What line is the sight glass typically placed in?

The sight glass is typically located in the liquid line of an HVAC system. This component serves an important function in monitoring the refrigerant's condition as it moves through the system. The liquid line contains high-pressure liquid refrigerant coming from the condenser, and the sight glass allows technicians to visually assess the refrigerant flow.

By observing the sight glass, technicians can determine whether the refrigerant is in a liquid state, whether there is a sufficient amount of refrigerant, and identify potential issues such as low refrigerant or air in the system. A clear view indicates the proper functioning of the system, whereas bubbles or a frothy appearance in the sight glass can signal that the system may be low on refrigerant or experiencing other problems.

In contrast, installing a sight glass in the drain line, suction line, or discharge line would not provide useful information about the refrigerant charge or flow quality in the same manner, as these lines serve different purposes within the HVAC system.