I have swiched the CH off now the weatehr is hot but now the hot water doesn't heat up - the heating control panel buttin lights up but the boiler doesn't fire up unless I also put the heating on again. The control panel was replaced last year as was the valve to switch on the heating (but not the one for the hot water). We haven't tried just the hot water since then - could the panel have been wired incorrectly to cause this? Panel is a Danfoss FP715-Si

Jenny, May 2008

with you saying ch valve im guessing you have an s plan system with a seperate valve for ch and for hw.

if hw works when heating on but not independantly then it must be the hw valve is getting power to open up and allow water flow (or has failed to open position) but not sending power down orange wire to fire up pump and boiler. which is why it works with both on cos the ch valve is supplying the live circuit to the boiler.

maybe valve not moving over enough to hit microswitch or burnt out.

an engineer and a multi meter should be able to tell you in minutes whats up for definate

iain, May 2008