Potterton Puma80 Pilot light goes out after hot water tap of

[diylady]

Help...

I have a Potterton Puma 80 that is behaving rather strangely , so strange that I've had the boiler man out twice and the problem doesn't seem to be solved.

The problem is intermittent but I have noticed that it usually occurs after running the hot water tap for a while - lets say a bath or washing up.

After about 2 minutes of turning the tap off there is a loud noise in my pipes and radiator (a bit like the sound you make dragging a spade on concrete) which then forces the pilot light to go out.

I have discussed this problem with lots of people who say that the noise is a backdraft of air in the pipes.

The boiler man has said that the pilot light going out is a safety cut out feature of my boiler when it is too hot and said my problem was due to the fact that all of my radiators are fitted with Thermostatic valves. He said one of them should not have this type of valve but a valve that keeps the radiator open. He told me to pull the top off one of the thermostatic valves and unscrew it to keep it open.
I have tried this but no joy - the pilot light keep going out. I am afraid to use the hot water!!

This problem occurs when the central heating has been both on and off.
I have bled the radiators - to just eliminate a air problem and the pressure of the boiler is between 1 and 2 bars

Can anyone help?

 

[kevplumb]

worth checking the hot water flow switch isn't sticking

 

[ChrisR]

That would be the first thing I'd have thought any "boiler man" on gods earth would know about, so it's just possible he's right about the thermostatic valves, but I very much doubt it. Make sure ONE of the rads' valves is full open (bathroom one perhaps) and then see if it does it.

It's easy to check the hot water flow switch , it puts a red light on inside the boiler!