Wiring replacement room stat

[Grantsteve]

I am looking to wire in a programmable room stat (Honeywell CM907) to
replace my existing manual one (Potterton).

Existing one is connected to Live, Switched Live (?) (Yellow with red case
at end) and Neutral. Live to connection marked 1, switched to 2 and
neutral to 4

New stat has A, B and C terminals. Although C has plastic flap over it.

Boiler is Potterton Puma 80e.

What wire goes where please? Wiring diagram for new stat shows only Live and Neutral with no mention of Switched.

Also, I have a breaker for the central heating if I throw that will it cut the supply to the room stat as well or is it likely to be wired with something else?

Thanks

 

[ELZ4742]

a & b mate, works as a switch so it doesnt mater which way round.

 

[Grantsteve]

Thanks for the prompt response.

Apologies for being simple but ...

I have 3 wires (L N and Switched) and 2 terminals (A and B)????

Also, I am right in thinking throwing the CH breaker will also do for the stat or is it a separate circuit? I don't want to get fried!

 

[ELZ4742]

im guessing here but do the terminals go N L L - A B?

the stat must be on the same s/f/ spur as the CH.

 

[bernardgreen]

Are you sure there are only 3 terminals

If the CM907 is what it appears to be then there may be 5 or 6 terminals

[L] [N] [E] [A] [C]

I cannot find a data sheet for it.


Live and Neutral supplying power to the thermostat and clock and this needs to be permanent

A B and C being a switch operated when heating is needed.

A and B would be linked when heating was required so connect live to A and switched Live to B ( A to C when heating not required )

So Red to [L] and [A]
Black to [N]
Yellow to


This is an assumption that RED in the cable is live but this may not be continuous Live as the boiler which supplies it may turn it off when the controller in the boiler is not on for Heating. Unless the thermostat has a battery back up the loss of Live will mean the clock will lose time.

 

[Grantsteve]

There is a little block inside the stat with 3 terminals in it, one marked A, one B and one C.

The wiring diagram shows Live into one (can't remember which now) Neutral into the other, no mention of Switched.

So are you saying I put Live and Switched into one terminal and Neutral into the other?

 

[ELZ4742]

needs a common, although the perm live is the common they tend not to be linked inside the controler.
they are be b & c on the cm 61`s.

check this out

http://europe.hbc.honeywell.com/products/pdf/en0h8547uk07r0106.pdf

 

[ELZ4742]

im confused, it sould be just live in live out, does it have batteries btw?

 

[bernardgreen]

There is a little block inside the stat with 3 terminals in it, one marked A, one B and one C.

The wiring diagram shows Live into one (can't remember which now) Neutral into the other, no mention of Switched.

So are you saying I put Live and Switched into one terminal and Neutral into the other?

http://europe.hbc.honeywell.com/products/pdf/en0h8547uk07r0106.pdf

Appears to be a battery operated device or "steals" from the switched circuit.

So live into [A] and switched live into and the neutral is not used.

 

[ELZ4742]

its battery operated.


put a wire in A the other in B

the boiler ends go in the relevent terminal, 4 & 5 maybe?

 

[Grantsteve]

Does this link help? ... wiring diagram

http://www.honeywell.be/DocsAdobePDF/EN/Chronotherm/CM90X_ig_EN.pdf

 

[ELZ4742]

Does this link help? ... wiring diagram

http://www.honeywell.be/DocsAdobePDF/EN/Chronotherm/CM90X_ig_EN.pdf[/QUOTE]

like i said before, they have 2 aa bateries in em right?

one cable in A one in B then whatever isnt L N E in the boiler

 

[Grantsteve]

Does this link help? ... wiring diagram

http://www.honeywell.be/DocsAdobePDF/EN/Chronotherm/CM90X_ig_EN.pdf[/QUOTE]

like i said before, they have 2 aa bateries in em right?

one cable in A one in B then whatever isnt L N E in the boiler

correct battery operated.

the stat that is in at the mo has three wires from the wall

Blue, Red and Yellow with red on end.

 

[ELZ4742]

ok, do you have an existing time clock?

the cm range have a clock and stat built in tegether so you can remove both of the old items.

from what i can gather, the original will be live (red) neutral (blu) yellow (s/live)

use the yellow & red, it matters not which way round they goin the stat,

connect the same cables in the boiler in the send and return terminals, disconect the blue.

i will advise that t &e should not be connected direct into the boiler, heat proof flex should be used instead

 

[Grantsteve]

There is a little block inside the stat with 3 terminals in it, one marked A, one B and one C.

The wiring diagram shows Live into one (can't remember which now) Neutral into the other, no mention of Switched.

So are you saying I put Live and Switched into one terminal and Neutral into the other?

http://europe.hbc.honeywell.com/products/pdf/en0h8547uk07r0106.pdf

Appears to be a battery operated device or "steals" from the switched circuit.

So live into [A] and switched live into and the neutral is not used.

Sorry didn't notice the edit.

This makes sense. Thanks all for your help