Boiler Fault Diagnosisin Hazel Grove & StockportEvidence, Not Guesswork.
Error code you don't recognise? Intermittent lock-out? Pressure dropping without a visible leak? A proper diagnostic, flue gas analyser, multimeter, gas tightness test, gets you an answer and a written price. Not a swapped-part-and-hope.
Boiler Fault Diagnosis, done properly.
Diagnostic work is where cheap engineers cost you the most. Guess the fault, swap a part, still broken. Guess again, swap another part. Suddenly you've paid £300 in parts and the boiler is still cycling. Proper diagnosis costs £98 and saves that entire experience.
A diagnostic visit means: full symptom history from you, visual inspection, flue gas analyser readings, gas tightness test at the meter, multimeter checks on sensors and PCB outputs, and a written summary of what's wrong plus a repair quote. All within the fixed £98 fee.
Anyone whose boiler is misbehaving in a way they can't explain. Intermittent lock-outs, obscure error codes, mysterious pressure loss, kettling, banging, delayed ignition, hot water going cold mid-shower, anything where the fault isn't blindingly obvious.
Before the fault gets worse. Intermittent faults become permanent ones. Slow pressure loss becomes fast pressure loss. Delayed ignition becomes ignition failure. Diagnose early, spend less overall.
Because good diagnosis is the difference between one part and three, one visit and three. It's also the difference between a repair and unnecessarily replacing a whole boiler when there was actually one component to swap.
The cost of putting it off.
Skipping proper diagnosis and going straight to 'swap the obvious part' is one of the most common false economies in domestic heating.
Parts churned, fault remains
Swap the PCB, swap the fan, swap the sensor, three parts later, still faulty. Diagnosis would have identified the right one immediately.
Diagnostic-free 'repairs'
A repair without diagnosis is a guess. If the guess is wrong, the customer usually foots the bill for the part anyway.
Unnecessary replacement
Boilers get scrapped that had one fixable part. Proper diagnosis is what prevents that.
Recurring lock-outs
Intermittent faults ignored for months become expensive replacements when a controlling part finally gives up entirely.
- Believing an engineer's diagnosis without a written report, memory is unreliable, notes aren't.
- Accepting 'I'll fit the part and see' as diagnosis.
- Ignoring a persistent error code because pressing reset makes it go away.
A clear five-step system.
No guessing, no meter-running. Every job follows the same repeatable process, that's how the result stays consistent.
- 01
Symptom history
We start with a proper conversation about when, how often, and under what conditions the fault occurs.
- 02
Visual inspection
Boiler, flue, controls, condensate, pipework and expansion vessel checked for obvious clues.
- 03
Combustion & gas checks
Flue gas analyser, gas tightness test at the meter, gas pressure and flow verified.
- 04
Electrical checks
Multimeter tests on sensors, PCB outputs and flame current, this is where most 'random' faults are actually located.
- 05
Written diagnosis & quote
You leave the visit with a written summary of what's wrong, a repair quote, and no obligation to proceed on the day.
What you actually get.
Fixed price up front
£98 inc. VAT, no meter running, no surprises.
Real evidence, not guesses
Flue gas analyser and multimeter output isn't opinion.
Fewer wasted parts
Diagnose first, swap once. That's how repairs stay affordable.
Written findings
You keep a copy, useful for second opinions, warranty claims, or landlord records.
No pressure to proceed
You can take the report elsewhere. Most people don't, but the option is yours.
Fixes rolled in
If the fix is quick and the part is on the van, we roll the repair into the visit with your approval.
The detail that matters.
Diagnostic work is the single area where kit and training separate engineers most obviously. Here's what proper diagnosis actually involves.
Flue gas analysis
Calibrated flue gas analyser reads CO, CO2, O2 and combustion ratio at low and high fire. Combustion problems that are invisible from the front panel become obvious in the readings.
Gas tightness testing
A U-gauge or electronic manometer at the meter is the definitive test for gas leaks anywhere on the supply. Non-optional on any proper diagnosis.
Electrical & sensor checks
Multimeter checks on flame current, thermistors, PCB output voltages, and control wiring, this is how you tell a failed sensor from a failed PCB from a wiring fault, without swapping any of them.
System-side checks
Pressure loss diagnosis, expansion vessel pre-charge testing, pump and motorised valve operation, because plenty of 'boiler' faults are actually system faults elsewhere in the house.
Questions we hear every week.
If you have a question that isn't answered here, ring John directly on 07442 536165.
Often booked together.
Odd fault? Book a proper diagnostic, not a parts guess.
£98 fixed, written findings, and the engineer who'll do the repair too.