Frequently Asked Questions

  1. What is a rotary screw compressor?

    Rotary screw air compressors consist of a male and female rotor. These rotors are precision machined to very tight tolerances and rotate at very high speed. Air is delivered to the rotor thru an inlet valve. As the rotors turn they begin to compress air and continue compression to the discharge housing on the air compressor.


  2. Do I need an air reservoir with a screw compressor?

    No. Rotary screw air compressors are positive displacement "pumps" Air is generated on demand as the inlet valve opens.


  3. Why is a cooler necessary?

    The rotary screw air compressor's rotors are immersed in an oil bath. Heat is generated during compression and is absorbed by the compressor oil. This oil is circulated thru a cooler and returned to the compressor.


  4. What is the average life cycle for a rotary screw air compressor?

    Vanair utilizes cutting edge technology in the rotary screw compressor product line. Design life exceeds 100,000 hours and exceeds truck life by a 5:1 factor.


  5. Why choose a Vanair PTO compressor over a portable compressor?

    Lower cost, enhances maneuverability of vehicle in congested areas, eliminates redundant PM's associated with two engines, eliminates theft from job site, eliminates multiple vehicles at job site, increases utilization of truck chassis.


  6. Will my Vanair compressor deliver the performance of my old portable compressor?

    Vanair compressors will out perform portables with a similar CFM rating due to the advantage of utilizing the vehicles higher output drive train.


  7. What is the output capacity of a Vanair PTO system?

    Vanair offers products ranging from 20 CFM to 1000 CFM


  8. What is the advantage of a screw compressor versus a reciprocating compressor?

    Rotary screw air compressors are designed for long life in severe operating conditions. Rotary Screws have significantly higher CFM ratings than Reciprocating compressors and provide pulse free air on demand. Reciprocals typically perform well only to about 50CFM.


  9. What type of vehicle can I mount my Vanair PTO compressor on?

    Typical PTO installations are completed on vehicles with a PTO provision or opening on the main transmission.


  10. Can I mount a Vanair unit on a vehicle with no PTO provision or opening?

    The Vanair Split Shaft driven compressors are made for vehicles where the transmission does not have a PTO opening or where the PTO opening is already occupied.


  11. When should I consider a Split Shaft versus a conventional side mount PTO unit?

    Vehicles equipped with a main transmission PTO provision should always be considered for a side mount application. Non-PTO transmissions are candidates for split shaft designs. Manual transmissions and Allison automatics provide ample horsepower and torque thru puts for all but very high CFM requirements.


  12. What is the recommended CFM output for my application?

    Please refer to the air tool consumption guide on this website to determine CFM capacities. If you will use multiple tools simultaneously, the air consumption is additive when determining the required CFM.


  13. What is the recommended PSI output for my application?

    Most pneumatic tools are rated at 90-110 psi. Higher pressures delivered to tools rated at 90 -110 psi will only shorten tool life. Please refer to the air tool consumption guide on this website.