how do I change a central heating wireless thermostat

[landlordray]

Hi , I was having problems with my wireless thermostat and receiver, turns out the receiver has developed a fault.

I have decided to change the old set up for a new receiver and wireless thermostat.

However the wiring set up is different on the new unit ( a Honeywell/Center unit EHE0200361 ) the old unit is a Salus ST620RF
Boiler is Worcester Greenstar CDI

Could anyone help me with the wiring please.

I have attached photos of the old and new receivers.

many thanks

 

[stem]

The wires move from the terminals at the Salus ST620RF, which I can't see the writing in the photo because of the wires but I believe from memory will be marked as below.

COM.......NO.......Earth.......L.......N

If they are different, don't proceed but post back what you have. If they are as above, then all of the wires are simply moved to the terminals at the BDR receiver that have the same function. So:

N & L are straightforward
Salus 'Com' corresponds to BDR 'A'
Salus 'NO' corresponds to BDR 'B'

The BDR is double insulated so doesn't need an earth connection, but the two earth wires need to remain connected, so they should be connected together in a separate screw terminal connector and safely tucked out of the way.

 

[landlordray]

Many thanks for your speedy reply.

Your are correct regarding the Salus terminals ie

COM NO Earth Live Neutral

Presume both 'L' terminals on the Center receiver are linked together as per your diagram?

thanks

 

[stem]

Presume both 'L' terminals on the Center receiver are linked together as per your diagram?

Yes they are linked together inside the BDR so effectively the same terminal. Some installations require a link between terminals L and A, (yours doesn't) So it's like that to facilitate it.

 

[landlordray]

That's great thanks..

makes sense now

 

[landlordray]

Just an update.


Fitted the new wireless thermostat and receiver a couple of days ago and everything is working a treat

 

[stem]

Great. Thanks for taking the time to reply. It helps anyone else with a similar project that finds this thread.