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7
Q7300L SERIES 2000 COMMERCIAL THERMOSTAT SUBBASE
OPERATION
Table 4. T7300 Thermostat/Q7300L Subbase Sequence of Operation.
a
Low speed fan is activated in the heat mode and high speed fan is activated in the cool mode.
Remote Temperature Sensing and Override
The subbase can be used with the T7147 Remote Sensors to sense temperature and provide the Occupied mode. The
subbase also can be used with the T7047 Remote Sensors if remote occupied control is not required.
Mode
System
Setting
Fan
Setting
a
Equipment
Call
Action
Loads
Energized
Occupied
Any
Auto
—
Thermostat in Occupied mode.
Damper control relay energized.
A2
Occupied
—
On
—
Depends on last system. If cool is the last
system, then call is for high speed fan.
When heat is the last system, then call is
for low speed fan.
GL or GH
Occupied
Heat
Auto
Stage 1 heat
Heat LED activated.
In hydronic applications, ML7984
approximately one-half open.
Pump interlock relay activated to energize
circulator pump.
In conventional applications, stage 1 heat
activated.
Low speed fan activated.
A2, GL, RM,
P2
Occupied
Heat
Auto
Stage 2 heat
In hydronic applications, ML7984 is fully
open. In conventional systems, no action.
A2, GL, RM,
BM, P2
Occupied
Cool
Auto
Stage 1 cool
Cool LED activated.
Cooling relay activated.
High speed fan activated.
A2, GH, Y
Unoccupied
Any
Any
—
Thermostat in Unoccupied mode.
Damper control relay de-energized.
—
Unoccupied
Any
On
—
Thermostat in Unoccupied mode.
System fan operates at appropriate speed
with call for heat or cool equipment.
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