Air gauges are essential pieces of equipment for your air compressor. Your typical air compressor comes equipped with two of them. One air gauge is there to display the air pressure level that is in the compressor tank, and reacts to the air pressure level being increased by the compressor pump.
That air gauge also displays the decreasing level of air pressure in the air tank as you use the compressed air.
The other compressor air gauge displays the pressure setting of the air regulator. This setting is created by the compressor operator adjusting the regulator setting with the regulator know. Doing so changes the air pressure level that the downstream application will receive after the compressed air from the tank passes through the regulator.
Description Of Air Gauges
A compressed air gauge will have a face under a plastic shield, on which pressure levels are printed. A needle is attached to a shaft protruding through the center of the face, and that needle is calibrated to rotate to a pressure as the gauge internal components are subjected to air pressure from the air line to which the regulator is attached.
A great deal more information is available about compressor air gauges if you care to watch the following video.
Air Gauge Faces
While there are a wide range of face diameters available, most of the lower end, general purpose gauges most of us have on our compressors and regulators will have a face diameters of 1 1/2″ or 2″.
How Gauges Are Installed
There are a number of ways to plumb the compressor air gauge. The most common is to have a male threaded fitting either on the back or the bottom of the gauge.
The operation of the air gauge will not be affected regardless of the mounting position. The two configurations are available to allow the user to pick the one that best suits their application.
Air Gauge Readings
Air gauges are built for the application.
For the typical homeowner or small workshop air compressor, gauges will offer a pressure range from zero up to around 200 PSI.
Don’t worry if yours doesn’t show that pressure range. The air gauge pressure range on your compressor has been selected to indicate the pressure range that your compressor will require.
Air Gauges Fail
Many (most?) of the air gauges on home and small workshop type air compressors are not of particularly great quality.
Over time, the needle may break, the needle shaft might fail, the plastic cover may get broken, or more likely, very humid air has, over often a short while, corroded the gauge internals to the point that the gauge doesn’t display pressure accurately anymore.
Replace The Gauge
Air gauges are pretty important to the safe operation of your air compressor, and to ensure that your downstream tools and applications get the correct operating pressure.
If the tank gauge fails, you won’t be able to see the cut out or cut in pressure levels as air is built and consumed, and you want to know this in the event that the pressure switch fails and a replacement becomes necessary.
When shopping for a new air gauge, it is helpful to take the old one with you. That will ensure that you match the mounting thread and acquire a gauge with the same, or similar, pressure range as the old.
Air gauges shouldn’t set you back more than $10-$15 for a general purpose type. If you select a stainless steel gauge, or one with different characteristics, it might be more. For the home compressor and small workshop compressor user, I recommend you stick with the basic unit.
About gauge pressure range
A visitor to this site suggested that, if it becomes necessary to replace a compressor gauge, that the gauge is replaced with a range where the upper pressure range of the compressor is in the middle of pressure range of the gauge.
The theory was that if the gauge only goes as high as the compressor pressure, this somehow leads to mis-readings on the gauge. True? Not True? I’d not heard of this.
I do know that replacement gauges for a small air compressor are $10 or so, while a more precision and wider ranging gauge may be quite a bit more. It would be up to the user, then, whether the investment in a new gauge and the size and type purchased, which gauge was acquired.