4-8
3. Turn unit off and the correct oil level should be
between 1/4 and 1/2 of the sight glass. If the level is above
1/2, oil must be removed from the compressor. To remove
oil from the compressor, follow step d. If the level is below
1/8, add oil to the compressor following step b. below.
b. Adding Oil with Compressor in System
Two methods for adding oil are the oil pump method
and closed system method.
Oil Pump Method:
One compressor oil pump that may be purchased is a
Robinair, part no. 14388. This oil pump adapts to a 3.785
liters (one U.S. gallon) metal refrigeration oil container
and pumps 0.0725 liters (3.5 ounces) per stroke when
connected to the suction service valve port. Also there is
no need to remove pump from can after each use.
When the compressor is in operation, the pump
check valve prevents the loss of refrigerant, while
allowing servicemen to develop sufficient pressure to
overcome the operating suction pressure to add oil as
necessary.
Backseat suction service valve and connect oil
charging hose to port. Crack the service valve and purge
the oil hose at the oil pump. Add oil as necessary.
Closed System Method:
In an emergency where an oil pump is not available,
oil may be drawn into the compressor through the suction
service valve.
CAUTION
Extreme care must be taken to ensure the
manifold
common
connection
remains
immersed in oil at all times. Otherwise air and
moisture will be drawn into the compressor.
Connect the suction connection of the gauge
manifold to the compressor suction service valve port,
and immerse the common connection of the gauge
manifold in an open container of refrigeration oil. Crack
the suction service valve and gauge valve to vent a small
amount of refrigerant through the common connection
and the oil to purge the lines of air. Close the gauge
manifold valve.
With the unit running, frontseat the suction service
valve and pull a vacuum in the compressor crankcase.
SLOWLY crack the suction gauge manifold valve and oil
will flow through the suction service valve into the
compressor. Add oil as necessary.
Run unit for 20 minutes, in cooling, and check oil
level.
c. Adding Oil to Service Replacement Compressor
NOTE
The correct oil charge is 4.0 liters (8.5 U.S. pints)
Service replacement compressors may or may not be
shipped with oil.
If compressor is without oil:
Add oil, (sections 1.3.b and 4.8.b.) through the
suction service valve flange cavity or by removing the oil
fill plug. (See Figure 4-2.) Some compressors have the oil
plug located on the crankcase, at the right or left side of
the oil pump.
d. To Remove Oil From an 06DR Compressor:
1. If the oil level recorded in step a.3 is above 1/2 of
the sight glass, oil must be removed from the compressor.
2. Close (frontseat) suction service valve and pump
unit down to 1.2 to 1.3 kg/cm
@
(2 to 4 psig). Frontseat
discharge service valve and slowly bleed remaining
refrigerant.
3. Remove the oil drain plug on the bottom plate of
the compressor and drain the proper amount of oil from
the compressor to obtain the 1/2 sight glass maximum
level. Replace the plug securely back into the compressor.
DO NOT FORGET TO OPEN SUCTION AND
DISCHARGE SERVICE VALVES.
4. Repeat Step a. to ensure proper oil level.
4.9 CHECKING OR REPLACING
MOISTURE-LIQUID INDICATOR
When the refrigeration system is operating, the
moisture-liquid indicator provides an indication of
moisture in the system.
The indicator element is highly sensitive to moisture
and will gradually change color in direct relation to an
increase or decrease in the moisture content of the
system. The safe, caution, and unsafe system operating
conditions are then easily determined by matching the
element color with the colors displayed on the reference
label.
To change indicator or lens:
a. Pump down the unit per section 4.1 and install new
indicator or lens.
b. Evacuate the unit per section 4.3 and add refrigerant
charge per section 4.4.
c. Start unit and after twelve hours re-check indicator.
If indicator does not indicate a safe condition, pump unit
down and change filter-drier. (Refer to section 4.10.)
4.10 CHECKING OR REPLACING THE
FILTER-DRIER
If the sight glass appears to be flashing or bubbles are
constantly moving through the sight glass, the unit may
have a low refrigerant charge, or the filter-drier could be
partially plugged.
To Check Filter-Drier:
a. One test for a restricted or plugged filter-drier is by
feeling the liquid line inlet and outlet connections of the
drier cartridge. If the outlet side feels cooler than the
inlet side, then the filter-drier should be changed.
b. Another test is that the moisture-liquid indicator
shows moisture in the system. (Refer to section 4.9)
To Replace Filter-Drier
:
a. Store the refrigerant in an evacuated container and
replace filter-drier. (Refer to section 4.1)
b. Evacuate the unit per section 4.3 and charge unit
with refrigerant per section 4.4.1.
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