Wiring a Replacement room thermostat for central heating

[Sam323]

am replacing my old thermostat with a new one, the old one had 3 wires connected to it, i tried to buy the same model so i can just easily rewire it . unfortunately the new one has a different wiring method . help please

 

[JohnD]

Your new one appears to be marked 24v, which is very strange, since UK room stats are usually 230v. Where did you get it? Have you lost the instructions?

 

[Madrab]

Your new one appears to be marked 24v, which is very strange, since UK room stats are usually 230v.

Not really, depends on whether the boiler has zero V rated contacts or not, stats can be rated to suit the application

 

[Madrab]

You may not have the correct stat there. If your boiler requires 240V switching then you need a stat that can handle 240 switching, not 24V, don't use that stat if that's the case! Which going by the old Satchwell stat, could very well be.

 

[Sam323]

i still have the box, ill return it and get another one stats 240v.

thank you all for your help, ill be back soon )

 

[Deleted member 267285]

Plenty that are still 230/240vac switching, and some are 24-240vac switching, which is similar what Rob said, but as stated the replacement one you bought is 24v.

 

[Madrab]

i still have the box, ill return it and get another one stats 240v.

thank you all for your help, ill be back soon )

What boiler do you have? The 24V one you have may be ok, that being said that old Satchwell has the neutral wiring compensator connected, which suggests it's switching 240V.

 

[Sam323]

Hello, I've just got this Digital thermostat i hope you guys help me to wire it. ive added pic of the boiler i hope that helps too.

 

[mcprinter]

I am DIY so you may want to wait for one of the Pros to confirm.

Isolate the supply first

Red to 4
Blue to 3
Yellow to 2
You will need to add a link wire from from 4 to 1 so your stat outputs 240 Live when it fires
Make the earth wire safe

Moes bht-002-gclw installation problems

Hello Can someone help me as trying to wire my new thermostat, I have enclosed a picture of my current setup and my new thermostat. I think the live is red and blue is neutral but not sure of what goes in the dry contact ports on new thermostat Any help would very much be appreciated Thank you

www.diynot.com

 

[Sam323]

many thanks to you mate, ill wait and see what the pros says about it

 

[Sam323]

I am DIY so you may want to wait for one of the Pros to confirm.

Isolate the supply first

Red to 4
Blue to 3
Yellow to 2
You will need to add a link wire from from 4 to 1 so your stat outputs 240 Live when it fires
Make the earth wire safe

Moes bht-002-gclw installation problems

Hello Can someone help me as trying to wire my new thermostat, I have enclosed a picture of my current setup and my new thermostat. I think the live is red and blue is neutral but not sure of what goes in the dry contact ports on new thermostat Any help would very much be appreciated Thank you

www.diynot.com

what should i do with the earth ?? what do u mean by safe ? should i cover it or ?

 

[mcprinter]

Cover it with sleeving and maybe put a terminal block on the end.
Need to make sure it cannot come into contact with any of the other wires or terminals.

I wouldn't cut it off. You may need it in the future

Did you get a backplate with the new stat?

 

[Madrab]

You aren't going to be happy, that one won't work either with the cabling you have. That programmable stat needs constant power as well as the switching wires.

Your wiring is only for a pass through thermostat, it basically takes the live power wire (Red) and sends that power across to the Switched live (yellow wire) that heads back to the boiler to fire it up when it calls for heat. The Neutral (Blue) wire is for the compensator part of the stat.

You need a 2 or 3 wire 240V live switching thermostat.

 

[mcprinter]

You aren't going to be happy, that one won't work either with the cabling you have. That programmable stat needs constant power as well as the switching wires.

Your wiring is only for a pass through thermostat, it basically takes the live power wire (Red) and sends that power across to the Switched live (yellow wire) that heads back to the boiler to fire it up when it calls for heat. The Neutral (Blue) wire is for the compensator part of the stat.

You need a 2 or 3 wire 240V live switching thermostat.

Am I missing something?
There is L+N to the old Satchwell TLX2259 and Live out
What is missing?

 

[Madrab]

OK, I should maybe have asked, what controls the boiler just now? I.e. is there a programmer that calls for the CH or is it just the boiler. Only when there is a call for central heating either from the boiler or the programmer is there 240v sent down the red live (L), then if the temp is too cold does the stat then switch that down the yellow (SL) to the boiler telling it to fire up.