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I am new to this site and find it very helpful so I am hoping somebody can help me today.
I have an old Honeywell 4200 3879-001 room thermostat which I want to change for a digital, more accurate one. I have found other threads on the subject but the one difference is mine has 4 wires going into it. Terminal 5 is unused.
My system is gas fired boiler with 3 port valve next to the hot water tank in the airing cupboard.
We have a Seimens RWB9 controlling the hot water and CH.
I notice the Honeywell DT90 is a common thermostat but don't know if this is any good for my purpose due to having the 4 wires coming out of the wall?
I would appreciate your help please
I have an old Honeywell 4200 3879-001 room thermostat which I want to change for a digital, more accurate one. I have found other threads on the subject but the one difference is mine has 4 wires going into it. Terminal 5 is unused.
My system is gas fired boiler with 3 port valve next to the hot water tank in the airing cupboard.
We have a Seimens RWB9 controlling the hot water and CH.
I notice the Honeywell DT90 is a common thermostat but don't know if this is any good for my purpose due to having the 4 wires coming out of the wall?
I would appreciate your help please
