Potterton puma 80 problem?

[topfridgeman]

Hello Guys,

I wonder if any of you have come across this problem before? I have a potterton puma 80 permanent pilot combi boiler.

When the DHW is used, the boiler dumps all it's water out of the ovepressure valve, just after the tap has been closed. I watched it at the boiler, when the tap is opened, everthing starts fine, and it produces hot water at the taps as it should. Once the tap is closed, say, after filling the sink, the burner stays on, and the pressure builds quickly, untill the overpressure valve blows off, and the pilot light goes out.

The boiler works fine on the central heating side. I'm pretty sure the pump is ok, and the fan, is 2 weeks old. I'm unsure whether it is the DV or another sensor, relay which is malfunctioning. The wiring diagram supplied with the boiler is dire.

Any ideas?
Thanks, Col.

 

[Gasguru]

Over to you zimmers

 

[bengasman]

Definitely not the pump

 

[Gasguru]

For starters have a look at the images here

 

[sooey]

Over to you zimmers

gasguru gizzago, the flow switch is sticking on.

 

[baxpoti]

Over to you zimmers

Another diverter valve ?

 

[topfridgeman]

Thanks guys,

I may have posted a little prematurely, having now read all the posts for the same boiler as mine. I will check the DHW flow valve and the microswitch. The red light does come on when there is hot water demand.

Is the flow switch valve serviceable, or is it better to replace it anyway?


Col.