Your AI onsite guide

Find the fault before you ring the helpline.

Every manufacturer manual, fault code and service figure for 2,200+ gas boilers, in one place. Stuck on one? Ask Flint and get a straight answer off that boiler's own manual in seconds, page and all. An extra pair of hands, not a replacement for one.

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Flint's Service Info screen for a Worcester Bosch Greenstar 8000 Life Combi: commissioning at a glance, showing CO2 max 9.5%, CO2 min 8.6% and a CO/CO2 ratio of 0.004 for natural gas, CO max 250ppm commissioning and 75ppm service, each block citing manual page 51, with the LPG figures below.
Real screen · every figure cites its manual page
2,200+
gas boilers, 45 makers
1,000+
manufacturer's manuals
60,000+
fault codes, decoded
1 tap
from any figure to its manual page

A simple service, the hard way

You've been here.

01There's no single home for manuals. You Google the model, dig out a PDF, and hope it's the right variant.
02Then you scroll 90 pages for one figure, on your phone, in a cold loft. You read it twice and still miss it.
03How do you get this one into service mode? Every make's different, and nobody remembers them all.
04You want the CO and CO₂ min/max, the gas rate, the gas valve settings. Three sub-menus deep, if it's there at all.
05So you ring the helpline. Hold music. Customer watching you. And the answer doesn't always land.
06And when you find something genuinely unsafe, you want the classification right, first time, with the customer stood there.

Flint gets you the same answer in seconds, not a phone queue.

What's inside

The whole job, in your pocket.

01
2,200+ gas boilers, one searchManuals across 45 makers, each maker's boilers listed in order under their range. Search by model name, GC number, the maker's own code, or a fault code.
02
Search by fault codeType the code off the display, F22 say, and see every boiler that uses it, grouped by maker with what it means, then tap straight into that boiler's codes.
03
The fault-finding chart, walked box by boxFor 700+ boilers, older ones with no fault codes among them, Flint walks the manual's own fault-finding chart: Yes, No, next box, and the manual page one tap away. The charts are read from the manual by machine, so the page is there to check against.
04
The manufacturer's manual, searchable1,000+ of them. Full-text search inside the PDF, so you land on the page instead of thumbing through ninety.
05
Fault codes, decodedOver 60,000 codes: what it means, the likely cause and the parts most often replaced. Grouped and in order, with a filter that matches what the boiler actually shows.
06
Type the GC, get the boiler and its bookThe GC number off the badge names the appliance from the official product register and finds the manual that prints that number, and it tells you plainly when the book in hand lists numbers other than yours.
07
The Edition 4 tightness test, start to finishPre-test checks, the let-by with its allowed rise, the test on its own clock, the pipework retest when it is called for, and the purge. Worked to IGEM/UP/1B Edition 4, with a job record to share or copy onto your paperwork.
08
Electronic and smart metersHow to wake each one and read the index for a gas rate, make by make, from the Gas Safe technical bulletin, with the watch-outs that catch people out.
09
Boiler age, off the serial numberType the serial from the badge and Flint works out whose boiler it is and when it was built, showing its working. Where a maker doesn't publish the rule, it says so rather than guess a year.
10
Calculators that earn their placeGas rate with a built-in stopwatch, metric and imperial. CO/CO₂ ratio pass or fail, temperature rise (ΔT), and expansion-vessel sizing.
11
Every maker's helpline, one tapThe UK technical line for every manufacturer, built in. Tap to call, no hunting for the number mid-job.
12
Your workbenchFavourites, recently-viewed, and private notes on any model: customer details, parts fitted, settings, kept on your device.

Not just the PDF

The manual, structured.

Flint lifts the figures out of the manual and lays them out like instrument readouts, so a service isn't a scrolling exercise. Open any section and the data is already there.

Service mode Combustion targets Gas & burner pressures Gas valve settings Technical data NTC sensor tables Spare part numbers Wiring diagrams
The right number for this boiler, not its family. A Greenstar 12 Ri ErP wants 9.65% CO₂ at max rate. The 15/18/24 Ri wants 9.8%. The badge on the front won't tell you which.
What the maker asks for, not the rule of thumb. Worcester's Ri manual wants CO under 200 ppm where the generic figure is 350. Flint gives you the one that's actually in the book.
Both rates, properly. CO₂ and CO targets at max and min, plus the ratio to check against at each. The service-mode sequence for the boiler in front of you, not a generic one.
The band, not just the figure. Where the manual prints a permitted range on a CO₂ figure, you get the range as well.
Every value carries its exact manual page, so you can check it against the book in a tap.
Flint's fault code list for a boiler, each code expandable to show what it means and the likely cause.
Fault codes, decoded
Flint's tightness test to IGEM/UP/1B Edition 4: fuel and test pressure, the pre-test checklist, and the let-by step with its own one-minute timer.
Tightness test, Edition 4
Flint's electronic and smart meter guide: how the display lags, a link to the gas rate calculator, meter volumes for the tightness test, and the meter list with watch-outs.
Smart meters, make by make
Flint's unsafe situations tool: pick the category of what you found, from a gas leak to a bypassed safety device, to get the IGEM/G/11 classification.
Unsafe situations
Ask Flint

A second opinion, in seconds.

Nobody's saying a chatbot knows your trade better than you do. Flint just reads the manual faster than you can. Ask about the boiler you're stood at, or tap a fault code and ask what's worth checking, and you get a straight, step-by-step answer off that model's own manual, with the page to prove it.

YouPressure keeps climbing. Customer's already had the heat exchanger and expansion vessel done. What else?
Flint
  1. Filling loop passing. Even slightly, it'll creep the pressure up. Check it's fully closed and not weeping.
  2. Expansion vessel pre-charge not set to the cold-fill pressure, or vessel undersized for the system volume.
  3. Vessel isolation / waterlogging on an external vessel, or a dead-leg on the zone valve holding pressure.

Sources: Greenstar 30i installation manual, p.42 (filling), p.51 (expansion vessel).

Unsafe situations, classified

Tap through what you've actually found and Flint gives you the IGEM/G/11 classification with the required action, numbered, in the order you do it. Where the incident is RIDDOR-reportable it says so and gives you the deadline.

IDARNCS

It's a paraphrased summary of IGEM/G/11 Edition 2, written for speed on site. It isn't the standard itself and it doesn't replace your judgement. Confirm the classification yourself before you leave.

The full service data

Combustion targets at max and min, gas and burner pressures, gas valve settings, NTC sensor tables, spare part numbers and wiring diagrams, laid out as figures rather than a PDF to scroll. Every value carries its manual page.

It won't go past the manual

Answers come from that model's manufacturer manual and a gas fault-finding reference, built with Gas Safe registered engineers. It won't contradict the manual or invent a procedure. The only method it'll walk you through is the standard, safe way to carry out a test.

It shows its working

Step by step, in real figures, with the page cited, exactly like a good answer off the phone. You can check every line against the book.

You're the engineer. Flint just fetches.

It doesn't decide, it doesn't sign anything off, and it doesn't authorise the work. The manual gates that on a competent person with a conforming analyser, and that's you. Flint only gets you the figures faster.

Pricing

One price. Everything in.

Flint
£3.99/ month
or £29.99 / yearSave £18

First 7 days free, in the app or on the web. Cancel inside the week and pay nothing.

Every manual, fault code and service figure for 2,200+ gas boilers. Search by fault code, the fault-finding charts, the Edition 4 tightness test, the smart meter guide, boiler age, the calculators, every maker's helpline, the unsafe-situations classifier, and Ask Flint answering off the boiler's own manual. One saved callback covers the year.

Get Flint Cancel any time, wherever you subscribed. The same login works on iPhone, Android and the browser.

Built for UK gas engineers.

Servicing and repair, domestic gas boilers. If you're a few years in, it's the mate you'd have rung, without the hold music. If you've been on the tools thirty years, it's a sanity check and every manual in one place, instead of hunting each one down. Either way it's fast, one-handed, and grounded in the manufacturer's own data.

Before you ask

Straight answers.

Is my boiler in there?

2,200+ gas boilers across 45 makers, from the big names to the ones you'd forgotten existed. Search by model name, GC number, the maker's own code or a fault code. If one isn't in there yet, tell us in the app and we'll add it. Check the full list.

How much is it?

£3.99 a month or £29.99 a year, the same price wherever you buy it, and you cancel wherever you subscribed. The first 7 days are free wherever you subscribe. That includes everything: every manual, fault code and service figure, the calculators, the helplines and Ask Flint. There is no free version.

Where do the AI answers come from?

Every Ask Flint answer is built from that model's own manufacturer manual and a gas fault-finding reference put together with Gas Safe registered engineers. It cites the manual page so you can check it, and it won't go past the manual or invent a procedure. You're the engineer signing it off, not the app.

Is the unsafe situations tool official?

No. It is a paraphrased summary of IGEM/G/11 Edition 2, written so you can tap through it on site and get the classification (Immediately Dangerous, At Risk or Not to Current Standards) with the required action in order, plus a flag when something is RIDDOR-reportable. It is guidance, not the standard itself, and it does not replace your judgement: confirm the classification yourself before you leave the installation.

Can I search by fault code?

Yes. Type the code off the display into the search on the home screen and Flint lists every boiler that uses it, grouped by maker with what the code means, and a tap takes you into that boiler's codes. Useful when you know the code but not yet which model it is.

What are the fault-finding charts?

Many manuals, older ones especially, fault-find with a flow chart rather than a list of codes. For 700+ boilers Flint walks that chart with you a box at a time, Yes or No, with the manual page one tap away. The charts are read from the manual by machine rather than checked by hand, so if a step looks wrong, the page is there to check and you can report the box.

Can Flint tell me how old a boiler is?

Type the serial number off the badge and Flint works out the make and the date of manufacture, and shows the arithmetic so you can check it. It only decodes where the manufacturer publishes the rule. For the makers who don't, it says so and gives you their own route, because a confident wrong year is worse than no answer when there's a warranty or a replace-or-repair quote riding on it.

What does it run on?

iPhone and Android, and the browser at app.flintfix.com. One account works across all three.

Get the app

Be the engineer who walks in already knowing.

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Prefer the browser? Open Flint at app.flintfix.com

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