Double Deck J4PG4 Installation Manual

Table 11-1 Trouble shooting chart (Continued)
SYMPTOM POSSIBLE CAUSE REMEDY
Dirty air filter Replace filter
Unit undersized for load Decrease load or increase unit size
Thermostat temperature set too low Reset thermostat
Low refrigerant charge Locate leak, repair, and recharge
Air in system Recover refrigerant, evacuate system, and recharge
Outdoor coil dirty or restricted Clean coil or remove restriction
Registers sweat Low evaporator airflow Increase speed of blower or reduce restriction - replace air filter
Restriction in liquid line, expansion device or filter
drier
Remove or replace defective component
Flow check piston size too small Change to correct size piston
Incorrect capillary tubes Change coil assembly
TXV does not open Replace TXV
Dirty condenser coil Clean coil
Refrigerant overcharge Correct system charge
Condenser fan not running Repair or replace
Air or non-condensible in system Recover refrigerant, evacuate & recharge
Defective compressor valves Replace compressor
Incorrect capillary tubes Replace coil assembly
Low evaporator airflow Increase speed of blower or reduce restriction - replace air filter
Operating below 65°F outdoors Add Low Ambient Kit
Moisture in system Recover refrigerant - evacuate & recharge - add filter drier
Excessive load Recheck load calculation
Defective compressor Replace
TXV hunting
Check TXV bulb clamp - check air distribution on coil - replace
TXV
Air or non-condensible in system Recover refrigerant - evacuate & recharge
Gurgle or pulsing noise
at expansion device or
liquid line
Air or non-condensible in system Recover refrigerant - evacuate & recharge
Manual reset overtemperature control tripped Reset or replace
Wire loose in limit circuit
Check wiring
Water in gas line Drain. Install drip leg.
No power to furnace Check power supply fuses, wiring or circuit breaker.
No 24 volts power supply to control circuit
Check transformer.
Miswired or loose connections
Check all wiring and wire nut connections
Misaligned spark electrodes
Check flame ignition and sense electrode positioning. Adjust as
necessary.
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 attempting to light unit.
Check gas valve.
Dirty air filter Clean or replace filter as necessary
Gas input to furnace too low Check gas pressure at manifold with that on unit nameplate
Unit undersized for application Replace with proper unit or add additional unit
Restricted airflow Clean or replace filter, remove any restriction
Limit switch cycles main burners
Check rotation of blower, temperature rise of unit. Adjust as
necessary
Tighten all screws around burner compartment
Cracked heat exchanger. Replace as necessary.
Unit over-fired. Reduce input (change orifices or adjust gas line
or manifold pressure).
Check burner alignment
Inspect heat exchanger for blockage. Clean as necessary.
Inadequate heating
Poor flame
characteristics
Incomplete combustion results in: Aldehyde odors,
carbon monoxide, sooting flame, floating flame
Burners will not ignite
No gas at main burners
Low vapor - cool
compressor - iced
evaporator coil
High vapor pressure
Fluctuating head & vapor
pressure
Circulating air blower &
inducer run continuously,
compressor will not start
Compressor operates
continuously
High head-low vapor
pressure
High head-high or normal
vapor pressure - Cooling
mode
Low head-high vapor
pressures
Both condenser fan and
compressor startup and
shutdown frequently
(about three minutes per
cycle)
Abnormal high discharge pressure caused the
high pressure switch act
Reference to the remedy of ‘High head-high or normal
vapor pressure-cooling mode’.
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