RT-SVX096A-EN
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Table 22. Troubleshooting chart (continued)
SYMPTOM POSSIBLE CAUSE REMEDY
High head-low vapor pressure
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
EXV does not open
Check the control wiring and valve body; replace the coil or the
valve body
High head-high or normal vapor
pressure - Cooling mode
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 and recharge
Low head-high vapor pressures
Defective compressor valves Replace compressor
Incorrect capillary tubes Replace coil assembly
Low vapor - cool compressor - iced
evaporator coil
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
High vapor pressure
Excessive load Recheck load calculation
Defective compressor Replace
Fluctuating head and vapor pressure Air or non-condensible in system Recover refrigerant - evacuate and recharge.
Gurgle or pulsing noise at expansion
device or liquid line
Air or non-condensible in system Recover refrigerant - evacuate and recharge.
Circulating air blower and inducer
run continuously, compressor will not
start
Manual reset overtemperature control tripped Reset or replace.
Wire loose in limit circuit
Check wiring.
Burners will not ignite
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.
No gas at main burners
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.
Inadequate heating
Dirty air filter
Clean or replace filter as necessary; check power supply
fuses, wiring, or circuit breaker.
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.
Troubleshooting
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