Strange thermocouple/pilot fault/remedy?

[stuartfreeman99]

Rare thing happened here to me-

My boiler pilot went out a few weeks back. It wouldn't re-light, well it would but wouldn't hold

So I called a local plumber / breakdown man and he checked it. He tested a few parts and cleaned the thermocouple tip but still no joy, and as I didn't have the manual, said he would be able to get hold of one and re-check things for me / order any new part as required after he came back from his holiday.

Anyway, yesterday my missus was on at me, fed up with using immersion/boiling a kettle for hot water. So I thought, I'll have a go again.

Funny enough, after releasing the button very very slowly, it stayed alight. It is on now still but will it go out again more than likely?
Why has it stayed on now? Is it because the boiler has been off for nearly 3 weeks or did cleaning the tip help?

Anyone experienced this before?

 

[ChrisR]

SImilar, yes. They produce a little bit of power, so when they're failing, it can fluctuate.
It'll probably pack up again soon.

 

[stuartfreeman99]

thank you for replying ChrisR

The engineer will probably replace it then

Why has it come on now though, it didn't work before... do you think cleaning the tip has made it work again for now? Or will it work randomly as you say now and again but pack up again soon? Just amazed me it worked and I didn't know why....

 

[bengasman]

I can think of at least two other reasons it could do that. Just the fact that it works, does not mean it is right, or works properly

 

[stuartfreeman99]

what are the 2 reasons then? it just seems amazing it works again now when it didn't before and nothing's been changed!

 

[gas_man_gaz]

what boiler is it?

 

[stuartfreeman99]

glowworm fuelsaver 40 b

 

[gas_man_gaz]

has he ordered a overheat stat aswell?

 

[bengasman]

what are the 2 reasons then? it just seems amazing it works again now when it didn't before and nothing's been changed!

Both are directly safety related, so out of scope to discuss here.

 

[stuartfreeman99]

Thermocouple is still alight, strangely. Apparantly the oerheat interruption device is ok and not faulty as he tested it this morning, and said if the pilot goes out again soon he'll order me one up.

I asked him why it came back on and he said the small current can vary when they are started to wear out. He said he has seen some thermocopule's bent into the pilot flame to keep them working, but it was illegal... but mine may last another few months or even longer