WorcesterBosch 350 Combi stopped working **now fixed**

[bionicmanc]

I've had a Worcester Bosch 350 Combi and for around 10 years have not had a single problem (is that a long time?).
Over the last 2 weeks, it's been intermittently failing to 'fire up' on hot water (ie. after turning the shower off and back on again a few times I get hot water) but today that's not working.
Tried the central heating (haven't used it for months) and this too is not working.
I've done a few tests, switching it off at the mains, turning it to HW only, HW & CH, etc. and I get the same result when I turn the HW or CH on, which is one click in the boiler and nothing else (seem to remember it used to click about 5 times then fire up).
When it's running, the fan runs and blows cold air out of the flue (obviously) and the 'overheat thermostat reset button' has not popped up.
Anyone any ideas on what the problem might be? Happy to call in the experts if there's not a simpe solution.

Cheers!

Mark

 

[fitz1]

possibly air pressure switch.

 

[fitz1]

are the red lights flashing

 

[bionicmanc]

Thanks for the prompt reply....no red lights flashing and pressure on the gauge is between 1 and 1.5 bar which dips down a bit when (not) fired up.
Is it possible for the air flow pressure switch to have an intermittent fault and can you it to prove that this is the faulty part?
Having read the servicing instructions, it would appear easy to replace the unit but is it worth checking that the pressure tube connections, etc. are ok? Could this be the problem?

 

[bionicmanc]

Sorry meant to say "can you test it in any way to prove that this is the faulty part?"

 

[fitz1]

check the tubes first. look for splits in them. if o.k , pull one off fan and suck on it . boiler should fire.

 

[bionicmanc]

Thanks for the advice, I'll give it a go tomorrow.

Mark

 

[bionicmanc]

fitz1,

I took your advice that it was the air pressure switch.
The pipes were fine but I took them off anyway and gave them a blow through and did the same with the electrical connections....the result is a perfectly working boiler again!
The intermittent fault may come back, but at least I know it's this part that will need replacing if it does.

Thanks very much for taking the time to help.

Mark