Bubbles showing in a liquid indicator usually means the system is

Bubbles showing in a liquid indicator usually means the system is

• A. Is short of refrigerant
• B. Head pressure is too high
• C. Is full of air
• D. Head pressure is too low

Answer: (A)

Bubbles in the liquid line sight glass indicate the refrigerant is not fully liquid as it flows toward the metering device. This typically means the system is undercharged. When there isn’t enough refrigerant, the pressure in the liquid line drops and some of the liquid flashes into vapor as it passes through the expansion device, creating visible bubbles. In this condition, you’d add refrigerant and recheck the charge until the sight glass clears and the system operates properly. Higher or lower head pressure or air in the system don’t produce the same clear, direct sign in the liquid indicator; those issues affect pressures or moisture/air handling rather than signaling a low charge.

Bubbles in the liquid line sight glass indicate the refrigerant is not fully liquid as it flows toward the metering device. This typically means the system is undercharged. When there isn’t enough refrigerant, the pressure in the liquid line drops and some of the liquid flashes into vapor as it passes through the expansion device, creating visible bubbles. In this condition, you’d add refrigerant and recheck the charge until the sight glass clears and the system operates properly. Higher or lower head pressure or air in the system don’t produce the same clear, direct sign in the liquid indicator; those issues affect pressures or moisture/air handling rather than signaling a low charge.