BravoTwoZero
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Has anyone seen this and know what is going on and how to fix, i'm at a loss. Needle bouncing from 5-9 Bar. I have just bought a new gauge but the same thing is happening. The pump is new also.
Bouncing Pressure gauge.
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Mine has been doing that for years. I just ignore it. I think it has to do with the type of pump being used for this purpose.
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BravoTwoZero
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Thanks, the gauge is a match to the pump so I was told, sort of defeats the object of having one.
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Is it filled with glycerine? A dry gauge may oscillate.
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BravoTwoZero
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No it's dry. Iv'e had a system running for years with a steady needle no bouncing around until I set up again after a few years not keeping fish. This gauge is recommended for this pump.
@exnisstech and @Reefer Matt are correct. That is a resulting pressure oscillation of a diaphragm pump. You could replace the pressure gauge with a 200 psi glycerine filled gauge. (Glycerine physically dampens the needle movement but not the pressure wave to the bourdon tube) Or you could put a needle valve between the tee and the gauge to create a very small orifice to dampen the pressure wave getting to the gauge.
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BravoTwoZero
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Thanks will give it a go. Never had this problem before always a steady needle.
Was the old gauge glycerin filled or maybe had a small orifice in the fitting?
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BravoTwoZero
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No, dry 15 years old worked a dream till I got a new pump, but this new gauge is for this type of pump. Not getting any joy from the supplier yet.
Was the old pump a diaphragm style also? Doesn't really matter. Pressure is pressure and you could do either of the above mentioned cures. (I would recommend the added valve option) Don't worry about the supplier, they just want to make sales.
I would replace the gauge with a glycerin-filled model. I have experienced the same with the non-filled gauges in my reef environment and my farm sprayers for the fields.
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BravoTwoZero
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If all else fails have to do so, thanks.
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BravoTwoZero
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Can you explain a bit more to the fitting of a needle valve may be a photo as the gauge is still bouncing. Thanks.
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Like @exnisstech said, i think the pump pressure output is fluctuating, and is normal.Has anyone seen this and know what is going on and how to fix, i'm at a loss. Needle bouncing from 5-9 Bar. I have just bought a new gauge but the same thing is happening. The pump is new also.
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BravoTwoZero
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In my old pump and gauge this never happened, also what's the point in having a gauge if you can't tell what the pressure is. At a bit of a loss.
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Is it a booster for the rodi? Was your old pump a diaphragm pump?
The gauge is telling you the pressure, which is fluctuating between 5 and 9 bar. Perhaps there is air in the system aggravating the symptom you see.
If the rodi system is outputing water, the pump seems to be working.
I think it is the nature of diaphragm pumps to oscillate output pressure.
Just place a valve between the "Tee" and the gauge like so. (This is just a drawing and not a representation of what the actual valve would look like.)
What size fitting is on the gauge that you have?
If it's 1/4", you could use something like this,
Links not working so look this up on Amazon,
TAISHER 1PCS 304 Stainless Steel Straight Needle Valve 1/4" Female NPT For Flow Control Water Gas Oil With Nipple
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BravoTwoZero
Community Member
Great thanks, been looking around and they do make a 14" ro needle valve so will try it. Just a thought I will try today is a flow restrictor ? I take it you adjust the valve till a steady needle ?
Just place a valve between the "Tee" and the gauge like so. (This is just a drawing and not a representation of what the actual valve would look like.)
What size fitting is on the gauge that you have?
If it's 1/4", you could use something like this,
Links not working so look this up on Amazon,
TAISHER 1PCS 304 Stainless Steel Straight Needle Valve 1/4" Female NPT For Flow Control Water Gas Oil With Nipple
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BravoTwoZero
Community Member
Yes new pump same as the old one and the gauge was the same too never had that problem before. Taken it apart and run straight from tap no air that I can see and gives 2Bar into the pump which is what it is rated for.
That's right, so it will be almost completely closed. (Just a side note, having air in the line would actually help dampen the oscillations as air is compressible vs. water which is not [for all intents and purposes here], much like how air gaps are used to dampen water hammer in household plumbing.)
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