Replacing a Room Thermostat: Honeywell linked to a Horstmann 425 Coronet Programmer

[mosscliffe]

I would like to replace my very old Honeywell Room Stat. I do not know the model number, but it is square and has a large dial and that is all, except the temperature variations between ON and OFF seem far too large.

I would like to fit one of the new programmable room stats and leave my Horstmann 425 Coronet on the 24 hours setting.

I was thinking about the Horstmann DTR2 ProgrammableThermostat, as that seemed quite flexible and most importantly had a 1 Hour setting and was also quite cheap.

I will have to use the original wires to the Honeywell Room Stat.

My question is - will I be able to wire the DTR2 stat with the existing wires to the Honeywell stat?

My original plan was to replace the Room Stat with a Wireless Programmer and then use a wireless room stat, which I could move as required, but that seemed to be complicated and I would have probably needed more wires than I had available. If this is possible, I would appreciate any advice.

Thanks

Richard

 

[aggis]

Re: Replacing a Room Thermostat: Honeywell linked to a Horstmann 425 Coronet Programm

Hi,
Check the wires in old r/stat, should be a live, switched live, neutral & may be an earth. Usually a diagragm inside stat case.
To fit new prog r/stat, fit live to common, switched to normally open [nc], cut back neutral cap/tape & same for earth. Not required.
Then test with multimeter.