Potterton Puma 100 Perm Pilot

[Barnettn]

I have a potterton puma with 2 strange faults.

1. With the boiler receiving CH demand it does not run. If i turn up the boiler CH stat the boiler lights then carries on running ok for a few days.

WHY?

2. I have just noticed that my HW temperature is nolonger hot - only warm. If i turn on a sink tap the bolier fires up / runs etc but the water only gets warm on the highest setting on the control panel knob. Turning the HW temp knob up and down makes no difference. If I manually turn the tap down to reduce the flow it gets hot as before.

Are these 2 faults related?

 

[ChrisR]

I'd check the resistances of the two temp sensors. If they were OK I'd call Potterton, but expect them to say change the PCB.

Poor HW can be caused by lots of things, most of which an engineer would find by measuring temps inside the boiler.

 

[Barnettn]

From memory the values are in the installation book. Do you know if they are correct in the book? OR do you know what they actually should be ?