KOMAC00607-09EN 63
An element inside the sight glass indicates the moisture condition corresponding to a given
element color. If the sight glass does not indicate a dry condition after about 12 hours of
operation, the circuit should be pumped down and the filter-drier changed. An oil acid test is also
recommended.
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 AWS 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 III 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 III controller, and manually select
the lead circuit as circuit #1, #2 or #3.
Preventative Maintenance Schedule
PREVENTATIVE MAINTENANCE SCHEDULE
OPERATION WEEKLY
MONTHLY
(Note 1)
ANNUAL
(Note 2)
General
Complete unit log and review (Note 3) X
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/Lubricant
Leak test X
Check liquid line sight glasses for clear flow X
Check compressor oil sight glass for correct level (lubricant charge) X
Check filter-drier pressure drop (see manual for spec) X
Check lubricant 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.
4. Coil cleaning can be required more frequently in areas with a high level of airborne particles.
5. Be sure fan motors are electrically locked out.
6. Replace the filter if pressure drop exceeds 20 psi.
7. The weekly fan filter cleaning schedule can be modified to meet job conditions. It is important that he
filter allows full air flow.
To Next Page
Loading...
Need help?
General
