Boiler won't fire up!

[fuddymucker]

Hi all,

My boiler (Valiant Combi-Heater VCW T3W) has been working fine until about 2 weeks ago when it shut down half way through my morning shower (

!), we then went on holiday for 2 weeks and have now arrived home to the prospect of freezing cold showers. The pilot light was still lit but it wouldn't fire up for either hot water or heating. I called a gas engineer out who wasn't particularly interested in fixing the old boiler and instead wanted to charge me £2k for a new unit (which I can't currently afford). His vague diagnosis of the fault was that he thought both the motherboard and flame supervision pcb's had blown, but in my electrical experience it is unusual for 2 out of 3 (according to said gas engineer) separate pcb's to fail at the same time.

Here's what's happening: pilot light is lit and reignites if you switch it off and back on again. Turning on the heating does nothing (there is power to the hard wired control unit and there is no thermostat other than on the boiler itself) whereas when turning on the hot water you can hear a click and the sound of running water through the pump (doesn't sound like the pump is running though). There is no rush of gas and thus the boiler is not firing up.

My question is this: does it sound like replacing any of the PCBs would fix this issue, or is there anything else I can check? Like most folk I'd like to get it fixed for next to nowt and I'm quite happy to do whatever I'm legally allowed to myself. Any help much appreciated!

 

[hertsboilers]

It is the oldest Vaillant boiler I came cross. It is better to give up and have a new boiler.

 

[ianmcd]

Have you tried re-setting the overheat thermostat ?

 

[fuddymucker]

Have you tried re-setting the overheat thermostat ?

How do I go about doing that?

 

[ianmcd]

Ha Ha knew you were going to ask that, I havent seen one for many years, I think if you take the two screws off the front plate that covers the controls then look down at the bottom right hand corner there is a reset switch there covered by a rubber boot if I remember correctly, if it clicks when you press it in that is what the problem has been, if it is not there as I said been a long time since I worked on one, change the title of your post and put Valliant in the title and one of the Valliant engineers will advise you better

 

[hertsboilers]

 

[fuddymucker]

ianmcd and hertsboilers - you are both legends! The switch was part of the pcb unit - I pressed it, it clicked and now I have hot water again! Interestingly it still isn't working for ch but frankly with the weather we've got at the moment that can wait! I'll reset everything tomorrow and see if the ch decides to work.

Thank you all for your help, it's much appreciated.

 

[AGAS]

but why has the stat tripped ????