If the running suction pressure at the refrigeration compressor of a TXV controlled air-cooled refrigeration system is below normal, which of the following can be a cause?

Correct Answer: Option C — a restricted liquid line strainer

A restricted liquid line strainer starves the thermostatic expansion valve of adequate liquid refrigerant, reducing mass flow to the evaporator. This starvation results in a starved coil, lower refrigerant boiling rates, and a significantly below-normal running suction pressure.