Testing The Heads-Up Display - 3M SCOTT AIR-PAK X3 PRO Operating & Maintenance Instructions

5 Observe the air supply indicator lights of the HUD and verify that they light properly in descending order.
6 When the gauge needle crosses the one-third mark but before it reaches the beginning of the red empty band,
close the purge valve. See
Confirm that the following occur:
•
The Vibralert end-of-service indicator alarm
sounds (rapid clicking).
•
The red light at the far left of the HUD flashes
at 10 times per second.
•
On units equipped with a PASS device, the
gauge light on the remote pressure gauge is
solid red.
7 After verifying that all alarms are functioning, open the purge valve slightly to vent the remaining residual air
pressure from the system. All alarms (except the accessory electronic end-of-service time indicator) stop when
the system pressure drops to zero.
8 When the air flow stops completely, close the purge valve (the pointer on the knob points up).
9 Stop the electronic end-of-service time indicator by pressing the manual reset (yellow) button on the control
console twice and then twice again after the flashing green light sequence.

Testing the Heads-Up Display

The Heads-Up Display (HUD) provides a visual monitor of the air supply in the cylinder and valve assembly. The
display is fitted to the mask-mounted regulator and appears across the bottom of the user's field of view through
the facepiece.
The HUD consists of four rectangular lights to represent the cylinder pressure at full and three-quarters, one-half, and
one-third full. A fifth red light (in the shape of a battery) indicates low battery.
The HUD operates as follows:
•
When respirator use begins, the HUD will initialize and illuminate all lights for 20 seconds. Verify the operation of
all lights every time respirator use starts and with every regular operational inspection.
•
After initialization, the rectangular indicator lights show the level of the air supply in the cylinder (see
•
When the cylinder is more than three-quarters full, two green lights near the center of the display illuminate.
•
When the cylinder is between one-half and three-quarters full, a single green light illuminates.
•
When the cylinder is between one-third and one-half full, a yellow light flashes once per second.
•
When the cylinder is less than one-third full, a red light at the far left of the display (the end-of-service time
indicator) flashes 10 times per second.
P/N 595373-01 Rev C
Figure 2-8.
202004
PERFORMING OPERATIONAL TESTING
To test the HUD,
control the needle
between 1/3 and
empty.
Figure 2-8 Remote pressure gauge
Figure 2-9):
13