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Installation, Operation & Maintenance Manual ( IOPCKKS60220510C1)
The refrigeration systems are
controlled. On any fault, only the associated system will be
affected by any safety / preventive action.
The other refrigerant system will continue in operation unless it is
affected by the fault as well. The unit control board monitors the
temperature limit switch of electric heat units.
COMPRESSOR PROTECTION
The compressors also have inherent (internal) protection. If there
is an abnormal temperature rise in a compressor, the protector
will open to shut down the compressor. The UCB incorporates
features to minimize compressor wear and damage.
An anti short cycle delay (ASCD) is utilized to prevent operation
of a compressor too soon after its previous run. Additionally, a
minimum run time is imposed any time a compressor is energized.
The ASCD is initiated on unit start up and on any compressor reset
or lock out.
FLASH CODES
The UCB will initiate a flash code associated with errors within the
system. Refer to UNIT CONTROL BOARD FLASH CODES Table 11.
RESET
Remove the call for cooling, by raising thermostat setting higher
than the conditioned space temperature. This resets any pressure
or freezestat flash codes.
ELECTRIC HEATING SEQUENCE OF OPERATIONS
The following sequence describes the operation of the electric
heat section. Two-stage heating (Heaters MUST use a two stage
thermostat) :
a.
Upon a call for first-stage heat by the thermostat, the heater
contactor will be energized. After completing the specified
fan on delay for heating, the UCB will energize the blower
motor. If the second stage of heat is required, second heater
contactor will be energized. After completing the specified
fan on delay for heating, the UCB will energize the blower
motor.
b.
The thermostat will cycle the electric heat to satisfy the
heating requirements of the conditioned space.
HEATING OPERATION ERRORS
TEMPERATURE LIMIT
If the UCB senses zero volts from the high temperature limit,the
indoor blower motor is immediately energized. This limit is
monitored regardless of unit operation status, i.e. the limit is
monitored at all times. If the temperature limit opens three times
within one hour, it will lock on the indoor blower motor and a flash
code is initiated (See Table 11).
SAFETY CONTROLS
The unit control board monitors the temperature limit switch of
electric heat units. The control circuit includes the following safety
controls :
independently monitored and
Temperature Limit Switch (AUTO)
This control is located inside the heater compartment and is set
to open at 120°F. It resets automatically. The limit switch operates
when a high temperature condition, caused by inadequate supply
air flow occurs, thus shutting down the heater and energizing the
blower.
RESET
Remove the call for cooling, by raising thermostat setting higher
than the conditioned space temperature. This resets any pressure
or freezestat flash codes.
FLASH CODES
The UCB will initiate a flash code associated with errors within the
system. Refer to UNIT CONTROL BOARD FLASH CODES Table 11.
START UP (COOLING)
PRESTART CHECK LIST
After installation has been completed :
1.
Check the electrical supply voltage being supplied. Be sure
that it is the same as listed on the unit nameplate.
2.
Set the room thermostat to the on position.
3.
Turn unit electrical power on.
4.
Set the room thermostat fan switch to on.
5.
Check indoor blower rotation.
- If blower rotation is in the wrong direction.Refer to phasing
section in general information section.
- Check blower drive belt tension.
- Check bearing lubrication. If it requires lubrication,
grease it.
6.
Check the unit supply air (CFM).
7.
Measure evaporator fan motor amp draw.
8.
Set the room thermostat fan switch to off.
9.
Turn unit electrical power off.
OPERATING INSTRUCTIONS
1.
Turn unit electrical power on.
2.
Set the room thermostat setting to lower than the room
temperature.
3.
First stage compressors will energize after the built in time
delay (five minutes).
4.
The 2nd, 3rd and 4th stage of the thermostat will energize the
respective compressors (if needed).
POST START CHECK LIST
1.
Verify proper system pressures for both circuits.
2.
Measure the temperature drop across the evaporator coil.
3.
Measure the system Amperage draw across all legs of 3 phase
power wires.
4.
Measure the condenser fan amp draw.
Page 20
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