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CH only comes on when DHW comes on

Posted: Mon Sep 08, 2008 9:09 pm
by NovaNath
Potterton Prima F with EP2001 control.

The DHW functions as it should.

The CH thermostat was turned down for the summer; when turned up to activate the CH, the boiler will only fire if the DHW is already on/coming on at same time as the heating.
Where the hot water is not on, the boiler makes no noises at all/no response. However the CH light iluminates on the valve and it hums/clicks quietly.

Any help greatly apreciated.
(my gut instinct is that it may be the EP2001 control not telling the boiler to fire)

Posted: Sat Sep 13, 2008 4:21 pm
by NovaNath
Diagnosed to the actuator on the three way valve

Posted: Sun Sep 14, 2008 10:50 am
by htg engineer
See looking through other questions and answers in the forum often leads to the correct diagnosis - there's been many many posts on this subject.


htg