An AXV system undercharge results in low suction pressure and bubbles in what?

In an AXV (Automatic Expansion Valve) system, an undercharge typically manifests as low suction pressure and the formation of bubbles in the sight glass. The sight glass is a small transparent component that allows operators to visually assess the state of the refrigerant within the system.

When the system is undercharged, there isn't enough refrigerant circulating, leading to inefficient heat transfer. This situation can result in a low pressure in the suction line, which can prevent the refrigerant from fully vaporizing. Consequently, instead of seeing a clear flow of refrigerant, the operator will observe bubbles in the sight glass, indicating that the refrigerant isn't present in sufficient quantities to maintain proper system operation. This visual cue is critical for diagnosing undercharging issues and helps technicians implement timely corrective measures to restore optimal functioning of the refrigeration system.