i have a domestic gravity fed pumped system with two mot. valves. the HW system works fine when controller demands heat boiler fires up.
CH side however will not fire up when controller demands heat. have power at wall stat. have replaced controller and wall stat with new, still boiler refuses to start. mot. valve is open manually
thanks Gavin & Tony, Spot on the valve motor was so loose it wasn't making the micro switch. I should have thought of that first. Tightened motor and the boiler fired up no probs.
Stew, February 2009
m valve not making micoswitch in ch valve
gavin, February 2009
The motorised valve may be open manually but is it making the microswitch to send power to the gasvalve to bring on the boiler.Sounds like either youve wired something wrong or the synchron motor inside the mot valve needs changing.
