Carrier 100/A Series Installation, Start-Up, Operating And Service And Maintenance Instructions page 50

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2. Cooling Mode
The thermostat "calls for cooling."
a. Single-Speed Cooling
(See Fig. 25 - 32 for thermostat connections)
The thermostat closes the R-to-G-and-Y circuits. The
R-to- Y circuit starts the outdoor unit, and the
R-to-G-and-Y/Y2 circuits start the furnace blower
motor BLWM on COOL speed.
The electronic air cleaner ternfinal EAC-1 is energized
with 115 vac when the blower motor BLWM is operating.
When the thermostat is satisfied, the R-to-G-and-Y
circuits are opened. The outdoor unit will stop, and the
furnace blower motor BLWM will continue operating on
the COOL speed for an additional 90 seconds. Jumper
Y/Y2 to DHUM to reduce the cooling off-delay to 5
seconds. (See Fig. 24.)
b. Two-Speed Cooling
(See Fig. 25 - 32 for thermostat connections.)
The thermostat closes the R-to-G-and-Y1 circuits for
low-cooling or closes the R-to-G-and-Yl-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 on low-cool speed (same speed as FAN). The
R-to-Yl-and-Y2 circuits start the outdoor unit on
high-cooling speed, and the R-to-Gand- Y/Y2 circuits
start the furnace blower motor BLWM on COOL speed.
The electronic air cleaner ternfinal 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 ternfinal EAC-I will remain
energized for an additional 90 seconds. Jumper YI to
DHUM to reduce the cooling off-delay to 5 seconds. (See
Fig. 24.)
3. Thermidistat Mode
(See Fig. 26-29 for Thermidistat connections.)
The dehunfidification output, DHUM on the Thernfidistat
should be connected to the furnace control thermostat
ternfinal DHUM. When there is a dehunfidify demand, the
DHUM input is activated, which means 24 vac signal is
removed from the DHUM input ternfinal. In other words,
the DHUM input logic is reversed. The DHUM input is
turned ON when no dehunfidify demand exists. Once 24
vac is detected by the furnace control on the DHUM input,
the furnace control operates in Thernfidistat mode. If the
DHUM input is low for more than 48 hours, the furnace
control reverts back to non-Thernfidistat mode.
The cooling operation described in item 2. above also
applies to operation with a Thernfidistat. The exceptions
are listed below:
a. When the R-to-G-and-Y1 circuit is closed and there is
a demand for dehunfidification, the furnace blower motor
BLWM will continue running at low-cool speed (same
speed as FAN).
b. When the R-to-G-and-Y/Y2 circuit is closed and there
is a demand for dehunfidification, the furnace blower
motor BLWM will drop the blower speed from COOL
to HEAT for a maxinmna of 10 nfinutes before reverting
back to COOL speed. If there is still a demand for
dehunfidification after 20 nfinutes, the furnace control
CPU will drop the blower speed back to HEAT speed.
This alternating 10- nfinute cycle will continue as long
as there is a call for cooling.
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c. When the "call for cooling" is satisfied and there is a
demand for dehunfidification, the cooling blower-off
delay is decreased from 90 seconds to 5 seconds.
Continuous Blower Mode
When the R-to-G circuit is closed by the thermostat, the
blower motor BLWM will operate on continuous-blower
speed (can be adjusted to FAN, HEAT, or COOL speed) at
the thermostat. Factory default is FAN speed. Ternfinal
EAC-1 is energized as long as the blower motor BLWM is
energized. During a call for heat, the blower BLWM will
stop during igniter warm-up (17 seconds), ignition (7
seconds), and blower-ON delay (25 seconds), allowing
the furnace heat exchangers to heat up more quickly, then
restarts at the end of the blower-ON delay period at HEAT
speed.
In heating, the furnace control CPU will hold the blower
motor BLWM at HEAT speed during the selected
blower-OFF delay period before reverting to
continuous-blower speed. When the thermostat "calls for
low-cooling," the blower motor BLWM will switch to
operate at low-cool speed (same speed as FAN). When the
thermostat is satisfied, the blower motor BLWM will
operate an additional 90 seconds on low-cool speed (same
speed as FAN) before reverting back to
continuous-blower speed.
When the thermostat "calls for high-cooling", the blower
motor BLWM will operate at COOL speed. When the
thermostat is satisfied, the blower motor BLWM will
operate an additional 90 seconds on COOL speed before
reverting back to continuous-blower speed.
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 speeds from the
room thermostat, momentarily turn off the FAN switch or
pushbutton on the room thermostat for 1-3 seconds after
the blower motor BLWM is operating. The furnace control
CPU will shift the continuous-blower speed from the
factory setting of FAN to HEAT speed. Momentarily
turning off the FAN switch again at the thermostat will
shift the continuous-blower speed from HEAT to COOL.
Repeating the procedure will shift the continuous-blower
speed from COOL to FAN speed. The selection can be
changed as many times as desired and is stored in the
memory to be automatically used following a power
interruption.
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