Thermostat replacement (from 4 wires to 2 wires). (pictures)

[petazetas754]

Hi,

I have bought a new digital thermostat (Salus RT500) to replace my old Honeywell analog one.

The old thermostat has 4 wires but the new one has only two. Do you know if I have bought the wrong thermostat? How do you actually make the connections from 4 wires to the 2 pins?

I have uploaded two pictures detailing the two thermostat plates.

View media item 43105 View media item 43107
Thank you in advance

 

[Dan Robinson]

1 & 3 go to L & SL.

Earth cn be used is you like. 2 should be made safe.

 

[petazetas754]

Thank you very much Dan_Robinson but how do you make a wire safe? Sorry for my ignorance.

 

[Gas1976]

You need to discard earth and neutral,make them safe and connect common and calling into the two connections on your new backplate,it doesn't matter which way round

 

[petazetas754]

Thank you Gas1976,

Which one is each?

earth
neutral
common
calling

 

[Gas1976]

Earth green/yellow,Grey neutral, red common and black calling,so just connect up red and black.

 

[Gas1976]

Make sure the power is off!!!

 

[petazetas754]

Ok, thank you guys for your prompt reply. I just need to find out how to make the wire safe. Should I used just duct tape an leaving it unconnected?

 

[Gas1976]

Cut off ther bare ends and use insulation tape

 

[imroberts]

I'd terminate in a choc block.

 

[petazetas754]

Excellent. You said the earth connection does not need to be connected. They said the same in the manual although the also say that it is ok if you do. Is this ok? what are the implications of connecting it?

 

[Gas1976]

Because the new thermostat is made of plastic it doesn't need to be earthed but the connection is there for joining earths,it won't do anything connected or not

 

[petazetas754]

Perfect. This forum is amazing. Thanks again guys.