CSV back pressure

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K_B

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280’ well pump depth. 110’ water level.
Red Lion RL12G15. 1.5HP, 12GPM
1” Poly pipe 200psi.
40/60 pressure switch. 20gal tank.

I put a gauge before the CSV to check back pressure. The CSV works as advertised, but my back pressure values are disturbing.

Open a hose, the pressure at tank (and CSV) drop to 40 and pump kicks on. Pressure at tank climbs to 53 (as set on the CSV) and holds, even if flow is increased/decreased. As expected.
But the back pressure before the CSV holds about 155psi while there is flow and climbs to 190psi after flow shut off and tank begins filling.
Pump shuts off at 60psi as it should. And back pressure drops to same as tank level (60psi).

Is my 200psi poly pipe going to take much of that? That is 190psi above ground. Much higher at the pump outlet, correct?

I appreciate any input here. Thanks.
 

Valveman

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That pump can go as deep as 548', which is the same as 237 PSI. Deducting 50 PSI for the 110' lift from static level is why you are seeing 190 PSI before the CSV, but there is still 237 PSI at the bottom. While a 1HP, 12 GPM would have been more ideal for a 280' well (static 110"), you should be fine with the 1.5HP. Poly pipe has higher burst pressure than some other types of pipe, and all pipe burst pressures are 2-5 times the rated pressure. With long barb fittings and two hose clamps each it will be fine. The water hammer at the bottom when a check valve slams shut on systems without a CSV will cause a spike pressure much greater than the smooth 237 PSI the CSV will put on the pipe.

With a pump that can build that much pressure you could turn it up from the standard 40/60. Adjusting the pressure switch to 50/70 would allow the CSV to be set to deliver strong constant 60 PSI, and soap in the shower would no longer be needed. :)
 
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K_B

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Thanks for the info. I was planning to call tomorrow. You alleviated my worries, so I’ll not bother you with a call.
Worst case, the poly pipe bursts at some point and I have to replace it. I have already pulled the pump once (a nice 6mo old Grundfos . I used a rim and a riding mower), so it’s not that big a deal. Finding higher psi rated poly pipe will be the issue. I’ll cross that bridge later if I have to.

I really like how long it takes to fill the tank after flow shut off. Again, I have/had no concerns with the CSV except the back pressure.

On a side note, the instructions when ordered said 53psi (and was highlighted to indicated someone actually at least saw it), but the pressure during flow with pump on, was 47psi. Easily adjusted though.
 
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