Portable air tanks typically range in capacity from 5 gallons to 8 gallons. The light weight of the small cylindrical tank makes it ideal for adding air to a low-pressure automobile tire. The air tank’s small capacity and pressure generally will not fill a completely flat tire. The portable air tank is also useful for inflating small air mattresses and has enough capacity to fill up four or five basketballs. Generally these portable air tanks are filled with a regular air compressor.
1. Set the portable air tank on the ground in close proximity to the air compressor. Use the pressure tire gauge to check for any remaining air in the tank if the air tank does not contain an onboard air gauge. Observe the safety label on the side of the portable air tank. The maximum pressure allowed for most portable air tanks is not greater than 120 PSI (pounds per square inch).
2. Start the air compressor. Allow the pressure of the air compressor to reach maximum, generally 120 PSI. Place the filling valve from the compressor to the filling valve on the air tank.
3. Fill the air tank to approximately 50 PSI. Open the lower water drain valve on the air tank and release any water condensate from the tank. Close the drain valve once all signs of water have ceased flowing from the valve.
4. Continue to fill the air tank from the compressor. Stop filling once the tank has reached the manufacturer’s displayed tank pressure maximum.