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

Correct Answer: Option D — A 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.

Solenoid valves operate exclusively as two-position open-or-closed devices for liquid isolation, whereas modulating valves adjust their orifice position infinitely along a spectrum based on variable electrical control signals.