Water Hammer When Pump Stops

[Chucky_ott]

As Reach previously stated, you can verify if the check valve at the pump is good by shutting off power to the pump, opening a faucet to release system pressure, and then removing the plug located on the tee on the top of your well head. The water level in the drop pipe shouldn't drop.

If the water level does drop, then the pump's check valve is bad and you'll need to replace it or keep the one at the top.

If the water level doesn't drop, then the pump's check valve is good and you can remove the one at the top. Wether you remove it or keep it will depend on which source you trust the most.

FWIW, check valves are kept closed by the internal spring (if it has one) and by the water pressure. If you have two check valves, the one closest to your pressure tank will be kept closed by the system pressure. In this scenario, the water pressure down the well pipe could be less than the system pressure. If you have a slight leak in the drop pipe, it could be significantly less. This could cause the check valve to not close properly and allow contaminants to be sucked in.

 

[Bannerman]

While not pertaining to your original topic, what is the Black section seemingly wrapped around the PVC pipe, between the ball valve and the excavated pit? There appears to be a gear clamp at the bottom of the black section.

Suggest removing the handle from that ball valve to prevent it from being closed by mistake.

That ball valve being unitentionaly closed, may result in your pump burning out since water flow from the pump will be deadheaded. As water cannot flow to the P tank, pressure will not build, causing the P switch to continue to supply power to the pump. As the running pump will not be moving water, it will overheat repeatedly untll it eventually fails.

 

[Sponsor]

 

[Reach4]

Right.. I know I will have to cut the pipe. As I said on my previous post, I tried removing the check valve prior to installing the new pipe, but I was not able to move that thing at all.

Any tips on the best way to remove it?

I think you are asking which way to turn the big nut on the union.

If you can see threads on the left side of the nut and to the right of the left-most hex, I would hold that left-most hex with a big wrench, and turn the big nut, with a bigger wrench, to bring the top of the nut closer to you if standing from the point of view of the photo. If that is the way you were turning, get bigger wrenches.

If you don't see threads between the big nut and either hex, Try taking a close-up photo of the union. I have a feeling that top toward the photographer is the way, but get another opinion. I am not experienced with those.

Also, is the tee, or the nipple between the tee and the union, galvanized steel? Use a magnet if there is any doubt. It is best to remove galvanized when you are doing work. Instead use brass, bronze, copper for tees. Alternatively you can use schedule 80 plastic for threaded nipples, but not for female threads.

EDIT:
If you cannot see threads on ether side, the union nut is going to have a bigger diameter hole seam on the thread side.

In the picture, the near side would be a smaller seam. To loosen, rotate counterclockwise when viewed from that side. And use a second wrench on the threaded side.

 

[Valveman]

Boy you sure promote the CSV eh? haha... but I get it. I will try the replacing the check valve and see how it goes before maybe trying out a CSV.

I am only "promoting" the CSV because it will solve your problem, which is why you here. Replacing the above ground check valve will not solve the problem. That check is working properly and the check on the pump is leaking back. A good check valve up top is like a thumb over a straw full of ice tea. The water will not drain out the bottom but is being held by a negative pressure. That negative pressure is what draws contamination into the pipe and then into the house. When the pump comes on the contamination drawn in and that slug of water between the two check valves becomes a projectile that hits the above ground check valve like a bullet. THAT is what makes the water hammer on pump start. That water hammer can destroy things from the faucet to the thrust bearing in the bottom of the submersible motor.

The check valves are worn because of all the pump cycles and slamming closed with every pump stop. Don't replace the above ground check valve or you will have the same or worse problem. Just remove the check valve. You can even take the poppet out and replace it with no guts so you don't have to change any piping. The added back pressure from the pressure tank may make the check on the pump close better. If the check in the bottom will not hold or there is a hole in the pipe, the pump will need to be pulled to solve the water hammer problem. But most times the added back pressure will get you a few more years out of the check valve on the pump.

Again, as the picture I showed, that would be the perfect place to install a Cycle Stop Valve. The Cycle Stop Valve will make the old check valve on the pump close much more gently, making it last even longer. If the system had been installed with a CSV to start with, the check valve would not be worn out now. Plus, a worn check valve can be the first sign the pump is being cycled to death. The pressure switch, control box, diaphragm in the tank, as well as the pump/motor itself are all destroyed by the same cycling on/off that wore out the check valve.

How long a pump system last is not about who you trust the most. It is about doing what makes common sense. It is well known that cycling on/off is the biggest killer of pumps and equipment. Therefore, it is just common sense that eliminating the cycling will eliminate the problems. I've guaranteed the CSV would solve this problem thousands of times in the last 33 years and there has never been a single one returned. Like they say, it ain't bragging if you can back it up.

 

[macster2075]

While not pertaining to your original topic, what is the Black section seemingly wrapped around the PVC pipe, between the ball valve and the excavated pit? There appears to be a gear clamp at the bottom of the black section.

Suggest removing the handle from that ball valve to prevent it from being closed by mistake.

That ball valve being unitentionaly closed, may result in your pump burning out since water flow from the pump will be deadheaded. As water cannot flow to the P tank, pressure will not build, causing the P switch to continue to supply power to the pump. As the running pump will not be moving water, it will overheat repeatedly untll it eventually fails.

Which section are you referring to? Not sure what you mean.

 

[Reach4]

Which section are you referring to? Not sure what you mean.

He is referring to the plastic ball valve in your photo, and the vertical section of pipe immediately below the ball valve.

 

[Valveman]

This is so confusing. So many peeps have different takes depending on who you ask. This is why I decided to check a few places to see if there is some consensus, but I see there isn't lol.

Some say It's a common misconception that you should only have one check valve in a well system. In reality, for most submersible pump systems, having multiple check valves is often recommended and can be beneficial.

Other's say only one check valve should be installed!

Then I also got this answer....
"The advice you're getting telling you you should remove that check valve from there because the system is not supposed to have 2 of them" is generally incorrect for a submersible well pump system. In most cases, having a check valve at the well head in addition to one down the well (either built into the pump or installed close to it) is a recommended practice for optimal system performance and longevity."

Frustrating say the least!

Yeah there is a lot of misinformation on the Internet. That is why I have been on this forum since like 2006, trying to help people, and keep them from falling for misinformation. Sounds like you are getting private messages from someone who doesn't want you to solve your water hammer problem. Could just be confirmation bias, thinking the way they did it is the best way, even when it is not. Or it could be someone who makes their living selling pumps and/or check valves. They know if you solve the problem by removing the extra check valve, others will solve their problems the same way, and people will stop using that extra check valve that causes so many problems and helps keeps the pump man in business.

 

[macster2075]

If the check valve down in the well has failed, then I have a few questions.. Please forgive my very bad illustration below.

if the check valve down the well is bad, then...

1 - Does that mean there won't be water between check valve 1 and 2?
2 - if there is no water there, that means there will be air instead?
3 - if there is air in that section of the pipe, where does that air go?
4- will I notice air coming out of the faucets when the pump starts?

 

[Reach4]

If there is no air leak, expect water in the pipe to be about 30 ft (depending on altitude and barometric pressure) higher than the water level in the well. There will be a vacuum and water vapor above the water level in the pipe.

If there is a small air leak, expect the water level in the pipe to match the water level in the well. There will be air in the pipe.

3. Comes out of your faucets.

4. Not sure of the timing of the air bursts.

There are systems that intentionally admit air. Those use tanks with no diaphragm (commonly called galvanized or "conventional" tanks). They have a special way to release the right amount of air.

 

[macster2075]

If there is no air leak, expect water in the pipe to be about 30 ft (depending on altitude and barometric pressure) higher than the water level in the well. There will be a vacuum and water vapor above the water level in the pipe.

If there is a small air leak, expect the water level in the pipe to match the water level in the well. There will be air in the pipe.

3. Comes out of your faucets.

4. Not sure of the timing of the air bursts.

There are systems that intentionally admit air. Those use tanks with no diaphragm (commonly called galvanized or "conventional" tanks). They have a special way to release the right amount of air.

Makes sense. I do not get any air bursts coming out of the faucets at any time at all.. not even when the pump starts and the faucet is running.

 

[Reach4]

Makes sense. I do not get any air bursts coming out of the faucets at any time at all.. not even when the pump starts and the faucet is running.

You can imagine that if there is 30ft of pipe with a vacuum, that when the pump starts, the column of water will rise fast. You can imagine that slamming against the poppet.

If there is a small leak at the pump now, removing that topside check valve may make that lower check valve totally seal. If it does not totally seal, the pump would start periodically -- maybe once per day if the leak was small. The pump would also run periodically if there was a small hole in the pipe below water.

 

[macster2075]

You can imagine that if there is 30ft of pipe with a vacuum, that when the pump starts, the column of water will rise fast. You can imagine that slamming against the poppet.

If there is a small leak at the pump now, removing that topside check valve may make that lower check valve totally seal. If it does not totally seal, the pump would start periodically -- maybe once per day if the leak was small. The pump would also run periodically if there was a small hole in the pipe below water.

Yeah I don't have that kind of issue. I figured even if the check valve down at the well is bad, and water on that pipe drops, the air left behind need to go somewhere and that somewhere is the faucet. I have never heard any air bursts coming out of the faucets in more than 10 years I've been here.

I ended up calling a local well and pump company, and I explained my situation to the guy who said he has over 25 years experience on the field. I explained to him my situation and he said there's nothing wrong with my system... the thump I hear when the pump comes on is normal, specially when a well is over 100 ft deep and the tank is also over 100 feet from the well.

He also said "do not remove the check valve at the head because it was placed there as a safety measure" - he said
"many "plumbers don't understand how well systems work which is why they think having a 2nd check valve is wrong"

He also said all the years he's been doing this there has always been 2 check valves and the 2nd is installed mainly as a backup.
The guy said as long as there is no loss of pressure and the pump is not cycling, leave it alone.

So for now, I'm just gonna do just that.. leave it alone haha... thank you all for trying to help!
Didn't think this topic was going to be so controversial...yikes.

 

[Chucky_ott]

"many plumbers don't understand how well systems work..."

Including him maybe? I'm not a pro but I do see why two check valves would not be ideal. The only reason I'd want two is as a backup if the first one fails. But if that were to happen, you could add one later on.

There are obviously two school of thought on check valves. Same for CSVs. If people who want two valves and believe the CSV will not be beneficial actually took the time to understand the technology, they could be convinced on the benefit of a single valve and the use of a CSV.

But people generally go by what they were told and are reluctant to change their ways.

Did your plumber explain why two valves are better? Does he understand why two valves might not be better?

As a side note, and to support my comment above, my pet peeve is when contractors give the reason to have the "weep holes" at the bottom of exterior brick cladding. Everyone seems to think it's to allow water to flow out. Well, when was the last time any water got behind a porous brick wall in enough quantities to require weep holes? Probably never. Those holes are actually there to equalize the pressure in front and behind the wall. Anyways, I digress...

 

[RetiredInGueydan]

Including him maybe? I'm not a pro but I do see why two check valves would not be ideal. The only reason I'd want two is as a backup if the first one fails. But if that were to happen, you could add one later on.

There are obviously two school of thought on check valves. Same for CSVs. If people who want two valves and believe the CSV will not be beneficial actually took the time to understand the technology, they could be convinced on the benefit of a single valve and the use of a CSV.

But people generally go by what they were told and are reluctant to change their ways.

Did your plumber explain why two valves are better? Does he understand why two valves might not be better?

As a side note, and to support my comment above, my pet peeve is when contractors give the reason to have the "weep holes" at the bottom of exterior brick cladding. Everyone seems to think it's to allow water to flow out. Well, when was the last time any water got behind a porous brick wall in enough quantities to require weep holes? Probably never. Those holes are actually there to equalize the pressure in front and behind the wall. Anyways, I digress...

"Weep holes" are placed on brick veneer walls to provide ventilation and remove condensation that forms between the brick and framed wall.

 

[FredG]

I don’t understand why someone would come here for advice, yet not even consider the advice given?

When that water hammer bursts a pipe or pipes, it will be expensive, and rightfully so. Murphy’s law never sleeps.

 

[GReynolds929]

Your well guy has 25 years of wrong experience. Just because that's always the way it's been done, does not mean it's the right or proper way to do something. As a side note I do believe that there are some jurisdictions that require an above ground check valve on a well, it's a bad rule but a rule nonetheless. Maybe you are in one of those jurisdictions?

 

[Valveman]

the thump I hear when the pump comes on is normal, specially when a well is over 100 ft deep and the tank is also over 100 feet from the well.

He also said "do not remove the check valve at the head because it was placed there as a safety measure" - he said
"many "plumbers don't understand how well systems work which is why they think having a 2nd check valve is wrong"

The "thump" on pump start is "normal" for someone who has been doing it wrong for 25 years. So many people come to this DIY site for help because they realize the local pump man is full of crap. You need to remember local pump guys are not there to make your pump system last a lifetime, they are making money. An extra check valve where it is not needed, a little smaller pressure tank than recommended, or even pushing variable speed pumps as the latest and greatest thing around are all ways to make sure they get to come back and see you regularly.

The ones who know how how a Cycle Stop Valve works understand that if they installed one for you they would never get another penny of your money, which is exactly why they "advise" against a CSV. But most, like the one you have been talking with really don't have a clue how pump systems should work, but they sure think they do. Lol!

How about this....you remove all check valves except for one good one on the pump and if you hear a thump I will pay you $100.00 just because I was wrong. Add a Cycle Stop Valve and if it doesn't work exactly as advertised, I will refund your money and pay the plumbers fee to install and remove it. I back up what I say. Your pump man is full of crap.

 

[GReynolds929]

He also said "do not remove the check valve at the head because it was placed there as a safety measure" - he said
"many "plumbers don't understand how well systems work which is why they think having a 2nd check valve is wrong"

He also said all the years he's been doing this there has always been 2 check valves and the 2nd is installed mainly as a backup.
The guy said as long as there is no loss of pressure and the pump is not cycling, leave it alone.

Check out pg.7-8 of this pdf.

https://fele.widen.net/content/mrbmponfcz/pdf/M1311_60Hz_AIM_Manual.pdf?u=bt7ctv

 

[Reach4]

Check out pg.7-8 of this pdf.

https://fele.widen.net/content/mrbmponfcz/pdf/M1311_60Hz_AIM_Manual.pdf?u=bt7ctv

I note that "A lower check valve
leads" is a typo in this 2023 version that was not in the 2015 version, which says leaks, as it should.

 

[FredG]

How about this....you remove all check valves except for one good one on the pump and if you hear a thump I will pay you $100.00 just because I was wrong. Add a Cycle Stop Valve and if it doesn't work exactly as advertised, I will refund your money and pay the plumbers fee to install and remove it. I back up what I say. Your pump man is full of crap.

I appreciate a guy who will put his money where his mouth is. Not many men left like this. You are wealth of knowledge Cary!

The reason most pump men(and other professionals) don’t know much about what they do, is because its just work to them. They could care less about learning beyond what it takes to do the job. This and many other forums are full of enthusiasts. Those people treat it differently, much like a hobby. The knowledge levels of the two are worlds apart.