Recovering Refrigerant from Existing System
Use the following procedure to recover refrigerant from an existing system (indoor coil, line set and outdoor unit).
1DISCONNECT POWER
Disconnect all power to the existing outdoor unit at the service disconnect switch or main fuse box/breaker panel.
MAIN FUSE BOX/BREAKER PANEL 
2CONNECT MANIFOLD GAUGE SET
Connect a gauge set, clean recovery cylinder and a recovery machine to the service ports of the existing unit. Use the instructions provided with the recovery machine to make the connections.
MANIFOLD GAUGES
SERVICE
DISCONNECT
SWITCH
RECOVERY MACHINE
LOW
HIGH
| CLEAN RECOVERY OUTDOOR UNIT |
3 | CYLINDER |
RECOVERING REFRIGERANT |
|
Remove existing HCFC−22 refrigerant using one of the following procedures: |
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IMPORTANT and/or long line sets.
METHOD 1:
Us this method if the existing outdoor unit is not equipped with shut−off valves, or if the unit is not operational and you plan to use the existing HCFC−22 to flush the system.
Remove all HCFC−22 refrigerant from the existing system. Check gauges after shutdown to confirm that the entire system is completely void of refrigerant.
METHOD 2:
Use this method if the existing outdoor unit is equipped with manual shut−off valves, and you plan to use new HCFC−22 refrigerant to flush the system.
The following devices could prevent full system charge recovery into the outdoor unit:
S S
Outdoor unit’s high or low−pressure switches (if applicable) when tripped can cycle the compressor OFF.
Compressor can stop pumping due to tripped internal pressure relief valve.
SCompressor has internal vacuum protection that is designed to unload the scrolls (compressor stops pumping) when the pressure ratio meets a certain value or when the suction pressure is as high as 20 psig. (Compressor suction pressures should never be allowed to go into a vacuum. Prolonged operation at low suction pressures will result in overheating of the scrolls and permanent damage to the scroll tips, drive bearings and internal seals.)
Once the compressor can not pump down to a lower pressure due to one of the above system conditions, shut off the vapor valve. Turn OFF the main power to unit and use a recovery machine to recover any refrigerant left in the indoor coil and line set.
Perform the following task:
AStart the existing HCFC−22 system in the cooling mode and close the liquid line valve.
BUse the compressor to pump as much of the existing HCFC−22 refrigerant into the outdoor unit until the outdoor system is full. Turn the outdoor unit main power OFF and use a recovery machine to remove the remaining refrigerant from the system.
NOTE
CWhen the low side system pressures reach 0 psig, close the vapor line valve.
DCheck gauges after shutdown to confirm that the valves are not allowing refrigerant to flow back into the low side of the system.
Figure 3. Refrigerant Recovery Procedure
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