Boiler thermostat upgrade

[Catalin Ionut]

Hi all good people
I have bought a wireless room thermostat, ESI model ESRT4RF to upgrade my old DRAYTON RST1. From my ICOS, ancient boiler, I have four wires, one live wire, one netral, one 'earth' and another wire that connects on the '3' terminal of the DRAYTON thermostat, first picture. Upon testing with my multimeter the '3' wire acts like a neutral.
I fitted the new one in and the boiler don't turn on for heating but when I plugged the old one in it is working. Any help please ?

 

[Captain Nemesis]

Youll need to put a link between L and 1

 

[ianmcd]

as above you will need to put a link between L and 1

 

[Catalin Ionut]

Thanks for the reply. After a few tries I managed to get it to work. I made a link between live and com and connected the black wire to the '2' terminal.

 

[ianmcd]

Colours of wires in heating controls mean absolutely nothing

 

[Captain Nemesis]

You better hope green/yellow means earth.

 

[ianmcd]

You better hope green/yellow means earth.

Never rely on it being an earth in a heating system

 

[Captain Nemesis]

Thanks for the reply. After a few tries I managed to get it to work. I made a link between live and com and connected the black wire to the '2' terminal.

The diagram on the RTS1 shows (red) that L is internally already linked to COM. It doesnt support volt-free, whereas the ESI does, so COM isnt connected to L internally. I guess that other models of the Drayton do have volt-free contacts, and 1 would be COM, not connected to L internally.

And it shows (yellow) that 3 is the normally open contact. I guess 2 would be the normally closed one in versions of that thermostat which can also be used for cooling, but the RTS1 only does heating, so only has a NO terminal.

You have to wonder from a manufacturing POV if its worth having different versions and whether if they didnt the savings in processes and inventory and all the admin for selling and accounting for different versions might outweigh the costs of a few more internal wires. No reason why they cant all offer volt-free, NC as well as NO...

 

[Captain Nemesis]

Never rely on it being an earth in a heating system

Thats why I said youd better hope it is, cos if it isnt then its been wired up by a moron.