Filter bypass indicator Question

   / Filter bypass indicator Question #1  


Elite Member
Apr 21, 2012
Cascade Mtns of WA state
Kubota B-series & Mini Excavator
Just bought this Parker filter on eBay for $30. It's new, un-used. 20GPM, 10micron, uses element 925580.


How do you "read" this indicator. Seems to me that it's currently indicating that it's bypassing at 0 psi (new never used)? Is it possible thats the reason it was $30? And then,,,,,,how does that bypass indicatore work? Is it simply a pressure gauge equal to the bypass spring? Or is it indicating --- that the bypass valve is actually "open"?


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   / Filter bypass indicator Question #2  
The 15P series filters use a differential pressure indicator. The indicator senses the difference in pressure between the islet and outlet of the filter. The indicator should unscrew from the filter and can be repalced as a separate item.

The by-pass valve is totally seperate from the indicator.
   / Filter bypass indicator Question
  • Thread Starter
Thanks oldnslo, for that link! I spent a lot of time trying to locate that document! I was thinking the bypass looked to be a separate item, but have not taken it apart yet.

What do you think about the indicator position. Should it be in the clean/green at 0 psi? Or does it need some pressure to start "indicating"?
   / Filter bypass indicator Question #4  
Not very familar with the Parker filter line but possible it does require some oil flow to start indicating properly. If you remove the indicator you might be able to press on the plunger that rotates the indicator just don't get to rough.
   / Filter bypass indicator Question #5  
It would seem to me that if it is a "differential" gauge, it should be reading in the middle with zero pressure. It's only off a little. Maybe from being jostled around or no lube (hydraulic oil).
   / Filter bypass indicator Question
  • Thread Starter
OK I figured it out. The SETSCREW on the indicator arrow was loose, allowing the indicator to spin willy-nilly.

WAS like this. New, and never used. Indicator showed that the filter was on "bypass". I bet that's why it was my kinda price - $30.


I was concerned that if the indicator was screwy, then MAYBE it actually WAS bypassing thus it may never actually force my oil thru the filter. I determined that the bypass is a completely separate valve, unrelated to the indicator position. They both operate off the same pressure differential but neither can affect the other.

The access to the indicators tiny setscrew thru the tiny threaded hole that holds the ID plate on. I tightened the setscrew and now the indicator sits in the clean green. At maximum it indicates just into the red. All good now!



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