Worcester Boiler & Hive Dual Channel Wiring help

[Kevine]

Hello all.

My current setup is Worcester Greenstar 24i Boiler and hot water cylinder. The boiler programmer/thermostat is the wireless Salus RT500F.


I'm looking to replace the Salus with a Hive dual channel and wanted to understand how the wires are connected back to the boiler.

I've checked the wiring panel on the boiler and i have a 3rd party wiring block labelled Ls, Ns & LR (LR & Ls are looped).

Checking the Hive single channel looks fairly straight forward (loop live and common and connect heating on (3) to LR but i'm trying to figure out using dual channel Hive how i connect the extra wires?

Also my current Salus RT500F, although it is a program only for the heating it does trigger the hot water cylinder so there must a valve/connection also.

Do i simply connect the Hive Heating on and Water on to the boiler LR and the Hive can independently switch the heating or water on?

Also, how would i disconnect the Salus RT500F, it's wireless so do i simply turn it off or do i need to disconnect some wires in the boiler also?

Thanks in advance.

 

[stem]

The Salus RT500RF is a room thermostat only designed to control central heating. There shouldn't be any wires there responsible for heating the hot water cylinder. In which case you can't replace it with the Hive receiver and expect it to control the hot water.

The Hive receiver would replace the existing programmer, that does have heating and hot water control functions. Then the Salus receiver (I assume you meant to type RT500RF and not RT500F) would be removed and the wires that went to its switching contacts joined together at their origin.

Edit
Don't get confused with the combi version of the Greenstar. That doesn't have a separate hot water cylinder, so it is usual in that case to replace the original room thermostat with a Hive single channel version.

If your hot water heating is being controlled by the central heating thermostat, something is seriously wrong with your installation. This needs putting right first before installing the Hive.

 

[Kevine]

Hi Stem. Many thanks for the response.

Checking further. The Salus receiver is installed next to the hot water cylinder and also there is a programmer next to it with Heating and Water set to 'always on'. I wasn't sure how that was used as the boiler only fires up via me setting schedules on the Salus RT500RF.
Perhaps the programmer is set to always on giving the control to Salus?

I guess i need to figure how the Salus receiver is wired/connected back to the boiler, is it likely this is done by a zone valve?

I've uploaded 2 pictures, one of the receiver and programmer and the other of the wiring at the bottom of the cylinder where the Salus receiver is. There are some valves there.

Many thanks in advance.

 

[stem]

OK thanks.

If both heating and hot water are set to be permanently 'on' at the programmer near the hot water cylinder then that is controlling the heating of the water, not the room thermostat. Hot water cylinders don't cause the boiler to fire often, because once they are heated and unless you are using a lot of hot water, they stay hot for hours on end. With your present set up, because the Salus is a combined programmer and and thermostat, the central heating needs to be left permanently 'on' at the programmer near the cylinder, otherwise it would override the Salus.

The existing programmer looks like a Siemens RWB9 (aka Landis and Staefa)

In which case the wiring terminals will be as below...

....and the Hive Dual Channel version is exactly the same. Lucky you, they are a straight swap

Once the Hive is installed, look at the wiring at the Salus receiver. Trace the cable from the Salus back to its origin and note where each of the wires are connected, and remove the entire cable. Then join together with a wire link, the terminals where the wires that went to the Salus 'NO' and 'COM' terminals were connected. Don't worry about any other connections, they are only to provide power to the Salus and can be disconnected. If you need any further help with this bit, post back a photo of the wires connected to the Salus.

No need to touch any of the wires at the boiler.

 

[Kevine]

That's great and makes the install reasonably easy, thanks a lot for providing the detail.

What's your opinion of the Hive vs other smart thermostats around, some have a few unique points but generally they all function much the same?

Thanks.

 

[stem]

You are probably asking the wrong person here. But as far as I can see they are pretty much the same. I have installed, and helped others install probably well over 100 now, but personally I don't have one, as they don't offer me any real advantage. Changing the temperature of my home from the office or Tesco's isn't really something I need to do. I have adequate control for what I need with a 7 day programmer and thermostat similar to the one you are taking out. Plus TRV's on the radiators.

I quite like the Honeywell Evohome because it controls each of the radiators via linked TRV's, and the Nest is supposed to learn you lifestyle, anticipate your needs (I understand that it can be a bit random when its in the learning process) and doesn't need the separate hub that Hive does. Not too sure about Tado, I have only fitted two and that was a while ago.

I have often asked those for whom I have installed these devices about the actual benefits and as yet no one yet has noticed any tangible energy savings, the only benefit most seem to see is the remote control.

 

[Kevine]

Yes, i think the main functions give the same, i did like the idea of zoning with linked TRV's but also don't like the idea of the boiler firing up for the sake of trying to get one room up to a desired temperature.

Nest has the learning but like you i've heard that can be random and most people switch it off! I like that the Hive is completely wireless (no wires for power) and has batteries so I could move the thermostat around (if needed).

Anyway, thanks for the great help.

 

[Kevine]

Hi Stem.

Attached here the wiring of the Salus receiver. The COM and L is looped so the COM had no cable itself, when i remove the cable how do i bridge NO and COM when i will only have the wire from NO.

Thanks.

 

[stem]

Was the red wire in COM?

 

[Kevine]

Yes, as i took it off the wall the red wire fell out but it was in COM yes. It's the live to the box

 

[stem]

OK Thanks, then:

1) Trace the cable back to its origin and note where the 'red' and 'yellow' wires are connected.

2) Disconnect the 'red', 'yellow', 'blue' and 'earth' wires and remove the entire cable.

3) Insert a wire to link together the two terminals where the 'red' and 'yellow' wires were previously connected

 

[Kevine]

Thanks!! Will do that.

 

[Kevine]

Hello again!

I've attached picture of the Siemens wiring of the programmer. 2 things:

1) Only the CH & HW 'ON' is connected. As i've read around i think that is fine, you only need to call the boiler ON anyway and not off.
2) Noticed there is a feed from the live out, trying to trace that and see if i can remove it completely, the Hive unit should stick straight over but with all the wires it is not fitting. I guess the extra live feed is just providing power somewhere so maybe it can be removed.

Thanks

 

[stem]

That's fine, they are were not connected before were they, and it worked, so you won't need to add them, your system doesn't need CH or HW off connections.

Noticed there is a feed from the live out, trying to trace that and see if i can remove it completely, the Hive unit should stick straight over but with all the wires it is not fitting. I guess the extra live feed is just providing power somewhere so maybe it can be removed.

NO! Keep them exactly as they are you will need both. Remember...

....and the Hive Dual Channel version is exactly the same. Lucky you, they are a straight swap

So, don't change anything (apart from the thermostat wiring of course). If you took a picture after the Hive installation it shouldn't look any different to the one you posed right at the start. Sometimes you can swap the fronts over without actually changing the backplates. They are supposed to be universal, but they don't always seem to be. Having said that I always swap them even if they do fit.