Mechanical to digital thermostat

[Mikeyt2016]

Hi there I have an old honeywell mechanical thermostat T6360B that I'm trying to change to a digital one THR840D the old one is numbered 1-3 and an earth the new box is a x b y c.

I thought being the same company would be the same any help much appreciated thanks

 

[sparkwright]

There should be a wiring diagram with the new stat.

I suspect on the cover of the old one there is a wiring diagram of that too.

On the old one, I would GUESS 1 is live, 2 is neutral, 3 is switched live - but it's only a guess and we need to check before we do anything.

 

[EFLImpudence]

You are correct

 

[EFLImpudence]

New one

 

[EFLImpudence]

So,
1 to A, L
3 to B, SL
2 N not needed, park safely

 

[Mikeyt2016]

Is the earth not needed either parked safely to?
Thanks so much for the help u guys are brilliant

 

[EFLImpudence]

Is the earth not needed either parked safely to?

That's right.

Make sure it cant touch anything. Don't cut it off, though.

 

[Mikeyt2016]

All done works a treat thank u so much for all your help