Specifications

Fan Switch — The fan switch is located on the bottom
right corner of the monitor thermostat. The fan switch con-
trols the system fan operation. See Fig. 29.
When the fan switch is set to ON, the monitor thermostat
energizes the fan relay continuously:
• when the monitor thermostat is in Occupied mode or the
monitor thermostat is configured for Construction mode.
• when any zone controller associated with the monitor ther-
mostat is in Occupied mode and the monitor thermostat is
configured as a Monitor Only thermostat.
• when the monitor thermostat or any zone controller asso-
ciated with the monitor thermostat is in Occupied mode
and the monitor thermostat is configured as a VVTt Moni-
tor thermostat.
• when the monitor thermostat and all associated zone con-
trollers are in Unoccupied mode and the monitor thermo-
stat energizes a Heating or Cooling mode.
NOTE: When the monitor thermostat or zone controller is in
Unoccupied Override mode, the fan operates as if it is in
Occupied mode.
When the fan switch is set to AUTO, the monitor ther-
mostat energizes the fan relay only during the system heat-
ing or system cooling modes during occupied or unoccupied
periods.
To control the fan switch setting, configure category 4,
option 20. The range is from 0 to 2. When the option is set
to 0, the thermostat will follow the setting of its mechanical
fan switch. When the option is set to 1, the thermostat will
perform as if the fan switch is set to ON (regardless of the
mechanical switch setting). When the option is set to 2, the
thermostat will perform as if the fan switch is set to AUTO
(regardless of the mechanical switch setting). The setting of
0 is the default setting.
Fan Operation for Heat — When the Fan Operation
For Heat option is set to OFF and the fan switch is set to
AUTO, the fan relay is energized by the monitor thermostat
only during a system cooling mode. During a system heat-
ing mode, the heating/cooling equipment is responsible for
fan operation.
When the Fan Operation For Heat option is set to ON and
the fan switch is set to AUTO, the fan relay is energized by
the monitor thermostat during system heating and cooling
modes.
To configure the Fan Operation For Heat option, set cat-
egory 4, option 1. Use the left set point buttons to toggle the
option ON and OFF.
Zone Caller — A zone caller is a zone controller or moni-
tor thermostat (if in VVT monitor thermostat mode) that has
sufficient zone demand to energize the heating/cooling equip-
ment. A zone cooling caller requires a demand of 1.5° F or
greater for cooling. A zone heating caller requires a demand
of 1.5° F or greater for heating.
System Mode — The monitor thermostat selects a sys-
tem mode based on the zone demand of all associated zones
to determine the operation of the system and heating/
cooling equipment.
For a Construction monitor system, the monitor ther-
mostat only checks its own zone demand. If the monitor
thermostat is a cooling caller, system cooling mode is se-
lected. If the monitor thermostat is a heating caller, system
heating mode is selected.
For a Monitor Only System, the monitor thermostat checks
the zone demand of the associated zone controllers. If the
majority of zone controllers are cooling callers, system cool-
ing mode is selected. If the majority of zone controllers are
heating callers, system heating mode is selected. If the num-
ber of zone callers for heating equals the number calling for
cooling, the monitor thermostat selects the system mode that
matches the zone caller of the greatest demand. If the de-
mands for both modes are equal, the heat mode is selected.
For a VVT Monitor System, the monitor thermostat checks
its own zone demand and the zone demand if the associated
zone controllers. If the majority of zone callers are cooling
callers, system cooling mode is selected. If the majority of
zone callers are heating callers, system heating mode is se-
lected. If the number of zone callers for heating equals the
number calling for cooling, the monitor thermostat selects
the system mode that matches the zone caller of the greatest
demand. If the demands for both modes are equal, the heat
mode is selected.
The monitor thermostat releases a system heating or cool-
ing mode when:
• the reference zone demand is satisfied to 0.5° F.
• the system mode reselect chooses the opposite system mode.
• both first and second stage heating and cooling tempera-
ture limits are exceeded when the reference zone is no longer
a zone caller and there are zone callers for the opposite
system mode.
SYSTEM MODE DEMAND — The System Mode Demand
option determines the minimum number of callers for a mode
needed before the monitor thermostat can select that system
mode. The range of values is 1 to 16. To configure the Sys-
tem Mode Demand option, set category 4, option 15. Use
the left set point buttons to raise or lower the value to the
desired setting. The default value is 1.
NOTE: The System Mode Demand option should be set as
high as possible to maximize equipment protection and en-
sure minimum operating airflow requirements.
Reference Zone — Once a system mode has been cho-
sen, the monitor thermostat selects a reference zone after each
system scan. The reference zone is the zone that has the great-
est demand of all zone callers for the selected system mode.
The reference zone is reevaluated with each system scan.
The reference zone does not change when all zone demands
are below 1.5° F. When demand is less than 0.5° F, the sys-
tem mode will clear and the reference zone is released after
3 minutes.
NOTE: The Construction monitor thermostat will always
select itself as the reference zone.
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