# pressure gauge destroyer



## dbsoccer (Aug 4, 2021)

My sprinkler system is as old as the house - about 35 years - and it seems I have (or could) replace the system pressure gauge every year.

The system is pretty straight forward. I have a 1" copper line that runs from inside the house. This line immediately goes to a 1" PVB and then into the ground where it transitions to 1" PVC. On the section of line on the outlet side of the PVB is a connection for system blow out and a pressure gauge.

My valve boxes are all located as close to the their respective sprinkler heads as possible meaning the boxes are at least 20" from the PVB (some are much farther). Downstream of the valves is 1" poly. I have all 1" Rainbird valves.

But despite buying even the highest quality, commercial, oil filled (you name it) pressure gauge, within a few months the mechanics inside the gauge apparently become damaged and the gauge readings are junk. I typically buy a gauge with a scale of 1-150psi as my water pressure can run close to 70-80 psi on a good day.

I suspect the issue is water hammer although I don't hear much noise when the valves are opening or closing.

I was hoping someone else has had a similar problem and could share their solution.


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## Delmarva Keith (May 12, 2018)

Does the gauge record the highest reading? I'd try a gauge with the two needles where one moves the other and keeps the highest reading. Check it every day or two and see what you see. Could be shock from water hammer or could theoretically be water expansion ahead of the backflow preventer but behind your zone valves, if the issue is overpressure.

I had a similar issue in regular household plumbing. An expansion tank resolved it.


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## Ravenallen1971 (Jun 26, 2020)

You could also look into getting a snubber for your gage. It slows the shock to the gage.


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## MasterMech (Sep 24, 2017)

dbsoccer said:


> My sprinkler system is as old as the house - about 35 years - and it seems I have (or could) replace the system pressure gauge every year.
> 
> The system is pretty straight forward. I have a 1" copper line that runs from inside the house. This line immediately goes to a 1" PVB and then into the ground where it transitions to 1" PVC. On the section of line on the outlet side of the PVB is a connection for system blow out and a pressure gauge.
> 
> ...


Could throw a miniature ball valve in-line with the gauge.


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## dbsoccer (Aug 4, 2021)

Thanks to all. I do, in fact, hear some hammer when my drip zone valves are opening. The gauges I've tried have had snubbers (very small orifice on the inlet) but they don't last much longer than the others. I do like MasterMech suggestion as I only need to the gauge to register a reading when I'm looking at it so it would not be a big deal at all to open a ball valve and read the pressure and then close it. 
Thanks!!


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## dbsoccer (Aug 4, 2021)

After further thought on this issue I feel, perhaps, my own stupidity may be causing the issue. Instead of water hammer or anything related, the gauges may have been damaged over the winter due to freezing. I go to great lengths to blow the water out of the system prior to the onset of sustained/significant temperatures below freezing. I must have a good system as I have not had anything freeze and break for several years (knock on wood). But I have never paid any attention to my pressure gauge. A small amount of water left in the bourdon tube and allowed to freeze would damage the tube and render the gauge useless. One of those, "Well duh!" moments.


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