Using The Room Thermostat For Specific Applications; Using The Special Features Of The Room Thermostat - Honeywell CM720 Installation Manual

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.
Specific Application:
HEATING Gas Boiler
(<30kW)
Oil Boiler
Thermal Actuator
Zone Valve

4.4 Using the Special Features of the Room Thermostat

Special Feature: Description:
Optimisation The thermostat will adjust the start time in the morning/afternoon
(Variable Start Time) 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.
Scheduled If the installation requires scheduled maintenance and the user
Maintenance Alert needs to be reminded that the service is due the parameter value
Period can be set to the required number of months (1-48). When the
preset period expires the CM721/CM727 will display the 'SERVICE'
icon.
Summer/Winter Auto This feature moves time automatically on the last Sunday of March
time change and the last Sunday of October. The feature is factory enabled.
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.
Upper/Lower The normal upper temperature limit of 35°C can be reduced to
Temperature Limit 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.
8
Setting: What to change:
Cycle/ Minimum Note: All parameters listed below belong to
Hour ON Time category 2 - System Parameters (see Installer
Parameters Table)
6 1 No changes required
3 4 Set 1:Ot parameter to 4
Set 2:Cr parameter to 3
12 1 Set 2:Cr parameter to 12
6 1 No changes required
CM700 Wireless - Programmable Room Thermostat
Enable/Disable
To enable: Set parameter
8:OP (category 1) to 1.
Set parameter 19:SP
to the required value to
enable maintenance alert.
Value set to zero disables
the function.
To enable: Set parameter
3:tC (category 1) to 1.
Set parameter 12:
tO (category 1) to the
required offset value.
Set parameter 6:uL
(category 1) to the desired
upper limit.
Set parameter 7:LL
(category 1) to the desired
lower limit.