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EN0H 8557 UK07 R0 09/06
CM921
WIRELESS PROGRAMMABLE THERMOSTAT
PRODUCT SPECIFICATION SHEET
The CM921 thermostat is designed to provide automatic time
and temperature control of heating or cooling systems in
villas and apartments.
It can be used as part of a system in conjunction with combi-
boilers, oil-burners and gas fired boilers, circulation pumps,
thermal actuators, zone values and electric heating systems
(<10A). In combination with other CM921 room units and
HC60NG receivers it can be used to control multi-zone
applications (up to 4 zones).
The radio frequency controlled CM921 system pack consists
of a room unit CMT921A and a relay box R6660D (HC60NG).
No wiring to the room unit is required. The installer only
needs to wire the relay box to the controlled device (e.g.
boiler) and mount the room unit in a suitable location where
RF communication is reliable. The CM921 uses reliable RF
communication technology in the 868MHz band.
The CM921 extra large LCD display, dynamic text display
and controls layout are identical to the CM901 ‘wired’
thermostat. The unit is ideal for consumers who want reliable
and precise temperature control from a modern looking,
simple to program and easy-to-use product.
FEATURES
•
CM921 can be installed without disrupting your room décor
as no wiring connection is required between the room unit
and the boiler
• Attractive, slim, ultra-modern styling makes it ideal for
location in any type of home
• 1-day heating programming
• A dynamic text display on the LCD that gives enhanced
feedback to the user / installer
• LCD Backlighting to illuminate the display for easier viewing
in low light conditions
• Reliable RF communication utilising 868 MHz band with 1 %
duty cycle limit to minimise communication disturbance
• Every room unit can be bound with several relay boxes (e.g.
to control several electric heating panels)
• Armchair programmed
• Holiday button that provides energy savings by reducing
to a constant temperature for 1 to 99 days when people are
on holiday, returning to normal operation (AUTO or
MANUAL) on the day of their return.
• EEPROM memory holds the user program indefinitely
• OFF position has an integral frost protection setting at
minimum 5°C (installer adjustable) so that pipes in the
house will never freeze in winter.
• Communication compatibility with other Honeywell product
such as HR80, HM80 and HCE80.
• CM921 can be used to control a zoning system with up to 4
zones
• Maximum system efficiency and extended boiler life due to
unique zoning system synchronisation
• Automatic Summer / Winter time change adjusts the time
automatically to daylight saving time.
• Standard room units and receiver boxes are used for zoning
applications algorithm
• When used with the table top stand the room unit can be
positioned anywhere in the room where RF communication
is reliable
• 24...230V 10A resistive, 3A inductive SPDT relay provides
compatibility with most domestic central heating systems
reducing the need to stock many different models.
• The HC60NG may be surface or wallbox mounted.
• Installer Set-Up Mode allows extra functions to be set at the
discretion of the installer to match the consumer
applications and needs:
• Optimisation
• Pump Exercise
• Upper / Lower Setpoint Limit Adjust
• Temperature offset
• Minimum ON time
• Cycle rate
• Heat / Cool Operation
• Proportional Band Width
• Fail-safe mode for communication loss
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