F.A.Q.

Q: What is CFM?
A: The notation CFM (Cubic Feet per Minute) refers to a volume of air produced by the air compressor at a given pressure or PSI (Pound per Square Inch)

Q: What is Duty Cycle?
A: A compressor's duty cycle determines the percentage of run time in a full cycle. A full cycle is determined by adding the compressor run time to its rest time.

Q: Does a compressor that has 100% Duty Cycle mean that I can run the compressor all the time? Can I run my compressor 24 hours a day?
A: No, you've got to remember that duty cycle is rated at 100psi, at an ambient temperature of 72F, but certainly a 100% duty cycle compressor can run for much longer periods of time than a 30% duty compressor under the same conditions.

Q: I'm interested in a compressor for my onboard setup. Which compressor would you recommend?
A: We would recommend either the 400C or the 450C for your setup.

Q: How do I know if I want the 400C or 450C?
A: The 400C pump is rated at 150psi working pressure and the duty cycle on this unit is rated at 33% duty at 100psi in 72 degree ambient temp. The 450C is rated at 150psi working pressure, the duty is rated at 100% at 100psi at 72 degrees ambient temp. TIP: If you need duty cycle, go with the 450C. If you want speed, go with the 400C (it is faster than the 450C).

Q: What else would you recommend for my onboard system?
A: Here are some suggested component parts for an onboard air system:

PART NUMBER
91025 - 2.5 Gallon Tank with 6 Ports
90005 - 5pc. Tank Port Fittings Kit
20052 - Onboard Air Hookup Kit (comes with 110/150psi pressure switch, gauge, fittings, terminals, etc.)
90007 - Air Source Relocation Kit
00035 - 35ft Hose with Close-ended Tire Chuck

Q: What is the difference between the "C" model compressor and the "H"?
A: The "C" model compressor is turned on with a pressure switch installed in an air supply tank. The "H" model compressor is a hard mount that has an ON/OFF switch located at the rear of the motor housing. The "H" series also comes with a quick connect stud installed at the end of the stainless steel braided leader hose, while the "C" compressor comes with a threaded hose end that would be installed into the air supply tank.

Q: When would I want t use a "C" compressor and when would I want to use an "H" compressor?
A: You would want to use the "C" model compressor in setups with air tanks (and you would run the appropriate pressure switch for that application). You would use an "H" model compressor for the direct inflation of tires via an air hose.

Q: Does a new compressor have to be broken in?
A: No, they do not. Typically after an install, you should power up the system from 0 to whatever the cut-off pressure is and check for any leaks that may be present.

Q: How do you check for leaks?
A: You can check for leaks by putting soap and water solution where the fitting connections are. If there are bubbles present that grow in size, then there are leaks.

Q: Does it matter where I install my compressors on my vehicle?
A: 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?
A: 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, cracks, or holes in the motor housing, then the compressor is not sealed and must be kept away from dust and moisture.

Q:Why is it important to have a sealed and moisture-resistant compressor?
A: The preference of a sealed-type compressor is due to the fact that in mobile pneumatics, compressors are likely to be exposed to outside elements.

Q: Is it possible to mount the compressor sideways? Must it be mounted with the cylinder upright?
A: Yes, you can mount our compressors in any direction or position because they are oil-less. The only position we do not recommend is an upside-down mount, since heat tends to travel upward.

Q: If I mount my compressor sideways, like on the frame rail of my truck, is there anything I should be careful of when doing this?
A: If you mount your compressor sideways to the frame rail, you should periodically check to make sure that your compressor is mounted securely. Use a thread-locking compound to keep the screws from backing off and causing the compressor to be mounted loosely.

Q:What is the largest air tank recommended for your compressors?
A: We recommend up to a 5 gallon tank for the 325 and higher series compressors.

Q: Is it possible to hook up more than one compressor to a single pressure switch?
A: Yes, it is possible to use one pressure switch on more than one compressor. You should always run a relay if you want to hook up multiple compressors to a single switch. You should check the amp draw on the switch first, and then you'll know how many compressors you can hook up to one switch.

Q: Can I use an adjustable pressure switch with my compressor?
A: We don't recommend that you use adjustable pressure switches with any VIAIR compressor. If you use an adjustable pressure switch, you can set the pressure switch higher than the maximum pressure that is rated for your compressor, or you may exceed the maximum rated working pressure for your air supply tank. Doing so will immediately void your warranty, not to mention, it is dangerous.

Q: Is amp draw of the compressor something I need to be concerned with?
A: Yes, the lower the amp draw, the better the compressor is. As a rule of thumb, the maximum amperage that a compressor should require is 30amps.

Q: What exactly is in the 5-piece tank fittings kit? (Part Number 90005)
A: The kit contains:
(1) 175psi Safety Valve
(2) 1/4" Compression Fitting
(1) Drain Cock
(2) 1/4" Plugs.

Q: Is there a way to increase the flow rate of my compressors, and improve my compressors' performance as well?
A: When using an onboard air system with multiple compressors such as P/N 38002, always plumb each compressors's leader hose to separate tank port. Doing so will increase flow rate by up to 20%, which will also increase your system's level of performance.

Q: How can I become a VIAIR products dealer?
A: You can become a VIAIR dealer by sending us a copy of your automotive business license and resale permit. We will then send you our dealer package with further instructions. We cannot accept any dealers in California at this time. Please fill out our dealer inquiry form for more information.