Wiring of new thermo stat

[NikSargeant]

Feel this should be simple but keen double check before I wire as I'm replacing the thermostat but also moving to a digital one. Live is obvious but insure what goes into the digital thermo open and closed holes :/ would really appreciate the help and attached the pictures of the current honeywell one and the new anself diagram. Its fir a room thermostat to control underfloor heating.

 

[stem]

The Honeywell wiring is

Terminal 1 = Live
Terminal 2 = Neutral
Terminal 3 = Switched Live
Earth = Earth

How it connects to the new thermostat depends on which version you have, GB or GC. But the connections for both are shown on the diagram you posted.

 

[NikSargeant]

Hi Stem, thanks 4 your help. We have water underfloor heating run by an oil boiler. Would the switch live go into the open or closed? Or does it need a loop? Thank you

 

[stem]

So you need the GC version of the thermostat.

The wire in old stat terminal 1 Live....Goes to GC L (4)

The wire in old stat terminal 2 Neutral....Goes to GC N (3)

The wire in old stat terminal 3 Switched Live....Goes to GC (2)

And you need to insert a link to connect GC terminals (L) and (1)

 

[NikSargeant]

Hi, so I did that and it shorted the fuse heres a picture of what I think you suggested

 

[CBW]

Hi, so I did that and it shorted the fuse heres a picture of what I think you suggested

No photo attached

 

[NikSargeant]

Hi, picture now attached....hopefully

I've removed the live loop at one end.

 

[NikSargeant]

If it helps here is the wiring diagram from the old honeywell thermostat

 

[CBW]

Did it blow a fuse, or trip? Did you isolate first? Are any wires “pinched” or trapped? Eg have you trapped any insulation in the terminal contacts?

 

[NikSargeant]

Nothing obvious but have taken all the wires out and rewired......now working

Thank you both

 

[stem]

Nothing obvious!! you should have gone to spec savers!

After you didn't tell me which version of the thermostat you had purchased when I initially asked, I told you that the instructions I had given were for the replacing the Honeywell with a GC type, which resembles the type of thermostat now in common use in the UK. I also said that the wiring changes according to the model you have.

The instructions that you posted clearly show that the GC version looks like this:

However, from your photograph we can see that you have actually installed a GA version which is wired differently internally. This type thermostat is used commonly in mainland Europe and as the picture shows is designed for use with a MOMO valve which requires open / close control signals.

Making the link with this version is not necessary. It's done internally for you.

 

[CBW]

Nothing obvious!! you should have gone to spec savers!

Me too

 

[NikSargeant]

So does that mean that No.1 is left with no wire if the loop is not required? We are findjngvtgd underfloor heating is permanently on, would the loop be causing this ir would it be something else?

 

[stem]

With the GA version of the thermostat, no external link is required.

Terminal 3 is 'Neutral' = Grey wire with blue sleeve that was in Honeywell 2

Terminal 4 is the 'Permanent Live' =Brown wire that was in Honeywell 1

Terminal 2 is the 'Call for Heat' = Black wire with brown sleeve that was in Honeywell terminal 3

Terminal 1= Heating satisfied which corresponds to terminal 4 of your old thermostat is not used and should be left empty.

 

[ianmcd]

That post made me laugh @stem you are usually a lot more patient than that