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Plumberpro, Home Appliance Technician
Category: Appliance
Satisfied Customers: 634
Experience:  Heating and hot water heating appliances experienced
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I have a CH/hw system powered by a Glowworm Micron boiler with

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I have a CH/hw system powered by a Glowworm Micron boiler with a built in 202918 programmer. In the Spring, the system developed an intermittent fault, which, with the onset of colder weather, has now become permanent, and an issue. It is as follows: when the programmer for the CH is set to an on phase, and the room thermostat (renewed) is calling for heat, the boiler will not fire. It only fires when hot water is drawn from the cylinder, and the cylinder thermostat calls for its replenishment. Apparently though, as the motorised valve on the heating circuit has opened, hw also flows to the radiators, which warm up. However, as soon as the cylinder is back up to temperature, the boiler switches off. Any idea what the problem is?
Plumberpro :

Hello. You have a faulty motorised valve . it is opening enough to let the hot water pass but is not making the switch to fire the boiler and pump. As they get weak they start to not pull all the way across and fail to close the switch as it should , replace the motorised valve and all be good .

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