Replacement for Honeywell CM921

[madwayne]

Looking at replacing my CM921 and maybe even the receiver, it’s 10 years old and even with new batteries in the CM921 it seems to be temperamental to touch, in screen sometimes goes blank.

bent the battery connector slightly and seems to be fairing much better, however I am expecting it to fail completely at some point.

1. what options do I have for a direct replacement?
2. smart replacement, programmable app option but still need a in house app?

looking for best value and best in class.
I do have Hone assistant so don’t mind if there is an integration for HA.

Would consider smart radiator Control, but can see that isn’t cheap and not sure how good it actually is.

Thanks

 

[CBW]

Loads of replacements available, sometimes better modulation is via the boiler, so would help to know setup if you're interested in that?

 

[madwayne]

Not sure what you mean to be honest. The boiler is fixed, the thermostat is wireless and fires the relay to start stop the boiler when thermostat at temperature. That thermostat allows a several time periods throughout the day.

not sure how we would control the boiler with no thermostat.

bolier is a Baxi it was only available for a few years because of issues with a seal and something else which to be fair we had replaced once under warranty and it’s been fine since(tempting fate).

I will see if I have the model in my emails.

 

[madwayne]

Baxi 32kW duotech GA according to my records

 

[CBW]

I didn't say use without a thermostat. So looking at the type of boiler, most Baxi boilers use standard on/off 230vac, so any would be suitable really.

 

[madwayne]

apologies, I didn’t understand the better modulation via the boiler.

As far as I was aware the system is on off control via the the programmable thermostat.

loking at ones to avoid/ recommendations so I can look them up to see which is a best fit.

 

[CBW]

Plenty of decent makes, probably avoid Salus and similar and Secure (previously Horstmann) and Chinese crap.

 

[madwayne]

Seen the Salus and Horstmann brands. Thought almost everything was china manufactured to some degree these days

 

[CBW]

. Thought almost everything was china manufactured to some degree these days

They are, but decent brands will have specific tolerances, I mean more the “smart” thermostats on Amazon and the likes for about £12 or whatever the cost is.

 

[madwayne]

Okay the Tado V3+ comes with an open window sensor, how does that work as there is only the one?

Seen these have smart features app controlled , geo fencing and the like and can add individual radiator control later.

I can pick one up for £100 which is less than a replacement CM921 option.

Anyone think these are good bad ?

 

[madwayne]

Found a useful video on the Tado wrt to explaining features and parts.

The window sensor, isn’t a window sensor as such it’s looking at temperatures changing rapidly due to drafts and the video says it’s hit and miss on open windows so probably wouldn’t use that feature as such.

so seriously considering this, radiator control is pricy, but if replacing the CM921 Ona like for like basis it probably works out cheaper for the new thermostat and receiver. Just won’t have individual room control.