RWB II ROTARY SCREW COMPRESSOR UNITS
MAINTENANCE
070.200-IOM (DEC 11)
Page 28
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 shutdown
unit, then open disconnect switches for compressor and oil
pump motor starters.
2. Close liquid supply service valve located before liquid
solenoid.
3. Immediately screw in the manual solenoid valve stem
to relieve liquid refrigerant pres sure trapped between
the solenoid and the service valve.
Excessive pressure from expanding
refrigerant trapped between stop
valve and solenoid may cause gas-
ket and O-ring failure and uncontrolled refrigerant re-
lease.
4. Close service valve located between the compressor and
the liquid injection thermovalve.
5. Carefully loosen capscrews securing the strainer cover to
the strainer. Allow pressure to relieve slowly.
6. When all entrapped refrigerant has been relieved, care‑
fully remove loosened capscrews (as liquid refriger ant is
sometimes caught in the strainer), strainer cover and strainer
basket.
7. Wash the strainer basket and cover in solvent and blow
clean with air.
8. Reassemble strainer.
9. Open service valve between compressor and liquid in‑
jection thermovalve and check for leakage.
10. Screw out manual solenoid valve stem.
11. Carefully open liquid supply service valve.
12. Leak test.
13. Close disconnect switches for compressor and oil pump
motor starters.
14. Start unit.
COALESCER FILTER ELEMENT(S)
Use of filter elements other than
Frick may cause warranty claim
may to be denied.
When changing the coalescer filter element(s) it is recom‑
mended that the oil be changed, cartridge(s) in oil filters
OF‑1, OF‑2, and OF‑3 (if applicable) be changed, and the fol‑
lowing applicable strainer elements be removed and cleaned.
1. Refer to oil changing 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 bulk head.
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: RE TIGHTEN AFTER THE
COM PRESSOR UNIT IS REPRESSURIZED, SINCE MAN-
WAY BOLTS WILL LOOSEN.
9. Refer to oil changing 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.
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 us‑
ing the bypass line on the suction trap. NOTE: Recover or
transfer all refrigerant vapor, in accordance with local
ordinances, before opening to atmosphere. The separa-
tor 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 ap plicable, the oil coolers
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 28" Hg 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
the oil will fill up in the separator faster than it shows
in the sight glass. Refer to the table in the OIL CHARGE
section for approximate oil charge quantities.
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