CM707 with Hive (Patrick's thread)

[Patrick Mahon]

Hi there,

I am attempting to replace my Honeywell CM707 thermostats with Hive Single channel receivers and thermostats. It is a new build property with a Logic System s24 boiler. There are CM707 thermostats up and down (2 zone) which control only heating. Near the boiler in the garage is a Honeywell ST9100C which I believe controls the entire system. On the cylinder in the airing cupboard is an ESi dual cyclinder thermostat which controls the call for hot water.

There are only 2 wires coming to the CM707 faceplates, a Live and Neutral which are attached to the B & A terminals respectively. When I attach these to the permanent live and neutral terminals on the Hive faceplate, it powers up the receiver but manually turning on central heating does nothing other than light up the green light. The boiler doesn't fire up.

What am I doing wrong?

 

[bernardgreen]

There are only 2 wires coming to the CM707 faceplates, a Live and Neutral which are attached to the B & A terminals respectively.

It is better to start a new thread and not jump onto an existing thread.

The CM707 is battery powered, it does not require Live and Neutral

A and B are a switch, Live to A and Switched Live from B to the boiler.

The Hive is very different

The Hive requires Live and Neutral to provide power to the control and Live and Switched Live to terminals 1 and 3

 

[Patrick Mahon]

As a new user, I couldn't figure out how to start a new thread thanks.

Are you saying that the Hive won't work as a replacement in this case without running new wiring to the Hive faceplate? I have a single channel receiver.

 

[bernardgreen]

Are you saying that the Hive won't work as a replacement in this case without running new wiring

That is the case.

 

[Patrick Mahon]

Ok thanks.

 

[Patrick Mahon]

Bernard - I'm being a bit thick here. In your wiring diagram on the multi channel hive, you show what looks like an internal loop between the Live terminal and the others. Would an equivalent not work on the single channel?

 

[Patrick Mahon]

I have 2 single channel hives to replace each of the CM707s. As I said in earlier post, I wired the L and N wires from the CM707 to the Permanent Live and Permanent Neutral on HIve single channel receiver. I push the manual CH button on the receiver, green light comes on but boiler doesn't fire up.

 

[stem]

The CM707 room thermostat is battery operated so doesn't have a 230V supply, it only has live switching wires connected to terminals A & B that pass through a switch that connects them together when the heating is 'on' (ie they are both live connections even if a blue wire has been used for one of them) as you can see from the diagram below.

Where have you got the neutral from?
What is connected to the Hive Common (1)?
What is connected to the Hive Heating on (3)?

If you have another timer somewhere (Honeywell ST9100C) that is presently controlling the heating, then that would need to be set permanently on 24/7 otherwise it will override the Hives.

It is rather unusual though to have a Honeywell ST9100C providing time control that is wired to programmable room thermostats that also provide time control. Are you sure the ST9100C isn't for something else? Hot water time control maybe?

 

[Patrick Mahon]

There is a grey and an earth wire but these were not attached to the CM707 faceplate, simply folded behind.

 

[stem]

Where have you got the neutral from?
What is connected to the Hive Common (1)?
What is connected to the Hive Heating on (3)?

 

[Patrick Mahon]

The brown wire is attached to CM707 B terminal, and a black wire to the A terminal. I ASSumed. I have made no internal connections, simply attached the brown to the L terminal on the Hive faceplat and the black to the L terminal on the Hive faceplate.

 

[Patrick Mahon]

That's black to the N terminal, not L.

 

[stem]

Telling us the colours of the wires is of no use unfortunately. What colour is used for what, would have been chosen by the original installer and varies from installation to installation. It is what they are connected to at each end that matters.

Electrically speaking, the CM707 is just a simple battery operated on/off switch. When it's 'on' the wires in terminals A and B are electrically connected together, so if one wire were live and the other neutral then when it turned on...... BANG!

So, the 'live' switching wires that were in A and B (ie the switch, would connect to the Hive Single channel terminals (1) and (3) which are also an on/off switch, exactly the same as the CM707 is.

Because the CM707 is battery powered it did not need a 230V supply. Hive does need a 230V supply, so this needs to be connected to the N & L terminals. This should come from the same 3A fused spur that supplies the rest of the heating system. You already have a live supply to the thermostat which you can link to the L, but you will also need a neutral for N. You maybe able to use the "grey wire that is folded behind" for this connection, but you need to find out first what it is connected to at the other end.

 

[Patrick Mahon]

Thanks. So basically confirms what Bernard fist said.

 

[stem]

It would appear so.

As a new user, I couldn't figure out how to start a new thread

For future reference. There's an orange box at the top of each forum marked 'Post New Thread'