MNL-0408
June 11, 2009 Page 81
7.6.1 One Flash - Compressor High Temperature
The compressor high temperature switch is located on the high pressure breathing air compressor, on
the third, fourth or fifth stage head, depending on model. The switch is N.C., Normally Closed, and is
connected to the PLC on terminal I1. The switch is wired into a wire harness using the Yellow and Vio-
let color wires. Refer to unit schematic for additional information. Under normal operating conditions,
the switch is closed and the I1 lamp on the PLC is illuminated. On a high temperature condition, the
compressor will shutdown, the I1 lamp will extinguish, and the alarm code will flash.
7.6.2 Two Flashes - Compressor Low Oil Pressure
The compressor oil pressure switch is located on the high pressure breathing air compressor, on the
back of the block, mounted with the oil pressure gauge. The switch is N.O., Normally Open, and is con-
nected to the PLC on terminal I2. The switch is wired into a wire harness using the Orange and Blue
color wires. Refer to unit schematic for additional information. During startup of the compressor, the
oil pressure switch is bypassed in the program for a period of 45 seconds. When the oil pressure has sta-
bilized, the switch should be closed. Should the compressor lose oil pressure, then the compressor will
shutdown, the I2 lamp will extinguish, and the alarm code will flash.
7.6.3 Three Flashes - Compressor Overrun Timer
The compressor has an overtime function, where if the compressor runs continuously for 5 hours, then
the compressor will shutdown, and the alarm code will flash. This is done to secure the equipment if it
were to be started and left unattended.
7.6.4 Four Flashes - Securus Monitor
See Figure 7-8. The compressor purification system may be equipped with a Securus
®
Electronic Mois-
ture Monitor System. This consists of a control module and cable connected to the purification cham-
ber. It functions as a capacitive sensor, sensing the moisture in the purified air. When the chemicals in
the purification cartridges have reacted with moisture to a point where they are no longer suitable for
purifying the air, then the Securus
®
Module will illuminate it’s red light. At the same time the alarm
relay in the Securus
®
module is connected to the PLC on terminal I5. On a Securus
®
alarm condition, the
compressor will shutdown, the I5 lamp will be illuminated, and the alarm shows on the LCD Display.
The warning relay is wired N.O., normally open. The switch is wired into a wire harness using the
Figure 7-9 High Temperature Switch Figure 7-10 Low Oil Pressure Switch
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