Chapter 4 Page 5
The gauge manifold is the common connection point for the hoses from the sealed system under repair, and for the hose to the refrigerant supply and the vacuum pump. The hand valves open or close the valve ports leading to the hoses directly below them.
The unit on the left is a compound gauge; that is, it will read either vacuum or pressure. The gauge on the right side will read pressure only. Each gauge will read only the pressure in the outlet hose directly below it. A bypass port around the hand valve is built into the manifold body. The valve merely opens (or closes) a passage way between the hose and the common manifold.
To properly connect the gauges to a system requiring repair, the hose leading from the compound
gauge (left side) should always be connected to the low side of the system at the suction line where either pressure or vacuum can be read. The hose from the pressure gauge on the right side of the manifold should always be connected to the high side of the system at the 2nd discharge line from the compressor where only pressure will be read.
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