Honeywell to Hive

[Julian1971]

Hi

We have been given a Hive Heating thermostat etc for a combi, we have a Honeywell mechanical controller in the hallway. We will using the person who installed our boiler to change them over, but ive taken a photo of the wiring of the Honeywell, we seem to have 3 wires going into terminal 1, and 3 into terminal 3.
This won't be a matter of just switching the cables over, like for like, will it?

 

[stem]

That thermostat has been incorrectly installed, I suspect that is because it isn't really suitable for the boiler to which it is connected. Whilst it will work in a fashion, it won't be as accurate as it should be.

In addition it looks like someone has used thin wires of the type used to install a burglar alarm, and probably explains why they have connected several wires to the same terminals in an effort to increase the cross sectional area of the conductor. I suspect, because of the wires, that your boiler has been wired for 24v control which is fine [Except the thermostat is designed to operate on 230V hence why it is not really suitable]

In any case, in addition to the switching wires for the heating, the Hive receiver will also need 230V to power it and those wires are definitely not suitable for 230V. So, it will be a case of removing what is there and starting again from scratch.

The Hive receiver doesn't have to be located where the existing room thermostat is located as it communicates with the Hive thermostat wirelessly, meaning it can be mounted fairly close to the boiler so running new wires between the boiler and the Hive receiver won't be a problem for an RGI. Probably 30 to 45 minutes or so to wire in.

EDIT:

We will using the person who installed our boiler to change them over

If they were responsible for installing the existing room thermostat, I recommend that you engage the services of someone else to install the Hive.