Replacing old Honeywell EE4 with Honeywell CM927 - HELP

[JonBx]

I replaced my old Honeywell thermostat with a new CM927 today but... it doesnt work... Power light is on - remote thermostat turns unit on at right temperature, but boiler doesnt fire up... I have reinstalled the old thermostat in case I had blown a fuse somewhere but that works perfectly.

Wiring on old unit goes 1 to 5

and wires go into 1 = Permanent live 2= neutral 3= switched live.

There are four wires going into the unit - two live and two neutral

The new unit has six slots N L L A B C

I wired 1 into L, the 2 neutrals into N and the switched live into B....

So why isnt it working?

 

[333rocky333]

A b and c are switch contacts.
You appear to be using only one of them.

http://europe.hbc.honeywell.com/netherlands/productcatalogue/pdf/en0h8556uk07r1006.pdf

 

[JonBx]

Ok - sussed it !

Had to put a bridging wire from second L connector to A - Stupid design if you ask me - and would have been soooooo easy to mention that L and A both need permanent live feeds!

 

[seco services]

and wires go into 1 = Permanent live 2= neutral 3= switched live.

There are four wires going into the unit - two live and two neutral

you've only give us 3, very much doubt you have 2 neutrals.
just cause it maybe blue don't assume its a neutral.

The new unit has six slots N L L A B C

N - NEUTRAL
L - PERM LIVE

A - LIVE
B - SW/L

 

[seco services]

Had to put a bridging wire from second L connector to A - Stupid design if you ask me -

no it's not the programmer thats stupid.
it's straight foreward when you know what your doing.

 

[JonBx]

There were 2 neutrals - twisted together and plugged into the same connector... dont know exactly why... but left them hooked together and sharing the neutral connector spot....

Thanks for your help

 

[JonBx]

A b and c are switch contacts.
You appear to be using only one of them.

http://europe.hbc.honeywell.com/netherlands/productcatalogue/pdf/en0h8556uk07r1006.pdf[/QUOTE]

Indeed! the wiring diagram you sent the link to would have told me the answer immediately = but it is not the one that came with the instructions with the unit - how bizarre

 

[333rocky333]

Ok - sussed it !

Had to put a bridging wire from second L connector to A - Stupid design if you ask me - and would have been soooooo easy to mention that L and A both need permanent live feeds!

I assume not everyone may want a feed there, as they may want to series it up in a control circuit or even a Lower voltage circuit.
They used to fit links in timers and advise to remove if not needed.
Nice looking unit, may get one myself.