Potterton Suprima Hot Water OK, No Heating

[tnarg999]

Have got a Potterton Suprima 30 Boiler, approx 11 years old. PCB was changed in 2003 to newer model #5102160 by previous owner. Board looks ok, no scorching etc. Boiler regularly serviced. System has header tank and cold water in the loft, plus airing cupboard with copper cylinder and cylinder stat.

Domestic Hot Water is working fine - nice and hot, but the radiators don't get warm. I have fiddled around with the three port valve in the airing cupboard pushing the bypass lever over. This seems to work as a one off, but the next time the heating is due to come on early morning, the same thing happens.

I have taken the motor head off the three port valve, and the valve itself doesn't seem stiff. (Can move it with fingers) Is it likely that the motor head need replacing or do the Pro's ever have problems with the way the roomstat/boiler/3 way valve talk to each other?

Thanks

 

[superdupergasman]

I assume you have the room stat turned up??

If so then the fault will lie with you head of the 3 port valve, when on CH only you should get 240Vac to the motor in the head.

If you do and it does not motor then its the syncron motor thats dead and easily replaced.

 

[tnarg999]

Yep, roomstat turned to max, although it does "click" at 25deg when turned manually , clearly isn't that warm - assume that the sensor in the roomstat is too ambitious, but I wouldn't have thought that was the problem?

I think I'll change the motorised valve head.