Frick RWF, Installation Operation & Maintenance

Page: 20 / 56

RWF ROTARY SCREW COMPRESSOR UNITS
MAINTENANCE
S70-600 IOM
Page 20
STRAINER - LIQUID INJECTION
To clean the liquid injection strainer the unit must be shut
down. The procedure is as follows:
1. Push [STOP] key on microprocessor panel to shut down
unit, then open disconnect switches for compressor and oil
pump motor starters.
2. Close liquid supply service valve located before liquid
solenoid.
Excessive pressure from expand-
ing refrigerant trapped between
stop valve and solenoid may cause
gasket and o-ring failure and uncontrolled refrigerant
release.
3. Close service valve located between the compressor
and the liquid injection thermovalve.
4. Carefully loosen capscrews securing the strainer cover
to the strainer. Allow pressure to relieve slowly.
5. When all entrapped refrigerant has been relieved, care-
fully remove loosened capscrews (as liquid refrigerant is
sometimes caught in the strainer), strainer cover and strainer
basket.
6. Wash the strainer basket and cover in solvent and blow
clean with air.
7. Reassemble strainer.
8. Open service valve between compressor and liquid in-
jection thermovalve and check for leakage.
9. Screw out manual solenoid valve stem.
10. Carefully open liquid supply service valve.
11. Leak test.
12. Close disconnect switches for compressor and oil pump
motor starters.
13. Start unit.
COALESCER FILTER ELEMENT(S)
When changing the coalescer filter element(s) it is recom-
mended that the oil be changed, cartridge(s) in oil filters
OF-1 and OF-2 if applicable be changed and the following
applicable strainer elements be removed and cleaned.
Use of filter elements other than
Frick must be approved in writing
by Frick engineering or warranty
claim may be denied.
1. Refer to CHANGING OIL, Steps 1 through 8.
2. Loosen manway cover retainer bolts, remove retainers,
manway cover and cover gasket. Discard cover gasket.
3. Remove and retain nut securing coalescer filter retainer.
4. Remove retainer, coalescer filter element and 2 O-rings.
Discard filter elements.
5. Install new coalescer filter element(s).
Seat element in center of locating
tabs on separator bulkhead.
6. Replace coalescer filter retainer and nut. Torque nut to 21
ft-lb. DO NOT OVERTIGHTEN NUT.
7. Install a new manway gasket and replace manway cover.
8. Tighten manway bolts. NOTE: RETIGHTEN AFTER THE
COMPRESSOR UNIT IS REPRESSURIZED, SINCE
MANWAY BOLTS WILL LOOSEN.
9. Refer to CHANGING OIL, Steps 9 through 14.
CHANGING OIL
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.
Use of oils other than Frick Oil in
Frick compressors must be ap-
proved in writing by Frick engineer-
ing or warranty claim may be denied.
Shut down the unit when changing oil. At the same time all
oil filter cartridges must be changed and all oil strainer ele-
ments removed and cleaned. The procedure is as follows:
1. Press the [STOP] key on the microprocessor panel to
stop the compressor unit.
2. Open the disconnect switch for the compressor motor
starter.
3. Close the suction and discharge service valves; also
close the liquid-injection and economizer service valves, if
applicable.
4. SLOWLY vent separator to low-side system pressure
using the bypass line on the suction trap. NOTE: Recover
or transfer all refrigerant vapor, in accordance with lo-
cal ordinances, before opening to atmosphere. The sepa-
rator MUST be equalized to atmospheric pressure.
Oil entrained refrigerant may vapor-
ize, causing a separator pressure
increase. Repeat venting and re-
covery procedure, if necessary.
5. Open the drain valve(s) located on the underside of the
separator and drain the oil.
6. Drain the oil filter(s) OF-1 and, if applicable, the oil cool-
ers and filter OF-2.
7. Remove the old filter cartridges, then install new ones
(as previously described in the section OIL FILTER (OF-1)
MAIN SINGLE/DUAL).
8. Remove, clean, and reinstall strainer elements in the
strainers.
9. Evacuate the unit to 29.88" Hg (1000 microns) vacuum.
10. Open the suction service valve and pressurize the unit
to system suction pressure. Close the suction valve and leak
test.
11. Add oil by attaching a suitable pressure-type hose to
the oil-charging valve located on top of the separator. Using
a pressure-type oil pump and recommended Frick oil, open
the charging valve and fill the separator until the oil level is
midway in the top sight glass. NOTE: Fill slowly because