RT-SVX069D-EN
35
Table 15. Troubleshooting chart (continued)
Symptom
Possible Cause
Remedy
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
TXV hunting
Check TXV bulb clamp - check air distribution on coil - replace
TXV
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
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.
Poor flame characteristics
Incomplete combustion results in: Aldehyde odors, carbon
monoxide, sooting flame, floating flame
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.
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’.
Troubleshooting
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