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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 seconds), ignition (7
seconds), and blower-ON delay (66 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
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 push-button on the room
thermostat for 1-3 seconds after the blower motor BLWM is
operating.
The
furnace
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 back 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.
before
reverting
back
control
CPU
will
shift
HEAT PUMP MODE
(See Fig. 50 - - 53 for thermostat connections.)
When installed with a heat pump, the furnace control automatically
changes the blower timing sequence to avoid long blower off times
during demand defrost cycles. When the R toW-and-Y1 or R to
W-and-Y1-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 heating cycle. The blower motor BLWM will remain on
until the end of the prepurge period, then shut off for 24 seconds 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 selected
blower-OFF delay period then switches to low-cool speed (same
speed as FAN). If the R to W-and-Y1-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 continuous-blower
speed.
When the R to W-and-Y/Y2, R to W-and-Y/Y2-and-G, R to
W-and-Y1-and-Y/Y2, or R to W-and-Y1-and-Y/Y2-and-G circuits
to
are energized the furnace 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 seconds 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
switches to COOL speed after a 3-second delay. If the R to
W-and-Y/Y2-and-G or R to W-and-Y1-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
the
R to W-and-Y1-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.
- - 52 - -
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