Question 107Refrigeration & AC - Assistant Engineer
70% to passWhich of the listed statements describes the reason why oil foaming occurs when starting a refrigeration compressor?
AThis phenomenon is inherent only in hermetically sealed units and is always provisional.
BThis 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.
CIf the oil level is not initially high, this condition is the result of agitation created by the movement of the mechanical components.
DThis will occur only if crankcase heaters are used.
AI Explanation
The correct answer is B) 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 that has been absorbed into the compressor oil to be released, creating foam or bubbles in the oil. This is a normal occurrence and is not inherent only to hermetically sealed units or dependent on the use of crankcase heaters. The other answer choices do not accurately describe the primary reason for oil foaming during compressor start-up.
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