35
V9.20
Mal-functioning
thermostatic
expansion valve.
Incorrect superheat setting: determine superheat
and adjust. If expansion valve is faulty, replace.
Expansion valve bulb not located correctly -
review installation instructions and correct.
Liquid flashing at the expansion valve inlet. See
"High liquid line pressure drop" section.
Condensing unit
never shuts off
System is wired incorrectly. Locate correct wiring
diagram for “Electronic” or “Valve” controlled
system, trace wiring and correct.
If a “Valve” control system, the low pressure
switch may have failed closed. Check switch and
replace if necessary.
No airflow
See "Evaporator fan not blowing" section
Insufficient liquid sub-
cooling
Low refrigerant
charge
System charged incorrectly. Review process and
correct.
Leak in system. Find and repair leak, recharge
system.
High liquid line
pressure drop
Check for plugged filter drier and replace if
necessary.
Inspect pipe routing for proper piping practices
and correct.
Liquid line picking up too much ambient heat -
may need to insulate.