Thermostat replacement help.

[Tanya413]

Hello, this is my first post and I would be really grateful if someone could kindly advise me.

Our thermostat broke and is currently stuck at 21C.

I have been looking for a replacement and I quite like the look of the thermostats by Salus but I can't figure out if their receiver box would be compatible with my boiler and the pre-existing wires.

My boiler is an 'ideal isar HE24'
The current thermostat is a honeywell CM921 with a 'BDR91' receiver box

I have attached pictures of the current receiver box and what I think is the wiring guide for it and one of the Salus systems I have been looking at.

If someone can confirm if these are compatible and explain how the wiring should go that would be fantastic.

Many many thanks.

Tanya.

 

[Aquarius]

Good evening Tanya,

Yes this looks compatible, as long as the Salus is for mains/volt free switching (24 - 230v). Not that I want to put you off, but heard mixed views about Salus, mostly bad.

 

[Tanya413]

Good evening Tanya,

Yes this looks compatible, as long as the Salus is for mains/volt free switching (24 - 230v). Not that I want to put you off, but heard mixed views about Salus, mostly bad.

Hello Aquarius,

Thank you very much for your reply.

I have checked and the Salus thermostats are 'Switching volt free and 230V'.

Obviously the live and neutral wires are straight forward but I'm a little puzzled how the remaining wires going to A and B would transfer over to the Salus, do you have any idea how this would work?

I have found some diagrams online which seem to show A as 'com' which by process of elimination leaves the wire currently going to B which presumably goes to 'NO' on the Salus.

Also I would like to know what model you would recommend if Salus are not very reliable.

Many thanks for all your help.

 

[Aquarius]

Yes you're correct with regards the com and no. Honeywell T6 gets a lot of love on the forums, I can’t really recommend as we (who I work for) only fit Honeywell mechanical thermostats or Siemens wireless - both are good, but Honeywell mechanical no good for your set-up.

 

[king of pipes]

Hello Aquarius,

Thank you very much for your reply.

I have checked and the Salus thermostats are 'Switching volt free and 230V'.

Obviously the live and neutral wires are straight forward but I'm a little puzzled how the remaining wires going to A and B would transfer over to the Salus, do you have any idea how this would work?

I have found some diagrams online which seem to show A as 'com' which by process of elimination leaves the wire currently going to B which presumably goes to 'NO' on the Salus.

Also I would like to know what model you would recommend if Salus are not very reliable.

Many thanks for all your help.

Avoid Salus as Aquarius has stated they have very poor reviews and I have had issues with them loosing pairing and disconnecting, better to stick with Honeywell or if cost is a issue then EPH is a reliable unit our sponsor Corgi direct have products available at a very reasonable cost.

 

[Tanya413]

Avoid Salus as Aquarius has stated they have very poor reviews and I have had issues with them loosing pairing and disconnecting, better to stick with Honeywell or if cost is a issue then EPH is a reliable unit our sponsor Corgi direct have products available at a very reasonable cost.

Hello,

Thank you for your advice on this. I think with what both of you have said and some reviews I have now seen about the Salus losing time I am looking to get the EPH which you pictured (the price on that site seems very reasonable).

Could you please explain how I would wire the EPH receiver up with the existing wires used with my Honeywell receiver, I have attached pictures and diagrams for both but I can't quite get my head around how it all works

Edit - (I just had a long hard look at the diagrams and I think it's clear now, my A wire goes to 2 on the EPH and the B wire goes to 3 🤞 )

Many thanks.

 

[Chuck]

The current thermostat is a honeywell CM921 with a 'BDR91' receiver box

You've tried new batteries, etc? If you're sure it's broken (and one of the kids hasn't been 'playing' with it and locked the setpoint) then you could save a lot of hassle and just buy a like-for-like replacement or a CM927 if you want 7-day programming. The programmer and receiver are available sepately or as a double pack.

 

[ShaunCorbs]

Combi pack 4 is brilliant and cheap

L to L
N to N

A to 2
B to 3

 

[Tanya413]

Just wanted to post a quick update to say that the thermostat is all up and running now, was a breeze to install and I'm really impressed with the unit. Thank you to everyone who gave advice and provided reassurance, it's great that forums like this exist to help empower people to do these simpler installs themselves.

 

[Aquarius]

Just wanted to post a quick update to say that the thermostat is all up and running now, was a breeze to install and I'm really impressed with the unit. Thank you to everyone who gave advice and provided reassurance, it's great that forums like this exist to help empower people to do these simpler installs themselves.

Which one did you install?

 

[Tanya413]

Which one did you install?

I installed the EPH Combipack 4