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cr0ft

Plumbers Arms member
Plumber
Gas Engineer
Nov 10, 2008
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Lincoln, Lincolnshire
Member Type
Heating Engineer (Has GSR)
Hi all. I have a Danfoss hard-wired room thermostat. Inside are 5 terminals. One for 230v Live supply, one for 230v Neutral. One is COM which is powered by a link from the 230v Live as per the manual.

My question is, will the thermostat be in the normally open or normally closed state when it's below the set temperature? I know I could test it with a multimeter but I'm wanting to do as much of the wiring properly as I can before my gas fitter gets here on the Friday so we're not wasting time testing wiring then.

I'm assuming the thermostat will be closed until it gets up to temperature then will move to the open position?

Thanks in advance for help.

PS I've forgotten the model number!
 
Just searched online and it seems to be a RMT230 model. I don't really understand why a room thermostat needs a 230V Line and Neutral connection at all, I thought they were just a simple loop in and loop out?
 
hi,. stat will be in closed position til its satisfied then it opens
some stats have anticipator built in, these need a neutral
imo
 
Thanks. It seems this one has an anticipator in so that answers my question about the 230v feed. I'm assuming I would only wire a motor return valve to normally open, a spring return valve doesn't need it of course.
 
Some stats have a relay inside that needs l & n or the switch won't work.
 

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