Low-pressure (LP) systems provide compressed air up to 150 psig pressure. For branches requiring lower pressures, pressure is usually reduced at reducing stations. The following list contains examples of air pressure requirements for LP air:

Figure 6-1.Typical components of a compressed air system.

Laboratories 5 to 50 psig Shops 60 to 125 psig Laundries and dry cleaning plants 70 to 100 psig Hospitals

Ordinary service

(tools, painting, and so forth)

20 to 50 psig

60 to 80 psig

Soot blowing for boilers 80 to 125 psig You will probably be called upon to fix some problem on one of these stations. The three most common problems are wet air, not enough air, or no air at all. First you must trace the system to the station and isolate the problem. It could be just an air valve that is halfway open, a piping leak, a malfunctioning air reducer, an empty air receiver, or an overfilled moisture separator. Figures 6-2, 6-3, and 6-4 are maintenance requirements for LP air compressor systems.

Figure 6-2.A maintenance index page for low-pressure air compressor systems (page 1 of 3).

Figure 6-3.A maintenance index page for low-pressure air compressor systems (page 2 of 3).