A technician is using a piercing-type access valve to recover refrigerant from a small appliance. Where should the piercing valve be installed on the appliance to ensure effective recovery?
- AOn the suction line of the compressor.
- BOn the liquid line before the metering device.
- COn the discharge line of the compressor.
- DOn the hot gas line after the condenser.
Show answer & explanationAnswer & explanation
Correct answer: A. On the suction line of the compressor.
For effective recovery, especially with a system-dependent (passive) recovery method often used on small appliances, accessing the suction line provides the lowest pressure point in the system. This allows for easier and more complete refrigerant removal, particularly if the compressor is non-operating. Accessing the high-pressure side (discharge or liquid line) is also possible but suction line access is generally preferred for overall recovery efficiency from the entire system.
Why the other options are wrong
- B. The liquid line is high pressure; while possible, suction side is generally better for overall system emptying.
- C. The discharge line is high pressure, which can be recovered from, but suction line access is often more comprehensive for full system recovery.
- D. The hot gas line is high pressure; similar to discharge, it's not the optimal single access point for overall system recovery.
Piercing Valve Placement for Recovery
For effective refrigerant recovery from a small appliance using a piercing valve, it should ideally be installed on the suction line of the compressor, as this provides access to the lowest pressure point in the system.
- Suction line access facilitates complete refrigerant removal.
- Allows for more efficient recovery, especially with passive methods.
- Ensures removal of refrigerant from the entire low-side circuit.
Memory trick: To suck it all out, the suction line's the route!