The Kussmaul Auto-Pump 120 VAC Air Compressor System, model 091-9B-1, is a specialized air compressor designed to maintain air brake system pressure in vehicles, particularly during long idle periods when pressure might drop due to slight seepage. This system is engineered to automatically start and stop, ensuring that the vehicle's air brake system remains at operational pressure, preventing it from falling below the brake lockup threshold.

Function Description:

The Auto-Pump system operates by compressing air and feeding it into the vehicle's air brake system. It is equipped with a heavy-duty pressure switch that monitors the system pressure. When the pressure drops below a factory-set cut-in point of 75 PSI, the compressor automatically activates. Once the pressure reaches the factory-set cut-out point of 95 PSI, the compressor stops. This automatic operation ensures continuous pressure maintenance without manual intervention. The pressure switch's start-up pressure is field-adjustable, allowing for customization, although the pressure differential between start-up and stopping is fixed at 20 PSI nominal.

A key design feature is the direct coupling of the motor to the compressor section, which eliminates the need for belts and pulleys. This design choice contributes to the system's long life and reliable operation by reducing potential points of failure and wear. The system also includes a moisture trap, which is crucial for capturing condensate that forms during air compression. This helps prevent water from entering the air brake system and the pump's output, which could lead to system failure and void the warranty.

Important Technical Specifications:

Model Number: 091-9B-1
Input Voltage: 120 VAC
Frequency: 50/60 Hz
Current Draw: 1.8 AMPS
Motor Horsepower: 1/8 HP
Motor Type: Shaded pole A.C.
Compressor Output: 1.0/1.3 CFM (Open Flow)
Maximum Output Pressure: 100 PSI
Pressure Switch Settings (Factory Set):
- Cut-in: 75 PSI
- Cut-out: 95 PSI
Switch Differential: 20 PSI (Nominal)
Output Connection: 1/4" NPT, Female
Weight: 15 lbs
Warranty: 1 Year

Usage Features:

The Auto-Pump is designed for straightforward installation and operation. It comes with a 120-volt A.C. line cord, allowing it to be plugged into an available outlet or permanently wired into the vehicle's 120-volt A.C. system. The compressor is calibrated at the factory, making it ready for immediate use upon installation. Users can adjust the pressure switch's cut-in and cut-out points by turning the range nut clockwise to increase pressure or counterclockwise to decrease it, but it is critical not to exceed 100 PSI cut-out to avoid voiding the warranty.

The system's automatic operation means that once installed and powered, it will independently manage the air brake pressure, reducing the need for manual checks or interventions. This is particularly beneficial for emergency vehicles or heavy-duty trucks that require constant readiness.

Maintenance Features:

The Auto-Pump is designed for minimal routine maintenance. The manufacturer states that it requires "no routine maintenance" beyond checking and draining the moisture trap periodically. This is a critical maintenance task, as accumulated moisture in the trap or the pump's output line can lead to water damage and system failure, which will void the warranty.

Installation Considerations:

Location: Components should be mounted in a suitable, high area above the air system, away from heat sources, dirt, or the engine compartment.
Compressor Position: The air compressor must be mounted in a position that ensures it is above the air pressure tank.
Output Line Routing: The output pressure line from the Auto-Pump must be routed downward to allow any moisture to drain away. This is a crucial step to prevent condensate from accumulating in the pump's output, which can cause failure.
Air Line Connections: All air line connections are 1/4" NPT. Teflon tape or an equivalent sealant should be used on all connections to prevent air leakage.
Check Valve: An external check valve is located between the compressor and the pressure switch, eliminating the need for an additional check valve.
Tubing: Flexible tubing from the compressor's outlet port to the air tank is required but not supplied with the unit.
Optional Mounting Plate: An optional mounting plate kit (091-09H-1) is available to help reduce vibration and noise, and to simplify pump mounting.

Important Cautions:

Water Damage: No condensate or water must be allowed to enter or accumulate in the output of the Auto-Pump. Water in the pump outlet will induce failure and void the warranty.
Voltage Requirements: The pump requires a minimum of 110 volts for operation. Operating at lower voltages may prevent the pump from starting and/or damage the unit.
Maximum Pressure: Do not exceed 100 PSI output pressure, as this will void the warranty.

The Kussmaul Auto-Pump system is a robust and reliable solution for maintaining critical air brake pressure in vehicles, emphasizing automatic operation and minimal maintenance, provided installation guidelines and critical cautions regarding moisture and pressure limits are strictly followed.

KUSSMAUL AUTO-PUMP - Page 3

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