A technician certified in Core and Type II arrives to find that the failed machine is a centrifugal chiller charged with R-123, a refrigerant that boils above normal room temperature. What may that technician do on the machine?
- ARecover the charge, since recovery is permitted under any type certification that is held
Recovery is not a universal privilege. Each type certification authorizes work on its own equipment class, and low-pressure recovery uses different equipment and technique than Type II work does.
- BOpen the machine, because an emergency service call suspends the certification requirement for that visit
Nothing in the rules suspends a certification requirement during an emergency. Downtime pressure is exactly when shortcuts get taken, which is why no exception exists even for a single visit.
- Nothing that opens the refrigerant circuit, because that machine requires Type III certification
- DPerform the repair as long as the recovered refrigerant is sent to a certified reclaimer afterward
Reclamation governs what happens to refrigerant after it comes out of the machine. Sending it to a reclaimer says nothing about who is authorized to open the circuit in the first place.
Why C is correct
Certification is tied to the appliance class, and this machine's refrigerant places it in the low-pressure class. A Type II holder may work on high-pressure and very high-pressure appliances only, so opening the R-123 circuit is out of bounds until the right certification is on site.
What this question is testing
This item checks whether the candidate holds the certification boundary under pressure, and whether they recognize R-123 behavior as the marker of a low-pressure appliance.
On the job
Campus and hospital plants still run older R-123 machines alongside newer high-pressure equipment, and the on-call technician does not always know which machine is down until arrival. The practical move is to work the non-refrigerant side, get the plant on backup or a rental chiller, and call in a Type III certified technician. Shops that cover these accounts usually require Universal certification for anyone on the chiller rotation for exactly this reason.
Memory technique
The card follows the machine, not the emergency. Wrong class, hands off the circuit.
Exam tip
Emergency, customer pressure and good intentions never appear in the rules. If an option offers an exception for urgency, it is wrong.
Where to look it up
40 CFR 82.161: Type III is required for low-pressure appliances. R-123 boils above room temperature, per the class definitions in 40 CFR 82.152.