IM 1131-2 55
System Maintenance
System Maintenance
System Maintenance
To provide smooth operation at peak capacity and to avoid
damage to package components, a program of periodic
inspections should be set up and followed. The following
items are intended as a guide to be used during inspection and
must be combined with sound refrigeration and electrical
practices to provide trouble-free performance.
The liquid line sight glass/moisture indicator on all circuits
must be checked to be sure that the glass is full and clear and
that the moisture indicator indicates a dry condition. If the
indicator shows that a wet condition exists or if bubbles show
in the glass, even with a full refrigerant charge, the filter-drier
element must be changed.
Water supplies in some areas can tend to foul the water-cooled
condenser to the point where cleaning is necessary. The fouled
condenser will be indicated by an abnormally high condenser
approach temperature (saturated discharge temperature minus
leaving condenser water temperature) and can result in
nuisance trip-outs. To clean the condenser, mechanical
cleaning or a chemical descaling solution should be used
according to the manufacturer's directions.
Systems with remote air-cooled condensers require periodic
cleaning of the finned surface of the condenser coil.
Cleaning can be accomplished by using a cold water spray,
brushing, vacuuming, or high-pressure air. No tools should be
used that could damage the coil tubes or fins.
The compressor oil level must be checked periodically to be
sure that the level is at the center of the oil sightglass located in
the compressor's equalizing line or on the compressor itself.
Low oil level can cause inadequate lubrication and if oil must
be added, use oils referred to in the following Compressor
Lubrication section.
A pressure tap has been provided on the liquid line
downstream of the filter-drier and solenoid valve but before
the expansion valve. An accurate subcooled liquid pressure
and temperature can be taken here. The pressure read here
could also provide an indication of excessive pressure drop
through the filter-drier and solenoid valve due to a clogging
filter-drier. Note: A normal pressure drop through the solenoid
valve is approximately 3 psig (20.7 kPa) at full load condition..
Electrical Terminals
All power electrical terminals should be re-tightened every six
months, as they tend to loosen due to normal heating and
cooling of the wire.
Compressor Lubrication
The oil level should be watched carefully upon initial start-up
and regularly thereafter.
All tandem and triple compressors on WGZ units come
equipped with oil equalization lines connecting the crankcase
of each set of compressors in each refrigerant circuit. This
allows the oil to move from one compressor crankcase to the
other during normal operation, and balance between the two
when the compressors are off. The oil sight glass is located in
the equalization line on one circuit of the WGZ 070 and both
circuits of WGZ 080 through WGZ 100. All other models have
the oil sight glass in the compressor body. In either case, the
oil level should be 1/4 to 1/3 of the glass.
POE type oil is used for compressor lubrication. This type of
oil is extremely hygroscopic, which means it will quickly
absorb moisture if exposed to air and may form acids that can
be harmful to the chiller. Avoid prolonged exposure of POE oil
to the atmosphere to prevent this problem. For more details on
acceptable oil types, contact your Daikin Applied service
representative.
The units are factory-charged with lubricant. It is important
that only the manufacturer’s recommended oils be used.
Acceptable POE oil types are:
• CPI/Lubrizol Emkarate RL32-3 MAF
• Exxon/Mobil EAL Arctic 22 CC*
• Hatcol 22CC*
• Everest 22CC*
• Copeland Ultra 32-3 MAF
• Parker Emkarate RL32-3MAF
• Virginia LE323MAF
• Nu Calgon 4314-66
Note: * These types of oils can only be used as "Top Off"
oils. This is defined as adding less than 50% of the
total amount of oil in the unit.
CAUTION
Warranty may be affected if wiring is not in accordance with
specifications. A blown fuse or tripped protector indicates a
short ground or overload. Before replacing fuse or restarting
compressor, the trouble must be found and corrected. It is
important to have a qualified control panel electrician service
this panel. Unqualified tampering with the controls can cause
serious damage to equipment and void the warranty. If motor
or compressor damage is suspected, do not restart until
qualified service personnel have checked the unit.
DANGER
The panel is always energized to ground even when the system switch
is off. To de-energize the complete panel including crankcase heaters,
pull the main unit disconnect.
Failure to do so can result in severe personal injury or death.
WARNING
To avoid injury from electric shock hazard, turn off all power and
perform lockout and tag-out of source before continuing with the
following service. Note that the unit might be powered from multiple
sources.
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