Emerson PFH020A-L, User Manual

Page: 110 / 117

4 MAINTENANCE
4.1 General
Access the condensing unit by removing the unit housing panel. Clean the air cooled condenser coil of all
debris that will inhibit airflow. This can be done with compressed air or with a commercial coil cleaner.
Check for bent or damaged coil fins and repair as necessary. During winter, do not permit snow to
accumulate on or around the condensing unit. Check all refrigerant lines and capillaries for vibration
isolation and support as necessary. Check all refrigerant lines for signs of leaks.
WARNING! Risk of electric shock. Can cause injury or death. Disconnect all local and remote
electric power supplies before working within. Turn Off power to unit at disconnect switch
unless you are performing tests that require power. With power and controls energized, unit
could begin operating automatically at any time.
WARNING! Hazardous voltage will still be present at condenser even with power turned Off at
the control panel. To isolate unit for maintenance, turn the unit Off at disconnect switch.
NOTICE
Risk of compressor slugging. Can cause equipment damage.
If condenser power is disconnected for a long period, do not attempt to start the condensing unit until 8
hours after restoring power. This allows time for liquid refrigerant to be driven out of the compressor. This
is especially important at low ambient temperatures.
4.2 Compressor Failure
If a compressor motor burns out, the stator wiring insulation decomposes, forming carbon, water and acid.
Not only must the compressor be replaced, but the entire refrigeration circuit must be cleaned of the
harmful contaminants left by the burnout. Successive burnouts of the same system can usually be
attributed to improper system cleaning.
NOTICE
Risk of improper cleaning. Can cause equipment damage. Damage to a replacement compressor caused
by improper system cleaning constitutes abuse under the terms of the warranty.
Before proceeding with a suspected burnout, check all electrical components: fuses, contactors and
wiring. Check high-pressure switch operation. If a compressor failure has occurred, determine whether it is
an electrical or mechanical failure. An electrical failure will be indicated by a distinct, pungent odor. If a
severe burnout has occurred, the oil will be black and acidic. In the case of a mechanical failure, there will
be no burn odor and the motor will attempt to run.
4.2.1 Electrical Failure—Burnout
In the event that there is an electrical failure and a complete burnout of the refrigeration compressor
motor, the proper procedures must be performed in order to clean the system to remove any acids that
would cause a future failure.
Vertiv | Liebert PFH Installer/User Guide | 33