Carrier 59SP5A Installation, Start-Up, Operating And Service And Maintenance Instructions page 76

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tion after 20 minutes, the furnace control CPU will drop
the blower speed back to HEAT speed. This alternating 10-
minute cycle will continue as long as there is a call for cool-
ing.
c. When the "call for cooling" is satisfied and there is a de-
mand for dehumidification, the cooling blower-off delay
is decreased from 90 sec to 5 sec.
4. 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. Terminal
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 see), ignition (7 see), and
blower-ON delay (25 see), allowing the furnace heat ex-
changers 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 satis-
fied, the blower motor BLWM will operate an additional 90
sec on low-cool speed (same speed as FAN) before revert-
ing back to continuous-blower speed.
When the thermostat "calls for high-cooling', the blower
motor BLWM will operate at COOL speed. When the ther-
mostat is satisfied, the blower motor BLWM will operate an
additional 90 sec 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 sec, 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
push button on the room thermostat for 1-3 sec after the
blower motor BLWM is operating. The furnace control
CPU will shift the continuous-blower speed from the fact-
ory 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.
5. Heat pump
(See Fig. 35 and 36 for thermostat connections.) When in-
stalled with a heat pump, the furnace control automatically
changes the timing sequence to avoid long blower off times
during demand defrost cycles. When the R-to- W-and-Y1
or R-to-W-and-Yl-and-G circuits are energized the fur-
nace control CPU will switch to or turn on the blower motor
BLWM at HEAT speed, and begin a heating cycle. The
blower motor BLWM will remain on until the end of the
prepurge period, then shut off for 24 sec then come back on
at HEAT speed. When the W input signal disappears, the
furnace control begins a normal inducer post-purge period
and the blower remains running at HEAT speed for the se-
lected blower-OFF delay period then switches to low-cool
speed (same speed as FAN). If the R-to-W-and-Yl-and-
G signals disappear at the same time, the blower motor
BLWM will remain on for the selected blower-OFF delay
period. If the R-to- W-and-Y1 signals disappear, leaving
the G signal, the blower motor BLWM will remain on for
the selected blower-OFF delay period then switch to con-
tinuous-blower speed. When the R-to-W-and-Y/Y2,
R-to-W-and-Y/Y2-and-G, R-to-W-and-Yl-and-
Y/Y2, or R-to-W- and-Yl-and-Y/Y2-and-G circuits are
energized the furnace control CPU will switch to or turn on
the blower motor BLWM at HEAT speed, and begin a heat-
ing cycle. The blower motor BLWM will remain on until
the end of the prepurge period, then shut off for 24 sec then
come back on at HEAT speed. When the W input signal dis-
appears, the furnace control begins a normal inducer post-
purge period and the blower switches to COOL speed after
a 3 sec delay. If the R-to-W-and-Y/Y2-and-G or R-to-
W-and-Yl-and -Y/Y2-and-G signals disappear at the
same time, the blower motor BLWM will remain on for the
selected blower-OFF delay period. If the R-to-W-and-
Y/Y2 or R-to-W-and-Yl-and-Y/Y2 signals disappear,
leaving the G signal, the blower motor BLWM will remain
on for the selected blower-OFF delay period then switch to
continuous blower speed.
Component Self-Test
Refer to page 66 for instructions.
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