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Page 20
Installation, Operation & Maintenance Manual (IOPCKKS60220510B1)
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 10).
SAFETY CONTROLS
The unit control board monitors the temperature limit switch
of electric heat units. The control circuit includes the following
safety controls :
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 10.
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. a. Check indoor blower rotation. If blower rotation is in the wrong
direction. Refer to Phasing Section in general information section.
b. Check blower drive belt tension.
c. 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 second stage of the thermostat will energize second stage
compressor 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.
SHUT DOWN
1. Set the thermostat to highest temperature setting.
2. Turn off the electrical power to the unit.
BELT DRIVE BLOWER
All units have belt drive single speed blower motors. The variable
pitch pulley on the blower motor can be adjusted to obtain the
desired supply air CFM.
TROUBLE SHOOTING
COOLING TROUBLE SHOOTING GUIDE
WARNING
TROUBLESHOOTING OF COMPONENTS MAY REQUIRE
OPENING THE ELECTRICAL CONTROL BOX WITH THE
POWER CONNECTED TO THE UNIT. USE EXTREME CARE
WHEN WORKING WITH LIVE CIRCUITS! CHECK THE UNIT
NAMEPLATE FOR THE CORRECT LINE VOLTAGE AND
SET THE VOLTMETER TO THE CORRECT RANGE BEFORE
MAKING ANY CONNECTIONS WITH LINE TERMINALS.
Troubleshooting of components may require opening theelectrical
control box with the power connected to the unit. Use extreme
care when working with live circuits! Check the unit nameplate
for the correct line voltage and set the voltmeter to the correct
range before making any connections with line terminals. When
not necessary, shut off all electric power to the unit prior to any of
the following maintenance procedures so as to prevent personal
injury.
CAUTION
LABEL ALL WIRES PRIOR TO DISCONNECTION WHEN
SERVICING CONTROLS. WIRING ERRORS CAN CAUSE
IMPROPER AND DANGEROUS OPERATION, WHICH
COULD CAUSE INJURY TO PERSON AND/OR DAMAGE
UNIT COMPONENTS. VERIFY PROPER OPERATION
AFTER SERVICING.