my pump won't turn off

[lojack]

help wanted , I have a standard 2 motorized valves,room stats etc set up with Baxi solo 2 pf 60 boiler. I believe the boiler has pump overrun facility.but the pump stays on forever I have replaced the Drayton lp522 programmer to no avail. any suggestions welcome.

 

[kevplumb]

just a wild guess

pump overrun stat

 

[croydoncorgi]

The pump SHOULD be wired to the BOILER, not to the programmer, which has no effect on overrun and asociated problems. Control sequence is:
programmer - room stat - zone valve - boiler - pump

If, as has been suggested, the fault is the overrun stat on the boiler, the pump will continue to run all the time there is power to the boiler, even when CH and HW are selected OFF on the programmer.

 

[lojack]

thanks kevp and croyd. will geta new stat and see how she goes.
cheques in the post.

 

[croydoncorgi]

Might be wiser to test the one you've got first...
The fault could also be caused by a jammed relay on the boiler PCB....

 

[nobody]

I had this problem, heating was on continually which is how I noticed and it was the zone valve which had failed. Most have a manual lever as well that you can see move when it switches on and off.

try turning the heating/hw on and off making sure that the stats would cause it to work. Watch to see if the valves do anything. If not does anything happen if you manually move them ?

I was lucky in that the valves we have fitted can haver the motor/controller replaced without having to unplumb them.