3.4 HOW TO REPLACE THE REFRIGERATION SYSTEM
1.When replacing the refrigeration cycle, be sure to discharge the refrigerant system by using a refrigerant recovery system.
2.After discharging the unit completely, remove the desired component, and unbrace the
3.Solder service valves into the
4.Solder the
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.
1)Connect the vacuum pump, as illustrated in Figure 22A.
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 the manifold and 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 counterclockwise. This will keep oil from foaming and being drawn into the vacuum pump.
3)Operate the vacuum pump for 20 to 30 minutes, until 600 microns of vacuum are 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 Figure 22B. Open valve C.
Discharge the line at the manifold connection.
5)The system is now ready for final charging.
7.Recharge as follows :
1)Refrigeration cycle systems are charged from the
in the
2)Connect the charging cylinder as shown in Figure 22B.
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
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
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
NOTE: THE REFRIGERANT R134a IS
USED SOME MODELS. CHECK THE SPECIFICATION LABEL ON THE CABINET.
When discharging refrigerant R134a, purging instrument should be used only for R134a, without mixing that of refrigerant R22.
When checking the leakage of refrigerant R134a, leakage test tool should be used only for R134a.
The pump for discharging should be high efficiency. Final discharging value must be managed below 0.5 Torr.
Maximum water should be less than quantity 150mg in the
If water quantity is over 150mg, it causes acid or corrosion in the cycle system and the capillary tube to be clogged by water and harmful materials.
The model charged the refrigerant R134a should be used dryer to prevent water from overflowing.
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