Look at Page 13 of the
pneumatics manual. The only gauges you really are required to have are the two closest to the compressor: One to show the compressor output pressure (located by the relief valve) and one to show the regulated "working" pressure (at the Norgren regulator). The third gauge shown at the Monnier regulator is optional, only of you need both 60 PSI and some other, lower pressure.
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