Potterton Suprima 60 rads only heat when DHW on

[DubbleDonkey]

Hi

My rads only heat when the hot water is on. On cold days when the hot water and rads have been on for an extended period the rads go cold. Running away some of the hot water restarts the sytem. Am I right in thinking this happens because the hot water reaches the thermostat temperature? My first thoughts were that the problem was with the motorised valves. I've had a look at them in the airing cupboard and there are two two port valves. A Honeywell one for the water and a myson one for the rads. When the rads are turned on either alone or in combination with the hot water the myson valve opens. It seems that this is not the problem. What I have noticed though is that the pump doesn't come on when just the rads are turned on. Has anybody got any ideas?

DubbleDonkey

 

[corgiman]

buggered central heating valve actuator

 

[DubbleDonkey]

Do you mean that the central heating motorised valve is not working correctly? If so surely the CH wouldn't work at all since there are two two port motorised valves?

 

[namsag]

As corgiman says its your heating valve that is faulty although it is opening there is a little cam inside that moves over and makes a micro-switch which brings the boiler and pump on yours either has a faulty micro-switch or the cam is not quite making it all the way over to activate switch... New head required if detachable or complete valve if not.

 

[DubbleDonkey]

Great. Many thanks for that. The actuator sits on top of the valve so it should be straightforward to replace it. I'll first check that the valve is correctly wired up.

 

[corgiman]

Great. Many thanks for that. The actuator sits on top of the valve so it should be straightforward to replace it. I'll first check that the valve is correctly wired up.

dont bother with that unless it has never worked correctly

how long have you been using the system?

 

[DubbleDonkey]

It has never worked since we moved into the property over a year ago.

 

[DubbleDonkey]

I had a quick look at the wiring. The valve I have is a Myson MPE 228. It has 3 wires for the auxillary. These are orange, grey and white (common). The grey wire is not connected to anything. Is this correct?

 

[DubbleDonkey]

Got it sorted at the weekend. It was the wiring.