Well water hammer on shutdown

[Homesteadder]

Hello folks. New here. Still working on my new well. It’s 420ft down with 175’ of 1.25”pex to the pressure tank. When the pump shuts down, there is a water hammer at the pressure tank and the relieve valve at the well head pops a little. The drillers installed a check valve at the well head. Could this be my problem?

 

[Valveman]

The check valve at the well head will not help the problem and will cause another water hammer on pump start. Most likely the check valve on the pump is sticking, and slams shut when water flow reverses. If the check valve in the well is not completely failed you maybe able to solve this problem by replacing the check valve at the well head with a Cycle Stop Valve model CSV1A. The CSV will reduce the flow rate to 1 GPM before the pressure switch shuts off the pump. At 1 GPM a check valve is only open the as much as the thickness of a piece of paper, so there is no water hammer on shut down. This also eliminates check valve failures as they no longer slam shut from the full open position, which is what caused the check valve to start sticking and ultimately to fail.

 

[Sponsor]

 

[Homesteadder]

I’ll look into it. The pump/plumbing and entire well is brand new. Should I ask the well company to replace pull pump and replace the check valve?

 

[Valveman]

Since the well is new it is most likely just sand locking up the check valve. I would first pump the well hard for hours or days until the water cleans up. Then I would remove the check valve at the well head and replace it with a Cycle Stop Valve. Just one more of many benefits of the CSV is that eliminating the pump cycling will also stop the water level in the well from surging up and down with each pump cycle. Develop the well by pumping it until it is clean, then eliminate pump cycling with a CSV, and the check valve will go back to work as there will be no more sand in the well.

If the well is not making any sediment, then the check valve sticking should be a warranty issue.