Hortsmann H21 replace to goole nest
- Thread starter Pans
- Start date
I'm afraid, given the pictures you show, it's a little tricky to work out exactly what's going on with your system.
Could we have a bit more information please?
Do you know what sort of heating system you have?
Is the switch on the back of the Horstmann set to 'Pumped System', or 'Gravity System'?
What is the model of the thermostat you show? It's also not exactly clear how the red wires are connected to it.
Edit: are there two red wires going into terminal 1, with a short red link wire over to terminal 4?
Are there any connector blocks hidden behind the Horstmann (possibly connecting together yellow wires)?
Could we have a bit more information please?
Do you know what sort of heating system you have?
Is the switch on the back of the Horstmann set to 'Pumped System', or 'Gravity System'?
What is the model of the thermostat you show? It's also not exactly clear how the red wires are connected to it.
Edit: are there two red wires going into terminal 1, with a short red link wire over to terminal 4?
Are there any connector blocks hidden behind the Horstmann (possibly connecting together yellow wires)?
Last edited:
- Joined
- 5 Nov 2024
- Messages
- 4,176
- Reaction score
- 2,095
- Country
The Horstmann should be simple enough. How do you plan on powering the Nest?
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
Similar threads
