HVAC Employment Readiness Practice Exam

The sight glass in a refrigeration system is positioned in the liquid line before the metering device. This location is crucial because it allows technicians to visually inspect the refrigerant flow and determine whether the system is functioning optimally. The sight glass shows the state of the refrigerant – whether it is in a liquid or vapor form.

Having it situated in the liquid line prior to the metering device enables technicians to monitor the condition of the refrigerant as it transitions from the condenser to the evaporator. A clear sight glass indicates that the system has an adequate amount of refrigerant; conversely, if bubbles or vapor are visible, it suggests that there may be issues such as low refrigerant levels or a restriction in the flow. This visual inspection point plays a significant role in maintaining system efficiency and identifying potential problems early on.