hi I’ve bought a hive garaging thermostat to replace a Honeywell CM67. On removing the old thermostat there are only two wires - live and neutral, also an earth but not connected, all worked fine, tried just using the two wires on the hive and everything says it is working but nothing at the boiler (oil fired hrm wall star). Any ideas?
Hive thermostat
- Thread starter Diyrosco
- Start date
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I think that the existing thermostat will have 3 terminals marked A, B & C, and there will only be wires connected to terminals A & B
But please check this carefully before proceeding!
If this is correct they are the switching wires and would connect to Hive terminals as follows:
The wire in A=Hive (1) Common
The wire in B=Hive (3) Heating on
The CM67 I know (again please check to make sure that this is the version you have) is battery powered, the Hive needs a 230V supply to power it, so this will need to be applied to the N & L terminals. It should come from the 'load' side of the same fused spur that supplies the main 230V supply to the boiler.
As you ask about replacing just a room thermostat, and don't mention hot water, I assume that your boiler is a combi version and that you don't have any stored hot water (ie a Hot water cylinder) If you do, then the dual channel version of the Hive is required and it replaces the existing programmer and not the thermostat.
But please check this carefully before proceeding!
If this is correct they are the switching wires and would connect to Hive terminals as follows:
The wire in A=Hive (1) Common
The wire in B=Hive (3) Heating on
The CM67 I know (again please check to make sure that this is the version you have) is battery powered, the Hive needs a 230V supply to power it, so this will need to be applied to the N & L terminals. It should come from the 'load' side of the same fused spur that supplies the main 230V supply to the boiler.
As you ask about replacing just a room thermostat, and don't mention hot water, I assume that your boiler is a combi version and that you don't have any stored hot water (ie a Hot water cylinder) If you do, then the dual channel version of the Hive is required and it replaces the existing programmer and not the thermostat.
You can do what you really want to, but don't understand why you would. 
Hive single channel is designed for 'combi' boilers that don't have timed hot water control
Hive dual channel is designed for 'heat only' boilers and provideds control of the heating and stored hot water
I assume that there is an existing programmer somewhere that controls the on/off times of the heating and hot water. If there is, you need to think how that will work (or won't work) when both it and the Hive are both trying to control the heating.
Hive single channel is designed for 'combi' boilers that don't have timed hot water control
Hive dual channel is designed for 'heat only' boilers and provideds control of the heating and stored hot water
I assume that there is an existing programmer somewhere that controls the on/off times of the heating and hot water. If there is, you need to think how that will work (or won't work) when both it and the Hive are both trying to control the heating.
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Hi,
Wondering if you got the hive receiver to replace the Cm67?
I have a CM67 that controls just the heating upstairs (zone 2) as part of a dual zoned system. Boiler is a worcester greenstar system boiler. I have replaced the honeywell timer that controlled downstairs heating (zone 1) and the hot water tank, with a dual channel hive system I already had from previous home. That all works fine.
Considering replacing my Cm67 with a single channel receiver and stat so I can have better control over the upstairs heating too. Appreciate any advice.
Like above mine has just 2 wires going to A live & B neutral.
Wondering if you got the hive receiver to replace the Cm67?
I have a CM67 that controls just the heating upstairs (zone 2) as part of a dual zoned system. Boiler is a worcester greenstar system boiler. I have replaced the honeywell timer that controlled downstairs heating (zone 1) and the hot water tank, with a dual channel hive system I already had from previous home. That all works fine.
Considering replacing my Cm67 with a single channel receiver and stat so I can have better control over the upstairs heating too. Appreciate any advice.
Like above mine has just 2 wires going to A live & B neutral.
D
Deleted member 267285
You would need to provide a permanent live and permanent neutral, which could be done at the wiring center, which a and b should go back to anyway.
Fit a Nest E rather than a hive and you can just use the existing two wires, Nest E is battery powered ond the two exising wires go to COM and NO on the nest, either way round
you can use a hive the receiver goes next to the corrosponding zone valve, but will involve wiring alterations
Do you know if the 2 wires that feed the current cm67 go to valve which in turn goes to boiler? I took the cm67 off and there is a 3rd wire and an earth looped back into the hole in wall. I'm presuming it's a 3 core and earth and they've just used the 2 cores. Or maybe the 3rd core is connected the other end for the option to fit a 3 wire programmer/thermostat?
Just not sure where to look for the other end of this cable.
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They are simply switching wires, the Hive thermostat, doesnt need wires it is battery powered, it is the receiver unit that is wired to and controls the zone valve,
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