PG80VTLA: Installation, Start-up, Operating and Service and Maintenance Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
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circuits switch the outdoor unit to high-cooling speed, and the
R-to-G-and-Y1-and-Y/Y2 circuits transition the furnace blower motor
BLWM to high-cooling airflow. High-cooling airflow is based on the
A/C selection. (See Fig. 55).
NOTE: When transitioning from low-cooling to high-cooling the
outdoor unit compressor will shut down for 1 minute while the furnace
blower motor BLWM transitions to run at high-cooling airflow.
The electronic air cleaner terminal EAC-1 is energized with 115 vac
whenever the blower motor BLWM is operating.
When the thermostat is satisfied, the R-to-G-and-Y circuit are opened.
The outdoor unit stops, and the furnace blower BLWM and electronic air
cleaner terminal EAC-1 will remain energized for an additional 90
seconds. Jumper Y1 to DHUM to reduce the cooling off-delay to 5
seconds. (See Fig. 36).
c. Two-Stage Thermostat and Two-Speed Cooling
See Fig. 34 for thermostat connections
NOTE: The air conditioning relay disable jumper ACRDJ must be
disconnected to allow thermostat control of the outdoor unit staging.
(See Fig. 36).
The thermostat closes the R-to-G-and-Y1 circuits for low-cooling or
closes the R-to-G-and-Y1-and-Y2 circuits for high-cooling. The
R-to-Y1 circuit starts the outdoor unit on low-cooling speed, and the
R-to-G-and-Y1 circuit starts the furnace blower motor BLWM at
low-cooling airflow which is the true on-board CF selection. (See
Table 4 and Fig. 55). The R-to-Y1-and-Y2 circuits start the outdoor unit
on high-cooling speed, and the R-to- G-and-Y/Y2 circuits start the
furnace blower motor BLWM at high-cooling airflow. High-cooling
airflow is based on the A/C (air conditioning) selection. (See Fig. 55).
The electronic air cleaner terminal EAC-1 is energized with 115 vac
whenever the blower motor BLWM is operating.
When the thermostat is satisfied, the R-to-G-and-Y1 or R-to-
G-and-Y1-and-Y2 circuits are opened. The outdoor unit stops, and the
furnace blower BLWM and electronic air cleaner terminal EAC-1 will
remain energized for an additional 90 seconds. Jumper Y1 to DHUM to
reduce the cooling off-delay to 5 seconds. (See Fig. 36).
4. Thermidistat Mode
See Fig. 28, Fig. 29, and Fig. 30 for thermostat connections.
The dehumidification output, DHUM on the Thermidistat should be
connected to the furnace control thermostat terminal DHUM. When
there is a dehumidify demand, the DHUM input is activated, which
means 24 vac signal is removed from the DHUM input terminal. In
other words, the DHUM input logic is reversed. The DHUM input
is turned ON when no dehumidify demand exists. Once 24 vac is
detected by the furnace control on the DHUM input, the furnace
control operates in Thermidistat mode. If the DHUM input is low
for more than 48 hours, the furnace control reverts back to
non-Thermidistat mode.
The cooling operation described in item 3. above also applies to
operation with a Thermidistat. The exceptions are listed below:
a. Low cooling-When the R-to-G-and-Y1 circuit is closed and
there is a demand for dehumidification, the furnace blower motor
BLWM will drop the blower airflow to 90 percent of low-cooling
airflow which is the true on-board CF selection. (See Table 4 and
Fig. 55).
b. High cooling-When the R-to-G-and Y/Y2 circuit is closed and
there is a demand for dehumidification, the furnace blower motor
BLWM will drop the blower airflow to 90 percent of
high-cooling airflow. High-cooling airflow is based on the A/C
(air conditioning) selection. (See Fig. 55).
c. Cooling off-delay-When the “call for cooling” is satisfied and
there is a demand for dehumidification, the cooling blower-off
delay is decreased from 90 seconds to 5 seconds.
5. Continuous Blower Mode
When the R-to-G circuit is closed by the thermostat, the blower
motor BLWM will operate at continuous blower airflow.
Continuous blower airflow selection is initially based on the CF
selection shown in Table 4 and Fig. 55. Factory default is shown in
Table 4. Terminal EAC-1 is energized as long as the blower motor
BLWM is energized.During a call for heat, the furnace control CPU
will transition the blower motor BLWM to continuous blower
airflow or low-heat airflow whichever is lowest. The blower motor
BLWM will remain ON until the main burners ignite then shut OFF
and remain OFF for the blower-ON delay (45 seconds in low-heat,
and 25 seconds in high-heat), allowing the furnace heat exchangers
to heat up more quickly, then restarts at the end of the blower-ON
delay period at low-heat or high-heat airflow, respectively.
The blower motor BLWM will revert to continuous-blower airflow
after the heating cycle is completed. In high-heat, the furnace
control CPU will drop the blower motor BLWM to low-heat airflow
during the selected blower-OFF delay period before transitioning to
continuous-blower airflow.
When the thermostat “calls for low-cooling”, the blower motor
BLWM will switch to operate at low-cooling airflow. When the
thermostat is satisfied, the blower motor BLWM will operate an
additional 90 seconds at low-cooling airflow before transitioning
back to continuous-blower airflow.
When the thermostat “calls for high-cooling”, the blower motor
BLWM will operate at high cooling airflow. When the thermostat is
satisfied, the blower motor BLWM will operate an additional 90
seconds at high-cooling airflow before transitioning back to
continuous-blower airflow. When the R-to-G circuit is opened, the
blower motor BLWM will continue operating for an additional 5
seconds, if no other function requires blower motor BLWM
operation.
Continuous Blower Speed Selection from Thermostat
To select different continuous-blower airflow from the room thermostat,
momentarily turn off the FAN switch or push button on the room
thermostat for 1-3 seconds after the blower motor BLWM is operating.
The furnace control CPU will shift the continuous-blower airflow from
the factory setting to the next highest CF selection airflow. (See Table 4
and Fig. 55). Momentarily turning off the FAN switch again at the
thermostat will shift the continuous-blower airflow up one more
increment. If you repeat this procedure enough you will eventually shift
the continuous-blower airflow to the lowest CF selection. (See Table 4
and Fig. 55). The selection can be changed as many times as desired and
is stored in the memory to be automatically used following a power
interruption.
NOTE: If the blower-off delay is set to the maximum, the adjustable
continuous-fan feature is locked (i.e., fan speed cannot be changed from
its current setting).
6. Heat pump
See Fig. 30 - Fig. 33 for thermostat connections.
When installed with a heat pump, the furnace control automatically
changes the timing sequence to avoid long blower off times during
demand defrost cycles. Whenever W/W1 is energized along with
Y1 or Y/Y2, the furnace control CPU will transition to or bring on
the blower motor BLWM at cooling airflow or low-heat airflow,
whichever is lowest. The blower motor BLWM will remain on until
the main burners ignite then shut OFF and remain OFF for 25
seconds before coming back on at heating airflow. When the W/W1
input signal disappears, the furnace control begins a normal inducer
post-purge period while changing the blower airflow. If Y/Y2 input
is still energized the furnace control CPU will transition the blower
motor BLWM airflow to cooling airflow. If Y/Y2 input signal
disappears and the Y1 input is still energized the furnace control
CPU will transition the blower motor BLWM to low-cooling
airflow. If both the Y1 and Y/Y2 signals disappear at the same time,
the blower motor BLWM will remain on at low-heat airflow for the
selected blower-OFF delay period. At the end of the blower- OFF
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