Why add another air tank to your air compressor? This is page two of an article about I need more air! Page one about I Need More Air is here. Page one begins our discussion about the benefits of adding another air tank and this page continues that theme.
If an air tool draws more air than the air compressor can deliver even when running full out the supply and pressure of compressed air to the air tool will decrease. At a certain point, dropping air flow and pressure will not allow the air tool to do the job it was designed to do. Ultimately, the air tool will stop as the tank pressure continues to drop.
Adding another tank will help resolve that by providing an additional reservoir of already-compressed air for the air tool to draw against too.
An additional tank will help… certainly, but, if the air tool demands more air supply than the compressor can delivery, even the second air tank will run down as well.
When you add another air tank
When you add another air tank, when you are not using compressed air, your air compressor will run and fill both tanks – the one that came with the compressor and the one you have just added.
This means that the air compressor motor will run longer before reaching cut out pressure and stopping. The compressor pump is now filling a larger volume.
Increased compressor run time
Note that you must make sure that your air compressor will handle the increased run time. If the duty cycle of the air compressor is too low – that’s the maximum run time allowable to avoid compressor overheating – then adding a tank may make your compressor run too long at any one time, and that may damage the compressor motor.
The manuals for the lower cost DIY air compressors may not even show you what your compressor duty cycle is. If your air compressor manual does not indicate the duty cycle of your brand and model, then our rule of thumb is that your air compressor should only run for a maximum of ten consecutive minutes. If it needs to run longer to fill the tanks, the we shut it down and let it cool for fifteen minutes before running the compressor again. After the compressor motor has cooled down, we will run the compressor again for the maximum ten minutes or until both tanks are full to the cut out pressure setting and the compressor stops automatically, whichever comes first.
Having the extra tank, means that you now will have a much larger reservoir of pre-compressed air to use when you next run your higher demand air tool.Just watch out for compressor overheating.
Plumbing the new air tank
You can use one similar to the “air pig” shown in the image.
Plumbing would need to be modified so that air from the compressor pump would flow both into the main tank on the compressor and this new tank at the same time.
Plumbed this way the one pressure switch on the air compressor would monitor the pressure in both tanks and shut the air compressor off when the pressure reached in both tanks reached the normal cut out setting of the original compressor and tank.
To add a tank to your DIY type air compressor, the simplest way is to add a tee to the tank. See the sketch below.
- The first air line is plugged into the discharge coupler on the compressor
- The other end of that air line has a coupler
- Plug that air line coupler onto the connector on the secondary tank
- Since the coupler on the other side of the Tee on the portable tank is checked, air will not flow out until a mating connector is inserted into the coupler on the secondary tank
- When you need air at the job, plug a second air line into the discharge coupler on the secondary tank, and air from both compressor tank and secondary tank will flow down the line to your air tool
Place Second Air Tank Near Job
Another benefit of having a secondary tank is that the secondary tank can be placed nearer the job site more easily.
To use an air nailer for shingles on a roof for example, it would be so much more convenient to leave the heavy air compressor at ground level, run an air line from it up to the secondary portable tank on the roof, and then run an air line from the secondary tank to the nail gun. More convenient to move around and more air supply closer to the nail gun are significant benefits.
If you add another air tank to your air compressor, you will be able to use higher demand air tools for a longer period of time. If, however, the air supply and pressure diminishes still, and your air tool starts to wind down, then stop, take a break, and let the air tanks come back up to cut out pressure.
Just be mindful of the duty cycle.