Potterton Puma 80 Pilot Problem

[wyvern]

I have just moved into a new house witha Potterton Puma 80 combination boiler and the pilot light refuses to stay lit. The previous owner says that the pilot light going out is a common problem on that model but after a few ignitions and the running of the HW it should stay on.

This problem is different in that the pilot ignites but when one slowly releases the gas knob to turn it to the flame logo it goes out. This happened 3 days ago now and I have tried it many many times. What can I do short of spending hundreds on a call out, new thermostat and new thermocouple?

Please please help

 

[MUGWUMP]

Excuse me if this is an insulting reply, as I couldn't find a manual on the web to check, but are you sure the "gas knob with the flame logo" isn't acting as some sort of emergency gas cut off when you turn it ? I only ask because our old baxi has a knob like this - keep it pushed in while lighting the pilot + release, or turn clockwise to kill the pilot - it is rather confusing without reference to the literature.

If not, it may just be the thermocouple, probably a fiver if you're OK to fit it yourself.

 

[ollski]

How long are you keeping it pushed in for when you ignite the pilot?....try keeping it pushed in for up to 3 mins to properly warm the thermocouple, then as mugwump says turn it the correct way. check that the thermocouple is in the pilot flame when you have it manually held open.

 

[wyvern]

Thank you Mugwump and Ollski

Pretty sure that turning the gas knob does not act as a cut off, and will hold it for at least 3 mins now. Fingers crossed and thanks again....

 

[ollski]

it shouldn't take that long but hey. There is a modification on the gas valve to prevent moisture from the cold feed inlet dropping onto the solenoid...post a pic up if you can and we can see if it has been done. You would hope it's your thermocouple, if not hope it's your overheat stat and if not hope it's not your thermoelectric valve (new gas valve).

 

[ChrisR]

WHat's the mod on the gas valve - never noticed that!

The pilot jets on these are quite prone to getting blocked, so the thermocuple doesn't get hot enough. The whole pilot tube/ assembly needs changing occasionally too. All corgi-only jobs.