Radiators getting hot when hot water only set on programmer

[shaunyab]

Has anybody came across this before.
On a y plan (GW ultimate 50 boiler) when the programmer is set to hot water only the radiators warm up substantially. When set to c/h only the cold warms up slightly but the radiators do warm up.
I am tending to point the finger at the three port valve. Any other thoughts?

 

[ollski]

The y plan valve is passing.....always a sure sign summer is coming.

 

[shaunyab]

the 3 port?

 

[shaunyab]

so total change of valve, not synchron motor?

 

[ollski]

well if the head is ok and detachable then you can change the body only.