Well pump hammer.

[sixd8rs]

Hello all. I have been fighting a banging pipe in my basement for quite some time. Years! Lately it is just loud. It's the supply line from the submerged well pump to my tank in basement. 1" PVC pipe that runs the length of house from tank then changes over to the black abs as it goes thru the foundation and out to well. Years ago as the well pump would come on you could hear the 1" PVC stretching in the straps against the floor joist tick, tick, tick, tick, then a bump when pump went off. It really didn't bother anyone in the house, as it was very faint. Pump failed and replaced it last year. No change until maybe 6 months ago. Started getting loud. It simply bangs really hard when the pump comes on now.
Here is what Ive done.
I've added straps all over the place thinking that was all it needed. Then replaced the pressure tank 3 weeks ago. It's original to the house and thought maybe it had something to do with the bladder in it. No change! Set the pressure on tank 2-3 Lbs below cut in press. It's at 27 and my cut in press is at 30 out at 50.
I'm a HVAC tech by trade...not a plumber. What am I missing? Is there a check valve on the pump in the well that could be leaking down causing the initial bang when the pumpstarts? Check valve at tank I assume is ok. Guage does not show any constant pressure drop as if it were leaking back.

 

[sarg]

Water hammer caused by having a check valve above water.
Keeps the pressure at the tank static but the hammer indicates the check valve at the pump may be leaking down.
There should only be one check valve in the system and that's at the pump.
Symptoms described are what my system was like until I replaced my pump and also the check valve before the pressure tank with a cycle stop valve (red).

 

[sixd8rs]

Water hammer caused by having a check valve above water.
Keeps the pressure at the tank static but the hammer indicates the check valve at the pump may be leaking down.
There should only be one check valve in the system and that's at the pump.
Symptoms described are what my system was like until I replaced my pump and also the check valve before the pressure tank with a cycle stop valve (red).
View attachment 38849

Thanks for the reply. I'll give the guys who replaced my pump last year a call. Hope it's under warranty.

 

[Valveman]

Just remove the check valve at the tank. Probably fine down hole.

 

[sarg]

Try what Valveman ( Cary Austin ) suggests. He is the resident expert.
Remove the above water check valve and then over time if your system cycles without using any water ...... THAT would indicate the check valve at the pump is not holding or there is a "leak" somewhere else. The pressure gauge should Hold and show no drop.

 

[sixd8rs]

Updating this.
Check valve at pump in well was bad.

 

[sarg]

Thanks for the update................. Sad you only got a year out of it.

 

[Twowaxhack]

Updating this.
Check valve at pump in well was bad.

What did that cost to repair.

 

[Valveman]

Sorry that was the check valve that failed. The only time a check valve works is when the pump shuts off. Check valve failure is just one of many problems caused by pump cycling.

 

[sixd8rs]

What did that cost to repair.

$308

 

[sarg]

$308

That seems remarkably cheap for the repair required.... unless you pulled the pump yourself and replaced just the check valve on the pump motor.