4.3 Using the Room Thermostat for Specific Applications
The CM727/721 RF room thermostat is a versatile controller that can be used to control many different
applications. For most typical applications, like wall-hung gas fired combination boiler control or zone
valve control, no adjustments from the factory settings are required. For other applications, like controlling
an oil burner, the best system performance can be achieved by modifying selected parameters of the
room thermostat in the Installer mode. The table below lists the most common settings used for specific
applications.
4.4 Using the Special Features of the Room Thermostat
Special Feature: Description: Enable/Disable
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.
Scheduled
Maintenance Alert
Period
If the installation requires scheduled maintenance and the user
needs to be reminded that the service is due the parameter value
can be set to the required number of months (1-48). When the
preset period expires the CM721/CM727 will display the ‘SERVICE’
icon.
Set parameter 19:SP
to the required value to
enable maintenance alert.
Value set to zero disables
the function.
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) to the desired
lower limit.
Specific Application: Setting: What to change:
Cycle/
Hour
Minimum
ON Time
Note: All parameters listed below belong to
category 2 - System Parameters (see Installer
Parameters Table)
HEATING
Gas Boiler
(<30kW)
6 1 No changes required
Oil Boiler 3 4 Set 1:Ot parameter to 4
Set 2:Cr parameter to 3
Thermal Actuator 12 1 Set 2:Cr parameter to 12
Zone Valve 6 1 No changes required
