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Honeywell CMT921 Wireless Room Thermostat

Product Code: 87377

Electronic sensing element. Wireless. Override facility. Holiday mode. Automatic BST/GMT time change.

  • Digital Display
  • 1
  • 2 or 3 On / Off Periods
  • 1 Pre-Set Programme
  • 24 Hour Programmable
  • Wireless
  • Frost Protection
  • ERP Control Class: IV
  • View more information

Product contents:
RF Room Unit and RF receiver Box

Switch/contact rating: SPDT 10(3)A. Temperature range: 5-35°C. H x W x D: 89 x 133 x 26mm. 2 x AA batteries supplied. 30m straight line transmitter range.

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Honeywell CMT921 Wireless Room Thermostat Instruction Manual



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Rated 1 out of 5 by what a load of absolute rubbis Bought a CM921 2-3 years ago, and the display is shedding screen information like fast. Contacted Honeywell and basically they do not want to know as I did not keep thd proof of purchase - I mean how many of us keep that info for 2-3 years. If you want a BAD PRODUCT AND A LOAD OF BULL FROM THE MANUFACTURER, THEN THIS IS THE PRODUCT TO BUY. 30 Sep 2015
Rated 1 out of 5 by Wireless room thermostat Our central heating installers used the seven day programmable version. As mentioned by other reviewers the LCD display has disintegrated and is now illegible after less than four years use. I contacted Honeywell and they said they will replace it. No questions asked, just proof of commissioning sheet. It makes me think these units have some sort of design fault. If the unit arrives from Honeywell I will consider it good customer service but time will tell. 26 Aug 2015
Rated 4 out of 5 by Vague Instructions The LCD panel on my existing thermostat unit died after 5-years, so I bought a complete new kit and tried to follow the instructions to tie the new thermostat to the relay. Very vague! On the third attempt to pair the two, I have a working system again. 26 Aug 2015
Rated 5 out of 5 by Very neat and easy to use Bought this to replace a faulty unit, was extremely easy to fit and a doddle to use. Very happy with both the unit and the price. 26 Mar 2015
  • 2016-02-05 T06:19:10.160-06:00
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3 Questions  1 Answer

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We've moved to a property and the date and times can only be programmed by going into the loft. Currently we have an RF Honeywell thermostat in the lounge but it only has the room temp buttons and the Eco button. Would this be easy to switch over?
11 Jan 2016
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, Decorator
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Hi! We have x2 Eberle Instat 6 thermostats controlling upstairs & downstairs zones. We would like to replace them with wireless programable thermostats, mounting the receiver in place of the existing stats which are 3 wire fed. Is there a wireless set-up that would suit?
Thanks Adrian, (a Bourne store customer)
8 Nov 2015
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23 Oct 2015
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, Other Trade
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If you would like the thermostat separately you will need to contact the manufacturer.
23 Oct 2015
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, Other Trade
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Download more info (pdf)

Brand Honeywell
Colour Beige
Display Type Digital Display
Manufacturer Guarantee 1 years
Manufacturing Standards RoHS/WEEE
Model No CMT921
Pack Size 1
Product Depth 26 mm
Product Height 89 mm
Product Length 133 mm
Product Type Wireless Room Thermostat
Product Width 133 mm
Programme Facility 24 Hour Programmable
Switch Type SPDT
Temperature Range 5-35 °C
Total Product Weight 0.46 kg