Fixed
Turned out to be the valve after all... perhaps the voltages i used with my meter to test the compnenets do not acurately represent the in use voltages and something was breaking down under load
Valve head replaced system now working
hmmmmm...
Not a short in the micro switches, or in fact any fault I can find inside the sunvic valve, all components test out as they should.
But the heating is still activated in some instances where water only is supposed to be on .... Help....!!!
The white wire is being energised when hot water only is turned on, but not via the room stat.
I suspect some internal short in the valve, the valve also seems to be defaulting to the fully operated position, i.e. for the heating only, when nothing is switched on in the controller, but in this...
I have checked the valve and can move it by hand, the powerhead moves to all three positions, but for some reason when just water is asked for it moves to the half way setting for water and heat...
I have a problem with our combined central heating and water heater system, it runs from a drayton LP722 controller using a three position sunvic valve to control heating/water/both.
When the water is turned on often the heating also comes on even when it is not turned on itself, I think that...