Question 224Refrigeration & AC - Assistant Engineer

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How does a refrigeration solenoid valve differ from a modulating valve?

ABoth valves operate in exactly the same manner, only the manufacturer's terminology is the differentiating factor.
BA liquid line solenoid valve is either completely opened or closed, whereas a modulation valve is infinitely positioned according to the strength of the applied electrical signal.
CSolenoid valves are only used in low voltage refrigeration control systems, while modulation valves are used in high voltage applications.
DA solenoid valve can only be installed in liquid lines.
AI Explanation

The correct answer is B. A solenoid valve is either completely open or completely closed, whereas a modulating valve can be positioned anywhere between fully open and fully closed based on the strength of the electrical signal applied to it. Solenoid valves are binary - they have two states, on or off. Modulating valves can vary their degree of openness to precisely control refrigerant flow. The other answer choices are incorrect because: A) The operation of the two valves is fundamentally different, not just a matter of terminology. C) Solenoid valves can be used in both low and high voltage refrigeration systems. D) Solenoid valves can be installed in both liquid and suction lines, not just liquid lines.

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Official Resources
46 CFR Machinery & Electrical 46 CFR Engineering USCG National Maritime Center
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