Bryant 589A - Manual (Page 26)

F. Heating Sequence of Operation
See Fig. 26-33 and unit wiring label.
On a call for heating, terminal ‘‘W’’ of the thermostat is en-
ergized, starting the induced-draft motor. When the hall-
effect sensor on the induced-draft motor senses that it has
reached the required speed, the burner sequence begins. This
function is performed by the integrated gas control (IGC). The
evaporator-fan motor is energized 45 seconds after flame is
established. When the thermostat is satisfied and ‘‘W’’ is deen-
ergized, the burners stop firing and the evaporator-fan motor
shuts off after a 45-second time-off delay.
A LED (light-emitting diode) indicator is provided on the con-
trol board to monitor operation. The control board is located
by removing the burner access panel. During normal opera-
tion, the LED is continuously on. See Table 7 for error codes.
Table 7 — LED Indications
ERROR CODE LED INDICATION
Normal Operation On
Hardware Failure Off
Fan On/Off Delay Modified 1 Flash
Limit Switch Fault 2 Flashes
Flame Sense Fault 3 Flashes
Four Consecutive Limit Switch Faults 4 Flashes
Ignition Lockout Fault 5 Flashes
Induced-Draft Motor Fault 6 Flashes
Rollout Switch Fault 7 Flashes
Internal Control Fault 8 Flashes
NOTES:
1. There is a 3-second pause between error code displays.
2. If more than one error code exists, all applicable error codes will be
displayed in numerical sequence.
3. This chart is on the wiring diagram located inside the burner access
panel.
G. Limit Switches
Normally-closed limit switch (LS) completes the control cir-
cuit through the thermostat R circuit. Should the leaving-air
temperature rise above the maximum allowable tempera-
ture, the limit switch opens and the R control circuit ‘‘breaks.’’
Any interruption in the R control circuit instantly closes the
gas valve and stops gas flow to the burners and pilot. The
blower motor continues to run until LS resets.
When the air temperature at the limit switch drops to the
low-temperature setting of the limit switch, the switch closes
and completes the R control circuit. The electric-spark igni-
tion system cycles and the unit returns to normal heating
operation.
H. Auxiliary Limit Switch — Rollout
The function of the switch is to close the main gas valve in
the event of flame rollout. The switch is located above the
main burners. When the temperature at the auxiliary switch
reaches the maximum allowable temperature, the R control
circuit trips, closing the gas valve and stopping gas flow to
the burners. The indoor (evaporator) fan motor (IFM) and in-
duced draft motor continue to run until switch is reset.
III. START UP COOLING SECTION AND MAKE
ADJUSTMENTS
CAUTION: Complete the required procedures given
in the Pre-Start-Up section on page 22 before starting
the unit.
Do not jumper any safety devices when operating the
unit.
Do not operate the compressor when the outdoor tem-
perature is below 40 F (unless accessory low-ambient
kit is installed).
Do not rapid-cycle the compressor. Allow 5 minutes be-
tween ‘‘on’’ cycles to prevent compressor damage.
Checking Cooling Control Operation
Start and check the unit for proper cooling control operation
as follows:
1. Place room thermostat SYSTEM switch in OFF posi-
tion. Observe that blower motor starts when FAN switch
is placed in ON position and shuts down when FAN switch
is placed in AUTO. position.
2. Place SYSTEM switch in COOL position and FAN switch
in AUTO. position. Set cooling control below room tem-
perature. Observe that compressor, condenser fan, and
evaporator blower motors start. Observe that cooling
cycle shuts down when control setting is satisfied. The
evaporator fan will continue to run for 30 seconds.
3. When using an auto.-changeover room thermostat, place
both SYSTEM and FAN switches in AUTO. positions.
Observe that unit operates in heating mode when tem-
perature control is set to ‘‘call for heating’’ (above room
temperature) and operates in cooling mode when tem-
perature control is set to ‘‘call for cooling’’ (below room
temperature).
IMPORTANT: Three-phase, scroll compressor units
(588A048,060 and 589A036-060) are direction-oriented. These
units must be checked to ensure proper compressor 3-phase
power lead orientation. If not corrected within 5 minutes, the
internal protector will shut off the compressor. The 3-phase
power leads to the unit must be reversed to correct rotation.
When turning backwards, scroll compressors emit elevated
noise levels, and the difference between compressor suction
and discharge pressures may be dramatically lower than
normal.
(Text continued on page 35.)
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