Another Hive installation question..

Hello and sorry for adding yet another Hive install question here, I've read loads of them but can't seem to find an answer to my question...

Today we had Hive installed by BG, we have a dual zone central heating system with separate hot water tank. The BG engineer set up Hive so that it is controlling the water and the downstairs zone.

He said it would be easy to just buy a second Hive thermostat and replace the upstairs controller so that Hive could control all of the houses radiators, so I have just ordered a multi-zone additional smart thermostat:



It was only after I had ordered this that I started to wonder about how this thermostat will talk to the second zone heating valve to be able to turn it on and off. I didn't watch the guy when he was installing the bits this morning.

So this is what is downstairs under our boiler (Logic Heat h15):



He removed this controller from the wall downstairs:



and fitted the Hive thermostat in its place. I removed the thermostat and this is the cables behind:



I would have though that those cables needed to connect to something to be able to control the heating / hot water, but they don't and one of them is not even connected for some reason?

Upstairs in the hot water tank cupboard, this is where I am guessing the valves are that control the water to the radiators etc:



and finally the upstairs thermostat is on the wall, and behind it are these cables:



I am guessing that the new Hive thermostat will replace the existing wall device above but not sure where those two cables connect to (do they control turning the heating on and off upstairs)?

Any advice would be gratefully received, the order is due to be delivered tomorrow and I'm hoping that it comes with some decent installation instructions but I'm not going to hold my breath

The two wires (black and brown) that go to the upstairs thermostat in your photo above, should go to the new Hive Single Channel receiver terminals as follows:

Brown wire goes to Hive 'Com' terminal (1)
Black wire goes to Hive 'Heating on' terminal (3)

[You will see that the terms used by Hive correspond with what is written inside your existing thermostat. (i.e. COM & ON)]



You can reroute the cable so that the new receiver is in an alternative position if you want to. Perhaps put it next to the existing dual channel receiver. Or disconnect that cable and run a new one in its place instead, if it's easier.

Then the Hive receiver needs 230V mains supply to power it. This connects to its N & L terminals. You can run this from the N & L of the existing receiver, or the fused side of the 3A spur that provides power to the heating system.

Chanandler said:

I removed the thermostat and this is the cables behind. I would have though that those cables needed to connect to something to be able to control the heating / hot water, but they don't and one of them is not even connected for some reason?

Click to expand...

That's fine, there are no wires there, or have ever been any wires there, that have anything to do with the hot water. The room thermostat controls the radiators only. There will be a separate thermostat for the hot water on the hot water cylinder upstairs. And guess what! that doesn't have anything to do with the radiators.

The installer will have taken the second option I mention above and replaced the existing thermostat cable with a new that goes straight to the receiver, instead of rerouting the existing one.

Thanks, that makes a lot more sense I didn't realise that the multi-room thermostat actually comes with a single channel receiver in the box too.

So I just remove the thermostat from the wall upstairs, replacing it with the single channel receiver that I will get tomorrow. Connect the two wires into the receiver as per your instructions above and then just find somewhere to place the Hive thermostat. I was thinking of putting it somewhere on the landing or doesn't it really matter as it runs on batteries?

Then to get it connected and linked up with the rest of the system, I guess I just open the app, go to install devices and then it should detect the new receiver and thermostat?

That's about right. Don't forget that you will need to get a 230V supply to the new Hive receiver as well as connecting the two thermostat wires. Your old thermostat was battery powered but the Hive needs a mains supply. This should come via the same 3A fused spur that feeds the rest of the heating system.

Ahh yeah, forgot about the power to the receiver. I've just had a look behind the wall plate that the current thermostat is attached too and there is an unused cable there too:



If that unused cable isn't power then I'm not sure how to get power to that area so will probably have to get an electrician in to wire it up properly. Shame that the receivers have to be wired into the mains, but guess they need to be to ensure continuous control.

I think the way I described is the easiest for DIY as the wiring connections are the simplest, although running a new cable to the thermostats present location requires more work. However there are other alternatives that require more electrical work and higher level of competence, but don't involve running a new cable over a long distance.

1) Mount the Hive receiver where the existing thermostat is located. Trace the other end of the unused grey wire, connect it to neutral at the other end and use that for the Hive (N). Then, because the brown wire that I said earlier would go to the Hive common (1) is actually a live, adding a link between Hive (1) and (L) will also allow it to provide the Hive live supply. The black wire goes to Hive 'Heating on' terminal (3) as before.

2) Do what the BG guy did and run a new thermostat cable. The existing thermostat cable will go to the wiring centre, (the junction box that the motorised valves are connected to, where the thermostat black wire will probably be connected to the upstairs motorised valve's brown wire.)

The existing cable would be disconnected and a new cable run to the receiver mounted at the side of the existing one, then a new cable added to link the new Heat link receiver N & L to the existing Heat link receiver N & L.

However, if you are unsure, or have any doubt, it's best to get a professional in to do it for you.

The receivers need 230V because being 'receivers' they use more power than a wired thermostat. It would be impractical to use batteries as they would need continual replacement, and for a new installation when you are running a cable to them anyway, using a cable with a couple of extra wires in is no problem.

Thanks so much for all your help, that all actually makes sense but I will have a little investigate tomorrow and decide whether to get someone out or have a go myself.

Just wanted to say thanks for all the help. I gave it a go, followed your guidance and after a few hours of tracing cables and deciding where to put the receiver, I ended up just wiring it in next to the heating / water cabling in the airing cupboard.



All is now working perfectly and I’m very oimpressed with Hive, its a fantastic product



Thanks again and hope you have a great Christmas