Old Vaillant Thermocompact vc gb 142 needs help..cutting out.

[Turbo2]

I `ve got a Vaillant Themocompact vc gb 142

My boiler was fitted in 1999.It has worked without fault since then..grateful for any perspectives.

A couple of weeks ago i came home to discover that the button on the front panel had popped out,pushed to reset and the boiler worked again for a few more days.Then the button started to pop out more and more regularly and now as soon as i push it back in to restart the boiler fires fine for ten seconds(always ten seconds) then the button pops again.

I can hear a very faint clicking/ticking that continues as the boiler is firing for it`s ten seconds,it's the same as the initial sparking sound just much quieter.

I spoke to one company who said i should replace it as it`s so out of date now,I`m not in the boiler replacement camp even though i`ve got this older model!.

 

[muggles]

Which button pops out? Is it the overheat? If so, you could have a sticking pump

 

[muggles]

Oops, duplicate post

 

[Turbo2]

It`s the black button that`s next to the on off switch and adjacent to the pressure gauge.

So would a not perfectly working pump cause that shutdown even if it only fires for 10 secs and has no heat in the system?

 

[muggles]

Yes - if the boiler is firing and there's no circulation, the boiler will overheat very quickly. https://www.dhsspares.co.uk/product/vaillant-161077-pump-1373950

 

[Turbo2]

I`ve just run the boiler for the ten secs it will run before shutting off and the pump does seem to be running,i can hear and feel it.

If the pump is in the process of failing and not running as well as it could would it still somehow cause the 10 second cutout?..thanks for the pump link.

 

[JohnD]

the pump does seem to be running,i can hear and feel it.

doesn't mean its pumping water. there might be a sediment blockage, or air, or a valve turned off or failed shut.

 

[muggles]

doesn't mean its pumping water. there might be a sediment blockage, or air, or a valve turned off or failed shut.

Or they're just hearing and feeling the water boiling up inside the heat exchanger!

 

[Turbo2]

All i (think i) hear is a soft whir from the pump and the combustion sound.i can't hear anything from elsewhere in the boiler from what i can tell..

Is there anything else that could cause the always 10 second shutdown apart from the pump?..i read about a flame supervision unit and an ignition sensor(or something)..are these possibilities?