My central heating is operated by a Honeywell T6360 thermostat and I have been experiencing inaccurate control and failure to come on. If I set the temperature to (say 20c) the boiler will fire up and warm the house. However, occasionally, once the room has reached temperature the boiler will flick off, but will not come back on again and the house gets cold. To get the boiler back on I have to turn the thermostat dial way down and then back up again until it clicks. I have replaced the thermostat with a Danfoss RET2000MS (used from eBay) and got the same result. So I tried a brand new Honeywell T6360 and the problem still persists. The hot water comes on/off fine and the system is controlled by a Honeywell ST91000c. Please can anyone help?
Room thermostat control
- Thread starter Lumpkin
- Start date
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Good afternoon Lumpkin,
How many wires are in the thermostat? (I’m guessing x2, perhaps x3 inc earth). Also where is is situated - Recommended height of approx 1.5 m from floor? Is it directly above or in close proximity of a radiator? Also is it in the same position as a radiator with a thermostatic control (trv)?
How many wires are in the thermostat? (I’m guessing x2, perhaps x3 inc earth). Also where is is situated - Recommended height of approx 1.5 m from floor? Is it directly above or in close proximity of a radiator? Also is it in the same position as a radiator with a thermostatic control (trv)?
Last edited:
Isn't it 3 wires + earth
Live
Neutral
Switched Live ( call for heat }
Earth
Live
Neutral
Switched Live ( call for heat }
Earth
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Ha ha shoulder weight ? it is wired correctly and sounds as if it is located properly, what boiler do you have ?
The boiler thermostat is the little black knob on the front of the boiler control panel, as you have the same fault with three different room thermostsats I think your problem is elsewhere
Turn your room thermostat down till the boiler goes off, then turn it back up till it clicks and go to the boiler an look through the viewing glass is the burner on or just the pilot or is it just sparking and nothing lighting
Probably a motorised valve failing, on some cycles it's no opening far enough to activate the microswitch inside.
I tried ianmcd's test above and the boiler fired up as it should. As this is an intermittent fault, so such a test could be inconclusive. Is there any further ways to test?
How can I test the microswitch in the motorised valves? I have an unvented cylinder system.
How can I test the microswitch in the motorised valves? I have an unvented cylinder system.
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I am not sure if we should use a wall thermostat to adjust room temperature, we need a room thermostat as other wise the central heating boiler would cycle off/on all summer, so we need a device to turn off boiler when weather has improved, and also of course turn on boiler when weather deteriorates, but the wall thermostat does not in the main control the main rooms, it is normally in the hall, and specially with gas boilers that modulate the room control should be by the thermostatic radiator valve (TRV) so as the sun (if any) moves around during the day warming rooms at different rates, each TRV compensates for this maintaining room temperatures at the set level.
Think you are asking too much of a simple single wall thermostat to control room temperatures. Specially if there is no neutral to heat the small resistor that should reduce hysteresis.
Think you are asking too much of a simple single wall thermostat to control room temperatures. Specially if there is no neutral to heat the small resistor that should reduce hysteresis.
Do you have 1 x 3 port mid position valve (Y Plan) 0r 2 x 2 port valves (S Plan) if you are not sure post pics usually near the HW cyl but not always
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