36
RT-SVX069A-EN
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’.
