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START UP & ADJUSTMENTS
Pre-Start Check List
√ Verify the unit is level and allows proper condensate
drainage.
√ Verify all clearance requirements are met and there is
free airflow to and from the outdoor coil.
√ Verify that the duct work is sealed to prevent air leakage.
√ Verify that the line voltage power leads are securely
connected and the unit is properly grounded.
√ Verify that the low voltage wires are securely connected
to the correct leads on the low voltage terminal strip.
√ Verify that the gas line service pressure does not exceed
10.0 inches WC (0.36 psig), and is not less than 4.5
inches WC (0.16 psig) for natural gas. For LP gas the
line service pressure must not exceed 14 inches WC
(0.51 psig) and must not be less than 11.0 inches WC
(0.40 psig).
√ Verify that the flame roll-out control is closed. If
necessary, press the red button to reset the control. DO
NOT install a jumper wire across the control to defeat
its function. If the control reopens upon start-up, DO
NOT reset the control without identifying and correcting
the fault condition which caused the control to trip.
√ Verify that the gas line has been purged and all
connections are leak tight.
√ Verify that all exterior panels are replaced and securely
fastened.
√ Verify that the outdoor fan turns freely.
√ Verify that the power supply branch circuit overcurrent
protection is sized properly.
√ Verify that the thermostat is wired correctly. The
thermostat function switch should be set to OFF and
the thermostat fan switch should be set to AUTO.
Start-Up Procedure
• Check all electrical wiring for loose connections and
tighten as required.
• Check unit for return air filters and condensate trap.
• Close all electrical disconnects to energize the system.
Air Circulation
Leave the thermostat system mode on OFF and set the
fan mode to ON. Blower will run continuously. Check the
air delivery at the supply registers and adjust register
openings for balanced air distribution. Examine ductwork
for leaks or obstruction if insufficient air is detected. Set
the thermostat fan mode to AUTO. The blower will stop
running. NOTE: When fan ON is selected, the blower will
operate at 50% of selected airflow when no call for heating
or cooling is present.
System Cooling
1. Set the thermostat's system mode to COOL and the
fan mode to AUTO. Lower the thermostat temperature
setpoint one degree below room temperature and verify
the Operating Sequence (pages 19-20). Verify that
the compressor and outdoor fan motor are energized.
NOTE: System will energize Y1 and run at stage 1
intermediate speed.
2. Feel the air being circulated by the indoor blower and
verify that it is cooler than ambient temperature. Listen for
any unusual noises. If unusual sounds occur, determine
the source of the noise and correct as necessary.
3. After determining the system is operating properly,
wait 2 minutes then lower the thermostat temperature
setpoint an additional 3-4 degrees until the system
energizes Y1 & Y2 and runs at stage-2 nominal rating
speed. Verify. operating codes as indicated by the two
digit display on the interface board. See Figure 14 and
Table 17 (page 31).
4. After the unit has run for approximately 5 minutes, set
the thermostat above room temperature. Verify the
outdoor fan and compressor stop running. The indoor
blower will stop after a 60 second delay.
System Heating
1. Set the thermostat to the lowest setting.
2. Follow the procedures given on the operating instruction
label in this installation instructions or attached inside
the louvered control access panel.
3. Set the thermostat one degree above room temperature
and verify the sequence of operation. See Operating
Sequence section (pages 19 & 20.)
4. Verify that the compressor and outdoor fan motor are
not energized.
5. After determining the system is operating properly,
after 1-2 minutes raise the thermostat temperature
set point an additional 3-4 degrees until the heating
system moves into 2nd stage or high heat operating
mode. The gas valve will energize to high heat mode
while the induced draft motor and indoor blower motor
both increase in speed.
6. After the unit has run for approximately five minutes,
set the thermostat below room temperature. Verify the
shutdown sequence; steps 10 -12 in the Operating
Sequence section (page 20).
Verifying & Adjusting Temperature Rise
Verify the temperature rise through the unit is within the
range specified on the unit data label for both high and
low firing rates. Temperature rises outside the specified
range could result in premature heat exchanger failure.
1. Place thermometers in the return and supply air stream
as close to the unit as possible. The thermometer on the
supply air side must be shielded against direct radiation
from the heat exchanger to avoid false readings.
2. Adjust all registers and duct dampers to the desired
position. Run the unit for 10 to 15 minutes before
taking any temperature readings. The temperature
rise is the difference between the supply and return
air temperatures.
NOTE: For typical duct systems, the temperature rise will
fall within the range specified on the data label (with the
blower speed at the factory recommended setting) shown
in Table 12 (page 27). If the measured temperature rise falls
outside the specified range, it may be necessary to change
17
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