EVACUATING THE REFRIGERANT SYSTEM.
After completion of system purging and before the system is charged with refrigerant the system must be evacuated
before new refrigerant is added. Refer to figure 4-4 for evacuation procedures.
CHARGING THE REFRIGERANT SYSTEM WITH A FULL CHARGE.
a. After completion of system evacuation in accordance with paragraph 4-9, the unit is ready for recharging.
b. Connect the refrigerant charging hookup as shown in figure 4-5 with a full cylinder of refrigerant R-22. Weigh
the cylinder so that 3 pounds 5 ounces (1.48kg) of refrigerant can be measured into the system.
The refrigerant cylinder used for recharging should be equipped with a large
capacity filter dryer.
Whenever available, use recycled refrigerant for charging the refrigeration system.
c. Attach charging line to unit. Do not tighten. Be sure refrigerant cylinder is in an upright position so only gas
will be drawn off.
d. Open refrigerant cylinder valve slightly and then close to purge air from the charging line. Tighten charging
line on service valve fitting.
e. Open valve on refrigerant cylinder about 2 turns.
Open the system discharge valve about 2 turns and allow pressure to equalize.
g. Start unit and run until 3 pounds 5 ounces (1.48kg) of refrigerant R-22 is added.
h. Backseat suction service valve.
Close refrigerant cylinder valve and remove charging line from valve.
Remove manifold and gages (figure 4-5).
Turn selector switch to "OFF" position.
ADDING REFRIGERANT TO THE SYSTEM.
a. General. Bubbles or a milky or frothy appearance of the refrigerant passing the sight glass in normal
operation is an indication that the system needs additional refrigerant. The normal refrigerant charge in the unit when
shipped is 3 pounds 5 ounces (1.48kg) of R-22 refrigerant. If bubbles or a milky or frothy appearance of the refrigerant is
visible in the sight glass, add refrigerant as follows:
b. Adding Refrigerant.
4-14 Change 3