Sunvic TLX2259 to Drayton RTS8 Thermostat

[Hawks5656]

Morning All,

Hoping you can help with a wiring question - I've searched through the items already posted but havn't found anything that matches this scenario.

We've recently purchased a house which has an old Sunvic TLX2259 which has clearly seen better days. The programmer fires up heating as per usual.. but thermostat seems dead on arrival .. hence i'm wanting to get it replaced.

Its gas central heating from a back boiler in the living room.. running into the hallway where the thermostat sits.

The current thermostat looks like this (apologies for the grime.. but I've got the major bits!)

From the other posts..

As both the wires already installed are red (with a black neutral) I wanted to check before making any changes.. but from what i've read in the forum,

My understanding is that 1: Live 3: Live Switched 4: Neutral


Looking at the diagrams for the drayton:

I'm a little confused as to which solution to go for - Fig 6 (bottom one) states for gas Central heating .. however, as mine does have a neutral connection (along with the two red wires) am I right in thinking fig 5 (top) would be best?

If so.. fig 5 shows two 'N' connections one for load (call for heat) into pin 3.. and one into pin 'N'

again I'm assuming the 'N load, call for heat' may be switched live? With permanent live into 'L' and Neutral into 'N'?

Appreciate any advice you can provide - If need be I'll get an electrician to check this one as it doesn't seem standard right now!

Many Thanks

 

[Echo the husky]

Your old thermostat has
1 Switched live
3 Permanent live
4 Neutral

You need to follow Fig5

old new
1 3
3 L
4 N

 

[Hawks5656]

Thanks so much for your quick response. much appreciated

 

[Ian Gill]

I'm in a similar boat and looking to replace tlx2259. Wiring looks like this - can anyone give me a steer on what is is/isn't compatible with? Ideally I'd get a Google nest. Newbie here - any help much appreciated!

 

[ericmark]

At the moment no images, got a feeling it is the site being slow. However gas boilers come in two flavours, non modulating and modulating, the latter is either controlled by a thermostat connected to ebus, or the TRV heads. Seems unlikely yours connects to ebus so the TRV is likely king.

However unless linked to the wall thermostat, the TRV head can't turn boiler off/on it can only turn it up/down, so a wall thermostat is normally fitted in the hall, and its only job is to turn off heating on a warm day.

But I found out the hard way, setting up central heating to work with TRV heads is not as easy as it seems. Very likely nothing wrong with thermostat, just not set up right.