Help with Hot Water and Heating Not Working

17 Mar 2008
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United Kingdom

Our central heating and hot water seem to come on only when they feel like it, which is becoming more often than not. If I fiddle with the valve position, cycle the programmer state and twiddle the HW tank thermostat then most times I can eventually the boiler to fire up although it can take a couple of hours of intermittent fiddling !

Boiler : Ideal Classic
Programmer : Horstmann CentaurPlus C27 controller
Valve : Honeywell three way

Feeding a standard set of radiators and a hot water tank in the airing cupboard. The tank has a thermostat for the HW and the lounge has a thermostat for the CH.

The programmer appears to be operating as expected, in that the CH and HW lights come on at the right times. I can't say for certain if it's switching the power OK behind the scenes. The boiler seems to be fine when it fires up. The thermostats 'click' when the dials move past the current temperature, so they seem OK, and I think it's unlikely both CH and HW thermostats would fail simultaneously. Also, the CH and HW fail to come on when the room is blatently cold and the HW is also very cold.

My thinking is that it's probably the valve or valve motor that's faulty but I'm not sure how to test that. My next options are the programmer or some sort of cutout in the boiler.

I've tried CH and HW independently and they both seem to be as unreliable as each other. At the moment, CH is off and HW is set to two periods in the day. the HW usually comes on in the morning but won't come on later in the evening despite there being no hot water.

Having trouble finding a local plumber to come out ... (!)

Thanks for your advice.

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