Into which appliance category does a machine charged with R-13 for very low temperature service fall?
Correct Answer
B) A very high-pressure appliance
The regulations split appliances into low-pressure, high-pressure and very high-pressure categories based on how the refrigerant behaves. R-13 has an extremely low boiling point and builds very high saturation pressure at ordinary temperatures, which places it in the very high-pressure group along with refrigerants used in the bottom stage of cascade systems. Very high-pressure appliances are serviced under Type II, not Type III, and they carry their own recovery requirements that differ from ordinary high-pressure equipment.
Why This Is the Correct Answer
R-13 boils far below zero and develops very high pressure when it sits at room temperature, which is the opposite of low-pressure behavior. That places the appliance in the very high-pressure category. Recognizing this class matters because candidates often assume every appliance is either low-pressure or high-pressure and forget the third group exists.
Why the Other Options Are Wrong
Option A: A low-pressure appliance, because the machine operates in a deep vacuum
A deep vacuum is the signature of the low-pressure class. R-13 pressurizes strongly at room temperature, so the machine is never in a vacuum on the high side.
Option C: A high-pressure appliance identical in class to an R-22 system
R-22 sits in the ordinary high-pressure group. R-13 goes further, into the very high-pressure category, and that distinction carries its own recovery rules.
Option D: A small appliance, because cascade freezers are factory sealed
Small appliance status depends on a factory sealed charge of five pounds or less, not on the service temperature or on the refrigerant used.
Memory Technique
Colder boiling point means higher pressure. R-13 boils near the bottom of the scale, so its pressure sits at the top.
Reference Hint
Three appliance classes exist: low-pressure, high-pressure and very high-pressure. R-13 and similar ultra low temperature refrigerants are very high-pressure.
More epa-608-type-3 Questions
Some jobs on a chiller count as a major repair under the refrigerant rules, which changes what a technician is allowed to do with a badly leaking machine. Which job falls into that category?
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The motor of a hermetic centrifugal chiller sits inside the pressure boundary rather than outside it on a shaft. What follows from that construction?
An oxygen monitor is used to decide whether a chiller machine room is safe to enter after a refrigerant release. Below what oxygen reading is the atmosphere treated as oxygen deficient?
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