Replacing honeywell T40(T6360B) thermostat for wireless stat

[sparkler13]

Hi, I am replacing a honeywell room stat T40 (T6360B) for a honeywell Wireless Room Stat R6660D. My question is I have four wires :-

1 = red (Live)
2 = Blue (neutral)
3 = Yellow (Switched Live)
Earth = Earth.

I dont think the new stat needs an earth or Neutral, can you confirm on which pins on the new stat I connect the live and switched live or correct me if I am wrong about earth and neutral?

Thanks
Martin

 

[plumbplumb]

your current stat is common and switch live.

The receiver box needs a perm live and neutral.

you can link Live to A but it will need rejigging at the other end and
B is calling (yellow)

 

[stem]

Red on the T40 (Live) goes to L on the R6660D

Blue on the T40 (neutral) goes to N on the R6660D

Yellow on the T40 (switched live) goes to B on the R6660D

Then you need to link L & A on the R6660D

Insulate the earth and tuck it away if there is not a terminal for it.

 

[plumbplumb]

Unless it comes via a clock or other external control before it.

What is it controlling??

If it has say a clock fitted before every time the clock switches in and out of it's time periods power is going to be cut to the receiver

 

[stem]

Plumbplumb is correct, if there is an upstream timeswitch that presently controls the central heating, then you will need to leave that set on permanently on, otherwise you will loose power to the new thermostat which will now be controlling the on and off times for your heating.

If it only has one channel for central heating and hot water that would mean that the hot water will be on 24/7. If it has separate channels for central heating and hot water that will be OK.

 

[sparkler13]

Hi, I am even more confused now. I have a 7 day timer in the airing cupboard controlling hot water and radiators individually,its the room stat at the bottom of the stairs I am replacing so it is just controlling room temperature wherever I put the wireless control.

The reason I was unsure about teh neutral was because of this post :-

//www.diynot.com/forums/viewtopic.php?t=40996

Thanks

 

[plumbplumb]

Your timer in the airing compartment will only send power to your current roomstat when the heating is switched on via the timer.

You are proposing replacing the current roomstat with a wireless roomstat.

The wireless roomstat can be placed anywhere however the receiver unit requires a permanent live to it.

Exchanging your current roomstat with the receiver means set up like it is every time the heating is switched off via your timer power will be cut to the receiver unit.

 

[stem]

The reason I was unsure about teh neutral was because of this post :-

//www.diynot.com/forums/viewtopic.php?t=40996[/QUOTE]
That post refers to a Drayton Digistat. The Drayton Digistat is a completely different unit. For one thing it is not wireless so doesn't have two parts.

More importantly, the Digistat is battery powered so it does not need a mains supply to operate it's circuitry. The live is only used as a control signal for switching on the heating. The Honeywell receiver you told us about is mains powered so does need a live and a neutral to operate.

I have a 7 day timer in the airing cupboard controlling hot water and radiators individually, its the room stat at the bottom of the stairs I am replacing so it is just controlling room temperature wherever I put the wireless control.

The Honeywell is not just a thermostat, it also includes the timing control functions presently operated by your programmer. So for it to work, you must leave the existing programmer heating permanently set to 'on' and let the new combined thermostat / programmer control the times and temperatures for your heating. (See page 17 of the operating manual "An explanation for householders")

If you just wanted a replacement thermostat, you have purchased the wrong item.

 

[sparkler13]

Thanks fo your post stem, can you suggest what I do need without a major rewire which is why I want it wireless??

 

[sparkler13]

If I can get another cable to the thermostat reciever can I do this so that it is also still controlled by the timer :-

N = Netral
L = Perm Live (new cable to patch panel)
A = Timer Live
B = Switched Live

Thanks

 

[stem]

You don't need to run a new cable. The switched live from the programmer to the existing room thermostat simply needs moving at the programmer end from the CH 'on' terminal to the permanent live connection. This is the "rejigging" Plumbplumb refers to in his first post.

Or as I said before, simply leave the central heating setting 'on' permanently at the existing programmer, it achieves the same thing.

Thanks fo your post stem, can you suggest what I do need without a major rewire which is why I want it wireless??

You can buy wireless thermostats, which are only thermostats and use your existing programmer to control the on and off times as now. But I assume you have already purchased the Honeywell R6660D. Can you take it back?

The Honeywell Y6630D1007 is a basic wireless thermostat, as is the Horstmann HRT4-ZW

 

[D_Hailsham]

Hi, I am replacing a honeywell room stat T40 (T6360B) for a honeywell Wireless Room Stat R6660D.

The R6660D is just the receiver/relay box. What is the control unit? Is it just a thermostat or is it a programmable stat?

This will determine how the receiver is wired up.

 

[sparkler13]

D_hailsham :- it is just a thermostat so not programmable.

 

[D_Hailsham]

D_hailsham :- it is just a thermostat so not programmable.

I assume that you will want to continue using your programmer to control the central heating times as well as the hot water times. In that case you will need to run a new 4-core cable (that's 4-core plus earth, although the earth is not used).

You have to wire the relay box as follows:

T40 ---------- Relay

Terminal 1 ----- A (this is connected to Programmer CH ON terminal)
Terminal 2 ----- N (probably connected to Programmer N terminal)
Terminal 3 ----- B (this is the switched live)

New wire
Permanent L to Relay L

The wires probably go into a large junction box. It's just a case of identifying the terminals.

 

[sparkler13]

Hi D_Hailsham,

I think you have just confirmed to me what I said above about runnning a new cable. Hopefully this should do what I want to do which is exactly what you have stated about keeping the timer. Thanks for your feedback.


If I can get another cable to the thermostat reciever can I do this so that it is also still controlled by the timer :-

N = Netral
L = Perm Live (new cable to patch panel)
A = Timer Live
B = Switched Live

Thanks