Auto Pump AC AD

Product Code: 091-9B-4-AD


  • Previously 091-9B-1-AD
  • 100 PSI Max Rating, 120V, 4A
  • Vehicle mount compressor ensures air brake system is properly pressurized for immediate truck departure from station
  • Automatically purges water separator bowl every time compressor cycles off via a normally open solenoid
  • Pressure switch regulated operation automatically senses low pressure in air system and restores proper pressure, preventing brake lock-up
  • No interference with engine mounted air compressor
  • Factory set PSI actuation points: 75 "On", 95 "Off" with Adjustment differential 20 PSI
  • Sealed ball bearings for long service life
  • Compact size
  • 2-year warranty
  • Part# 091-9B-4-AD replaces Part# 091-9B-1-AD
PSI 100
Input Voltage 120
Orientation vertical
Auto Drain yes
Input 120 Vac, 50/60 Hz, 1.8 Amps
Output 1.0/1.3 CFM, Open Flow, 100 PSI Max
Warranty 2 Year
Weight 16 lbs
Motor Type Shaded Pole AC
Motor Horsepower 1/8 HP
Pressure Switch Adjustable Set-Point Factory set to 75 PSI Cut-In, 95 PSI Cut-Out
Outlet Connection 1/4 NPT, Female

The Auto Pump AC AD is an 091-9B-1 Auto Pump with an Automatic Drain installed.  A normally open solenoid valve drains the moisture from the trap each time the compressor shuts down. The Auto Drain assures that the filter bowl is always drained and does this without intervention by maintenance personnel.

The Auto Pump AC AD is a 120-volt 60 Hz shaded pole A.C. motor operating a single cylinder air compressor. During long idle periods of the vehicle, when even the slightest seepage can cause an air brake system pressure to drop below the brake lockup pressure, the Auto Pump AC automatically starts to maintain the pressure. 

The Auto Pump AC motor is directly coupled to the compressor section eliminating all belts and pulleys and assuring long life and reliable operation. A heavy-duty pressure switch is adjusted to start the compressor when the system pressure drops below 75 PSI and stops the compressor when 95 PSI is attained. The startup pressure is field adjustable - the pressure differential between start up and stopping is fixed.