Please help with my Honeywell CM927 dilemma!

[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?

 

[glasgowgas]

cause you havent wired it correctly

your new receiver has a permanent live to L

a permanent neutral to N

and your switched live and live return go in A and B

 

[namsag]

What sort of system are you fitting it to

 

[JonBx]

Ok - sussed it !

Had to put a bridging wire from second L connector to A - B is correct as switched live = all works now....

 

[jackthom]

To keep it as simple as possible, A also has to be connected to Permanent Live and then B will become Switched Live.

Edit:You just beat me to it.

 

[JonBx]

Indeed = that would work too!

Thanks all for your very speedy help. l: