Bryant 588A Installation, Start-Up And Service Instructions Manual page 49

SYMPTOM
Integrated control
motor
(units 589A048,060
208/230 v)
IFM does not run.
Integrated control
motor (units
589A048,060
208/230 v)
IFM runs when it
should be off.
Integrated control
motor (units
589A048,060
208/230 v) IFM
operation is
intermittent.
IFM — Evaporator (Indoor) Fan Motor
SYMPTOM
Burners will not ignite.
Inadequate heating.
Poor flame characteristics.
Cooling (cont)
CAUSE
Blower wheel not secured to shaft
Insufficient voltage at motor
Power connectors not properly
seated
Motor programmed with a delay
profile
With thermostat in OFF the voltage
on G,Y1,Y/Y2,W with respect to
common, should be 1 ⁄ of actual
2
low voltage supply
Water dripping into motor
Connectors not firmly seated
Heating
CAUSE
Water in gas line
No power to furnace
No 24-v power supply to control
circuit
Miswired or loose connections
Burned-out heat anticipator in
thermostat
Broken thermostat wire
Misaligned spark electrodes
No gas at main burners
Dirty air filter
Gas input to furnace too low
Unit undersized for application
Restricted airflow
Blower speed too low
Limit switch cycles main burners
Incomplete combustion results in:
Aldehyde odors, carbon monox-
ide, sooting flame, floating flame
—49—
REMEDY
Properly tighten blower wheel to shaft.
Determine cause and correct.
Connectors should snap easily; do not
force.
Allow a few minutes for motor to shut off.
If measured voltage is more than
thermostat is incompatible with motor. If
voltage is less than
Verify proper drip loops in connector wires.
Gently pull wires individually to be sure they
are crimped into the housing.
REMEDY
Drain. Install drip leg.
Check power supply fuses, wiring, or circuit breaker.
Check transformer.
NOTE: Some transformers have internal overcurrent
protection that requires a cool-down period to reset.
Check all wiring and wirenut connections.
Replace thermostat.
Run continuity check. Replace wire if necessary.
Check flame ignition and sense electrode positioning.
Adjust as necessary.
1. Check gas line for air. Purge as necessary.
NOTE: After purging gas line of air, wait at least
5 minutes for any gas to dissipate before attempt-
ing to light unit.
2. Check gas valve.
Clean or replace filter as necessary.
Check gas pressure at manifold. Match with that on
unit nameplate.
Replace with proper unit or add additional unit.
Clean or replace filter. Remove any restriction.
Use faster speed tap if available, or install alternate
motor.
Check rotation of blower, thermostat heat antic-
ipator settings, temperature rise of unit. Adjust as
necessary.
1. Tighten all screws around burner compartment.
2. Cracked heat exchanger. Replace.
3. Unit overfired. Reduce input (change orifices or
adjust gas line or manifold pressure).
4. Check burner alignment.
1 ⁄ , the
2
1 ⁄ , the motor has failed.
2