Yet another room thermastat

[diynotb0t]

Hi Folks,

I just wanted to ask if its possible to replace my existing room thermastat with a newer remote style?

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• diynotb0t
• 21 Nov 2010
• 1

I've got a 70s style Honeywell with 42000 4879-001 marked on the inside. I was hoping something a remote version like this was compatible, or this

I've been looking on the wiki and found some articles around wiring but I'm not confident in doing it myself so I wondered; should I ask an electrician or a plumber to do this for me? What should I expect to be charged?

I've got three wires going into the back (as shown below), (silly question but...) is this a two wire stat (ie, we dont count the earth?) or three wire? Does it make a difference?

Thanks for any tips.

All the best

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• diynotb0t
• 21 Nov 2010
• 1

Untitled

• diynotb0t
• 21 Nov 2010
• 1

ps, perhaps I should mention its wired up as per the diagram as far as I can tell. Blue goes into '2', earth into '3' and Brown into '1'. ta

 

[londonboy]

You could use any wireless stat, or a 2 wired stat.

You cannot use the earth for anything other than earth (like the previous installer has).

Wireless:

http://www.screwfix.com/prods/84067...ing-Controls/Honeywell-Y6630D-Room-Thermostat


Wired:

http://www.screwfix.com/prods/46637/Plumbing/Central-Heating-Controls/Drayton-RTS8-Room-Thermostat

I am an electrician and would charge about £50 to install either versions.
Beware not all electricians will touch heating systems.

 

[diynotb0t]

Thanks for the reply.

 

[diynotb0t]

Hello again,

Just to check then, I bought a thermastat ready to install, it has L and N connections as well as a L1, LX, and L2 which it describes as voltless connections.

Here's the manual with wiring diagrams http://www.screwfix.com/prods/89164...trols/Siemens-RDH10RF-SET-GB-Room-Thermostat#

There doesn't seem to be an earth connection so in my install I'd expect the earth to be blanked off? If its a matter of just connecting L and N, I figured I could do that but I want to be sure its wired correctly. Any general advice?

 

[diynotb0t]

You cannot use the earth for anything other than earth (like the previous installer has).

Sorry, has the previous installer wired up the earth as earth, correctly or is he using it as some kind of switch wire? I wasn't sure from your comment...

 

[londonboy]

Its wired incorrectly, the green/yellow (earth) has been used as a live conductor. It needs to be changed at the other end of the cable (at the boiler, or airing cupboard).

 

[diynotb0t]

Groan... Nightmare, I'm not going anywhere near the box in the airing cupboard, there's like a million wires

I hope I bought the right replacement one then!

Thanks

Ps, should it have been sleved or just swapped for another colour?