Thermocouple in boiler worn??

[loucooper]

I believe the thermocouple has been damaged/tip worn in my boiler as the (permanent)pilot light went out today. When trying to reignite when releasing the button, it keeps going out.

Are thermocouples standard or different sizes for different boilers. Are they easy to fit?
I have seen one in Screwfix but will it fit my potterton boiler? i am a good diyer and would be prepared to do the job myself. or is it illegal as the boiler is gas ?

 

[malkie]

Potterton ? need the name and model

 

[loucooper]

hi it is a potterton flamingo II. quite old i beieve, it was here when i moved into the house 14 years ago. it is wall hung and has a balanced room sealed flue i believe through the external kitchen wall.

 

[malkie]

a universal im very sure will do it,but how big is the pilot flame and is it touching the actual T/C tip

 

[loucooper]

how do i measure the pilot flame to check?

 

[malkie]

just looking at it,is the boiler casing off and can you see the pilot flame when you light it,is it a decent size flame or small and is it touching the thermocoupler tip

 

[loucooper]

oh sorry - yes i can see it and it touches the thermocouple tip. the tip looks a bit black though and i'm thinking its got burnt out.. it is od though so i suppose this is just wear & tear.

 

[malkie]

you could try wire wool on the tip see if its build up od crap is stopping the flame being enough to keep the t/c closed but its 99% gone as you say,some flamingos im sure have there own t/coupler what model is yours

 

[malkie]

has yours got a overheat button on it

 

[malkie]

They were situated on the right hand side of the thermostat mounting knob if its there has it popped out

 

[loucooper]

oh i see, similar to an overheat cut out on immersion heaters, that have to be manualy reset. no it doesn't have one. how would this affect the thermocouple from lighting/holding the gas valve solenoid(s) open anyway?

 

[loucooper]

just found the boiler catalogue and it shows spares part page - and there is a thermocouple available. is this part still available do you think-as the boiler is very old now. or maybe a universal would do? but i'd prefer a part direct from potterton if available still?

 

[malkie]

i worked on a potterton flamingo 40 recently and his boiler had a overheat button so i was just checking with you,if a overheat stat kicks in it cuts everything off as safety and until the overheat button is pressed or reset it wont allow the boiler to work,nothing at all not the pilot,it will let the flame light but when you take your hand away from the gas valve button it dies out,so a dodgy overheat stat can cause it as well

 

[loucooper]

malkie - yes i understand now. my boiler has none though, so i am sure it's the thermocouple worn. is it better to try and order one from potterton and quote the part number as per manufacturers instructions? would it still be available to order after these years ?