Hi,

I have a Sweetwater aq101 rocking piston compressor. Last year I installed a pressure gauge coming right out of the compressor (9” of line in between compressor and gauge). When I turned the compressor on the needle would rapidly oscillate between two values. I assumed this might be because of “how rocking pistons work”. This spring I went to turn the compressor on and the gauge was jammed. Opening up the gauge I found that the gear on the needle was completely worn out. I assume this is from several months of oscillating back and forth.

Any suggestions on how I might better set up a new gauge so that this doesn’t happen again?

Thanks in advance.

Ted

IMHO you get what you pay for. I THINK a liquid filled gauge will cure the oscillating and a higher quality gauge will last much longer.

An oil filled gauge will sure help. Another must on this type of pump is an in-line orifice of sorts. Best way to do this is fill the inside of hose barb going to gauge with solder then drill a very small hole in center. 1/32" would be sufficient for airflow, if it was liquid in the line, 1/16" would be ok. This will baffle the pressure and allow a much steadier reading.

This is an interesting idea Snipe. If I get a better oil gauge, do you the solder modification is a “nice to have” or a “must have”?

As mentioned, a liquid filled gauge will dampen the bouncing of the needle on the gauge. A liquid filled gauge should last on that compressor at least 8-10 years.

We use this in several of our aircraft systems to stabilize critical readings in certain avionics that still use what we call "steam" gauges (direct, non electrically modified signal).
I won't say it's a must have, but it takes the pulse down to a buffered level without changing actual pressure values.

Very helpful, thanks everyone. I will order a liquid filled and see what happens, and modify with solder if needed

Closing the loop on this. I ordered and installed this gauge: https://www.amazon.ca/Winters-Stainless-Pressure-Internals-Accuracy/ . Everything now seems to be working well now, so I guess I just needed a better gauge.