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NOTES
Replacement of the refrigeration cycle.
1. When replacing the refrigerating cycle, be sure to discharge the refrigerant by using a refrigerant recovery sys-
tem.
2. After discharging the unit completely, remove the desired components, and unbraze the pinch-off tubes.
3. Solder service valves into the pinch-off tube ports, leaving the valves open.
4. Solder the pinch-off tubes with service valves.
5. After doing the above procedures, the valve must be closed and left in place on the system for any subsequent
procedures.
6. Evacuate as follows:
6-1. Connect the vacuum pump, as illustrated figure 72A.
6-2. Start the vacuum pump. Slowly open manifold valves A and B with two full turns counterclockwise and leave
the valves closed.
The vacuum pump is now pulling through valves A and B up to valve C by means of manifold and the entire
system.
CAUTION : If high vacuum equipment is used, just crack valves A and B for a few minutes, then open slowly
with the two full turns counter-clockwise. This will keep oil from foaming and being drawn into the vacuum
pump.
6-3. Operate the vacuum pump for 20 to 30 minutes, until 600 micron vacuum is obtained.
Close valves A and B and observe vacuum gauge for a few minutes.
A rise in pressure would indicate a possible leak or moisture remains in the system.
With valves A and B closed, stop the vacuum pump.
6-4. Remove the hose from the vacuum pump and place it on the charging cylinder. See figure 23B. Open valve C.
Discharge the line at the manifold connection.
6-5. The system is now ready for final charging.
7. Recharge as follows :
7-1. Rotary compressor systems are charged from the high-side. If the total charge cannot be put in the high-side,
the balance will be put in the suction line through the access valve which is installed as the system is opened.
7-2. Connect the charging cylinder as shown in figure 72B. With valve C open, discharge the hose at the manifold
connection.
7-3. Open valve A and allow the proper charge to enter the system. Valve B is still closed.
7-4. If more charge is required, the high-side will not take it. Close valve A.
7-5. With the unit running, open valve B and add the balance of the charge.
a. Do not add the liquid refrigerant to the low-side.
b. Watch the tow-side gauge, allow pressure to rise to 30 Ibs.
c. rum off valve B and allow the pressure to drop.
d. Repeat steps B and C until the balance of the charge is in the system.
7-6. When the unit is operating correctly, use the pinch-off tool with the unit stillrunning and the clamp on the
pinch-off tube. Using a tube cutter, cut the pinch-off tube about 2 inches from the pinch-off tool. Use sil-fos
solder and solder the pinch-off tube closed. rum off the unit, allow setting for a while and then test the leak-
age of the pinch-off connection.
---30--
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