chimney sweep mode?

Yes, in practice. Makers use different names for the same function: service mode, chimney sweep mode, test mode, calibration mode, check programme. Each one holds the burner at a fixed rate, usually maximum then minimum, so you can take a stable combustion reading.

Can I adjust the gas valve while it's in service mode?

Only where the manual gives an adjustment procedure, and only with an analyser in the flue. Many current boilers are set at the factory and the manual says not to touch the gas valve. Where a manual says that, it is shown with the procedure above.

Other makers

Alpha Ariston Atag Baxi Biasi Chaffoteaux Ferroli Glow-worm Halstead Heatline Intergas Johnson Starley Keston Main Potterton Remeha Sime Vaillant Viessmann Vokera Worcester Bosch

Service mode and combustion checks are work for a competent, Gas Safe registered engineer. These procedures are taken from the manufacturers' manuals and inform your judgement; they don't replace it. Always work to the manual for the exact appliance, its data badge and the current standards.