Bryant 310AAV Wiring Diagrams, Troubleshooting, Cooling Mode, Continuous Blower Mode, Heat Pump

310AAV

d.Flame-Proving- When the burner flame is proved at the flame-proving sensor electrode FSE, the furnace control CPU begins the blower-ON delay period and continues to hold the gas valve GV open. If the burner flame is not proved within two seconds, the control CPU will close the gas valve GV, and the control CPU will repeat the ignition sequence for up to three more Trials-For-Ignition before going to Ignition-Lockout. Lockout will be reset automatically after three hours or by momentarily interrupting 115 vac power to the furnace, or by interrupting 24 vac power at SEC1 or SEC2 to the furnace control CPU (not at W, G, R, etc.) If flame is proved when flame should not be present, the furnace control CPU will lock out of Gas-Heating mode and operate the inducer motor IDM until flame is no longer proved.

e.Blower-On Delay- If the burner flame is proven, the blower motor is energized on HEAT speed 25 sec after the gas valve GV is energized.

Simultaneously, the electronic air cleaner terminal EAC-1 is energized and remains energized as long as the blower motor BLWM is energized.

f.Blower-Off Delay- When the thermostat is satisfied, the R-to-W circuit is opened, de-energizing the gas valve GV, stopping gas flow to the burners, and de- energizing the humidifier terminal HUM. The inducer motor IDM will remain energized for a 5-second post-purge period. The blower motor BLWM and air cleaner terminal EAC-1 will remain energized for 90, 120, 150, or 180 seconds (depending on the blower- OFF delay selection). The furnace control CPU is fact- ory-set for a 120-second blower-OFF delay.

2.Cooling Mode

(See Fig. 26 for thermostat connections.) The thermostat closes the R-to-G-and-Y circuits. The R-to-Y circuit starts the outdoor unit, and the R-to-G and Y circuits start the furnace blower motor BLWM on COOL speed. The electronic air cleaner terminal EAC-1 is energized with 115 vac when the blower motor BLWM is operating. When the thermostat is satisfied, the R-to-G-and-Y cir- cuits are opened. The outdoor unit will stop, and the fur- nace blower motor BLWM will continue operating on the COOL speed for an additional 90 sec. Cut jumper J2 to reduce the cooling off-delay to 5 sec. (See Fig. 25.)

3.Continuous Blower Mode

When the R-to-G circuit is closed by the thermostat, the blower motor BLWM will operate on continuous-blower speed (same as HEAT speed). Terminal EAC-1 is ener- gized as long as the blower motor BLWM is energized.

During a call for heat, the blower BLWM will stop during igniter warm-up (17 sec), ignition, and blower-ON delay (25 sec), allowing the furnace heat exchangers to heat up more quickly, then restarts at the end of the blower-ON delay period at HEAT speed.

When the thermostat “calls for cooling”, the blower motor BLWM will operate at COOL speed. When the thermostat is satisfied, the blower motor BLWM will operate an addi- tional 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 opera- tion.

4.Heat Pump

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-Wand- Y or R-to-W-and-Y-and-G circuits are

energized the furnace control CPU will continue to 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 in- ducer post-purge period and the blower switches to COOL speed after a 3 sec delay. If the R-to-W-and- Y-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 signals disap- pear, leaving the G signal, the blower motor BLWM will continue running the blower motor at HEAT speed after the selected blower-OFF delay period is completed.

Step 4 —Wiring Diagrams

Refer to Fig. 25 and 41 for wiring diagrams.

Step 5 —Troubleshooting

Refer to the service label. (See Fig. 45–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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