Nortek FG7SC, Руководство по установке

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from the factory pre-wired for 4 blower speeds. There is a fifth
alternate speed available on the motor. To utilize the alternate
speed, remove the wire at the motor plug of the desired speed to
be changed (H, MH, ML, L). Reconnect this wire to the alternate
motor plug speed tap.
Verifying Burner Operation
CAUTION:
The door over the burners may only be open
for inspection purposes only. The door must be
installed during unattended operation.
1. Remove the burner compartment door.
2. Set the thermostat above room temperature and observe
the ignition sequence. NOTE : The burner flame should
carry over immediately between all burners without lifting
off, curling, or floating. The flames should be blue, without
yellow tips.
3. After validating the flame, change thermostat setting to
below room temperature.
4. Verify the burner flame is completely extinguished.
5. Replace the burner compartment door.
Verifying Operation of the Supply Air Limit
Switch
NOTE : A properly functioning limit switch should turn off
the gas valve when the return is blocked (time depends on
how well the return air is blocked). The circulating air and
combustion blowers should continue to run when the limit
switch opens.
1. Verify the blower door is securely mounted in place and
that there is power to the furnace.
2. Block the return airflow to the furnace by installing a close-
off plate in place of or upstream of the filter(s).
3. Set the thermostat above room temperature and observe
the Operating Sequence.
4. Remove the close-off immediately after the limit switch
opens. If the furnace continues to operate with no return
air, set the thermostat below room temperature, shut off
power to the furnace, and replace the limit switch.
System Operation
(Gas) Heating Mode
When the thermostat calls for heating, the circuit between R
and W is completed. The furnace control board initiates the
ignition sequence. Approximately 30 seconds after the gas
flame has proven, the blower motor will start. The blower will
continue to operate after the call for heat has been removed
for a selectable (switch on furnace control board) number of
seconds. NOTE: All on- and off-delays for heating continue
to be controlled by the furnace control board.
Cooling Mode
When the thermostat calls for cooling or heat pump heating,
the circuit between
R
,
G
, and
Y
(
O
is ignored by the blower)
is completed. The blower runs at the selected cooling motor
torque.
Manual Fan
Select the speed using the jumper on the Nordyne/UTEC
control board or dipswitch on the Emerson control board.
Fault Conditions
There is a green and a red LED (labeled “Status”) on the
motor control board to provide system faults as described
below. Refer to Table 15 (page 49) for Nordyne/UTEC boards
or Table 14 (page 49)
for Emerson boards to determine
motor control board fault conditions.
OPERATING SEQUENCE
The operating sequences for the heating, cooling, and fan
modes are described below. Refer to the field and furnace
wiring diagrams:
Figure 26 (page 25)
,
Figure 27 (page 25)
,
Figure 34 (page 32)
and
Figure 36 (page 34)
.
Heating Cycle
1. The thermostat calls for heat by energizing the W terminal
with 24VAC.
2. The control verifies the pressure switch is open.
3. If the pressure switch is open, the control energizes the
inducer and waits for the pressure switch to close. The
pressure switch must close within 10 seconds.
4. The control runs the inducer for a 30-45 second pre-purge.
5. The control energizes the Hot Surface Igniter (HSI) output
for the appropriate warm-up time limit.
6. The control energizes the main gas valve for 3 seconds.
7. If the flame proved and ignites the gas, the control de-
energizes the HSI. The gas valve and inducer remains
energized. The control goes to blower on delay.
8. If flame is present, the control energizes the blower on
the selected HEAT speed 30 seconds after the gas valve
opened. The gas valve and inducer remain energized.
9. When the thermostat demand for heat is satisfied, the
control de-energizes the gas valve. The Inducer output
remains on for a 30 second post-purge period.
10. Blower off timing begins when the thermostat is satisfied.
For Nordyne/UTEC boards, the control will operate at the
selected HEAT speed of 60, 90, 120, or 180 seconds. If
the blower off delay jumper is not present, the fan should
still operate for 120 seconds at the selected HEAT speed.
For Emerson boards, the blower off delay will be 150
seconds. The Indoor blower motor is de-energized after
a blower off delay as selected by the movable jumper.
Cooling Cycle
1. The thermostat calls for cooling by energizing the Y terminal
with 24VAC.
2. The control energizes the blower in cooling speed and
sends 24VAC to the contactor in the condensing unit
3. When the thermostat removes the call for cooling, the
contactor in the outdoor condensing unit is de-energized
and the control continues to run the fan for a period of 60
seconds.
Fan Mode
• When the thermostat energizes the
G
terminal for
continuous fan (without calling for heat or cooling), the
indoor fan is energized on the selected FAN speed. See
Figure 27 (page 25) for fan speed settings.
• If a call for cooling occurs during continuous fan, the
blower will switch over to the selected COOL speed.
• If the W terminal receives a call for heat during continuous
fan, the blower will de energize.
• A call for fan is ignored while in lockout.