# Flint: Boiler Onsite Guide — Boiler app for gas engineers > Onsite guide for UK gas engineers with boiler manuals and fault codes. (iPhone/iPad app by Onspec Software.) - Source: https://appshunter.io/ios/app/flint-boiler-onsite-guide/id6792139380 (this page in markdown: same URL + `.md`) - Developer: [Onspec Software](https://appshunter.io/developer/6792139382) - Category: Business, Productivity - Price: Free - Age rating: 4+ - Requires: iOS 15.5 · 81 MB - Languages: American English - Released: 2026-08-05 - Data updated: 2026-10-20 - Monetization: free with in-app purchases - User reviews in markdown: https://appshunter.io/ios/app/flint-boiler-onsite-guide/id6792139380/reviews.md ## What is Flint? 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 Payment is charged to your Apple Account at confirmation of purchase, or at the end of the free trial. Subscriptions renew automatically unless auto-renew is turned off at least 24 hours before the end of the current period. Your account is charged for renewal within 24 hours prior to the end of the current period. Manage your subscription and turn off auto-renewal in your Apple Account settings after purchase. Terms of Use: https://flintfix.com/terms.html Privacy Policy: https://flintfix.com/privacy.html Flint is a product of OnSpec Software Ltd. ## Key features - 2,300+ gas boilers from 45 manufacturers - 60,000+ fault codes with manual references - 1,000+ manufacturer manuals with full-text search - Service figures for over 2,100 models - Interactive fault-finding charts - AI-powered Q&A for manual queries - Onsite calculation tools (gas rate, CO/CO2, etc.) ## Is Flint safe? Not enough ratings yet to assess Flint. ## Is Flint legit? Flint: Boiler Onsite Guide has limited verification signals. The AppsHunter Legitimacy Score for Flint is 58 out of 100 points across 7 verification signals from App Store and developer data. ## Recent user reviews (2 of 2) All indexed reviews: https://appshunter.io/ios/app/flint-boiler-onsite-guide/id6792139380/reviews.md ### 5/5 — Great app, time saver *2026-10-05* Flint is a genuinely useful app for heating engineers. It saves a lot of time hunting through manuals when fault finding or looking for boiler-specific information on site. What I particularly like is that Wes is clearly putting the work into developing it properly and listening to feedback from engineers using it in the real world. The coverage is already impressive and it keeps improving. Definitely worth having on the phone if you work across different boiler manufacturers. ### 5/5 — So handy *2026-10-04* So I’ve been using this app quite daily, actually, as it gives me all the manuals in the palm of my hand, and if there’s something I don’t understand in it, I can get it to explain it for me using the AI and also can retrieve anything from the manual. Not quicker than I can find it. as well as having ordered normal standard stuff accessible right in front of you, it’s a real time saver. ## Frequently asked questions about Flint ### What boilers does Flint cover? Flint covers over 2,300 domestic gas boilers from 45 different manufacturers. Each boiler has its own dedicated page with detailed information. ### How does the 'Ask Flint' feature work? You can type questions in plain English, and 'Ask Flint' will provide answers derived directly from the boiler's manual, citing the specific page for verification. It acts as a search tool for the manual content. ### What kind of onsite tools are included in Flint? Flint includes tools for calculating gas rate, performing tightness tests, analyzing CO/CO2 ratios, determining temperature rise (ΔT), sizing expansion vessels, and classifying unsafe situations. ### Is Flint available on Android devices? Based on the provided data, Flint is supported on iPhone, iPad, and iPod. Information regarding Android availability is not included. ### How often is Flint updated? The app was last updated on October 17, 2026, indicating a recent update. The frequency of future updates is not specified but suggests active development. ### What is the subscription cost for Flint? Flint offers a subscription with a 7-day free trial. After the trial, it costs £3.99 per month or £29.99 per year. Payment is charged to your Apple Account. ### Does Flint have ads? Yes, the application contains advertisements. This is indicated by the 'hasAds' flag being true in the provided data. ### Can I cancel my Flint subscription? Yes, subscription payments are charged to your Apple Account at the confirmation of purchase or end of the free trial. You can manage and cancel your subscription through your Apple Account settings. ## Version history (last 5 releases) ### 1.4.4 — 2026-10-17 Scan the badge. Tap the camera in the search box, point it at the boiler's data badge, and Flint reads the GC number and opens the boiler. No typing with gloves on. Read it to me. Service-mode procedures and fault-finding steps now have a speaker button. Put the phone down, keep both hands in the boiler, and Flint reads the steps out. ### 1.4.3 — 2026-10-12 Checked against the manuals. Every wiring table, service-mode procedure and combustion figure in Flint has now been read against the page of the manual it came from, and corrected where the page said otherwise. Figures the book could not confirm are held back rather than guessed. If you spot one that still looks wrong, tell us through Help & feedback in the app. ### 1.4.2 — 2026-10-04 Backend improvements. ### 1.4.1 — 2026-10-03 Search by fault code: type what the display says (F22, E133) and see which makers use it, what it means, and the boilers. Fault-finding charts for 1,100+ boilers, walked box by box with the manual page a tap away, plus a link to each book's sequence of operation. Browsing a manufacturer lists every model in order under range headings. New subscriptions start with 7 days free. ### 1.4.0 — 2026-10-02 Add an analytics update. --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-10-20.*