A Guide to Spray Rig Controls

AST equipment does the tough work so you can spray easier and with less effort.

This blog will go over the controls you’ll need to know to operate your spray rig so you can take full advantage of its capabilities.


Flow Dividers




After you start your engine you will be able to control your RPM. The normal operating RPM is 3000-3200 while mixing or pumping texture.

There is an RPM gauge and RPM control on the engine that you can use to adjust your RPM to get it in this range.

Air System Controls

Once your engine is on and your compressor is building pressure, you will control your air using the ball valve on the spray gun.

Another important air control to know about is the air tank drain valve. On trailers, this is located on the rear of the trailer frame under the engine.

On skid units the air tank drain valve is located on the bottom of the power pack frame.

Gun Ball Valve
Air Tank Drain Valve
More Gun Controls

As mentioned earlier, you control your air flow with the 1/4″ ball valve on the gun. In addition, your gun has the following controls:

All spray rigs are equipped with either an air or electric switch. An electric switch is shown in the photo (see the arrow on the right). This is used to turn the material pump on or off.

The other ball valve on the gun (see the arrow on the left in the photo) is for closing off the material flow after the pump has been shut off with the switch. This is only used to stop any residual pressure from pushing material through the gun after the pump is off. Closing this valve with the pump on can result in a hose bursting because of the buildup of pressure.

Gun Controls
Flow Dividers

The flow dividers on the front of the tank control the speed of the material and agitation hydraulic pumps.

The top flow divider controls the pump motor speed. Adjust this to increase or decrease the amount of material being pumped to the gun. For reference, with a new stator tube most contractors set this in the 3-5 range.

The bottom flow divider controls the agitation motor speed. The agitation motor is what spins the mixing paddles in the tank. Adjust this control to speed up or slow down the mixing paddles.

Flow Dividers
Additional Resources

The AST Big Rig Operating Manual is a great resource for getting more information about the operation of your spray rig. English and Spanish versions of the manual can be found on our website here: Product Manuals and Tech Support

We also have full-time support available by phone or text at 253-833-4342. Our hours are Monday-Friday 7:30-4 Pacific time.




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