Hive wiring, replacing current programmer + thermostat

[Craig24]

Hi all,

Lurk and read a lot on here but only signed up today. I am looking to replace my current Siemens RWB27 programmer and Robus thermostat with a Hive v2. I have a Greenstar 30si boiler. They both appear to have the same back plate so I'm hoping to just slot the Hive onto the existing backplate but I'm unsure what to do with the current thermostat? Photo of the current Siemens backplate (one wire came lose when I removed the front, will reconnect this) -

 

[Agile]

I do hope that you don't plan to open up your boiler for this job!

Its a room sealed case! Should only be opened by a gas safe registered person.

Tony

 

[Craig24]

No I wasn't planning on doing so, I didn't think I would need to touch the boiler?

 

[ollski]

You don't need to, it's the only thing Tony ever posts any more, I think on auto copy and paste.

 

[stem]

I'm unsure what to do with the current thermostat?

The current wired room thermostat needs to be removed as the Hive carries out both functions of the thermostat and programmer.

If you just remove the room thermostat wiring, it will leave the wiring 'open circuit' and so the heating won't work, so you need to bypass the wiring. This can be done in two ways.

1. Remove the existing room thermostat & replace it with a junction box. Then, join the two switching wires that previously went to the thermostat together inside. If there is also a neutral present then that should be isolated / insulated out of the way. This is the easiest way, but leaves a junction box on show and the original thermostat wires will still be live.

2. Trace the existing room thermostat wires back to their source. Where this will be depends upon the personal preferences of the installer. For example, it could be the programmer, or a wiring centre. Once the wires have been traced, they can be removed at source and the terminals that the switching wires were connected to joined together there. This way is more difficult for DIY, but the original thermostat and wiring can then be removed for a more professional finish.

 

[Craig24]

The current wired room thermostat needs to be removed as the Hive carries out both functions of the thermostat and programmer.

If you just remove the room thermostat wiring, it will leave the wiring 'open circuit' and so the heating won't work, so you need to bypass the wiring. This can be done in two ways.

1. Remove the existing room thermostat & replace it with a junction box. Then, join the two switching wires that previously went to the thermostat together inside. If there is also a neutral present then that should be isolated / insulated out of the way. This is the easiest way, but leaves a junction box on show and the original thermostat wires will still be live.

2. Trace the existing room thermostat wires back to their source. Where this will be depends upon the personal preferences of the installer. For example, it could be the programmer, or a wiring centre. Once the wires have been traced, they can be removed at source and the terminals that the switching wires were connected to joined together there. This way is more difficult for DIY, but the original thermostat and wiring can then be removed for a more professional finish.

Thanks for the detailed reply. I think I will go with option 1 as all the cables are actually hidden behind a unit and won't be seen. I'll let you know how I get on, its a Robus RRF10 thermostat. Am I right in thinking the Hive can just slot onto the exisiting programmer backplate with the current wiring then?

 

[stem]

Am I right in thinking the Hive can just slot onto the exisiting programmer backplate with the current wiring then?

No, the RWB27 uses terminals 2 & 4 for switching as per your photograph, if you look at the Hive Single Channel diagram it uses terminals 1 & 3 (Common & Heating On)

The Lives and Neutrals are OK as they are.

I've assumed that your version of the Hive is the single channel as I believe your boiler is a combi.

 

[Craig24]

No, the RWB27 uses terminals 2 & 4 for switching as per your photograph, if you look at the Hive Single Channel diagram it uses terminals 1 & 3 (Common & Heating On)

The Lives and Neutrals are OK as they are.

I've assumed that your version of the Hive is the single channel as I believe your boiler is a combi.

Yes correct its the single channel version, so I need to swap 2 to 1 and 4 to 3? Thanks for your help.

 

[stem]

Yes that's the idea.

I can't advise regarding the thermostat wiring as I'm not familiar with the Robus, but when you open it up there should be a wiring diagram inside the lid. I believe there will be a neutral wire so that needs isolating, and the remaining two wires will be the switching wires that should be connected together. If in any doubt, post a photo of it, preferably showing the wiring diagram.

 

[Craig24]

Yes that's the idea.

I can't advise regarding the thermostat wiring as I'm not familiar with the Robus, but when you open it up there should be a wiring diagram inside the lid. I believe there will be a neutral wire so that needs isolating, and the remaining two wires will be the switching wires. If in any doubt, post a photo of it, preferably showing the wiring diagram.

Thank you, I'll give it ago later and post back.

 

[Craig24]

Ok, so I have changed the wires from 2 to 1 and 4 to 3, I've left the thermostat in and turn on for now. When I turn the heating on with the Hive the thermostat lights up as if it's turning the heating on but it never comes on.

Here is the photos of inside the thermostat -

 

[Craig24]

Ok, after powering everything off and on the Hive is now working but with the thermostat still in place. Thanks for the help so far. Looks like it has 4 wires, not sure which 2 to connect?

 

[jackthom]

Can you confirm how many wires are coming out of the white flex and their colours. It's hard to make out from the photo. Allegedly terminals 2 and 4 become connected together in the Robus when there is a call for heat, but I'm not encouraged by seeing a blue wire coming from terminal 2.
I'd strongly advise getting hold of a cheap multimeter to check the operation and wiring of the old thermostat before linking up any of the wires. Screwfix have a reasonable one for a tenner.

 

[stem]

Thanks the wiring diagram in the lid makes everything clear. So, looking at your photo, It looks like, Blue from the flex goes to terminal 2 & Brown from the flex goes to terminal 3 if so, they are the switching wires that need connecting together. If that's wrong, post back what goes where before doing anything.

The other wires are for the lamp. So remove the Brown link between terminals 3 & 5 and discard it.

The remaining wire going to the lamp terminal 6, will be a neutral, isolate / insulate it away on its own. Leave the black tape on, in case someone else comes along later and thinks it's an earth.

 

[Craig24]

Thanks the wiring diagram in the lid makes everything clear. So, looking at your photo, It looks like, Blue from the flex goes to terminal 2 & Brown from the flex goes to terminal 3 if so, they are the switching wires that need connecting together. If that's wrong, post back what goes where before doing anything.

The other wires are for the lamp. So remove the Brown link between terminals 3 & 5 and discard it.

The remaining wire going to the lamp terminal 6, will be a neutral, isolate / insulate it away on its own. Leave the black tape on, in case someone else comes along later and thinks it's an earth.

Done exactly as you said above and all is now working fine. Thank you for all your help.