Service Manual 20
- Replacement of the refrigeration cycle.
1. When replacing the refrigeration cycle, be sure to
discharge the refrigerant system using a Freon
TM
recovery System.
If there is no valve to attach the recovery system,
install one (such as a WATCO A-1) before venting
the Freon
TM
. Leave the valve in place after
servicing the system.
2. After discharging the unit completely, remove the
desired component, and unbrace 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. Evacuate as follows.
1) Connect the vacuum pump, as illustrated Fig. 35A.
2) Start the vacuum pump, slowly open manifold
valves A and B with two full turns counterclock-
wise and leave the valves closed.
The vacuum pump is now pulling through valves A
and B up to valve C by means of themanifold
and entire system.
3) Operate the vacuum pump for 20 to 30 minutes,
until 600 microns of 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 remaining in the sys-
tem. With valves A and B closed, stop the vacu-
um pump.
4) Remove the hose from the vacuum pump and
place it on the charging cylinder. See Fig. 35B.
Open valve C.
Discharge the line at the manifold connection.
5) The system is now ready for final charging.
6. Recharge as follows :
1) Refrigeration cycle 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 you installed
as the system was opened.
2) Connect the charging cylinder as shown in Fig.
35B.
With valve C open, discharge the hose at the
manifold connection.
3) Open valve A and allow the proper charge to
enter the system. Valve B is still closed.
4) If more charge is required, the high-side will not
take it. Close valve A.
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 Low-side gauge; allow pressure to
rise to 30 lbs.
c. Turn off valve B and allow pressure to drop.
d. Repeat steps B and C until the balance of the
charge is in the system.
6) When satisfied the unit is operating correctly, use
the pinch-off tool with the unit still running and
clamp on to the pinch-off tube. Using a tube cut-
ter, cut the pinch-off tube about 2 inches from the
pinch-off tool. Use sil-fos solder and solder pinch-
off tube closed. Turn off the unit, allow it to set for
a while, and then test the leakage of the pinch-off
connection.
NOTICE
CAUTION: If high vacuum equip-
ment is used, just crack valves A
and B for a few minutes, then
open slowly with the two full turns coun-
terclockwise. This will keep oil from
foaming and being drawn into the vacu-
um pump.