Air pressure regulators limit the amount of air pressure that can reach your tools. You should use one to protect your air tool’s lifespan.
They do this by means of an internal rubber diaphragm and a tension spring. As you adjust the regulator knob tighter, the seal is closed more tightly, reducing airflow.
Less airflow means less pressure.
They are almost always used to move from higher pressure to lower pressure. They cannot increase pressure output higher than pressure input.
When Does An Air Compressor Need A Regulator?
If you were to remove the regulator from your air compressor, you would be supplying raw tank pressure to your line.
In a lot of cases, this is 150 PSI or higher, which will damage most pneumatic tools.
If you are only using compressed air for filling tires, a regulator is not as important. However, most readers will also use their tank for air tools and need the regulator.
See Related: Pressure Switch Adjustments
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Disclaimer: This article is for information purposes. Compressors can be deadly to work with and this article does not provide enough training to qualify someone to work on a compressor safely.
Why Regulate Your Air Compressor?
Each tool requires an exact pressure. For the small shop, the regulator controls the airflow to the downstream pressure of the air system (even if that is a solo nail gun).
In larger factories, a high-pressure line runs through the entire shop and regulators are used to create lower pressure that will meet the demands of each tool.
This control valve limits the airflow. If you are working in a large factory, it is a common job responsibility to frequently check each pressure gauge to ensure the proper pressure is being used.
Ultimately, most small tools use about 90 PSI. If you run 150 PSI unregulated air through them, you’ve shortened their lifespan to just a few uses before you blow the seals.
A Filter regulator will help remove oil and debris from the air line while protecting the internal seals of your pneumatic tools from too much pressure. (Compressors may have an air intake filter as well).
Air Pressure Injection Injury
In shop class, we were instructed to not spray the air compressor on our hands as it could push air through the skin and cause an air embolism in our veins.
I thought that was a little odd since I had been playing with Grandpa’s air compressor since I was 6 and had sprayed my hand (and my sibling’s faces) countless times.
Maybe I just got lucky.
As the National Institute Of Health (NIH) points out in this report, the risks of a high-pressure injection injury can be wide-reaching and difficult to repair.
Air pressure over 100 PSI can easily peel the skin off your hand and damage the underlying tissues.
Removing the regulator suddenly turns your air hose into a potentially deadly — or at least painful — weapon.
Air Compressor Pressure Regulators Are Pulse Dampening
Air pressure systems are fluid. Just as with hydraulic systems, every pulse is translated throughout the systems.
This means each stroke of the compressor piston should be translated throughout the air line. This pulsation can affect your air tools’ function.
These help to smooth this airflow.
For example, if you have the pressure switch adjusted so that the compressor tank maintains between 100 and 120 psi, but the regulator is set at 90 psi, you should never notice a pulse.
So long as the available pressure is higher than the set pressure of the regulator, the seal helps to create a smooth flow of air.
Now, if the demand for compressed air exceeds the supply, then the pressure in the tank might drop to the point that you’ll see some of this pulsation.
As the compressor kicks in and tries to catch up with the demand, it is common to see some pressure-pulse until the pressure gets above the original regulator set point.
Having a larger tank size can reduce how often this happens.
Air Compressor Regulators Reduce Costs
For large shops, pneumatic power is one of the larger costs.
Since a regulator limits the downstream air pressure, it helps to reduce wasted air.
By examining the tools in use and regulating the pressure down to the lowest acceptable setting, you can reduce the amount of air being used.
Large shops will sometimes provide regulators at each work station, so the airflow can be adjusted to each use type.
How To Regulate Air Pressure
This is probably one of the simplest tasks you can do.
1. Turn on your compressor. You need to let the tank fill so you can adjust the pressure based on the gauges, and the gauges need airflow to work.
2. Unlock the large control knob. Generally, this requires you to push down or pull up on the knob to engage it.
3. Turn the knob slowly in a clockwise direction to reduce air pressure.
4. Relock the knob into the new pressure setting.
This is one of those things that newbies forget to adjust. If you are loaning your tools to a friend, make sure everything is adjusted before you send it to them.
Components of an Air Compressor Pressure Regulator
There will be a few major parts:
- Large control knob
- Possibly a gauge to see pressure
- Possibly a filter
- Inside will have a spring and seal
The pressure inside of the tank is controlled by the pressure switch. This switch controls the cut in and cut out pressure when the compressor should engage in. The pressure switch is a cutoff safety mechanism that controls the tank pressure and the safety of the compressor mechanisms.
It is a defence against tank over-pressurization.
The regulator valve controls the pressure setting for everything outside of the air tank.
Generally, you don’t need to adjust the pressure switch unless you are replacing it.
Types of Air Compressor Pressure Regulators
One gauge will show the tank pressure, and then the regulator will have a separate gauge that shows the amount of pressure going to the air line.
When shopping for a new one, there are some added options you can get.
- Includes Air Filter
- Includes Air Filter and Desiccant (drying)
- Includes Water/Oil Separator
- With locks
- With or Without Gauges
- FRL (Filter-Regulator-Lubricator setups)
All of these are industrial-grade relieving regulators that are generally installed in the air line between the compressor and the air tool.
At a minimum, I like to have an air filter on mine. An air filter and desiccant are nice if you are sandblasting or running a spray gun.
When shopping for a new regulator, it should be rated for the max PSI that your compressor can produce. If your compressor is rated for 155 PSI, you shouldn’t buy a 145 PSI regulator.
Having a water trap is especially handy for humid summers. Just turn the T-shaped drain valve at the bottom to release the water.
Precision models will hold line pressure within .5 to 1.5 PSI. You can shop based on their accuracy.
While not as common, these can be set up in a master-slave configuration. A master can be air-piloted to a slave that is installed remotely. This makes it ideal for hard-to-reach or hostile locations.
In large shops, it is common to set the tank pressure relatively high and then to have individual regulators installed at each station. This offers the ultimate control and allows you to get the exact pressure.
The Air filter helps to reduce the amount of oil and grime that reaches your air tools, while the drying system helps to capture water. A good regulator extends the life of your tools.
Relieving & Non-Relieving Air Regulators
Most air compressors use a relieving air regulator. If, for some reason, the downstream air pressure exceeded the amount set by the regulator, the excess would be vented back into the atmosphere.
When working with noxious gasses, a non-relieving regulator is used instead.
Frequently Asked Questions
My Regulator Is Restricting Too Much CFM
This is more of an advanced problem. Since these work by reducing the airflow, it is possible that a small model will also reduce the CFM too much. Also, there is sometimes a reverse correlation between CFM and pressure. You may need a special high CFM low PSI regulator. Options are easily available that allow for 5 PSI with 12 CFM for 1/4″ lines. You will also need a 60-gallon air compressor (or larger) to create a high CFM.
How To Tell If Air Compressor Regulator Is Bad
Generally, you are going to know it is bad because it has started leaking air, and you can’t tighten the loose area enough to stop the air leak. The other major fail point is the internal seal, which means that you cannot reduce the pressure, even with it fully tightened in the clockwise position. Random pressure drops are also a typical symptom of a bad regulator. Cheap Harbor Freight models may not last as long. I like to go with Ingersoll Rand models when possible. But all of these models are relatively cheap. When in doubt, replace.
What Happens if I Don’t Adjust the Pressure Regulator?
Pressure that is too high will ruin your tools. Pressure that is too low will cause the tool to underperform (such as nails that are driven part-way through the wood). Match the PSI of the air line to the PSI rating of your tool.
What Happens If I Install My Regulator Backwards?
These only work in one direction. If you look closely, there is a small directional arrow printed on the regulator that will indicate which way the airflow should go. If you mount it backwards, it won’t be able to work, and the pressure gauge will just reflect the tank pressure. Generally, it does not harm the regulator (although there is always that outside chance that there is some design that could be damaged by a backwards installation).
Why Is The Pressure Dropping Lower Than The Regulator Setting?
When using a high volume of air, such as when blowing dirt off of something, it can be very hard for the compressor to keep up unless you have a massive reserve. If you are fighting major pressure drops, it almost always because the demand is too high for your compressor.