hot water no problem
ch not operating
room stat set at 30C
3 port valve opened manually
ch on overide
ch will still not operate.

mark, October 2010

'3 port valve opened manually' Why?
Does is not open automatically? Therein lies your problem.

Check for 240v to the diverter valve white wire, if there is no 240v then fault is external to either clock/roomstat, if 240 is present and it's not opening the diverter valve actuator would be the problem

Carefree, October 2010