Question 117Refrigeration & AC - QMED
70% to passWhich of the listed statements describes the reason why oil foaming occurs when starting a refrigeration compressor?
AThis condition is the result of the sudden low-pressure created in the crankcase at start up causing the release of refrigerant absorbed within the oil.
BIf the oil level is not initially high, this condition is the result of agitation created by the movement of the mechanical components.
CThis will occur only if crankcase heaters are used.
DThis phenomenon is inherent only in hermetically sealed units and is always provisional.
AI Explanation
The correct answer is A. This condition is the result of the sudden low-pressure created in the crankcase at start up causing the release of refrigerant absorbed within the oil. When a refrigeration compressor is started, the sudden drop in pressure within the crankcase causes any refrigerant gas dissolved in the compressor oil to be released, leading to foaming of the oil. This is a normal occurrence and is not related to the oil level, use of crankcase heaters, or being specific to hermetically sealed units. The other answer choices do not accurately describe the reason for oil foaming during compressor start-up.
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