info@atplumbing.co.ukWinteringham, North Lincolnshire — covering Scunthorpe, Hull, Grimsby & surrounds Mon–Fri 8am–5pm · Family-run · Gas Safe registered 55626207576 593045 HomeAboutServices Service Areas Our WorkReviewsContact07576 593045Request Estimate - Home - Services - Fault FindingBoiler Fault Finding · Mon–Fri # Boiler error codes and heating faultsdiagnosed properly in Scunthorpe —before we quote, before we replace. We find the actual fault — not the part the previous engineer guessed at. Diagnosis booked Mon–Fri, fixed-price repair in writing, no replacement parts thrown at the problem hoping it sticks. Request a Free Estimate 07576 593045 ★★★★★Diagnosis booked Mon–Fri · Repair quoted in writing before any work · 12-month workmanship guarantee. ## Get a Free Quote Tell us about the job — we'll reply fast with a no-obligation estimate. 18 yearsin plumbing & heating Gas SafeRegistered — every gas job certified G3 CertifiedUnvented hot water qualified Mon–Fri8am–5pm Fixed priceQuote in writing before work starts Service overview ## Real diagnosis, not parts roulette The most expensive boiler repair is the one that didn't fix the problem. We see it constantly — a PCB swapped to fix what was actually a faulty sensor, a pump replaced to fix what was actually a stuck motorised valve. Every wrong part costs you, in money and in time without heat. We diagnose first. ### What it is Systematic fault diagnosis on combi, system and regular boilers — all major brands. Includes pressure testing, gas-rate verification, flue gas analysis, controls testing, motorised valve checks and sensor resistance measurement to isolate the real fault before quoting. ### Who it's for Homeowners and landlords across Scunthorpe, Brigg, Messingham, Scotter, Kirton Lindsey, Barton-upon-Humber, Hull, Grimsby and Doncaster whose boiler is throwing error codes, locking out, losing pressure, making noises or simply not delivering heat or hot water. ### When it's needed Boiler showing an error code (modern boilers all log their own fault codes); no heating; no hot water; intermittent operation; hot water but no heating; heating but no hot water; banging or kettling; pressure falling daily; or anything that's already had one failed repair. ### Why a professional matters Modern boilers have 15+ sensors and 20+ failure modes. Codes are signposts, not diagnoses. Replacing the part the code points to has a roughly 50% hit rate — proper diagnosis pushes that close to 100%, and that's the difference between one bill and three. What goes wrong ## Common faults — and what really causes them From thousands of call-outs across North Lincolnshire, here's what we actually find behind the symptom: ### Low pressure faults Usually a slow leak — most often the expansion vessel internal diaphragm, sometimes the PRV, occasionally a rad valve. Topping up daily masks it and corrodes the system. ### Pump pressure sensor faults Often the sensor itself; sometimes the pump; sometimes a blocked auto air vent. We test before we replace. ### Boiler firing then locking out Typically gas pressure, faulty ignition lead, or a flame-sense electrode that's carboned up. £30 part, often replaced as a £350 fan. ### Hot water cold after a few seconds Combi with a stuck diverter valve — well-known fault on Worcester Greenstar 30Si, fixable with a cartridge for ~£80 not a new valve at £280. ### Banging during heating cycles Air locks, sludge in the heat exchanger, or thermal shock from a stuck three-port valve. Three different causes, one symptom. ### Boiler 'works fine, then doesn't' after rain Almost always a condensate pipe freezing or kinking outside. Re-route internally and the call-outs stop. Our process ## Our fault-finding process Methodical — because the fault is rarely where the code points. - 01 ### History & Symptoms Quick conversation: when did it start, what's been done already, any patterns, any noises. Half the diagnosis. - 02 ### Visual & Pressure Boiler casing off, visual check, system pressure, gas working pressure and standing pressure all recorded. - 03 ### Code Read & Reset Fault log read (modern boilers store history), reset tested, behaviour observed under load. - 04 ### Component Testing Sensors tested by resistance, pump by current draw, valves by manual operation, flue gases analysed. Hard data before any part is swapped. - 05 ### Written Diagnosis & Quote Confirmed root cause, repair options and fixed price — in writing — before any parts are fitted. - 06 ### Repair, Test & Guarantee Repair carried out, system run under load to verify, 12-month workmanship guarantee logged in writing. Benefits ## Why diagnosis-first saves money ### Right fix, first time Methodical testing isolates the actual fault. Average call-out goes from 3 visits to 1. ### No wasted parts We don't replace anything we haven't proven faulty. You don't pay for guesses. ### Honest economic advice If your 14-year-old boiler is uneconomical to repair, we'll tell you with numbers — and quote the install fairly if you'd rather replace. ### Carry common parts PCBs are ordered; pumps, valves, sensors, ignition leads, expansion vessels live in the van. Often fixed on the first visit. ### Warranty preserved If your boiler is still under manufacturer warranty, we diagnose and then escalate to the right warranty engineer — without breaking the seal. ### 12-month guarantee On every repair we do. Same fault returns inside 12 months, the return visit is free. Recent work ## Real jobs, real installs. A few recent fault finding jobs completed across North Lincolnshire. In detail ## Brands, codes and what we diagnose Every modern boiler has its own fault language. We speak all of them. Get a fixed quote ### Worcester Bosch Greenstar 4000, 8000, i, Si, CDi — full diagnostic suite. Common faults: D5 reset loop, EA ignition lockout, A1 pump failure, A21 flue gas fault. Genuine parts via local trade counter, where available. ### Vaillant Vaillant gas boilers diagnosed and repaired on a code-by-code basis — we read the fault log, test the suspect component before we replace anything. ### Ideal Logic, Logic Max, Vogue, Vogue Max. Common: L2 ignition lockout, L9 ignition fan, F1 low pressure. Strong parts availability locally for Scunthorpe and Doncaster engineers. ### Baxi & Potterton Baxi 600, 800, Duo-Tec; Potterton Promax, Titanium. E133 ignition, E168 fan, E160 sensor — diagnosed and repaired. ### Glow-worm, Main, Alpha Same diagnostic principles, fewer parts in van but next-day available through local trade. common fault codes diagnosed routinely. ### Older non-condensing units Worcester 24CDi, Ideal Classic, Glow-worm Energy — we still repair them where it's economical, and tell you straight if it isn't. ### System & controls faults Not every 'boiler fault' is in the boiler. Stuck three-port valves, failed pumps, dead programmer outputs, room stats not calling — diagnosed at system level, not just at the appliance. Frequently asked ## Straight answers, in plain English. Can't see your question? Ring Azim directly on 07576 593045. ### How much is a diagnostic call-out? Flat fee of a small flat fee. That covers the diagnosis. Any repair you proceed with is quoted in writing on top — and the diagnostic fee is deducted from larger repairs over £300. ### How quickly can you attend? Mon–Fri 8am–5pm across Scunthorpe, Brigg, Messingham, Scotter and Barton-upon-Humber. Mon–Fri 8am–5pm for Hull, Grimsby and Doncaster — earlier you call, better the slot. ### What if you can't fix it on the first visit? If we need to order a specific part, we leave the system safe, give you a fixed-price quote, and return as soon as the part arrives. No charge for the second visit beyond the original fee and parts. ### Will you tell me if it's not worth fixing? Yes — honestly. We'll show you the cost of repair vs the cost of replacement and the realistic remaining life. No commission, no upselling — your call. ### Do you cover oil-fired boilers? No — we cover gas appliances only. We don't carry out oil-fired (OFTEC) work. ### Is my boiler too old to be worth repairing? Generally we'd consider replacement once a boiler is 14+ years old, out of warranty, and needing £300+ of repair. Under that, repair usually wins. We'll lay out the numbers either way. ### Will my home insurance cover this? Some home insurance policies cover unexpected breakdowns — we'll provide a written report and invoice that satisfies most insurers. Check your policy wording or ask us before we attend. ### Do you guarantee the repair? 12-month workmanship guarantee on every repair, in writing. Same fault returns, we come back free. Related services ## More from A T Plumbing & Heating View all services Heating Repairs & ServicingBoiler InstallationsGas Safety Certificates Next step ## Boiler down? Get a real diagnosis today. Diagnostic visits Mon–Fri 8am–5pm across North Lincolnshire and the Humber. Fixed-price repair in writing, parts proven faulty before they are swapped. Request a Free Estimate 07576 593045 - Gas Safe registered - G3 certified - Fully insured - Family-run · Gas Safe registered 556262 Phone 07576 593045 Email info@atplumbing.co.uk Based 17 High Burgage, Winteringham, DN15 9NE Hours Mon–Fri 8am–5pm · Sat/Sun closed Gas Safe registered plumbing & heating engineers based in Winteringham, North Lincolnshire. Family-run · Gas Safe registered 556262 across Scunthorpe, Hull, Grimsby, Doncaster and the wider Humber region. ## Services - Plumbing - Heating - Boiler Installations - Fault Finding - Full Central Heating Installation - Bathroom Fitting - Gas Safety Certificates - Underfloor Heating - Unvented Cylinders (G3) ## Areas - Scunthorpe - Hull - Grimsby - Doncaster - Brigg - Kirton Lindsey - Messingham - Scotter - Barton-upon-Humber ## Contact - 07576 59304507927 450996 - info@atplumbing.co.uk - 17 High Burgage, Winteringham, DN15 9NEFamily-run · Gas Safe registered 556262 · Company No. 11810388 © 2026 A T Plumbing & Heating (Lincs) Limited. All rights reserved. Privacy PolicyCookie PolicyTerms & Conditions Call Now Get Estimate