I have switched the system from summer to winter mode, but now have constant radiator heat although the stat is at zero and the timer is turned off. I am getting a constant 240v at the diverter plug (when in winter mode). With the diverter head valve mech disconnected, but elec connected the three way valve appears to be ok and motoring. When trying to push in manually the spring valve, there appears to be a lot of resistance but am not sure how much. Please help

Ade, October 2008

I have the 100HE which is almost identical. I have the same problem. When in winter mode no matter what the manual timer is set to, the boiler fires up and turns on the CH. I've also checked the 3 way valve actuator and it seems to be working fine. When in winter mode the actuator pushes the valve all the way in. When hot water is switched on or when in summer mode it releases the valve. It seems that these are the only 2 positions the actuator has - is that correct?

Also the PCB is quite hot - is this normal or does this suggest a faulty PCB that would cause the problem above?

Andy Hoyle, October 2008