Performa 28 hw works ch kicks in but does not circulate plz

[yzor]

Hello,

I have a Potterton Performa 28.
The hot water works perfectly. The problem I have is with the central heating, it does not circulate the heated water. When I switch the CH on the temp increases to 80 degrees in about 20 seconds and then cuts the boiler out for a couple of mins, it then restarts with the same problem.


The CH flow pipe heats up but it seems the return is not working.

I checked the pump via the vent screw with a screwdriver and stopped the pump without much force. I have replaced the pump with a new one but still have the same problem.

Could it be the PCB?

Can anyone please shed some light.

 

[Baxmax]

The return filter is probably blocked its on the return iso valve.3/4" with 1/2" blank or your filling loop on the end.

 

[bengasman]

Either blocked filter or knackered diverter

 

[yzor]

Thank you all

The problem was the return valve filter completely blocked

Thanks again