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Sequence of Operation
The unit's operation is controlled by the remote room thermostat.
Once the thermostat is placed in the COOL position, the unit's
operation is automatic. A fan switch on the thermostat also
provides for continuous operation of the evaporator fan if desired.
This is the ON position. With the fan switch in the AUTO
position, the fan will only operate with the cooling cycle. Continu-
ous fan mode during cooling operation may not be appropriate in
humid climates. If the indoor air exceeds 60% relative humidity
or simply feels uncomfortably humid, it is recommended that the
fan only be used in the AUTO mode.
Cooling
On a call for cooling, the indoor fan "G" and the compressor
circuit "Y" are energized. The indoor fan circuit "G" energizes the
the fan relay coil this closes the fan relay contacts (FDR-1) and
the indoor fan motor(IDFM) starts. The compressor circuit "Y"
energizes the (MS) contactor coil this powers the compressor
(CPR) and the outdoor fan motor (ODFM). When the thermo-
stat determines that further cooling is not required, the contactors
are de-energized.
Short Duration Shut Down
To shut down the unit for a brief period of time, turn the
thermostat system switch to OFF and place the fan switch in the
AUTO position.
Heating
On a call for heat, the thermostat "W" is energized, which
connects to unit "W", which energizes the "AH" heater contactor
coil. The "AH" contactor closes powering the heater, provided all
element limits are closed.
Note: The indoor thermostat must be configured for electric
heat to provide a "G" signal to energize the indoor fan relay (FDR-
1) during the heating mode. The heater control circuit will not be
energized unless the indoor fan relay (FDR-2) is energized.
ICM FAN MOTOR ADJUSTMENTS (TCH048, 060F ONLY)
If the airflow needs to be increased or decreased, see the Airflow
Table in the Service Facts. Information on changing the speed of
the blower motor is in the Blower Performance Table.
Blower speed changes are made on the ICM Fan Control mounted
in the control box. The ICM Fan Control controls the variable
speed motor.
There is a bank of 8 dip switches (See Figure 7), located at the
upper left side of the board. The dip switches work in pairs to
match the cooling/heat airflow (CFM/TON), Fan off-delay op-
tions, and electric heat airflow adjustment. The switches appear
as shown in Figure 7.
7
ICM FAN CONTROL
CFM
SELECTION
LIGHT
Page 8
DIP
SWITCHES
Start-Up
Pre-Start Quick Check List
•Is the unit properly and securely located and level with the
proper clearance?
•Is the ductwork correctly sized, run, taped, insulated and
weatherproofed with the proper unit arrangement?
•Is the condensate line properly sized, run, trapped, and
pitched? Does it drain freely?
•Is the filter of the correct size and number? Are the supply
and return registers unobstructed?
•Is the wiring properly sized and run according to the Unit
Wiring Diagram, Figures 5 and 6?
•Is the power supply correct for the unit's requirements?
•Are all wiring connections, including those in the unit
itself, tight?
•Is the thermostat well located, level, correctly wired, and
accurately adjusted?
•Do the outdoor fan and the indoor fan turn free without
rubbing? Are both fans tight on their shafts?
•Has the indoor blower speed tap been determined andthe
proper speed set? See the Unit Wiring Diagram,Figures 5
and 6.
•Has all work been done in accordance to the applicable
local and national codes?
•Are all cover and access panels in place to prevent air loss
and to protect against safety hazards?
•Have all tools and debris around, on top of, and under the
unit been removed?
Starting the Unit In the Cooling Mode
IMPORTANT: Before starting the system in the cooling
cycle, turn the thermostat switch to "OFF" and close the
unit disconnect switch. This procedure energizes the
compressor crankcase heat (if equipped) thereby vapor-
izing any liquid HCFC-22 in the crankcase.
precaution against foaming at start-up which could
damage the compressor. Allow the heat to operate for a
minimum of eight (8) hours.
The TCH048-060F units do not have sump heat as shipped.
NOTE: The crankcase heater is a field installed option on
some models.
NOTE: See the section on "Sequence of Operation" for a
description of the cooling operating sequence.
•To start the unit in the cooling mode, set the thermostat
system switch to COOL.
Move the thermostat COOL indicator to a setting below
This is a
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