Bryant 312AAV - Manual (Page 20)

furnace control CPU will hold the blower motor BLWM at
HI 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 LO-HEAT). When the thermostat is satis-
fied, the blower motor BLWM will operate an additional 90
seconds on low-cool speed 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 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 opera-
tion.
Continuous-Blower Speed Selection from Thermostat-
To select different continuous-blower speeds from the room
thermostat, momentarily turn the FAN switch or push-
button on the room thermostat to OFF (AUTO) 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 LO-HEAT to HI-HEAT speed.
Momentarily turning the FAN switch to OFF (AUTO) again
at the thermostat will shift the continuous-blower speed
from HI-HEAT to COOL. Repeating the procedure will
shift the continuous-blower speed from COOL to LO-
HEAT 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.
6. Heat Pump
(See Fig. 26, 27, 28, and 29 for thermostat connections)
When installed 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/W1-and-Y1 or R-to-W/W1-and-Y1-and-G circuits
are energized the furnace control CPU will switch to or turn
on the blower motor BLWM at low-cool speed (same speed
as LO-HEAT), and begin a low-heat 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
LO-HEAT speed. When the W/W1 input signal disappears,
the furnace control begins a normal inducer post-purge
period and the blower remains running at LO-HEAT speed.
If the R-to-W/W1-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/W1-
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/W1-and-Y/Y2, R-to-W/W1-and-Y/Y2-
and-G, R-to-W/W1-and-Y1-and-Y/Y2, or R-to-W/W1-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 COOL speed, and begin a high-heat 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 HI-HEAT speed. When the W/W1 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/W1-and-Y/Y2-and-G
or R-to-W/W1-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/W1-and-Y/Y2 or R-to-W/W1-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.
1. Heat pump MUST have a high pressure switch for dual fuel
applications.
2. Refer to outdoor equipment Installation Instructions for
additional information and setup procedure.
3. Select the “ZONE” position on the two-speed heat pump
control.
4. Outdoor Air Temperature Sensor must be attached in all
dual fuel applications.
5. Dip switch No. 1 on Thermidistat should be set in OFF
position for air conditioner installations. This is factory
default.
6. Dip switch No. 1 on Thermidistat should be set inON
position for heat pump installations.
7. Dip switch No. 2 on Thermidistat should be set in OFF
position for single-speed compressor operation. This is
factory default.
8. Dip switch No. 2 on Thermidistat should be set in ON
position for two-speed compressor operation.
9. Configuration Option No. 10 “Dual Fuel Selection” must be
turnedON in all dual fuel applications.
10. NO connection should be made to the furnace HUM
terminal when using a Thermidistat.
11. Optional connection. If wire is connected, dip switch No. 1
on furnace control should be set in ON position to allow
Thermidistat/Thermostat to control furnace staging.
12. Optional connection. If wire is connected, ACRDJ jumper
on furnace control shouild be removed to allow
Thermidistat/Thermostat to control outdoor unit staging.
13. Furnace must control its own high-stage heating operation
via furnace control algorithm. This is factory default.
14. The RVS Sensing terminal “L” should not be connected.
This is internally used to sense defrost operation.
15. DO NOT SELECT the “FURNACE INTERFACE” or
“BALANCE POINT” option on the two-speed heat pump
control board. This is controlled internally by the
Thermidistat/Dual Fuel Thermostat.
16. Dip switch D on Dual Fuel Thermostat should be set in
OFF position for single-speed compressor operation. This
is factory default.
17. Dip switch D on Dual Fuel Thermostat should be set in ON
position for two-speed compressor operation.
III. START-UP PROCEDURES
1. Purge Gas Lines:After all connections have been made,
purge the lines and check for leaks.
WARNING: Never purge a line into a combustion
chamber. Never use matches, candles, flame, or other
sources of ignition for the purpose of checking leakage.
Use a soap-and-water solution to check for leakage.
Failure to follow this warning can cause fire, explosion,
personal injury, or death.
2. Component Self-Test:The furnace control allows all com-
ponents, except the gas valve, to be run for short period of
time. This feature helps diagnose a system problem in case
of a component failure. To begin component test procedure,
short (jumper) the C
OM
-24v terminal on control and the
TEST/TWIN 3/16-inch quick-connect terminal on control
(behind the C
OM
-24v terminal) for approximately 2 sec.
(See Fig. 22.)
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