HPS Rotary Screw Compressor Units
070.700-IOM (MAR 21)
Page 30
Maintenance
When replacing or repairing components that are exposed
to refrigerant pressure (including suction strainer) proceed
as follows:
1. Press the
STOP
key on the control panel to shut down
the unit.
2. Open the disconnect switches for the compressor and
pump motor starters.
3.
Close the suction and discharge service valves, and
the liquid injection and economizer service valves, if
applicable.
4. Slowly vent the separator to low-side system pressure
using the bypass line on the
suction trap.
Notice
Recover or transfer all refrigerant vapor, in accordance
with local ordinances, before opening to atmosphere.
The separator must be equalized to atmospheric pres-
sure.
Warning
Oil-entrained refrigerant may vaporize, causing a
separator pressure increase. Repeat venting and
recovery procedure, if necessary.
5. Make the replacement or repair.
Notice
Replace all gaskets and O-rings with new ones. Suction
Strainer: remove, inspect and clean as necessary and
replace using a new gasket.
6. Isolate the low pressure transducer, PE-4, to prevent
damage during pressurization and leak test.
7. Pressurize the unit and leak test.
8.
Evacuate the unit to 29.88 in.Hg (1000 microns).
9.
Open the suction and discharge service valves, low
pressure transducer, and the liquid injection and
economizer service valves, if applicable.
10. Close the disconnect switches for the compressor and
oil pump motor starters.
11. The unit is ready to put into operation.
12. Perform checkpoints on prestart checklist, then start
the unit.
Oil filter (
OF-1) cartridge style
HPS compressor units are furnished with one main oil
filter (OF-1). A second oil filter (OF-2) is installed as
optional equipment to facilitate the changing of the filter
element(s) without unit shutdown.
Notice
Use of
filter elements other than Frick may cause
warranty claim to be denied.
The procedure to change filter cartridge(s) is as follows:
1.
If a single oil filter is installed, press the
STOP
key on
the control panel to shut down unit. Then, open the
discon nect switches for the compressor and oil pump
motor starters. If
dual oil filters are installed, open the
outlet, then inlet service valves of the standby filter.
Warning
Open the inlet service valve slowly to prevent a sud-
den pressure drop, which could cause an oil filter
differential alarm.
2.
Close the outlet, then the inlet service valves of the filter
being serviced.
3. Open the
bleed valve and purge pressure from the oil
filter cartridge.
Notice
Recover or transfer all refrigerant vapor, in ac-
cordance with local ordinances, before opening to
atmosphere.
4.
Remove the plug from the bottom of the filter canister
and drain the oil. Remove the canister cover and dis-
card the gasket. Remove the screws securing the filter
assembly. Pull the filter assembly from the canister and
discard the gasket and the element.
5. Flush the canister with clean compressor oil. Wipe dry
with a clean, lint-free cloth and replace the plug.
6.
Install a new filter element. Tighten the six 3/8 in. hex
head cap screws to 10 ft-lb (13.55
N⋅m
) torque.
Figure 35: Superfilter II, current design
Warning
Do not mix oils of different brands, manufacturers, or
types. Mixing of oils may cause excessive oil foam-
ing, nuisance oil level cutouts, oil pressure loss, gas
or oil leakage and catastrophic compressor failure.
7.
Replace the gasket and reinstall the canister cover.
Torque cover bolts first to finger tight, then 95 ft-lb
(128.8
N⋅m)
, then 195 ft-lb (264.38
N⋅m
).
8.
Evacuate (pull a vacuum on) the filter canister to elimi
-
nate non-condensibles.
9. Fill the canister with new Frick
refrigeration oil as
needed.
10. Open outlet service valve and leak test.
11.
The filter is ready to place in service.
Strainer - Liquid injection
To clean the liquid injection strainer the unit must be shut
down. The procedure is as follows:
1. Press the
STOP
key on the control panel to shut down
unit, then open disconnect switches for the compressor
and oil pump motor starters.
2. Close the liquid supply service valve located before
liquid solenoid.
