honeywell cm 921 thermostat

[jimy]

Hi all,
Honeywell cm 921 thermostat problem, digital numbers are fading. i have tried to repair in past with limited success but time to bite the bullet and buy new.
I am having difficulty in finding a new cm 921. the closest i can find is a cm (t )921 with receiver box at screw fix £ 119, not sure what the T stands for.
If I get the thermostat and receiver would it just be a strait swap.
regards to all.
Jimy.

 

[lightning]

You can strip them and blow dry the long strip

 

[jimy]

Thanks for the reply, I have done the repair a couple of time but only lasts a short time, but will have another go
Boiler getting serviced in couple of weeks so will have a word with the man.
Still looking into the CM (t) 921 as sold by Screwfix as replacement.
Regards.
Jimy.

 

[Dan Robinson]

The T4R is the replacement, but required you changing the receiver too (the wiring is the same though).

Depending on your boiler it gives you OpenTherm connectivity too which is a significant upgrade.

 

[jimy]

Hello,
Boiler is Worcester/ Bosch about 5 years old.
Will look into that .
Regards,
Jimy.

 

[Dan Robinson]

It won't take OpenTherm then. Worcester are about as sofisticated as a Morris Minor.

 

[jimy]

And I thought they were the Dogs
Jimy.

 

[Dan Robinson]

The joys of marketing over substance. They're mediocre at best.

 

[D_Hailsham]

I am having difficulty in finding a new cm 921. the closest i can find is a cm (t )921 with receiver box at screw fix £ 119, not sure what the T stands for.

CMT921 is the part number for the complete package. If you want just the room unit it's part number is CMS921. The relay, on its own, has a completely different part number as it's common to several wireless devices.

 

[jimy]

Thanks for the relpy D. Screwfix do the cmt921. It is the only one I have found so far.
Regards. J.