72
AGZ 025D through 190D
OMM 1087-1
Unit Maintenance
General
On initial start-up and periodically during
operation, it will be necessary to perform
certain routine service checks. Among these
are checking the liquid line sight glasses,
taking condensing and suction pressure
readings, and checking to see that the unit has
normal superheat and subcooling readings. A
recommended maintenance schedule is located
at the end of this section.
Compressor Maintenance
The scroll compressors are fully hermetic and
require no maintenance other than checking oil
level.
Lubrication
No routine lubrication is required on AGZ
units. The fan motor bearings are permanently
lubricated and no further lubrication is
required. Excessive fan motor bearing noise is
an indication of a potential bearing failure.
The compressors in this unit use POE
lubricant. POE lubricant is required with
refrigerant R-410A. Do not use mineral oil.
Electrical Terminals
Condensers
The condensers are air-cooled and constructed
of 3/8" (9.5mm) O.D. internally finned copper
tubes bonded in a staggered pattern into
louvered aluminum fins. Maintenance consists
primarily of the routine removal of dirt and
debris from the outside surface of the fins and
repairing any fin damage. McQuay
International recommends the use of foaming
coil cleaners available at most air conditioning
supply outlets. Use caution when applying
such cleaners as they can contain potentially
harmful chemicals. Care should be taken not to
damage the fins during cleaning. The coils
should be thoroughly rinsed to remove any
cleaner residue.
If the service technician determines that the
refrigerant circuit contains noncondensables,
recovery can be required, strictly following
Clean Air Act regulations governing refrigerant
discharge to the atmosphere. The Schrader
purge valve is located on the vertical coil
headers on both sides of the unit at the end
opposite the control box. Decorative panels
cover the condenser coils and must be removed
for servicing. Recover with the unit off, after a
shutdown of 15 minutes or longer, to allow air
to collect at the top of the coil. Restart and run
the unit for a brief period. If necessary, shut the
unit off and repeat the procedure. Follow
national and local regulations regarding
refrigerant venting and reclamation when
removing refrigerant from the unit.
Optional High Ambient Control
Panel
Consists of exhaust fan with rain hood, two
inlet screens with filters, necessary controls
and wiring to allow operation to 125
°
F (52
°
C).
The option can be factory or field installed as a
kit.
•
It must be supplied on units operating at
ambient temperatures of 105
°
F (40.6
°
C) and
above.
•
It is automatically included on units with
fan VFD (low ambient option).
•
Check inlet filters periodically and clean as
required. Verify that the fan is operational.
!
DANGER
Electric shock hazard. Turn off all power
before continuing with following service.
Summary of Contents for AGZ-D 25
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