How do I know that I have to change the filter

by DK

How do I know when to change my online compressed air filter?

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Aug 17, 2015
Compressor filter element change
by: Bill

You typically don't have to change the filter, unless the bowl is damaged, or oil carryover from the compressor lubrication has crazed and cracked the bowl from the inside.

What you do need to change periodically is the filter element.

How do you know when it's time to change the compressed air filter element? The telltale is, of course, that the air tools no longer run properly for no apparent reason.

The other way to know is to either use a filter delta P system, or have a filter housing that has an indicator built in.

The delta P system is simply have a pressure gauge installed upstream and downstream beside the filter.

As air is flowing to the application, the two gauges will vary, with the upstream gauge showing a higher pressure than the downstream gauge. The less variance, the cleaner the filter element.

It is common to see up to a 10 PSI difference with a new filter and filter element.

As the element becomes plugged, the pressure drop across the filter will increase.

At what pressure drop do you change your filter element?

You decide, based on the sensitivity to pressure drop your air-driven equipment has.

On a system of mine, I'd change out the element when the pressure drop across the filter reached 25 PSI. Sooner, if the equipment I was running didn't react well to the lower and slower pressure supply.

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