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 D — a restricted liquid-line strainer

A restricted liquid-line strainer starves the thermostatic expansion valve of adequate refrigerant flow, resulting in reduced mass flow to the evaporator, lower boiling refrigerant volume, and an abnormally low running suction pressure at the compressor.