I've been away for a couple of days so haven't had chance to check out your suggestions.
I hope the new 3-port valve I fitted isn't faulty, but I will check it out in any case as per instructions.
If the radiators are getting hot through the return, what's the likely cause ?
Thanks for...
I changed the complete valve and I double checked that I wired it correctly.
Only a couple of the radiators downstairs appear to be getting hot. The boiler is on the wall in the kitchen and flow goes directly up to air separator, then pump, then 3-port valve in the upstairs cupboard housing...
I have a fully pumped open vent system that's started to heat the radiators when the programmer is set to Water Heater only. I've just changed the 3-port mid position motorized valve (Honeywell V4073) hoping this would cure the problem, but the fault is still there. Help please !