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 chokes the flow of liquid refrigerant entering the thermostatic expansion valve, starving the evaporator coil. This starvation reduces the mass flow rate and lowers both the evaporating temperature and the running suction pressure at the compressor.