48
10.0 DIAGNOSTICS AND TROUBLESHOOTING
10.7
Service Analyzer Chart (cont.)
Diagnostics
FLOODING
SYMPTOM POSSIBLE CAUSE CHECK OR REMEDIES
Superheat and
suction pressure
uctuate (EXV is
hunting)
Oversized EXV Install correct EXV
Unequal refrigerant ow through evaporator circuit Ensure suction line thermistor is in correct location in a
clean section of copper pipe
Moisture freezing and partially blocking EXV Recover refrigerant, change lter-drier, evacuate system
and recharge
TXV does not
regulate at all
External equalizer line not connected or line
plugged
Connect equalizer line in proper location, or remove any
blockage
Sensing bulb lost its operating charge Replace TXV
Valve body damaged during soldering or by im-
proper installation
Replace the TXV
10.8
Troubleshooting Tips
COOLING MODE
TROUBLESHOOTING TIPS
SYSTEM
PROBLEM
INDICATORS
DISCHARGE
PRESSURE
SUCTION
PRESSURE
SUPERHEAT
Normal: 5
o
-15
o
F
[2.8
o
-8.3
o
C]
SUBCOOLING
Normal: See
Charging Chart
COMPRESSOR
AMPS
Overcharge High High Low High High
Undercharge Low Low High Low Low
Liquid Restriction
(Filter Drier)
Low Low High High Low
Low Indoor Airow Low Low Low Low Low
Dirty Outdoor Coil High High Low Low High
Low Outdoor
Ambient Temperature
Low Low High High Low
Inefcient
Compressor
Low High High High Low
Indoor TXV Sensing
Bulb Charge Lost or
Bad Thermistor
Low Low High High Low
Poorly Insulated
Indoor TXV Sensing
Bulb or Thermistor.
Bad Thermistor.
High High Low Low High