CM921
CHRONOTHERM
4
EN0H 8557 UK07 R0 09/06
Special Features
Description
Setting
Optimisation
(Variable Start
Time)
The thermostat will adjust the start time in the morning/afternoon
so the desired temperature is reached by the start of the program
period. The system will restrict the start time to a max of 2 hours.
To enable: Set parameter 8:OP
(category 1) to 1.
Heating or Cooling
Operation
This product can be used for heating or cooling applications. If
you select cooling mode the control algorithm and factory default
program will be modified. You can independently modify the
heating and cooling profile.
To enable: Set parameter 4:HC
(category 2) to 1.
Summer/Winter
Auto time change
This feature moves time automatically on the last Sunday of
March and the last Sunday of October. The feature is factory
enabled.
To enable: Set parameter 3:tC
(category 1) to 1.
Temperature Offset
If the thermostat is located in a particularly hot/cold location for
reliable signal transmission reasons then the measured/displayed
temperature can be adjusted by +/- 3°C. This is useful if the
homeowner wants the reading to match another appliance
temperature display.
Set parameter 12:tO (category
1) to the required
offset value.
Upper/Lower
Temperature Limit
The normal upper temperature limit of 35°C can be reduced to
21°C to save the homeowner energy. The normal lower limit of
5°C can be increased up to 21°C to protect inhabitants from cold.
Set parameter 6:uL (category 1)
to the desired upper limit.
Set parameter 7:LL (category 1)
Parameter
Installer Set-
Up Number /
Abbreviation
(Press + or -
keys to
select)
Factory Setting
Optional Setting
Category 1 Parameters – Room Thermostat Settings
Display
Description
Display
Description
AM-PM / 24hr Display
1:Cl
24
24 hr clock display
12
12 hr AM / PM clock display
RESET Time /
Temperature Program
2:rP
1
Time / Temperature profile set
to factory default
Changes to 0 when one of the
time/temp profiles are changed
0
1
Time / Temperature are as programmed
To restore the factory profile set to 1
Automatic
Summer/Winter Time
Change
3:tC 1
Automatic
Summer/Winter
Time Change Enabled
0
Automatic Summer/Winter Time Change
Disabled
LCD Backlighting
5:bL
1
Backlighting Enabled
0
Backlighting Disabled
Upper Temperature
Limit
6:uL
35
35°C Upper Temp. Limit
21 to 34
21°C to 34°C adjustment in 1°C steps
Lower Temperature
Limit
7:LL
5
5°C Lower Temp. Limit
6 to 21
6°C to 21°C adjustment in 1°C steps
Optimisation
8:0P
0
Optimisation disabled
1
Optimisation enabled
Temperature Offset
12:tO
0
No offset
-3 to +3
-3°C to +3°C adjustment in 0.1°C steps
Proportional Band
Width
13:Pb
1.5
1.5°C Proportional Band
1.6 to 3.0
1.6°C to 3.0°C adjustment in 0.1°C steps
Reset Parameters to
Factory Defaults
19:FS
1
All settings held are the factory
defaults.
Changes to 0 when one of the
parameter values are changed
0
1
Settings are as modified above
To restore the factory profile set to 1
INSTALLER PARAMETER TABLES