The next job uses a different refrigerant than the one just pulled out of the recovery machine. What has to happen before that job starts?
Correct Answer
D) Recover the refrigerant left inside the machine and its hoses so the next charge is not contaminated
A recovery machine holds refrigerant in its internal circuit, its oil separator, and its hoses after a job ends. Starting a different refrigerant on top of that residue contaminates both the machine and the receiving cylinder. The correct step is to run the machine's self-clearing or purge cycle so the residual refrigerant goes into the cylinder for the refrigerant it belongs to, and only then connect the next appliance. Venting the residue in any form is prohibited.
Why This Is the Correct Answer
The machine has to be cleared into the proper cylinder before switching refrigerants. Most recovery machines have a self-clearing cycle for exactly this, which pulls the residual charge out of the internal circuit and hoses and sends it to the cylinder, leaving the machine ready for a different refrigerant without cross-contamination.
Why the Other Options Are Wrong
Option A: Flush the machine's hoses with dry nitrogen and let it vent to the outdoors
Blowing the residue out with nitrogen releases refrigerant to the atmosphere, which the venting prohibition forbids regardless of where the discharge is aimed.
Option B: Swap the machine's filter-drier and begin the next job with the residual charge still inside
Changing the drier does nothing about refrigerant sitting in the machine's circuit and hoses. The residue still mixes with the next charge.
Option C: Warm the machine so the previous refrigerant boils off through its relief valve
Deliberately relieving refrigerant through a relief valve is a knowing release. Relief valves are safety devices, not a way to empty a machine.
Memory Technique
The machine keeps a mouthful after every job. Spit it into the right cylinder, never onto the floor.
Reference Hint
40 CFR 82.154 venting prohibition; recovery equipment self-clearing procedures protect against cross-contamination.
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?
A technician recovers R-134a into a cylinder that still holds recovered R-12 from an earlier job. What is the consequence for that refrigerant?
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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