During a vacuum test, Technician "A" states that a compressor should pull 24" hg with 100 psig discharge pressure. Technician "B" says it should pull 26" hg to 28" hg when discharging to the atmosphere. Who is correct?

In a vacuum test for a refrigeration or air conditioning system, the pressure reading is an important indicator of the system's ability to remove moisture and impurities. Technician "A" mentions that the compressor should pull 24" Hg with a 100 psig discharge pressure. This is a relevant point because, at 100 psig, the system is pressurized and should be able to achieve a certain level of vacuum when the compressor is running.

Technician "B," on the other hand, suggests that it should pull a vacuum of 26" Hg to 28" Hg when discharging to the atmosphere. This range is often considered appropriate, as it indicates a stronger vacuum, which is essential for effective system performance and moisture removal.

Both readings provided by the technicians can be accurate under different circumstances. The ideal vacuum levels can vary depending on the type of system and the specific application, but both ranges presented are seen as acceptable in real-world scenarios for their respective conditions. Thus, it is possible for both technicians to be correct, making it reasonable to conclude that both perspectives reflect valid points regarding the expected vacuum levels during different operational scenarios of the compressor.