4 Wire Thermostat... Now with pictures.

[dan83590]

I am redecorating our living room and I want to change the thermostat for something newer, something easier on the eye...

There are two cables to the existing stat. It is wired from left to right earth x2, red, red (permanant live), blue, yellow wires. There is also a black wire that is just left unconnected.

What should I replace it with?

I'd like something with a digital display, can any stat be fitted or do I have to stick to the same wire configuration?

 

[twgas]

a bit more info wouldn't go amiss

 

[dan83590]

What do you need bud?

 

[twgas]

type/model of stat, type of system etc. the more info the better.

 

[dan83590]

Valliant COMBI/compact boiler, a Drayton control type RTC.

Any other info needed?

 

[twgas]

Do you know where the cables go, old airing cupboard, boiler or previous boiler position

 

[dan83590]

I am fairly sure they go back to the boiler. There is also a timer on the system.

 

[dan83590]

In this picture the wires are labeled as:

E - EARTH
2 - COOLING - RED
1 - HEATING - RED (permanently live)
N - NETRAL - BLUE
3 - LINE - YELLOW (live when heating off and stat above room temp)

 

[jackthom]

I can't advise on which model to go for but you don't have to worry much about matching the connections in line with the old one.

A modern battery powered digital thermostat will only require 2 connections.
The permanant Live and the Switched Live wires.

A traditional mechanical unit will also need the Neutral connection.

So you can please yourself and buy whichever one seems the best. Then come back if you still aren't too sure about the wiring.

 

[dan83590]

So I just blank off the other wires?

 

[jackthom]

I can only see three connections (plus the earth) to the thermostat itself so a mechanical one will likely use all three. Some digital ones wont need the Neutral (and possibly the Earth also) so they can just be carefully covered up and held back.

 

[dan83590]

Brill thanks.

 

[dan83590]

I've bought a SUNVIC TLX6501

It's connections are labelled

NO
COM
NC

Do you know which wires I should be using?

Also there is a small switch inside the unit that can be set to either HEATING or COOLING. Which do I set it to?

 

[Rampage]

Heating, as it's not for Air Conditioning

One of those questions that sounds obvious when someone's awnsered it

 

[dan83590]

What a der brain I feel!!!

So which wires go where, anybody know?