The problem we are having with our central heating seems to stem fro
the Honeywell 3 port valve. In the summer with the heating off an water on the upstairs radiators get warm. In the winter SOMETIMES the last radiator in the loop stays cold unti the water has heated sufficiently for the cylinder stat to turn wate heating off then it warms up straight away. Looking at the valve postition, there would appear to be only postitions the valve operates in - heating only or mid position heatin and water. With water heating only the valve doesn't move on the springs away fro the mid position. I have checked the wiring from the valve and all would appear to be i order but for 1 thing, the water only state. I have a live current on white!!!! This I know isn't correct. Upo further investigation I note that if I disconnect the wire from th thermostat that connects to the white, then the white lead is stil live!!!!! This to me indicates a fault with the circuit board. If I take the valve head off, the spindle moves with a pair of plier but only by a very small amount, maybe 10° each way. With the head removed the valve motor moves quite a lot further an returns on the spring. Any ideas on this. Thanks
-- barrowfordred