Swapping mechanical to digital thermostat

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BLM007

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Morning all, and merry Christmas.
I am looking to replace my old sangamo choice rstat1 with a moes but-002 go. A bit of back ground. Downstairs we have water underfloor heating upstairs there are radiators. I have 4 room stats downstairs and leave the boiler on all. The time and control the temp via room stats and this works well. The problem is that the upstairs has only a mechanical thermostatic switch that we now need to manually adjust when we want the radiators to come on. I wanted to switch to a moes but 002 to be able to set a timer for this. I am a bit lost on the wiring. The sangamo has a live and live switch connected with the neural not connected. The bht 002 needs all 4. I have connected the live at the boiler and can get bht operational but cannot get the heating to operate. I have 240 v on live and neural, and live switch but i cannot get heating on. Any ideas ?
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Last edited:
BLM007 said:
I have connected the live at the boiler
Click to expand...
your thermostat does not connect to the boiler in any way, it gets wired to the zone valve controlling that zone , the valve tells the boiler when to come on
 
Ian thanks, you are correct it does not need connected to the boiler. I grouped it in with other neutrals to get power to moes thermo, otherwise it does not power up. I can hear the moes switch “click” when adjusting temp but the valve at boiler does not move.
 
Ian, please see below, colours are as per picture above. The Boiler end i have but notes as to where the cables are.
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For 230V motorised valve control, the new stat replaces the Honeywell as follows:

Brown wire (Live) in Honeywell 1, goes to new stat L 4

Grey (Switched live) wire in Honeywell 3, goes to new stat 2

Insert a link between new stat 4 and 1 so that the two terminals are joined together.

The black wire needs to become a neutral connection. So assuming that these are both ends of the same wire....

2.jpeg


....then the thermostat end connects to the new stat N 3, and the other end to an existing neutral connection. Ideally a blue sleeve should be slid over each end to show that it is being used as a neutral connection.
 
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