AADCO 737 Series Operating Instructions Manual page 20

wear. The compressor relief valve eliminates this problem.
8.10 The AUX POWER outlet, Figure 1, is a four-conductor connector, one lead (the
red lead) carries power to the cooling fan located within the compressor
silencer housing. Power is applied to the cooling fan continuously, whether the
compressor in on or off, thus maintaining a favorable temperature within the
compressor silencer housing.
8.11 The compressor supplies air via the ballast tank to the pure air generator
through the PUMP fitting, Figure 1 (58), on the rear of the generator unit. This
air passes through the compressor pressure relief valve, Figure 8 (23), through
the check valve, Figures 1, 2 and 9 (24), and into the ballast tank, Figures 1, 2
and 9 (16), where its pressure is monitored by the pressure switch, Figures 5
and 6 (17), and the INPUT PRESSURE gauge, Figure 4 (3).
8.12 At 80-psig the pressure within the ballast tank causes the pressure switch to
open, removing power from the coil of the solid state relay, which in turn
removes power from the compressor and the compressor relief valve.
8.13 When power is removed from the compressor, the compressor pressure relief
valve vents the connecting tubing to atmospheric pressure and causes the
check valve, Figures 1, 2 and 9 (24), to close, confining the pressurized air
within the ballast tank.
8.14 This pressurized air enters the purification reactor, Figures 5, 6, 7 and 7a (18).
During the purification process, the air within the ballast tank is consumed,
decreasing the pressure within the tank again to 60-psig. At this point the
entire procedure is repeated, producing the on and off operation of the
compressor.
8.15 This system will operate efficiently only if some preventive maintenance is
performed every three or four weeks of sustained operation. These procedures
are covered in Section 12.0
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