Why does system-dependent recovery generally take longer to finish than recovery performed with a self-contained machine?
Correct Answer
C) It has no pump of its own, so flow slows as the appliance and the container approach the same pressure
Passive recovery is driven entirely by the pressure difference between the appliance and the recovery container. As refrigerant moves across, appliance pressure falls and container pressure rises, so the driving force shrinks and flow slows to a trickle near the end. A self-contained machine has its own compressor and keeps pulling regardless of how low the appliance pressure gets, which is why it finishes faster and can reach the required level on systems where passive equipment stalls.
Why This Is the Correct Answer
System-dependent equipment relies on the appliance's own pressure and compressor to move refrigerant. As the two pressures equalize the driving force disappears, so the last part of the charge comes out very slowly. A self-contained unit supplies its own pressure difference and does not suffer that slowdown.
Why the Other Options Are Wrong
Option A: Its filter-drier restricts flow in order to protect the recovery cylinder from moisture
A filter-drier causes a modest pressure drop but is not what makes passive recovery slow, and drying is not accomplished by restricting flow.
Option B: It has to be stopped and restarted every few minutes to keep it from overheating
Duty cycling to prevent overheating describes the behavior of some active machines with their own motors. Passive equipment has no motor of its own to overheat.
Option D: It routes refrigerant through the appliance's compressor windings, which restricts the flow path
Refrigerant is not routed through the motor windings during recovery. The flow path is through the tubing and access valves, not through the electrical side of the compressor.
Memory Technique
Water runs downhill until the levels match. Passive recovery stops for the same reason.
Reference Hint
40 CFR 82.152 definition of system-dependent recovery equipment: refrigerant removal depends on the appliance's components.
More epa-608-type-1 Questions
A technician certified under Section 608 is asked to service the air conditioning system in a customer's pickup truck. What credential does that particular job actually require?
Facing an unfamiliar packaged refrigeration unit on the bench, how should a technician decide whether the small appliance rules apply to it?
What feature defines a self-contained recovery unit and sets it apart from the system-dependent kind?
When system-dependent recovery equipment is used on a small appliance whose compressor still runs, how can that working compressor be put to use?
Recovery from a small appliance has slowed down and the pressure is barely moving. What accepted technique helps drive the remaining refrigerant out?
After the recovery unit stops pulling on a small appliance, how does a technician confirm that the recovery is actually complete?
A sealed small appliance offers no service port at all. What has to happen before recovery equipment can be connected to it?
As refrigerant from a string of small appliances collects in a recovery cylinder, what fill limit applies to that cylinder?
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Refrigerant recovered from a small appliance is going back into service once the repair is finished. When may it be reused without first being sent to a reclaimer?
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