For UK gas engineers

The gas engineer app for manuals, fault codes and service data

Most trade apps do paperwork. Flint does the reference side: what the manual says about the appliance you are stood in front of, without scrolling ninety pages of PDF in a loft.

WhatHow much
Manufacturers48
Gas boilers1,100+
Fault codes, decoded50,000+
Models with the manual on file96%
Models with structured service figures900+

What is in it

Try the calculators first

Four of them are free on this site, no account needed. They are the same calculations that are in the app.

What it costs

£3.99 a month, or £29.99 a year. One saved callback covers the year. There is no advertising in it and no free tier for new accounts, so what you pay is what funds it.

What it is not

It is not job management. No certificates, no invoicing, no diary. If that is what you need, a trade admin app does it better and the two sit alongside each other fine.

It is gas only, domestic. It does not decide anything, sign anything off, or authorise work. That gates on a competent person with a conforming analyser, which is you.

The app

Start on the web, then sign in on your phone

Create the account in a browser, and the same login works in the iPhone app, the Android app and at app.flintfix.com. On iPhone a code has to be redeemed on the web, so starting there saves a step.

Get Flint

£3.99 a month, or £29.99 a year. Cancel any time.

Common questions

What is the best app for gas engineers?

It depends what you need it for. Job management apps handle certificates, quotes and invoicing. Flint is a reference app: manufacturer manuals, fault codes, structured service figures and calculators for 1,100+ gas boilers, plus an AI that answers from that boiler's own manual with the page cited.

Is there a free app for gas engineers?

The calculators on this website are free to use with no sign-up. The app itself is £3.99 a month or £29.99 a year, with everything included and no advertising.

Does Flint replace the manufacturer helpline?

It answers most of what you would ring for, faster, because it reads the manual for that exact model. The helpline numbers are built into the app for when you still need them.

What phones does it work on?

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

Flint is a reference tool for competent, Gas Safe registered engineers. Everything here informs your judgement and never replaces it. Always work to the manufacturer's instructions and the current standards, and check every figure against the appliance data badge and manual.