LIQUID LINE SIGHT GLASS
A liquid line sight glass allows for quick, visual confirmation of refrigerant charge when the metering device is an expansion valve.
Cooling Mode
In the cooling mode, refrigerant is pressurized and cooled in the condenser. With adequate pressure and cooling the refrigerant "sub-cools" and condenses into a liquid state. This transition can be seen through the sight glass.
Heating Mode
In the heating mode, refrigerant is pressurized and cooled in the indoor coil. With adequate pressure and cooling the refrigerant "sub-cools" and condenses into a liquid state. This transition can be seen through the sight glass.
Reasons for a bubbly sight glass:
* Allow the system to run for at least 10 minutes before attempting to determine charge by the sight glass.
* Be cautious not to confuse a clear sight glass with an empty sight glass.