Startup & Adjustments; Pre-Start Check List; Start-Up Procedure; Air Circulation - Nordyne iHybrid DF6SF Series Installation Instructions Manual

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

WARnInG:
If this unit is equipped with crankcase heaters,
allow 24 hrs for heating of the refrigerant
compressor crankcase prior to start up and
anytime the power has been removed for more
than 12 hrs. Failure to comply may result in
damage or cause premature failure of the
system.
• 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.
18

Short Cycle Protection

1. With the system operating in cooling mode, note the
temperature setting of the thermostat and gradually raise
the set-point temperature until the unit de-energizes.
2. Immediately lower the set point temperature of the
thermostat to its original setting and verify that the indoor
blower is energized.
3. After approximately 5 minutes, verify the compressor
and fan energize and the temperature of the discharge
air is cooler than the room temperature. notE: This is
available only for the single phase models.

System Cooling Operation (2-Stage)

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 outdoor unit and blower energize on 1st stage cool.
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
1-2 minutes and then lower the thermostat temperature
set point an additional 3-4 degrees until the cooling system
moves into 2nd stage or high cool operating mode. The
compressor and indoor blower will increase in speed.
4. Allow the cooling system to operate for several minutes
and then set the temperature selector above room
temperature. Verify the fan and compressor cycle off with
the thermostat. notE: The blower should also stop in
approximately 60 seconds, unless the fan switch is set
to the ON position.

System Heating (Heat Pump Mode)

1. Set the thermostat system mode to HEAT and the fan
mode to AUTO. Raise the thermostat temperature set
point one degree above room temperature and verify
the outdoor unit and blower energize on 1st stage heat.
2. Feel the air being circulated by the indoor blower and verify
that it is warmer 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, raise
the thermostat temperature set point an additional 1-2
degrees until the system moves to 2nd stage heat pump
mode of operation. The compressor and blower will
increase in speed during 2nd stage cooling.
notE: If thermostat differential is set too high the gas
heat system may energize (depending on thermostat
model) and de-energize the heat pump outdoor system.
Gas heat will remain in operation until the thermostat
call for heat is satisfied.
4. Allow the heating system to operate for several minutes
and then set the temperature selector below room
temperature. Verify the system shutdown sequence.
Note: The blower will remain operating for 60 or 150
seconds after the call for heat is removed depending
on if the system was in heat pump or gas heat mode,
respectively, unless the thermostat switch is set to the
ON position.