Continuous Blower Mode; Heat Pump Mode; Defrost Mode; Start-Up Procedures - Carrier 58TMA Installation, Start-Up, And Operating Instructions Manual

(3.) When the thermostat is satisfied, the R to G-and-Y1
or R to G-and-Y1-and-Y/Y2 circuits open. The out-
door unit stops, and the furnace blower continues
operating on the cooling speed for an additional 90
sec.

4. Continuous Blower Mode

a. When the R to G circuit is closed by the thermostat, the
blower motor BLWM operates on low-gas-heat speed
(identical to low-cool speed). Terminals EAC-1 and EAC-2
are energized with 115v as long as the blower motor
BLWM is energized.
b. During a "call for heat," the blower motor BLWM stops
during ignitor warm-up (17 sec), ignition (7 sec), and
blower on delay (45 sec), allowing the furnace heat
exchangers to heat up quickly.
(1.) The blower motor BLWM reverts to continuous
blower speed after the heating cycle is completed. In
high-gas- heat, the furnace control CPU holds the
blower motor BLWM at high-gas-heat speed during
the selected blower off delay period before reverting
to continuous blower speed.
(2.) When the thermostat "calls for low cooling," the
blower motor BLWM continues to operate on low-
cool speed. When the thermostat is satisfied, the
blower motor BLWM continues on continuous blower
speed.
(3.) When the thermostat "calls for high cooling," the
blower motor BLWM operates on high-cool speed.
When the thermostat is satisfied, the blower motor
BLWM operates an additional 2 sec on high-cool
speed before reverting back to continuous blower
speed.
(4.) When the R to G circuit is opened, the blower motor
BLWM continues operating for an additional 90 sec if
no other function requires blower motor BLWM
operation.
5. Heat Pump
NOTE: An accessory interface kit is required with single-speed
heat pumps. See interface kit Installation Instructions for single-
speed heat pump thermostat and interface connections. No inter-
face kit is needed for 2-speed heat pumps. See 2-speed heat pump
Installation Instructions for thermostat connections.
a. Single-Speed Heat Pump Cooling
(1.) The thermostat and interface kit close the R to
G-and-Y/Y2 circuit to start the furnace blower motor
BLWM on high-cooling speed. (The Y/Y2 input to the
furnace control is necessary to provide adequate cool-
ing airflow.)
(2.) The EAC terminals EAC-1 and EAC-2 are energized
with 115v when the blower motor BLWM is operat-
ing.
(3.) When the thermostat is satisfied, furnace blower motor
BLWM continues operating on the high-cooling speed
for an additional 90 sec.
b. Two-Speed Heat Pump Cooling
(1.) The thermostat R to G circuits start the furnace blower
motor BLWM on low-cooling speed. The thermostat
R to G-and-Y/Y2 circuits start the furnace blower
motor BLWM on high-cool speed.
NOTE: The furnace control CPU controls blower motor BLWM
speed by sensing only G (for low-cooling speed) and Y2 (for
high-cooling speed).
(2.) The EAC terminals EAC-1 and EAC-2 are energized
with 115v when the blower motor BLWM is operating
on either cooling speed.
(3.) When the thermostat is satisfied, the furnace blower
motor BLWM continues operating on the cooling
speed for an additional 90 sec.
c. Single-Speed Heat Pump Heating
(1.) The thermostat and accessory interface kit R to G-
and-Y/Y2 circuits start the furnace blower motor
BLWM on heat pump high-heat speed (identical to
high-cool speed).
(2.) The EAC terminals EAC-1 and EAC-2 are energized
with 115v when the blower motor BLWM is operat-
ing.
(3.) When the thermostat is satisfied, the furnace blower
motor BLWM continues 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 heat
and starts the furnace blower motor BLWM on heat
pump low-heat speed (identical to low-cooling speed).
Closing the R-Y/Y2 circuit to the furnace provides
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 EAC 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 continues operating on the heating speed for
an additional 90 sec.
(4.) Opening the R-Y2 circuit reduces the blower motor
BLWM speed to heat pump low-heat speed.
6. Defrost
a. When the furnace control R to W/W1-and-Y/Y2 circuits
are closed, the furnace control CPU continues blower
motor BLWM operation at the heat pump heating speed
until the end of the prepurge period, then shuts 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 then operates
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 W/W1 circuit is opened, the
furnace control CPU begins the normal inducer post-purge
period, and the blower motor BLWM remains on for the
blower off delay period. If the R-G circuit remains closed,
the blower motor BLWM reverts 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
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