66
9.0 DIAGNOSTICS & TROUBLESHOOTING
Diagnostics
9.10 Troubleshooting Tips
COOLING MODE
TROUBLESHOOTING TIPS
SYSTEM
PROBLEM
INDICATORS
DISCHARGE
PRESSURE
SUCTION
PRESSURE
SUPERHEAT
Normal: 5°–15°F
[2.8° – 8.3°C]
SUBCOOLING
Normal: See
Charging Chart
Overcharge
High
High
Low
High
Undercharge
Low
Low
High
Low
Liquid Restriction (Drier)
Low
Low
High
High
Low Indoor Airflow
Low
Low
Low
Low
Dirty Outdoor Coil
High
High
Low
Low
Low Outdoor
Ambient Temperature
Low
Low
High
High
Inefficient
Compressor
Low
High
High
High
Bad Indoor Suction
Pressure Transducer or
Faulty Measurement
Low
Low
High
High
Poorly Insulated
Indoor Vapor Line
Thermistor or Bad Thermistor
High
High
Low
Low