Is it advisable to install a sight glass in a cap tube system?

Installing a sight glass in a capillary tube refrigeration system is generally not advisable because cap tube systems experience the continuous flow of refrigerant in a liquid state and do not typically accumulate refrigerant in a manner that would allow for effective visual observation through a sight glass. The primary function of a sight glass is to show the presence of liquid refrigerant in a system, which is more relevant in systems that utilize expansion valves or other mechanisms where liquid refrigerant could accumulate or where phase change occurs in sight. In a capillary tube setup, the design facilitates a direct flow of refrigerant without such accumulations, rendering a sight glass unnecessary and potentially misleading regarding the system's performance.

Moreover, installing a sight glass could also introduce risks such as refrigerant leaks or failures at the sight glass joint, which could compromise system performance and reliability. Thus, the inefficiency and potential drawbacks associated with a sight glass in a cap tube system culminate in the conclusion that it is of no value.