Air Compressor Controls And Adjusting System Pressure - Miller Bobcat 200 Air Pak Owner's Manual

7-2. Air Compressor Controls And Adjusting System Pressure

!
After the air compressor shuts off,
the blow down cycle begins and
takes several minutes. When gauge
reads zero, open cap slowly to re-
lease remaining pressure.
1 Air Compressor Case Pressure
Gauge
2 Pressure Sensor
Pressure sensor measures compressor
outlet pressure. A check valve in the com-
pressor allows the outlet pressure to re-
main while the case pressure is reduced.
See Section 6-4 to set compressor pres-
sure.
3 Over Pressure Switch (200 ± 10 psi)
Over pressure activates at 200 ± 10 psi
(1379 ± 69 kPa), disables compressor, and
displays AC OP (see Section 11-8). Power
to compressor is disabled until air compres-
sor switch is turned off or case pressure is
reduced below 125 psi.
.
A complete Parts List is available at www.MillerWelds.com
1
4
7
2
NOTICE − Frequent over pressure cycling
can cause clutch and belt damage.
4 Pressure Relief Valve
The compressor is also equipped with a
mechanical safety valve (pressure relief
valve) that will open if pressure reaches
225 psi.
5 Temperature Sensor
Compressor shuts down due to over-
temperature and AC TEMP displays (see
Section 11-8). The error condition automat-
ically resets when temperature reduces.
Power to compressor is disabled until air
compressor switch is turned off.
Compressor Blow Down
6 Blow Down Valve
.
To prevent foaming or sudden release
of pressure, allow 10 minutes after
shutdown before opening the com-
5
3
pressor fill cap or performing other
compressor maintenance.
To control the release of air mixed in the
compressor oil (while running), the com-
pressor goes through a blow down cycle
when the compressor is turned off or the
engine is stopped. The blow down valve
slowly discharges the pressure in the com-
pressor.
Compressor Idle Down And Standby
Mode
7 Compressor Outlet
When MAX pressure is reached, the blow-
down valve is de-energized and the com-
pressor begins reducing case pressure. If
no air is used, the compressor case pres-
sure continues to drop. After 45 seconds,
the clutch disengages and the engine idles.
If there is a rapid pressure drop on the outlet
of the compressor, or if pressure is below
MIN pressure, the clutch and compressor
engage until MAX pressure is reached.
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