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IMM AGS-2
Do not use the sight glass on the EXV body for refrigerant charging. Its purpose is to view
the position of the valve.
Lead-Lag
A feature on all McQuay AGS air-cooled chillers is a system for alternating the sequence in
which the compressors start to balance the number of starts and run hours. Lead-Lag of the
refrigerant circuits is accomplished automatically through the MicroTech II controller.
When in the auto mode, the circuit with the fewest number of starts will be started first. If
all circuits are operating and a stage down in the number of operating compressors is
required, the circuit with the most operating hours will cycle off first. The operator can
override the MicroTech II controller, and manually select the lead circuit as circuit #1 or #2.
Preventative Maintenance Schedule
PREVENTATIVE MAINTENANCE SCHEDULE
OPERATION
WEEKLY
MONTHLY
(Note 1)
ANNUAL
(Note 2)
General
Complete unit log and review (Note 3)
X
Visually inspect unit for loose or damaged components and
visible leaks
X
Inspect thermal insulation for integrity
X
Clean and paint as required
X
Electrical
Sequence test controls
X
Check contactors for pitting, replace as required
X
Check terminals for tightness, tighten as necessary
X
Clean control panel interior
X
Clean control box fan filter (Note 7)
X
Visually inspect components for signs of overheating
X
Verify compressor and oil heater operation
X
Megger compressor motor
X
Refrigeration/Oil
Leak test
X
Check liquid line sight glasses for clear flow
X
Check compressor oil sight glass for correct level (oil charge)
X
Check filter-drier pressure drop (see manual for spec)
X
Check oil filter pressure drop (Note 6)
X
Perform compressor vibration test
X
Perform oil analysis test on compressor oil
X
Condenser (air-cooled)
Clean condenser coils (Note 4)
X
Check fan blades for tightness on shaft (Note 5)
X
Check fans for loose rivets and cracks, check motor brackets
X
Check coil fins for damage and straighten as necessary
X
Notes:
1.
Monthly operations include all weekly operations.
2.
Annual (or spring start-up) operations include all weekly and monthly operations.
3.
Log readings can be taken daily for a higher level of unit observation.
