Flint

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Everyone
50+
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About this app

Flint is the onsite guide for UK gas engineers. The manufacturer's manual, the fault codes, the service figures and the fault-finding chart for 2,300+ domestic gas boilers, in your pocket and ready before you've unclipped the case.

FIND IT FAST
• 2,300+ gas boilers across 45 manufacturers, one page per boiler. Search by make and model, by the maker's own code, or by the GC number off the badge: Flint names the appliance from the official product register and checks the manual really covers your number
• 60,000+ fault codes: what it means, the likely cause, and the parts that usually get changed. Every code traced to the manual it came from
• 1,000+ manufacturers' manuals with full-text search, so you land on the page instead of thumbing through ninety of them
• Service figures for 2,100+ models: combustion targets at max and min rate with the maker's tolerance band, gas pressures, service mode, gas valve settings, sensor tables. Every figure cites the manual page it came from, and every wiring table, service-mode procedure and combustion figure has been read back against that page

FAULT-FINDING CHARTS
Older boilers have no fault codes; the manual gives a flowchart. Flint walks it with you, one box at a time: the question, Yes or No, the next box, into the LED table where the chart hands over, and on to the section it sends you to. 1,100+ boilers, with the manual page always one tap away.

ASK FLINT
Type a question in plain English and get an answer built from that boiler's own manual, with the page cited so you can check it. It reads the manual faster than you can. It doesn't decide, it doesn't sign anything off, and it won't go past what the manufacturer printed. You're the engineer. Flint just fetches.

TOOLS
• Gas rate, with a built-in stopwatch, metric and imperial
• Tightness test with the let-by and stabilisation timers, and the permitted drop for your meter
• CO/CO₂ ratio against the 0.004 limit
• Temperature rise (ΔT) and expansion vessel sizing
• Boiler age from the serial number, decoded from the maker's own scheme and showing its arithmetic so you can check it
• Unsafe situations: tap through what you've found and get the IGEM/G/11 classification, ID, AR or NCS, with the action that goes with it. A paraphrased summary written for speed on site, not the standard itself, and no substitute for your judgement
• Every manufacturer's UK technical helpline, tap to call

BUILT FOR THE VAN, NOT THE OFFICE
Dark, glare-friendly screen. Big, tappable controls. Made for standing at the boiler, not sitting at a desk.

WHO IT'S FOR
Gas Safe registered engineers, heating and plumbing engineers, and apprentices who want the manual and the fault code without the faff.

SUBSCRIPTION
One subscription, everything above included. New subscribers get the first 7 days free.
Monthly: 7 days free, then £3.99 per month
Annual: 7 days free, then £29.99 per year
The free trial becomes a paid subscription when it ends unless cancelled before then. Subscriptions renew automatically until cancelled. Cancel any time in Google Play.

Given a code by Flint? Open Account, then Redeem, and enter it. It gives you 30 days of everything with no card and nothing to cancel.

Terms of Use: https://flintfix.com/terms.html
Privacy Policy: https://flintfix.com/privacy.html

Flint is a product of OnSpec Software Ltd.
Manuals, fault codes, charts and service data for 2,300+ UK gas boilers.
Updated on
Oct 13, 2026

Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
  • No data shared with third parties
    Learn more about how developers declare sharing
  • This app may collect these data types
    Personal info, Financial info, and Device or other IDs
  • Data is encrypted in transit
  • You can request that data be deleted

What’s new

Scan the badge: tap the camera in the search box, point it at the data badge, and Flint reads the GC number and opens the boiler. Read it to me: service-mode and fault-finding steps have a speaker button, so both hands can stay in the boiler.
Content rating
Everyone
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App support

About the developer
ONSPEC SOFTWARE LTD
admin@onspecsoftware.com
52 Manor Farm Road SOUTHAMPTON SO18 1NQ United Kingdom
+44 7568 227794