Carrier 58TUA - Manual (Page 13)

c. Single-speed heat pump heating
(1.) The thermostat and accessory interface kit R to G-
and-Y circuits start the furnace blower motor BLWM
on heat pump high heat speed (identical to high
cooling speed).
(2.) The electronic air cleaner terminals EAC-1 and EAC-2
are energized with 115v when the blower motor
BLWM is operating.
(3.) When the thermostat is satisfied the furnace blower
motor BLWM will continue operating on the heat
pump high heat speed for an additional 90 sec.
d. Two-speed heat pump heating
(1.) The thermostat closes the R to G circuit for low
heating and starts the furnace blower motor BLWM on
heat pump low heat speed (identical to low cooling
speed). Closing the R-to-Y2 circuit to the furnace will
provide blower motor BLWM heat pump high heat
speed.
NOTE: The furnace control CPU controls blower motor BLWM
speed by sensing only G for heat pump low heat speed and Y2 (for
heat pump high heat speed).
(2.) The electronic air cleaner terminals EAC-1 and
EAC-2 are energized with 115v when the blower
motor BLWM is operating on either heating speed.
(3.) When the thermostat is satisfied, the R to G or
R to G-and-Y2 circuits are opened. After opening the
R to G-and Y2 circuit, the furnace blower motor
BLWM will continue operating on the heating speed
for an additional 90 sec.
(4.) Opening only the R to Y2 circuit will reduce the
blower motor BLWM speed to heat pump low heat
speed.
6. Defrost
a. When the furnace control R to WAVl-and-Y/Y2 circuits
are closed, the furnace control CPU will continue blower
motor BLWM operation at the heat pump heating speed
until the end of the purge period, then shut off until the end
of the HSI ignitor on period (22 sec).
b. When installed with a heat pump, the furnace control CPU
automatically holds the blower off time to 22 sec during the
HSI ignitor on period. After 17 sec of the HSI ignitor on
period, a trial for ignition sequence occurs as described
above for gas heating. After flame is proved and without a
blower on delay, the blower motor BLWM will operate on
high gas heat speed during defrost. For both single-speed
and 2-speed heat pumps, defrost mode is in high-gas heat
only.
c. When furnace control R to WAVl circuit is opened, the
furnace control CPU will begin the normal inducer post
purge period and the blower motor BLWM will remain on
for the blower off delay period. If the R to G circuit remains
closed, the blower motor BLWM will revert to continuous
operation.
START-UP PROCEDURES
1. Component test—The furnace features a component test
system to help diagnose a system problem in the case of a
component failure. To initiate the component test procedure,
ensure that there are no thermostat inputs to the control, and
all time delays have expired. Short the twin/test terminal to
ground or COM for 1 to 4 sec. (See Fig. 10 for terminal
locations.)
A93348
Fig. 10—Control Center
A93377
Fig. 11—Setup Switches on Control Center
(Factory Settings)
NOTE: The component test feature will not operate if the control
is receiving any thermostat signals, or until all time delays have
expired.
The component test sequence is as follows:
a. The furnace control checks itself, operates the inducer
motor on low speed for 7 sec, and on high speed for 7 sec,
then turns off.
b. The hot surface ignitor is energized for 15 sec, then turns
off.
c. The blower motor operates on low gas heat/heat pump low
heat/low cooling/continuous fan speed for 7 sec.
d. The blower motor operates on high gas heat for 7 sec.
e. The blower motor operates on heat pump high heat/high
cool speed for 7 sec, then turns off.
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