Adding Wireless Room Thermostat to Central Heating System

[richarddowell]

Hi,

I've just bought a Honeywell CM-67 RF NG, which I am hoping to fit myself. My existing system doesn't have a room thermostat, and it looks like I'm going to need a bit of help to get the wiring right. I have a Honeywell junction box, which has a separate block marked 'room thermostat', with terminals 1, E, 2, 3 (1 and 3 are currently linked). The CM-67 relay box (HC60NG) has terminals N,L,L, A,B,C,D,E. I assume I only have to connect N, first L, A, B, but I'd appreciate help on getting it right. Assuming that the junction box is wired correctly I hope this will be pretty easy.

Many thanks.

Richard

Richard Dowell, Cheltenham UK

[Lurch]

On 26 Sep 2005 06:10:02 -0700, [e-mail] scrawled:

I'm assuming 1 + 3 are the link for the roomstat so all you need to do is remove the link and connect 1 + 3 to the call for heat pair on the relay box. L + N go to L + N. I'd be more specific if I had the instructions in front of me.

[Mike Hibbert]

Richard,

I have exactly the same roomstat, and only live in Churchdown, so if you want to pop and have a look at the wiring "in situ" let me know. I have a Worcester Bosch Highflow 400 boiler.

Mike

[Set Square]

I assume you have read the installation instructions which came with it?

If you haven't got any, you can find them at

5 shows the wiring for the relay box. You need a mains supply to L and N, and the load to be switched is connected to A and B. The other terminals are not used. Exactly *what* you connect to A and B depends on your heating system.

Do you have a combi or conventional boiler? If the latter (i.e. a system which heats the radiators *and* provides stored hot water) what zone valve(s) does it have?

[richarddowell]

Thanks for both replies so far. Stuart, if it helps the CM67 iinstallation instructions are at

Thanks for the offer. I'll have a go this weekend but I may well beg for your help when it doesn't work.

Richard.

[Mike Hibbert]

No probs, I will send you my phone number in a mail

[Lurch]

On 26 Sep 2005 09:13:41 -0700, [e-mail] scrawled:

[richarddowell]

> Figure 5 shows the wiring for the relay box. You need a mains supply to L

Thanks for that. I have a conventional boiler with a single zone valve. The junction box is, on closer inspection a Honeywell Wiring Centre

42005748-001, which has separate terminal blocks for each component and is, presumably, designed to make wiring easier.

Richard

[richarddowell]

Thanks Stuart. This looks as though it shpould be pretty easy (famous last words).

Richard

[Set Square]

>>> Figure 5 shows the wiring for the relay box. You need a mains supply

I presume that your zone valve is a 3-port jobby - with the input connected to the pump and the two outputs feeding the HW and CH circuits? In that case, you've got a Y-Plan system.

Have a look at the Y-Plan wiring diagram in

You will see that the room stat needs to be connected between 4 and 5 in the wiring centre. If these 2 terminals are currently strapped together, remove the strap before connecting the stat. [Don't worry about the connection shown to 2 in the wiring centre. The stat in the Honeywell diagram is an older type which needs a neutral connection. Yours doesn't.]

Just in case your system is wired in a non-standard fashion, and doesn't correspond to the terminal numbering shown (all things are possible!) the important thing is to make sure that one side of your programmable stat is connected to the CH feed from the main programmer, and the other side is connected to the white wire from the valve actuator.

[richarddowell]

Thanks for all the replies. For anyone else with the same set up, the connections are exactly as described by Stuart - N&L to power and A&B to 1&3.

Richard

[Lurch]

On 8 Oct 2005 02:11:10 -0700, [e-mail] scrawled:

Top job. I had every confidence!