Wiring Diagrams; Troubleshooting - Bryant 311AAV Installation, Start-Up, Operating And Service And Maintenance Instructions

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 ther-
mostat 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 push-
button 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.
5. Heat pump
(See Fig. 27-30 for thermostat connections.)
When installed with a heat pump, the furnace control auto-
matically 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-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 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 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.
Step 4—Wiring Diagrams
Refer to Fig. 24 and 46 for wiring diagrams.
Step 5—Troubleshooting
Refer to the service label. (See Fig. 50—Service Label.)
The Troubleshooting Guide can be a useful tool in isolating
furnace operation problems. Beginning with the word "Start,"
answer each question and follow the appropriate arrow to the next
item.
The Guide will help to identify the problem or failed component.
After replacing any component, verify correct operation sequence.
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