Bryant DURAPAC PLUS 581B Installation & Service Instructions Manual page 46

PROBLEM
Burners Will Not Misaligned spark electrodes.
Ignite
No gas at main burners.
Water in gas line.
No power to unit.
No 24 v power supply to control circuit.
Miswired or loose connections.
Burned-out heat anticipator in thermostat.
Broken thermostat wires.
Inadequate Heating Dirty air filter.
Gas input to unit too low.
Unit undersized for application.
Restricted airflow.
Blower speed too low.
Limit switch cycles main burners.
Too much outdoor air.
Poor Flame Incomplete combustion (lack of
Characteristics combustion air) results in:
Aldehyde odors, CO (carbon monoxide),
sooting flame, or floating flame.
Burners Will Not Unit is locked into Heating mode for a
Turn Off one minute minimum.
Table 34 — Perfect Humidity™ Adaptive Dehumidification System Subcooling Mode Service Analysis
PROBLEM
Subcooling Mode (Liquid Reheat)
Will Not Energize.
Low System Capacity.
Loss of Compressor Superheat
Conditions with Subcooling/Reheat
Dehumidification Coil Energized.
Table 35 — Perfect Humidity Dehumidification System Hot Gas Reheat Mode Service Analysis
PROBLEM
Reheat Mode Will Not Energize.
Loss of Compressor Superheat
Conditions with Subcooling/Reheat
Dehumidification Coil Energized.
Excessive Superheat.
Table 33 — Heating Service Analysis
CAUSE
CAUSE
No power to control transformer from
evaporator-fan motor.
No power from control transformer to liquid line
solenoid valve.
Liquid line solenoid valve will not operate.
Liquid line solenoid valve will not open.
Low refrigerant charge or frosted evaporator coil.
Thermostatic expansion valve (TXV).
CAUSE
No power to control transformer from
evaporator-fan motor.
No power from control transformer to hot gas
line solenoid valve.
Hot gas line solenoid valve will not operate.
Low refrigerant charge or frosted evaporator coil.
Thermostatic expansion valve (TXV).
Liquid line solenoid valve will not operate.
Hot gas line solenoid valve will not close.
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Check flame ignition and sensor electrode positioning. Adjust as needed.
Check gas line for air purge as necessary. After purging gas line of
air, allow gas to dissipate for at least 5 minutes before attempting
to relight unit.
Check gas valve.
Drain water and install drip leg to trap water.
Check power supply, fuses, wiring, and circuit breaker.
Check transformer. Transformers with internal overcurrent protection
require a cool-down period before resetting. Check 24-v circuit breaker;
reset if necessary.
Check all wiring and wirenut connections.
Replace thermostat.
Run continuity check. Replace wires, if necessary.
Clean or replace filter as necessary.
Check gas pressure at manifold. Clock gas meter for input. If too low,
increase manifold pressure or replace with correct orifices.
Replace with proper unit or add additional unit.
Clean filter, replace filter, or remove any restrictions.
Use high speed tap, increase fan speed, or install optional blower, as suit-
able for individual units, Adjust pulley.
Check rotation of blower, thermostat heat anticipator settings,
and temperature rise of unit. Adjust as needed.
Adjust minimum position.
Check economizer operation.
Check all screws around flue outlets and burner compartment.
Tighten as necessary.
Cracked heat exchanger. Replace heat exchanger.
Overfired unit — reduce input, change orifices, or adjust gas line or mani-
fold pressure.
Check vent for restriction. Clean as necessary.
Check orifice to burner alignment.
Wait until mandatory one-minute time period has elapsed or reset power to
unit.
Check power source and evaporator-fan relay. Ensure all
wire connections are tight.
1. Fuse open; check fuse. Ensure continuity of wiring.
2. Low-pressure switch open. Cycle unit off and allow low-
pressure switch to reset. Replace switch if it will not
close.
3. Transformer bad; check transformer.
1. Solenoid coil defective; replace.
2. Solenoid valve stuck open; replace.
Valve is stuck closed; replace valve.
1. Check charge amount. Charge per Fig. 52-55.
2. Evaporator coil frosted; check and replace low-
pressure switch if necessary.
1. Check TXV bulb mounting, and secure tightly to suction
line.
2. Replace TXV if stuck open or closed.
Check power source and evaporator-fan relay. Ensure all
wire connections are tight.
1. Fuse open; check fuse. Ensure continuity of wiring.
2. Low-pressure switch open. Cycle unit off and allow low-
pressure switch to reset. Replace switch if it will not
close.
3. Transformer bad; check transformer.
1. Solenoid coil defective; replace.
2. Solenoid valve stuck closed; replace.
1. Check charge amount. Charge per Fig. 52-55.
2. Evaporator coil frosted; check and replace low-
pressure switch if necessary.
1. Check TXV bulb mounting, and secure tightly to suction
line.
2. Replace TXV if stuck open or closed.
Valve is stuck; replace valve.
Valve is stuck; replace valve.
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REMEDY
REMEDY
REMEDY