Which of the following is an indication that refrigerant may be low?

The correct choice indicates that all listed symptoms can indeed suggest low refrigerant levels in a system. Low refrigerant can lead to a variety of performance issues that manifest in several ways.

Buildup of ice on the evaporator coil is a classic sign of low refrigerant. When refrigerant levels drop, the coil may not absorb enough heat from the surrounding air, causing moisture to freeze on the coil surface. This can lead to reduced cooling efficiency and potential system damage if not addressed.

Low airflow from vents can also suggest low refrigerant levels. In this case, the lack of sufficient refrigerant can prevent the evaporator coil from absorbing enough heat, which in turn means less cool air is circulated through the ducts.

High noise levels from the compressor can occur as well when refrigerant is low. The compressor works harder to compensate for the insufficient refrigerant, which can create unusual noises due to increased stress on the unit.

Recognizing all these indicators is crucial for diagnosing potential issues with refrigerant levels and ensuring the efficient operation of an HVAC system.