Replacing Honeywell T40 with Drayton Wiser Heathub

J

JonnyGo

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I am trying to install a new Drayton HeatHub (1zone), just trying to work out wiring as I am replacing Honeywell T40 thermostat. Images attached of exisiting wiring and new HeatHub wiring diagram.

Cheers

Jon
[GALLERY=media, 101009]10D3C2B1-6E84-4DE4-988F-3E8C1B45CB6B by JonnyGo posted 20 Jan 2018 at 4:34 PM[/GALLERY]
[GALLERY=media, 101010]300856EA-92E8-4C64-B994-FA00420DCFE8 by JonnyGo posted 20 Jan 2018 at 4:36 PM[/GALLERY]
[GALLERY=media, 101011]19C18F8F-886D-4523-B543-1F40F0FA2030 by JonnyGo posted 20 Jan 2018 at 4:37 PM[/GALLERY]
 
I'm a bit puzzled why you are asking this, because all of the information you need is shown in the photos you have posted. From them, the wires at the existing thermostat are identified as:

1=Live (Brown wire)
2=Neutral (Grey wire)
3=Switched Live, heating 'on' (Black wire)

From your last photo, the Drayton unit you want to install has the wiring as shown below.

Capture.JPG

The Live (Brown wire) goes to Drayton 'L' terminal
The Neutral (Grey wire) goes to Drayton 'N' terminal
The Switched Live (Black wire) Goes to Drayton terminal 3 'On'
Finally add a link between the Drayton L terminal and terminal 1 'Common'
 
Last edited:
No need to be puzzled, I know the basics, but just want to be sure that I get it the right way round, as rather not knock out the central heating for a day or so while I try to fix a false assumption. Not that warm here at the moment and wife would not be impressed!

Thanks for the input, that marries with what I was assuming, just needed a second check.

Cheers

Jon
 
Hi all, having the same issue as the OP but under the hood of the T40 I have a slightly different wiring arrangement, is it simply that my "earth wire" is actually the switched live wire and I have no earth wire wired in?
16645480188268606333676626185618.jpg
 
Clearly not permitted to use a green/yellow wire for anything other than earth, as a cable technically one could over sleeve one core, but since 1966 it has been required to run an earth wire even if not required in an installation, with the exception of a lamp suspended from a ceiling rose, so only when multi-cables are used can you over sleeve green/yellow wires.

So this needs correcting, and clearly both ends of the cable, and that leaves you with only two cores, so looking at moving where the main control is located. I had the same, which is why I fitted Nest Gen 3 as although the base has 9 connections in my case, the thermostat/controller only has 2, although not pleased with Nest as it does not link to TRV heads.

Be it wireless or wired, it needs a change. Many battery powered wall thermostats can work with two wires, but for wireless types, I think Nest e is about the only one where the base is battery powered.

Cheap wired is OK, but don't use cheap wireless, as it needs some fail safe, so if batteries go flat or the wireless connection is lost, the boiler will switch off.
 
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