wiring thermostat

[scampbell1982]

Hi, i have bought a programmable digital thermostat to replace an old turn dial one and wasnt sure about the wiring with it being 2 wire connection.The second picture is how its wired now with the turn dial thermostat and third is how it shows to wire it for a combi but i am adding it as well as the programmer so do i just ditch the neutral?thanks.

Thermostat

• scampbell1982
• 24 Dec 2019

Thermostat2

• scampbell1982
• 24 Dec 2019

Thermostat3

• scampbell1982
• 24 Dec 2019

 

[CBW]

This doesn’t make much sense, one picture shows a conventional system and the other a combi

 

[ianmcd]

yes on the existing thermostat just teminate the neutral by putting it into a terminal strip and isolate it and move it somewhere safe and just use the other two wires

 

[scampbell1982]

This doesn’t make much sense, one picture shows a conventional system and the other a combi

the first is a combi wired through a programmer.

 

[scampbell1982]

So i take it i just terminate it and dont join it together like this?

Thermostat4

• scampbell1982
• 24 Dec 2019

 

[ianmcd]

So i take it i just terminate it and dont join it together like this?

Thermostat4

• scampbell1982
• 24 Dec 2019

No if there are actually two wires in the neutral they have to be joined together, but dont worry if there is just one wire in there, its very common either way

 

[scampbell1982]

Right now i have one going to the thermostat and have it split 3 ways with a wago 222 connector in a junction box near the programmer, ill just disconnect the one going to the stat and leave the 2 going to the programmer and boiler.

 

[ianmcd]

Right now i have one going to the thermostat and have it split 3 ways with a wago 222 connector in a junction box near the programmer, ill just disconnect the one going to the stat and leave the 2 going to the programmer and boiler.

yes that is exactly how to do it

 

[ericmark]

This is how I would wire, so the programmer only controls the DHW time, and the programmable thermostat does CH.

 

[scampbell1982]

thanks

 

[scampbell1982]

View attachment 179342
This is how I would wire, so the programmer only controls the DHW time, and the programmable thermostat does CH.

i might consider doing that depending on the options for control on the stat when i get it.

 

[ianmcd]

This is how I would wire, so the programmer only controls the DHW time, and the programmable thermostat does CH.

it is a combi boiler and just a thermostat not a programmable room stat

i might consider doing that depending on the options for control on the stat when i get it.

hought you had a combi ? what make and model is your boiler ?

 

[scampbell1982]

It is a combi, grant vortex pro 26 oil external.

 

[ianmcd]

edit, have just noticed that your new thermostat is a programmable room thermostat, so once wired up as described , you will have to leave your programmer set at constantly on, and let the new programmable stat control your heating or it wont work

 

[ericmark]

edit, have just noticed that your new thermostat is a programmable room thermostat, so once wired up as described , you will have to leave your programmer set at constantly on, and let the new programmable stat control your heating or it wont work

This is why my plan by-passes the old programmer for central heating.

However it seems rather basic and I wonder what is missed out?