At what angle should the bulb of a TXV be installed on a 1 1/8 OD suction line?

The bulb of a thermal expansion valve (TXV) should be installed at an angle of 45 degrees on a suction line. This angle is optimal because it allows the bulb to accurately sense the temperature and pressure of the refrigerant in the suction line, ensuring the TXV responds correctly to changes in load conditions. Installing the bulb at this angle helps in promoting proper heat exchange, which is critical for its operation.

A 45-degree installation is ideal because it enables the refrigerant to fill the bulb adequately, ensuring reliable performance. Additionally, it helps to prevent potential issues such as liquid refrigerant accumulation around the bulb, which can lead to improper sensing and thus inefficient system operation.

Other angles, such as 30 degrees, 60 degrees, or 90 degrees, are not conventional for this application and can lead to inadequate performance of the TXV. Installations at these angles may restrict the flow of refrigerant to the bulb or affect its ability to accurately gauge the temperature, which can result in improper metering of refrigerant and ultimately decreased efficiency of the system.