Operating Pressures
After the unit has operated in the cooling mode for a short period of time, install pressure
gauges on the gauge ports of the discharge and suction line valves.
Note: Always route refrigerant hoses through the port hole provided and have
compressor access panel in place.
Check the suction and discharge pressures and compare them to the normal operating
pressures provided in the unit's Service Manual.
Note: Do not use pressures from Service manual to determine the unit refrigerant
charge. The correct charge is shown on the unit nameplate. To charge the system
accurately, use superheat charging or weigh the charge.
Voltage
With the compressor operating, check the line voltage at the unit. The voltage should be
within the range shown on the unit nameplate. If low voltage is encountered, check the size
and length of the supply line from the main disconnect to the unit. The line may be
undersized for the length of the run.
WARNING
Bodily injury can result from high voltage electrical components. If operating checks must be performed
with the unit operating, it is the technician's responsibility to recognize these hazards and proceed
safely. Failure to do so could result in severe personal injury or death due to electrical shock or contact
with moving parts.
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