VIAIR Corporation

Frequently Asked Questions:

Q: Does a new compressor need to be “broken in”?

New compressors do not have to be “broken in”. After an install, power up the system to pressurize the system’s air tank to the pressure switch cut-off pressure and check for any leaks.

Q: How do I check for leaks in my system?

Check for leaks by spraying a soap and water solution on your fitting connections. If there are bubbles present that grow in size, then there are leaks. Re-seal any connections that may be leaking using thread sealant. VIAIR recommends Loctite 545 as a thread sealant.

Q: Does it matter where I install my compressors on my vehicle?

This depends on several factors such as available space, whether or not the compressor is of a sealed or vented type, as well as personal preference and aesthetics. Make sure to utilize the rubber insulators to keep vibration and noise to a minimum.

Q: How can I tell whether the compressor is sealed or non-sealed?

Manufacturers will normally specify if a compressor is sealed against moisture and dust, and in many cases, you can tell the difference by simply inspecting the compressor. If you see vents, holes in the motor housing, then the compressor is not sealed and must be kept away from dust and moisture.

Q: Is it important to have a sealed and
moisture-resistant compressor?

Depending on the mounting location of the compressor, this is extremely important. The preference of a sealed-type compressor is due to the fact that compressors are likely to be exposed to outside elements, such as mounting to a chassis rail.

Q: Is it possible to mount VIAIR compressors sideways,
or must it be mounted with the cylinder upright?

You can mount in any direction or position since VIAIR compressors are oil-less. The only position we do not recommend is an upside-down mount, since heat tends to travel upward, and does not dissipate well in the motor housing. A sideways mounting may reduce the life of the piston seal, since everything is governed by gravity and has a weight associated with it.

Q: What is the largest air tank
recommended for VIAIR compressors?

We recommend up to a 5.0 gallon tank for the 325C and higher series compressors.

Q: Does each compressor require its own pressure switch?

No, you may control more than one compressor with a single pressure switch. Always run a relay if you want to hook up multiple compressors to a single switch however.

Q: Can I use an adjustable pressure switch with my compressor?

VIAIR does not recommend that you use adjustable pressure switches with any VIAIR compressor. If you use an adjustable pressure switch, you will be able to set the pressure switch higher than the maximum working pressure that is rated for your compressor, or you may exceed the maximum rated working pressure for your air supply tank.

Q: Do I need to concern myself with the amp draw of the compressor?

Always make sure that your vehicle’s charging system can handle the load placed on it, with all electrical systems active (including compressors). If your alternator puts out less than your full system load, consider replacing the alternator or have it rebuilt to provide more output. A quality deep cycle battery is also a good idea.

Q: Is there a way to increase the flow rate of my compressors, and improve performance as well?

When using an onboard air system with multiple compressors such as P/N 38002, always plumb each compressor’s leader hose to separate tank ports. Doing so will increase flow rate by up to 20%, which will also increase your system’s level of performance.

Q: My compressors sound like they’re “ramping up” when they start. How do I avoid this?

Always make sure that your vehicle’s engine is running prior to powering up your compressors. Rated performance is determined at charging voltage of 13.8 volts. Performance data listed in all VIAIR catalogs and its website are determined by operating the units at an ambient temperature of 72 degrees Fahrenheit, up to 100 PSI.

Q: What is “Duty Cycle”?

In short, Duty Cycle is the amount of time that a compressor can be run in a full cycle (typically one hour) that includes the compressor’s run time and rest time. All VIAIR compressors are equipped with a thermal overload protector to protect the unit in case of over duty cycle or high temperature operation.

Q: I operated my compressor for a long time and now it won’t turn back on. Did I damage the compressor?

This is unlikely. The compressor is equipped with a thermal overload protector to keep the motor from overheating to the point of permanent damage. Allow the compressor to cool for 30-45 minutes before you attempt to turn the unit on again.

Q: I want to move the mounting feet of the compressor to work with my specific installation. Is there anything I should avoid?

The direction of the bolts hold the compressor together. Changing the direction will allow the compressor to vibrate apart, and may cause the unit to fail catastrophically, which voids the compressor’s warranty.

Q: Does my VIAIR compressor have a warranty?

All VIAIR compressors come with a One Year Manufacturer’s Defect Warranty. Click Here for more information.