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Central Heating Issue When Boiler in off Position it Still Lights up

Postby PaulCrate » Tue Oct 31, 2017 8:57 pm


I have a recent issue with my central heating. When the boiler timer/control is set to the off position, the boiler will still light and the radiators will get hot when the room thermostat is turned up. Turning the stat down will stop the boiler

I suspect the three way valve is a fault here. My thinking is, when the stat is turned up, the boiler will light no matter what the controller is set to. The three way valve won't open as the CH switch is in the off position. The boiler will hen go off shortly after as the water is then at temperature. If the valve has failed, the water will flow to the rads and the cycle will continue as if it was in the on position?

Does that make sense?

I am running a test at the moment wIth the room stat turned down, the HW set to on and the CH set the off. I suspect the rads will stay hot

Any thoughts?
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