Compressor Is Not Operating
Check to see if the compressor run indicator is on, calling for
cooling.
Low pressure cutout will keep compressor from engaging even if the
electronic unit controller is calling due to low charge.
Check for power in and out of pressure control as both Low and High
side
pressure cutout will keep compressor from engaging.
Head Pressure Too High
Check that the condensing coil is not restricted.
Check that the condenser filter is not restricted.
Check that condenser fan motor is working and the condenser fan is
not
damaged.
Check for restrictions.
Check that refrigerant is not overcharged.
Check the sub-cooling.
Check that the service valves are fully open.
Head Pressure Too Low
Check unit for refrigerant leaks.
Perform pump-down procedure to verify the valves are pumping.
If equipped, check
if sight glass is flashing or showing low charge.
Low Suction Pressure
Check that evaporator fan motors are working.
Check that the air flow is being directed through the evaporator coil. (All
interior panels and must be in place as well as the evaporator fan
shroud.)
Check for restrictions.
Check that the Evaporator Coil is clear of ice and debris.
If equipped, check the sight glass for flashing
.
High Suction Pressure
Check for refrigerant being overcharged.
Check for refrigeration restrictions.
Perform pump-down procedure to verity the valves are pumping.
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