Urgent advice needed as my Gas boiler has a mind of its own!?

Hey thanks soooo much for all your immediate and very detailed tech advice!

I told him immediaitely it was probably a sensor not picking up correct signals as you pointed out...or perhaps another fault within either the ignitor or the automatic shutdown (sorry dont know technical name for parts, but sure you know what im talking about) anyways all the 1st Engineer said was that it could be any one of several problems but that he had *cleaned the electrodes*? i think thats what he said..hoping this may have worked (it didnt) hence the order for a new circuit board! He checked the flues and carbon emmissions etc for leakage/escape and found nothing.

Therefore ... in my eyes as an engineer.... that should at least narrow down the obvious fault possiblities.
However, like you pointed out... Random avereging of testing is the lazy workman's way of clutching at straws and all its doing it causing the company to pay for unneccessary repeat call outs.

But, as you noted, Its not my responsibility... it is my landlords.. however they live in Japan for heavens sake and even tho iv received 3 warning letters from the 3 registered Gas Engineers regarding the ventillation not being safe (ie they wont cut holes in the windows as its a grade A listed Georgian Townhouse apartment) In a World Heritage Site so they dont want to spoil the look of their beautiful home lol They would rather risk the safety of their tennants.

Anyways i havent touched it...

All iv done is press the reset button the odd time (which is exactly what they had asked me to do)
but this gave no effect.

Therefore in light of your more detailed report... Im going to let this engineer come out tomorrow & see what he says.
If he hasnt a clue? I will show him your advice... see if he puts itinto practise by replacing whatever it may be... then write to British Gas saying their engineers are cr*p! lol

Again

Sincere Thanks for your immediate response and advice.

I will update tomorrow and let you know how i go.

Kindest regards

Pauli
May 2009

1) If you're a tennant then the landlord is respoonsible for repairs - if you tinker with the boiler (beyond the user controls level) he could hold you liable for the costs of any future repairs.

2) You will know as an engineer in electronics that equipment such as a gas boiler can not possibly have a mind of its own - equipment either works, does not work or has an intermittent fault.

3) When the boiler gets a call for heat the fan is started - a pressure switch senses the correct pressures in the sealed unit and signals the control electronics. The PCB causes the pilot electrode to spark and opens the pilot gas valve. A heat sensor monitors the heat of the pilot flame and signals the control board which opens the main gas valve and the boiler fires up. If the pilot fails to ignite the fault may be fan, case seals, flue, pressure switch, PCB (not recognising pressure switch, failing to make spark or failing to open pilot gas valve) or the pilot gas valve not operating.

If the pilot flame does light but the boiler not fire up the fault may be: pilot flame too feeble to properly signal control board, heat sensor not working, PCB not recognising or acting on signal from heat sensor, and most often, main gas valve not working.

Boiler engineers who are not too clued up on diagnosis sometimes change bits at random - generally they do not understand electronics and will often change the PCB on "spec.".

4) If you have a hot water storage tank it should ideally have an immersion heater in it for emergencies such as yours - your new property with a combi will not have such a luxury and bath filling will take longer than you might wish especially in the winter when the incoming water will be cooler.

5) Much will depend on the pilot flame on your boiler - if it's coming on and you have to wait for an extended and variable period before the boiler actually fires up I would suspect the pilot injector being partially blocked and not producing a big enough flame to trigger the next stage - I only offer this because this is what happend to my Potterton boiler which, at the time, appeared to have a mind of its own.

Good luck...

Peccavi
May 2009