Discharge Pressure
a) Faulty condenser temperature regulation
a) Check condenser control operation
b) Suction shut-off valve partially closed
b) Open valve
c) Insufficient refrigerant in system
c) Check for leaks. Repair and add charge
d) Low suction pressure
d) See Corrective Steps for low suction pressure below
e) Compressor operating unloaded
e) See Correction Steps for failure of compressor to load
up below
f) Condenser too large*
f) Check condenser rating table against the operation
g) Low ambient conditions*
g) Check condenser rating tables against the operation
Suction Pressure
a) Lack of refrigerant
a) Check or leaks. Repair and add charge
b) Evaporator dirty
b) Clean chemically
c) Clogged liquid line filter-drier
c) Replace cartridge(s)
d) Clogged suction line or compressor suction
gas strainers
d) Clean strainers
e) Expansion valve malfunctioning
e) Check and reset for proper superheat. Replace if
necessary
f) Condensing temperature too low
f) Check means for regulating condensing temperature
g) Compressor will not unload
g) See Corrective Steps for failure of compressor to
unload
h) Insufficient water flow
h) Adjust gpm.
Compressor will not unload or load up
a) Defective capacity control
a) Replace
b) Unloader mechanism defective
b) Replace
c) Faulty thermostat stage or
broken capillary tube
c) Replace
d) Stages not set for application
d) Reset thermostat setting to fit application
