Which of the following is NOT a low-pressure appliance refrigerant?
a.CFC-11
b.HCFC-123
c.R-1233zd
d.HFC-404A
Explanation
HFC-404A is a high-pressure blend used in commercial refrigeration, not a low-pressure chiller refrigerant. CFC-11, HCFC-123, and R-1233zd are all low-pressure refrigerants that run in a vacuum. Sorting refrigerants by pressure class is a common exam task.
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Related questions on this topic
- The main reason a torch must never be used to warm a low-pressure chiller during recovery is that:
- In a low-pressure chiller, the evaporator normally operates:
- A technician recovering R-123 reaches 25 mm Hg absolute but the reading rises back up after the recovery machine stops. This usually indicates:
- Excessive water in a low-pressure chiller can freeze and rupture tubes because low-pressure refrigerants:
- When handling a large recovery cylinder of R-11 removed from a chiller, the technician must remember to:
- A high-efficiency purge unit on a chiller is often equipped with a purge-rate log because a rising rate:
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