Frequently Asked Compressor Questions
Q: How do I calculate the complete cost of a compressor?
A. 20% operating cost for inspection, maintenance and repair. 65% cost for energy and demand to operate the system. For example, at $.06 per kWhr, the estimated cost of compressed air is $.02 per 100 cfm ($0.0002 per cubic foot). A Mattei 10 HP air compressor delivering 35 cfm=$0.007/minute, $0.42/hour, $10.08/day, $302.40/month or $3,628.80/year.
Q. Is there an advantage to storing compressed air?
A: “Free air” that is useful is considered “air above the pressure being used”. You are able to create a surplus of this “free air” ready to accommodate work demands. Pneumatic tools and work processes require 90-100 psi. 193 cubic feet of compressed air can be stored in a 120-gallon receiver at 175 psi.
Q: Should I add an air dryer to my compressor system?
A: An aftercooler or air dryer reduces the amount of water suspended in the air. Hot air holds more water, so the ideal system for the maximum removal of water is a refrigerated air dryer. For example, a 10hp compressor with air entering the system at 75º and 75% relative humidity produces water at the rate of 6.3 gallons per day. A refrigerated air dryer would remove a total of 6 gallons of water (leaving only .3 gallons in the system). An air-cooled aftercooler with a separator would remove 4.3 gallons per day.
Q. I need to control the dewpoint and contaminants from my compressed air system. What do I need to purchase?
A: Air compressor system filters are available in a full range of micron dimensions. Based on your application, Mattei Air Compressors can recommend the correct filter as part of our custom air compressor solution. Assuming a common dewpoint of 35º a refrigerated air dryer should be acceptable for most applications. If however you are shooting waterborne paints you will need a much lower dew point to achieve the 5-10% relative humidity required. Oudoor applications subject to freezing temperatures should deploy a desiccant dryer to achieve dewpoints as low as -40º F.
Q. The temperature of my air compressor is running higher than the manufacturer recommended operating temperature. How do I correct this over-heating air compressor problem?
A: Low oil levels can cause your air compressor to be running hot. Check the oil level as your first step and add Mattei OEM oil. If the over-heating is not corrected by adding oil, then rule out ambient temperature that is too high; a restriction in the system’s air or water flow; or ventilation around the compressor working area.
Q. I am considering an air compressor system for my high volume auto repair shop. Do I need to include an air dryer or can I add it later?
A: Air dryers are not required but are highly recommended to keep your Mattei air compressor running at peak performance with the least investment in maintenance. If you use your air compressor system for auto body paint you could experience paint spotting. Hidden costs of water in the system includes rusted parts that can cause sluggish air compressor performance serving your pneumatic tools, tools that do not last as long as they could in a dried air environment and air lines not working at maximum air output. If however you are shooting waterborne paints you will need a much lower dew point to achieve the 5-10% relative humidity required. Waterborne painting applications should deploy a desiccant or membrane type dryer to achieve dewpoints as low as -40º F.
Q. I have an air dryer on my air compressor system but I am still getting excessive water in the compressed air line. How do I correct this?
A: Be sure to check and automatic drain trap mechanisms to be sure they are working properly. Manually drain the air receiver. (Consider adding a Mattei Automatic Tank Drain for convenience). Also, adding a moisture separator to the air line will reduce moisture in the future. If draining does not resolve your issue then have your air dryer serviced. If it is no longer serviceable replace the air dryer.
Q. My air pressure has dropped when I use my pneumatic tools. How do I pinpoint the problem?
A: Follow this checklist to rule out problems:
- Clogged or worn filter elements
- Holes in distribution piping
- Leaks at the connection, valves or lines
- Excess system pressure drop
- Hose diameter too small for the flow required
- Quick-disconnect bore too small for the flow required