______________________________________________
HARRIS
888-9058-001
WARNING: Disconnect and lockout AC primary power prior to servicing
169
e
. Connect a source of vacuum to the tee at the manometer, and gradually supply
vacuum until +12 volts appears at J-3 pin 2.
f.
Note the manometer reading when the air switch closes.
g.
Adjust the air switch threshold to -0.25 inches H20 column. Turn the adjustment
screw in top of cabinet clockwise to increase the pressure differential required to activate
the switch, or counter-clockwise to decrease the differential.
h.
Remove vacuum and check to see that J-3 pin 2 falls to 0 volts.
i.
Reconnect the air tubing in the cabinet and check for normal operation. Press
transmitter ON, and confirm air switch operation by momentarily switching the fan
breaker off while observing the air loss LED.
Figure 7-4 Back Door Sample Point