Loud bang in well pump

Old 02-16-12, 08:21 PM
Thread Starter
Join Date: Feb 2012
Location: usa
Posts: 1
Received 0 Votes on 0 Posts
Loud bang in well pump

I have a 100' deep well with 1/2 horse submersable pump with built-in check
valve, also a check valve at the head of the pump, and one at the surface in the pipe. After the pump starts running, there is no pressure increase for a few seconds, then I hear a loud knock or bang, then the water starts flowing in the pipe and the pressure builds up to the 60 pounds. It sounds like a pressure valve has been stuck, and finally pops open. This problem developed a few months ago, after about 3 years of operating normally.
What is this delay and subsequent bang or knock before the pressure starts building? Would this indicate a flawed pressure valve? Or pump defect?
Old 02-17-12, 03:33 AM
chandler's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Dec 2005
Location: USA
Posts: 39,964
Received 9 Votes on 8 Posts
Welcome to the forums! I am by no means a pump expert, but have installed a few in my years. It does sound as if a check valve is sticking. The banging noise is probably coming from ill fitted snubbers on the pipe in the hole. I am assuming this is a small bore well. You can't do too much with the valve at the pump head, but what if you removed the one at the top and replaced it with a length of pipe, temporarily. If it is the culprit, then you can replace it if necessary. Often a check valve at the top wouldn't be necessary since you have basically double protection at the pump itself. Let us know what happens.
Old 02-17-12, 06:24 PM
waterwelldude's Avatar
Join Date: Jun 2008
Location: S.E. Texas
Posts: 1,038
Received 0 Votes on 0 Posts
Depending on the type of set up you have, you may not be able to remove the check valve at the top.
If the pressure switch and a sniffer/sheadervalve are in the check valve on top, you will need to leave it there.
It does sound as if you may have a hole in the drop pipe or a leaking check valve in the well.
Have you noticed more air in the tank than it would normally have?
The sound you hear could be just the sound of the check valve popping open when the water hits it. It may be time for a new one. Over time they ware and can start to stick.

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: