6-5
62-11848
6.2.10
Expansion Valve
Low suction pressure with high
superheat
Low refrigerant charge
External equalizer line plugged
Repair
Broken capillary
Repair
Superheat setting too high
Low superheat and liquids
lugging in compressor
Superheat setting too low
External equalizer line plugged
Repair
Pin and seat of expansion valve eroded or held open by
foreign material
Fluctuating suction pressure
Improper bulb location or installation
Insulation missing from sensing bulb
Replace
Low superheat setting
High superheat
Expansion valve setting
6.2.11
Malfunction Hot Gas Solenoid, Condenser Pressure Regulating Valve, or Quench Valve
Valve does not function
properly
No power to valve
Check
Improper wiring or loose connections
Check
Valve improperly assembled
Coil or coil sleeve improperly assembled
Movement of plunger restricted due to:
a. Corroded or worn parts
b. Foreign material lodged in valve
c. Bent or dented enclosing tube
Valve shifts but refrigerant
continues to flow
Foreign material lodged under seat
Defective seat
Table 6–2 Mechanical Indications
INDICATION / TROUBLE
POSSIBLE CAUSES
REFERENCE
SECTION