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6. The 30-second HEAT FAN ON delay time begins
after the main burners light.
7. The unit delivers heat to the conditioned space until
the thermostat is satisfied.
8. Gas valve(s) de-energizes. The induced draft blower
continues operation for a 30-second post-purge.
NOTE: Induced draft blower remains at low speed (or
switches from high to low if operating at high stage
heat) for the 30-second post purge.
9. Ignition control begins timing the HEAT FAN OFF
delay. There is an adjustable HEAT FAN OFF delay
of approximately 90/120/150/180 seconds (factory
set at 150). If the unit is operating at high stage
when the call for heat is removed, the blower will
operate for 30 seconds at high heat speed then
switch to low heat speed for the remainder of the
selected HEAT FAN OFF delay.
PCBAG127 Ignition Module
NOTE: After the HEAT FAN OFF delay time has elapsed,
the blower will de-energize. This allows any additional heat
in the heat exchanger to be transferred to the conditioned
Defrost Cycle
NOTE: The defrost board is equipped with a jumper for
SmartShift™ defrost technology operation. This operation
turns the compressor off for 30 seconds at defrost
initiation and termination. The unit is factory shipped for
SmartShift™ defrost technology operation. To operate unit
at rated efficiencies, move the jumper on the defrost board
from "DLY" to "NORM".
During operation the power to the circuit board is controlled
by a temperature sensor, which is clamped to a feeder tube
entering the outdoor coil. Defrost timing periods of 30, 60
and 90 minutes may be selected by setting the circuit board
jumper to 30, 60 and 90 respectively.
Accumulation of time for the timing period selected starts
when the sensor closes (approximately 30 ± 5°F) and when
the wall thermostat calls for heat. At the end of the timing
period, the unit's defrost cycle will be initiated provided the
sensor remains closed.
space.
Upon a call for defrost, the blower will continue to run
and the defrost board will send a W1 signal to the ignition
control. At the same time the compressor will stop for 30
seconds, if the SmartShift™ defrost technology delay
feature is selected on the defrost board. At this time,
the reversing valve shifts from heat to cool position and
condenser fans shut off. The inducer motor will immediately
energize for a 15 second prepurge.
A 7-second trial for ignition begins by energizing the low
and high stages of the gas valve along with this spark
ignition. Main burners light and control detects presence
of flame. The compressor (after its 30/OFF second delay)
restarts in cooling mode to defrost the condensor coil.
When the sensor opens (approximately 60°F), the
defrost cycle is terminated and the timing period is reset.
If the defrost cycle is not terminated due to the sensor
temperature, a twelve minute override interrupts the unit's
defrost period. At this time the W1 signal is removed from
the ignition control board, the compressor will stop for a 30
second SmartShift™ defrost technology delay (if selected)
and the reversing valve slides back to its normal heat
position.
Cooling
1. Thermostat calls for cooling.
2. When the thermostat call is for cooling, the
compressor and outdoor fan are energized .
3. The indoor blower will energize approximately 6
seconds later.
4. The unit delivers cooling to the conditioned space
until the thermostat is satisfied.
5. The compressor and outdoor fan will be de-energized
when the thermostat opens.
6. The indoor blower continues to run at low cool speed
for approximately 60 seconds after the thermostat
is satisfied. This allows additional cooling from the
indoor coil to be transferred to the conditioned space.
Then, the indoor blower is de-energized.
NOTE: A 180-second anti-short cycle is integral to
the control and prevents recycling of the compressor.
Cooling Operation
NOTE: Mechanical cooling cannot be reliably provided at
ambient temperatures below 50° F.
1. Turn on the electrical power supply to the unit.
2. Place the room thermostat selector switch in
the COOL position (or AUTO if available, and if
automatic changeover from cooling to heating is
desired).
3. Set the room thermostat to the desired temperature.
Fan Only
1. Thermostat calls for FAN ONLY by energizing "G".
2. The indoor blower is immediately energized at the
low heat speed.
3. The indoor blower is immediately de-energized once
15
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