Sequence Of Operation; Heating Mode; Cooling Mode - Bryant 395CAV Series Installation, Start-Up, And Operating Instructions Manual

Notes:
1. Heat pump must have a high pressure switch for dual fuel applications.
2. Refer to outdoor equipment Installation Instructions for proper setup.
3. Select the "zone" position on the 2-speed heat pump control.
4. Outdoor air 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 in ON 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 2-speed compressor operation.
9. Configuration Option No. 10 "Dual Fuel Selection" must be turned ON in all dual fuel applications.
10. No connection should be made to the furnace HUM terminal when using a Thermidistat.
B. Sequence of Operation
CAUTION: Furnace control must be grounded for
proper operation, or control will lockout. Control is
grounded through green wire routed to gas valve and
burner bracket screw.
Using the schematic diagram shown in Fig. 16, follow the
sequence of operation through the different modes. Read and
follow the wiring diagram very carefully.
NOTE: If there is a power interruption and any thermostat call,
the control initiates a 90-sec blower only on period before starting
another cycle.

1. Heating mode

When the wall thermostat "calls for heat," the R-W circuit
closes. The furnace control performs a self-check, verifies
the pressure switch contacts are open, and starts inducer
motor.
a. Prepurge period—As the inducer motor comes up to
speed, the pressure switch contacts close to begin a
15-sec prepurge period.
b. Igniter warm-up—At the end of the prepurge period, the
igniter is energized for a 17-sec igniter warm-up period.
c. Ignition sequence—When the igniter warm-up period is
completed, the gas valve opens, permitting gas flow to
the burners where it is ignited. After 5 sec, the igniter is
de-energized and a 2-sec flame-sensing period begins.
d. HUM terminal is energized with the gas valve. See
accessories in the Electrical Connections section.
TWO-STAGE FURNACE
CONTROL
THERMOSTAT
Heat Pump only
O
Y1
W
Y2
G
R
C
See notes 1, 2, and 9.
Fig. 14—Single-Stage Furnace with 2-Speed Outdoor Unit
—12—
2-SPEED
AIR CONDITIONER
OR HEAT PUMP
O
Y1 Y1
Heat Pump
only
W W2
Y2
Y/Y2
G W3
R
R
DHUM
C
COM
HUM
HUMIDIFIER
(24 VAC)
e. Flame-sensing—When burner flame is sensed, the con-
trol begins the blower on delay period and continues
holding the gas valve open. If burner flame is not sensed,
the control closes the gas valve and repeats ignition
cycle.
NOTE: Ignition sequence will repeat 3 additional time before a
lockout occurs. Lockout automatically resets after 3 hr, or can be
manually reset by turning 115v off (not at thermostat) for 3 sec
minimum, then on again.
f. Blower on delay—Forty-five sec after burner flame is
proven, the blower motor is energized on heating speed.
Simultaneously, the humidifier and electronic air cleaner
terminals (HUM and C
and EAC-2 for electronic air cleaner) are energized. If
jumper is across PL7-6 and PL7-9, blower on delay is 66
sec.
g. Blower off delay—When the thermostat is satisfied, the
circuit between R-W is broken, de-energizing the gas
valve stopping gas flow to the burners. The blower
motor and EAC remain energized 90, 135, 180, or 225
sec (depending on the blower off-time selection). The
furnace is factory set for a 135-sec blower off delay.
h. Post-purge—The inducer motor remains energized 5 sec
after the burners are extinguished. If jumper is across
PL7-6 and PL7-9, the post-purge period is 15 sec.

2. Cooling mode

i. Single-Speed Outdoor Unit — See figures 9, 10 and 12.
The thermostat closes the R to G and Y circuits The
R-Y/Y2 circuit starts the outdoor unit, and the R to G and
Y/Y2 circuits start the furnace blower motor on COOL
A99439
-24V for humidifier, EAC-1
OM