Heating and Air Conditioning: Tools and Equipment

Manifold Gauge Set

DESCRIPTION





- The manifold gauge set is used to determine the systems high and low pressures, the correct refrigerant charge, system diagnosis and operating efficiency. It is designed to read both high and low pressures at the same time, because these pressures must be compared to determine correct system operation.
- Referring to the image, a vertical line drawn through the centre of the center service hose will divide the manifold set into its LOW and HIGH side.
- The manifold gauge set consists of a charging manifold fitted with two stop hand valves, a compound gauge and a high pressure gauge. The compound gauge which should be connected to the suction or low pressure side of the system registers both vacuum and pressure. The high pressure gauge is connected to the delivery or high pressure side of the system.

NOTE: For safety reasons the accuracy of both gauges must be checked at frequent intervals.

Gauge Manifold
- The manifold is designed to control refrigerant flow when connected into the system, pressure is registered on both gauges at all times. During tests both the high and low side hand valves are in a closed position (turned inward until the valve is seated).
- Refrigerant will flow around the valve stems to the gauges and register the system low and high pressures on the respective gauges. The hand valves isolate the low and the high sides from the central portion of the manifold.

Low Pressure Side Gauge
- This gauge has a dial reading from 0 to 150 PSI (pressure scale) in a clockwise direction and a 0 to 30 inches of mercury (vacuum scale) in counter clockwise direction. This low pressure gauge is called a compound gauge, it has a dual purpose which is to register both pressure and vacuum. This gauge is used to measure the evaporator outlet pressure.

High Pressure Side Gauge
- This gauge has a dial reading from 0 to 500 PSI in a clockwise direction and is a pressure gauge only.