Water hammer bouncing pressure gauge needle AFTER pressure tank fills

**hawkhunter** · 10-25-2012, 01:23 PM

I have a sta-rite 3/4 submersible pump, about an 80- 100' well if memory serves. Sta-rite control box, pumptrol switch, H2ow-to pressure tank. Recently, after max pressure is reached, the needle on the gauge wildly bounces around and pressure slowly drops even if no water is being used. No water hammer or needle fluctuation when the pump is on, actually is sounds real smooth. I though maybe I had a water-logged tank so I drained it. It worked fine, until following day and it started up again. So, I drained the tank again, cleaned the pressure switch and it was fixed...ya sure....2 days later is started doing the same thing again. I'm hoping it's not the foot valve and was wondering if I should try replacing the pressure tank and switch. The tank is only a few years old and the pressure switch about 10. The tank seemed to drain completely and have good pressure. Have you had any experience with this type of problem,and if so, what corrected it? The only other thing that may or may not be of note is the drought conditions we've had here this past summer. I've noticed neighbors who water getting large amounts of rust stains on their siding when this hasn't been an issue in the past. Also noted my whole house filter with rust like never before, and yes I changed it was well when the problem was discovered. I dont' know if low water levels can affect a well this way. Any help would be most appreciated.

**valveman** · 10-25-2012, 04:15 PM

Originally Posted by hawkhunter

the needle on the gauge wildly bounces around and pressure slowly drops even if no water is being used.

I know you don't want to hear this, but the only way the pressure could drop if you are not using any water, is if the water is going back down the well. The check valve at the pump is bouncing as it leaks back. This causes irratic pressure on the gauge and a loss of pressure. Probably have some rust stuck in the check valve or the check valve is worn from cycling the pump on and off too much.

**hawkhunter** · 10-26-2012, 12:09 PM

Thank you for your reply, and you are right, I don't want to hear that! I suppose I could put a check valve on it for the time being.

**cacher_chick** · 10-26-2012, 03:21 PM

A regular submersible does not use a foot valve. There is a check valve built into the pump, and it is pretty common for installers to put a check valve just above the pump in the drop pipe.

**hawkhunter** · 10-26-2012, 04:42 PM

Thanks, I just assumed a foot valve was standard on a submersible. Maybe I'll pull the cover this weekend and see if there is one in the drop pipe. I'd like to place one in the basement right were the pipe enters. If the other(s) have failed, it shouldn't do any harm.

**craigpump** · 10-26-2012, 07:23 PM

You would be much better off pulling the pump and putting a new check valve on it, eventually that check may fail and you would have to pull it anyway. In some states it is against code to have a check valve on the tank. The reason is because when the check valve on the pump fails the water runs out the drop pipe through the pump which in turn creates a vacuum in the drop pipe. That vacuum could pull contamination in to the system through a connection between the pitless adapter and the offset pipe to the house.

**hawkhunter** · 10-27-2012, 07:19 AM

Yes, the best possible solution is to pull the pump. The check valve would not be on the tank, but where the inlet pipe enters the building. As far as code, I've read some states don't allow and some require it, so who's to say? IMO the risk of contamination is slight as long as there are no other faults in the system aside from the check/foot valve.

**cacher_chick** · 10-27-2012, 07:50 AM

Another good reason to pull the pump is that you might find that the drop pipe is rusting through, which is the actual cause of your problem.

Better to fix it right now rather than to be out of water when it is -20 F outside.

**craigpump** · 10-27-2012, 08:47 AM

Better to fix it right now rather than to be out of water when it is -20 F outside.

Yep or Thanksgiving Day, Christmas Day, New Years Eve........

**LLigetfa** · 10-27-2012, 10:31 AM

Originally Posted by cacher_chick

Another good reason to pull the pump is that you might find that the drop pipe is rusting through, which is the actual cause of your problem...

If the well casing is PVC and the leak gets worse, the pump might not shut off and the recirc will heat the water enough to melt the PVC and collapse the well. Meanwhile the OP may be oblivious to this until it's too late and a new well needs to be drilled.