Honeywell CM921 Wireless Programable Room Stat

[jj4091]

I have the above which needs replacing. There seem to be a few OEM ones that pair with the existing BD 951 relay box. Has anyone any experience of different manufacturers and whether they are as temp. sensitive as the Honeywell one. They are much cheaper but I don't want to waste money on one that does not maintain the room temp. as well as the Honeywell.

 

[cross thread]

£50 will get you a brand new plumb centre own brand ,it’s a Honeywell ,complete stat and receiver.

 

[jj4091]

£50 will get you a brand new plumb centre own brand ,it’s a Honeywell ,complete stat and receiver.

Can't find one here https://www.wolseley.co.uk/heating/controls-and-valves/wireless-thermostats/?Brand=Honeywell+Home do you have a link please. OR do you mean this one https://www.ebay.co.uk/itm/32591260...KUaJMhRrZW9kOmZfkgTh13boPT7gZAPQaAjaaEALw_wcB

 

[cross thread]

Centre brand is plumb centres own make ,( it’s a Honeywell)

 

[CBW]

https://www.wolseley.co.uk/heating/controls-and-valves/wireless-thermostats/?Brand=Center - note the subtle difference a little more than £50 though.

 

[jj4091]

Centre brand is plumb centres own make ,( it’s a Honeywell)

It appears Centre is a Timeguard product not Honeywell so the relay box would also need changing which is something the OEM ones in my first post avoid. But the same question really are they very temp. sensitive.

 

[MNW67]

There seem to be a few OEM ones that pair with the existing BD 951 relay box. Has anyone any experience of different manufacturers and whether they are as temp. sensitive as the Honeywell one.

Is that a BDR91 relay box?

I don't think anyone will actually have done a direct comparison between two particular thermostats. But most modern thermostats use an algorithm called TPI to control the temperature and are very precise. Probably less than a quarter of a degree in practice. This is how the CM921 works and also the Center model. Do you have some links to the OEM ones you are talking about?

 

[CBW]

If it’s is a BDR91 then should be some on eBay. I have some spare if these, but had issues with some recently.

 

[jj4091]

Is that a BDR91 relay box?

I don't think anyone will actually have done a direct comparison between two particular thermostats. But most modern thermostats use an algorithm called TPI to control the temperature and are very precise. Probably less than a quarter of a degree in practice. This is how the CM921 works and also the Center model. Do you have some links to the OEM ones you are talking about?

Thanks for that it is exactly what I wanted to know. Don't have any links without googling again but they all claimed to work as you suggest so it looks like they will be ok