An air conditioning manifold gauge set is a chambered device designed to control the flow of pressure and gases. AC gauges are used for measuring the pressure in a closed-system air conditioning unit to evaluate or troubleshoot it. This device can be used to transfer refrigerant to and purge AC systems. Read the suction pressure on the gauges by locating the compound gauge, finding the pressure and vacuum measurements and reading the suction pressure.
Instructions
- 1
Find the compound gauge. There are two gauges on a manifold set -- one red and one blue. The compound or low pressure gauge is the blue one on the left side. There are several circles of numbers within this gauge.
2Look for the pressure and vacuum measurements by finding the outer circle of numbers on the compound gauge. This circle measures pressure and vacuum. Do not pay attention to the inner circles because they measure temperature. The pressure and vacuum scale will be partially black and partially red.
3Read the suction pressure. Look for the red numbers on the outer measurement circle. The black numbers measure pressure and they are in pounds per square inch (PSIG). The red numbers measure the pressure below atmospheric pressure. The vacuum or suction pressure part of the gauge goes from 0 to 30 HG or inches of mercury.
4Know what a suction pressure reading means. Suction pressure is when the low pressure reading on the gauge is so low that it dips below atmospheric pressure. This could mean that the air conditioning system has a defective expansion valve. The expansion valve controls the flow of refrigerant into the evaporator of an air conditioning system.
