Help wiring new thermostat (UK)

[Antonio01989]

Hello,
I have never done any electrical wiring myself, but I think I should be able to do this with some kind advise from you.
I would like to replace my traditional thermostat with a programmable Drayton.
The gas central heater is a combi boiler (Worcester).
When I opened the current thermostat I can see four wires in total one of which I can recognise as earth/ground.
In the new thermostat I can only see three slots to connect wires.
Could anyone please advise which cable I should connect where in order to install the new thermostat?
Many thanks in advance for your help.
Photos below.

- Current thermostat (front and inside)

- New thermostat (box and inside)

- Instructions

 

[littlespark]

Hello.
What you have appears to be battery powered only, but will switch the 230v mains supply coming from the boiler.

ISOLATE the supply to the boiler before starting any work!


you are right about the earth wire, so as your new programmer doesn’t have an earth terminal, it needs to be safely terminated into a floating connector block and left in the back box if there is one.
The neutral is no longer needed, so that can be placed in a floating connector too.

Do not cut these wires short as you may need them again in the future, and the will still be connected at the boiler or wiring centre, so they must be safely terminated.

That leaves brown to C and black with brown sleeve to terminal marked ON

It will need a couple of battery’s before working, but it looks like there’s a mains powered version that you could have bought that would work as you have a neutral present.

 

[Antonio01989]

Hello.
What you have appears to be battery powered only, but will switch the 230v mains supply coming from the boiler.

ISOLATE the supply to the boiler before starting any work!


you are right about the earth wire, so as your new programmer doesn’t have an earth terminal, it needs to be safely terminated into a floating connector block and left in the back box if there is one.
The neutral is no longer needed, so that can be placed in a floating connector too.

Do not cut these wires short as you may need them again in the future, and the will still be connected at the boiler or wiring centre, so they must be safely terminated.

That leaves brown to C and black with brown sleeve to terminal marked ON

It will need a couple of battery’s before working, but it looks like there’s a mains powered version that you could have bought that would work as you have a neutral present.

Many thanks for your help, much appreciated, it is clear.

May I just check if this is the what I need to buy, please?

I think this is used to join two cables, but not sure if it is also ok to terminate a floating cable.

I was planning to go for the 15A if ok.

Thanks.

 

[littlespark]

5A would be fine. There’s no power running through it, it’s just to keep the ends safe from touching something that may be live.
or go with WAGO connections, but whatever you choose it will take up room in the programmer box.
when you connect into something like this, you want no copper conductor showing outside the connection.

 

[Antonio01989]

5A would be fine. There’s no power running through it, it’s just to keep the ends safe from touching something that may be live.
or go with WAGO connections, but whatever you choose it will take up room in the programmer box.
when you connect into something like this, you want no copper conductor showing outside the connection.

Thank you very much for your help.

 

[UNG]

What you have appears to be battery powered only, but will switch the 230v mains supply coming from the boiler.

One problem with the Drayton Digistat battery units when the batteries die the stat runs the heating continuously so it's worth replacing the batteries every 12 months whether it needs it or not.
If I'm installing battery stats I normally use the Horstmann units as they fail to off when the batteries die

 

[Antonio01989]

One problem with the Drayton Digistat battery units when the batteries die the stat runs the heating continuously so it's worth replacing the batteries every 12 months whether it needs it or not.
If I'm installing battery stats I normally use the Horstmann units as they fail to off when the batteries die

Thanks for the heads-up

 

[brianmoooore]

One problem with the Drayton Digistat battery units when the batteries die the stat runs the heating continuously.
the Horstmann units fail to off when the batteries die.

Not really sure that' an advantage! If the 'stat's locked on, there are other ways of controlling the temperature, even if it's just opening a window, but if it's locked off, all you can do is wrap yourself up in a duvet.

 

[UNG]

Not really sure that' an advantage! If the 'stat's locked on, there are other ways of controlling the temperature, even if it's just opening a window, but if it's locked off, all you can do is wrap yourself up in a duvet.

Or put a few new batteries in the stat or is that too obvious a solution for some people??

 

[brianmoooore]

Or put a few new batteries in the stat or is that too obvious a solution for some people??

That rather assumes that you have new batteries of the correct type handy, and that they realise there's replaceable batteries in the thing.

 

[UNG]

That rather assumes that you have new batteries of the correct type handy, and that they realise there's replaceable batteries in the thing.

You must be really bored

User instruction are wonderful things even the daft customers I work for can work out how to change the batteries in a thermostat when they die and most households I know have 1 or 2 packs of AA batteries in a drawer if not it is not to difficult to nip to the corner shop and if that is closed most people are not too far from a 24 hour filling station

 

[brianmoooore]

You must be really bored

is not to difficult to nip to the corner shop and if that is closed most people are not too far from a 24 hour filling station

Both eight miles away in my case, and yes, I am fairly bored, having been nowhere for almost thirteen months!

 

[littlespark]

If battery’s are that easy to come by, why is there never a 9v square one available? Some people would rather do without a beeping smoke alarm than go get one.

 

[Boiler Repairs]

One problem with the Drayton Digistat battery units when the batteries die the stat runs the heating continuously so it's worth replacing the batteries every 12 months whether it needs it or not.
If I'm installing battery stats I normally use the Horstmann units as they fail to off when the batteries die

Not over keen on battery stats for manny reasons, attending a callout for failed batteries in winter when we’re busy is one of them.

 

[7029 dave]

Not over keen on battery stats for manny reasons, attending a callout for failed batteries in winter when we’re busy is one of them.

Easy work, would do that all day long.