Frick SGXH-4021 - General Maintenance; Maintenance Safety Precautions; Changing Oil; Recommended Maintenance Program

070.650-IOM (JUL 19)
Page 36
SGC/SGX ROTARY SCREW COMPRESSOR
MAINTENANCE
Maintenance
5. Protect the compressor during long periods of shut-
down. If the compressor sits for long periods without run-
ning, it is advisable to evacuate to low pressure and charge
with dry nitrogen or oil. This is particularly true on systems
known to contain water vapor.
6. Preventive maintenance inspection is recommended any
time a compressor exhibits a noticeable change in vibration
level, noise, or performance.
7. Check the operating oil pressure to the SB-3 and SB-4
portsdaily.Ifoutsideisspecied,itmustbeadjusted.
8. Check the operating oil pressure to the balance piston
SB-2 port daily.
CHANGING OIL
Warning
DO NOT MIX OILS of different brands, manufacturers, or
types. Mixing of oils may cause excessive oil foaming,
nuisance oil level cutouts, oil pressure loss, gas or oil
leakage and catastrophic compressor failure.
Shut down the unit when changing oil. At the same time all
oilltercartridgesmustbechangedandalloil strainer ele-
ments removed and cleaned. The procedure is as follows:
1. Stop the compressor unit.
2. Lock out the motor starter.
3. Close the suction and discharge service valves
4. Using appropriate equipment, lower the compressor
pressure to 0 psig.
5. Open the drain valve(s) and drain oil into a suitable
container.
6. Draintheoillter(s)andtheoilcoolers.
7. Removetheoldltercartridges,andinstallnewones.
8. Remove, clean, and reinstall elements in the strainers.
9. Evacuate the unit.
10. Open the suction service valve and pressurize the unit
to system suction pressure. Close the suction valve and
leak test.
11. Add oil.
12. Open the suction and discharge service valves.
13. Remove the lockout from the motor starter.
14. Start the unit.
RECOMMENDED MAINTENANCE PROGRAM
In order to obtain maximum compressor performance and
ensure reliable operation, follow a regular maintenance
program. Check the compressor unit regularly for leaks,
abnormal vibration, noise, and proper operation as well as
maintaining a log. Perform an oil analysis on a regular basis. It
is a valuable tool that can identify the presence of moisture,
acid, metallics, and other contaminants that shorten the
compressor's longevity if not corrected. In addition, periodic
vibration analysis can be useful in detecting bearing wear
and other mechanical failures.
GENERAL INFORMATION
This section provides instructions for normal maintenance,
a recommended maintenance program, and troubleshooting
and correction guides.
Warning
This section must be read and understood before at-
tempting to perform any maintenance or service to
the unit.
Caution
Cylinder assembly under high spring load. Consult
manual before disassembly. Improper disassembly may
cause injury due to spring tension release.
NORMAL MAINTENANCE OPERATIONS
When performing maintenance you must take several pre-
cautions to ensure your safety:
1. IF UNIT IS RUNNING, PRESS [STOP] KEY.
2. STOP MOTOR AND LOCK OUT STARTER BEFORE
PERFORMING ANY MAINTENANCE.
3. WEAR PROPER SAFETY EQUIPMENT WHEN
COMPRESSOR UNIT IS OPENED TO ATMOSPHERE.
4. ENSURE ADEQUATE VENTILATION.
5. TAKE NECESSARY SAFETY PRECAUTIONS REQUIRED
FOR THE GAS BEING USED.
GENERAL MAINTENANCE
Proper maintenance is important in order to assure long and
trouble-free service from your screw compressor. Some areas
critical to good compressor operation are:
1. Keep oil clean and dry, avoid moisture contamination.
After servicing any portion of the refrigeration system,
evacuate to remove moisture before returning to service.
Water vapor condensing in the compressor, while running
or more likely while shut down, can cause rusting of critical
components and reduce life.
2. Keep suction strainer clean. Check periodically, particu-
larly on new systems where welding slag or pipe scale could
nditswaytothecompressorsuction.Excessivedirtinthe
suction strainer could cause it to collapse, dumping particles
into the compressor.
3. Keep oil lters clean.Ifltersshowincreasingpressure
drop, indicating dirt or water, stop the compressor and
changelters.Runningacompressorforlongperiodswith
highlterpressuredropcanstarvethecompressorofoil
and lead to prematurebearing failure.Dual oil ltersare
recommendedsothatthe lterscanbechanged without
shutting down the package.
4. Avoid slugging the compressor with liquids (oil). While
screw compressors are probably the most tolerant of any
compressor type available today about ingestion of some
liquid, they are not liquid pumps. Make certain a properly
sized suction accumulator is used to avoid dumping liquid
into compressor suction.