Panasonic CW-XC244HU - Manual (Page 11)

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— 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 refrigerant from unit
completely, remove the desired component, and
unbrace the pinch-off tubes.
3. Braze service valves into the pinch-off tube ports,
leaving the valves open.
4. Braze the pinch-off tubes with Service valves.
5. Evacuate as follows.
1) Connect the vacuum pump, as illustrated Fig.
17A.
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 (Figure 17B) by means of
the manifold 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 system. With valves A and B closed, stop
the vacuum pump.
4) Remove the hose from the vacuum pump and
place it on the charging cylinder. See Fig. 17B.
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. 17B.
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 (0.2MP).
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
cutter, cut the pinch-off tube about 2 inches from
the pinch-off tool. Use sil-fos brazing rod and
braze 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.
NOTES
If high vacuum equipment is used, just slightly
loosen the valves A and B for a few minutes, then
open slowly with the two full turns
counterclockwise. This will keep oil from foaming
and being drawn into the vacuum pump.
CAUTION