WWJ (Six reasons Submersibles Fail)

[Valveman]

Yeah I read that.

“The use of multiple check valve is to helps to absorb the shock of large volumes of water dropping in the pipe when the pump cycles off.”

As usual many people use multiple check valves as a Band Aid for problems that should not be happening. The spring in a spring loaded check valve should close the check valve before the water reverses direction. So there should be no water “dropping” to start with. Then if the water never drops, it never creates the “shock” that would need to be “absorbed” by any extra check valves. Then of course if the pump is not “cycling”, the check valve is not even being used, as the check only works when the pump shuts off.


“It is very important to properly install “A” check valve to help insure a trouble free water system.”


“Without “A” check valve or improperly placed, several undesirable conditions may immediately occur….conditions such as motor and pump backspin when during shut off; pump up-thrust during startup; and water hammer, which can occur at either pump start up or shut down.”

Looks like Franklin only cares that “A” check valve be used to prevent these undesirable conditions. “Check valve manufacturers often recommend multiple check valves.” Of course they do, they make check valves. They would like for you to put one at every joint no matter how bad it is for the system.

I also read…”There is however, a risk of water hammer if the lower check valve fails”. And….”Vacuum causes water hammer when the pump starts”.

There is no “risk of water hammer or a vacuum” unless you use more than one check valve.

Unless the upper check valve leaks back, there is always a vacuum between multiple check valves. This is obvious in the video you made, which shows a tremendous water hammer when the pump starts. Not only does the pressure gauge peg out instantaneously, but you can also hear and feel the shock when the pump starts and the water hammer occurs. You can also see the gauge go erratic when the pump shuts off and those check valves start bouncing.

Your video proves my point. Multiple check valves cause water hammer.

 

[Valveman]

Sure you have seen where "someone said" put a check valve every 100'. But you should be able to see the truth for yourself in your own video. That needle is twisting around the gauge like a weeping willow in an Oklahoma tornado. It's just a blur like the Road Runner making tracks to get away from the coyote. And you don't even need to look at the gauge. That "pssst" you hear on pump start is water hammer trying to blow everything apart.

 

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[PumpMd]

That is a good video. You don't even need the gauge to see the water hammer on pump start. The water just shotgunned out the faucet for a second on pump start. And if you had not been releasing water just prior to the pressure gauge, the gauge needle may have broken off from bouncing so hard.

That is not water hammer, it is the pressure surge from the pump starting. When I find some time, I am going to post some videos with removing the 2nd check valve on my uncle's well and what we will see.

 

[Reach4]

When I find some time, I am going to post some videos with removing the 2nd check valve on my uncle's well and what we will see.

That will be a very interesting video.

 

[Valveman]

That is not water hammer, it is the pressure surge from the pump starting.

That is the very definition of water hammer. That pump cannot even build as much pressure as we can see on the gauge. Water hammer from the additional check valve is what causes the pressure surge you see. Again, excellent video!

The "pressure surge" (water hammer) will be much less with only 1 check valve. The gauge won't even flicker when the flow is reduced as when using a CSV, which is obvious on the second video.

 

[PumpMd]

That is the very definition of water hammer. That pump cannot even build as much pressure as we can see on the gauge. Water hammer from the additional check valve is what causes the pressure surge you see. Again, excellent video!

The "pressure surge" (water hammer) will be much less with only 1 check valve. The gauge won't even flicker when the flow is reduced as when using a CSV, which is obvious on the second video.

The reason why you can see that "Pressure Surge" is because the pump can produce more water than what the hydrant can let out.

 

[Valveman]

The reason why you can see that "Pressure Surge" is because the pump can produce more water than what the hydrant can let out.

Again, that is the very definition of water hammer.

 

[Valveman]

It is not the same, water hammer sounds totally different then pressure surge, you will see this same "Pressure Surge"(Not Water Hammer) at pump start with one check valve as well.

No wonder you are confused. A pressure surge turns into water hammer when it hits any elbow, tee, closed valve, partially closed valve, etc. That is what makes that "pssst" noise in your video. When you hear the thud or pop noise everybody recognizes as water hammer, it is from that pressure surge hitting something. Then whatever it hits bounces that pressure surge through the system again. Pressure surges cause water hammer, water hammer causes pressure surges. The only way to eliminate water hammer, is to eliminate the surge that causes it.

 

[Valveman]

It is causing a problem right now, and you just don't realize it. There are very few things more destructive than the "pressure surge/water hammer" that happens on pump start when you have a negative pressure between two check valves. The pressure surge on start up doesn't hurt the check valves because they are open at the time. But the fact that the check(s) are open means that shock wave "water hammer" is passed right on down to the pump and motor thrust bearing.

It is a testament to the check valves that they will survive for 18 years with that kind of abuse. And it is also why you have to use more than one check valve. It is not the everyday load you are spreading between multiple check valves, it is actually the abuse from so many water hammer events. You can't catch or control water hammer/pressure surges, they have to be prevented. Restricting the flow before the pump starts or stops and eliminating the cycling is the only way to really stop all that destruction from happening.

 

[Valveman]

Maybe I am just not explaining it right. Think of it this way.

The pressure surge that happens when the pump starts causes water hammer at every elbow, tee, closed valve, dead end, etc. Then the water hammer that happens when the pressure surge hits things causes another pressure surge that ricochets back and forth in the pipeline.

Then when the pump shuts off the check valves slam shut as the water reverses direction. This causes a water hammer, which produces a pressure surge, that ricochets back and forth in the pipeline.

This is why you see the gauge swing from one extreme to the other several times when the pump starts or stops. In really long pipe lines sometimes the gauge will swing back and forth like that for 15 minutes after a pump starts or stops. It will start out swinging from one extreme to the other, bouncing off the stops in the gauge. Then the swings will gradually get less and less and then the gauge will steady when the water has finally stopped ricocheting back and forth in the pipeline. It happens really fast on a small system like in your video, but it is still happening, and it is still very destructive.

 

[Boycedrilling]

You'll appreciate this valveman.

Last I had a customer that his 50 hp line shaft turbine wore out. Everything , bowls, tube & shaft, tension bearing. Needed to replace everything. They ran it till it wouldn't run any more. 300 gpm, 390 ft set, 10 ft swl as I remember. I went over the criteria with my pump distributor. We determined that it was about $20k less expensive to switch to a submersible.

Because of the high static water level and the huge draw down, the pump would be starting in an upthrust condition. My distributor told me there would be no warranty on the pump and motor, UNLESS a control valve (i.e. Cycle Stop Valve) was installed on the pump discharge.

This was for a cherry orchard. Unfortunately it was located in a frost pocket and has produced a very poor or no crop each year. The farmer decided to tear the cherry orchard out and is going to move the water right to a different piece of property.

 

[Valveman]

The pump starting up at 70' to water and going to about 70psi on the gauge(not pegged out) from moving the water up the pipe and you are just seeing the high amperage that is sent to the motor at start up(for a split second) and what pressure the pump throws at start up(pressure surge), this is why I am not concerned with start up. When the pump shuts off to send that shock wave down the pipe is what I have seen being helped by using the 2nd check valve and by helped I mean for very long time as my uncles check valves are doing, plus the 50+yrs of testing check valves this way and what they have shown us.

On my uncle's well, I can't show you this because his water level doesn't drop far enough(strong well). However, I am interested to see if you have a high static water level that doesn't drop, you should be able to get away with using just the one check valve. I think we are going to see everything staying the same after I remove the check valve.

Better look at that gauge again. It does peg out completely on pump start. And the actual pressure is way higher than that gauge can read. It just happens so fast you can't see it very well. That kind of a shock wave from the water hammer travels at 3000 to 8000 feet per second. (A 30-06 bullet only travels at 2400 FPS) You will not see that water hammer shock wave on pump start with just one check valve on the pump, because there is no negative pressure between two check valves to cause that problem.

However, only one check valve in the system at pump stop won't make much difference. Unless you use something like a CSV to reduce the flow rate before the pump shuts off, the check valve will slam from the wide open position, and you will have water hammer. It doesn't matter if you have one check valve or many, except the extra check valves will take some of the abuse and make them last longer. It doesn't matter how far it is to static water. And start up amps have nothing to do with it.

Your uncle has figured out a way to make things survive this abuse for several years. But if he had figured out how to stop the problem from happening in the first place, he wouldn't be having to figure out how to deal with the abuse.

 

[Valveman]

You'll appreciate this valveman.

My distributor told me there would be no warranty on the pump and motor, UNLESS a control valve (i.e. Cycle Stop Valve) was installed on the pump discharge.

I am not too surprised. Even pump distributors will suggest a CSV if they have no other way of dealing with the problem. But ONLY if they have no other way of dealing with the problem. On average or normal systems, the CSV knocks them out of a lot of profit, so they will not bring it up.

 

[PumpMd]

I don't want to change the subject so I have a quick question to ask. I have heard when using a Dole Valve, they want the dole valve to be sized to at least 50% of what your gpm rate is on the pump and no lower. I haven't seen this stated anywhere from researching, has anyone else came across this?

I had a job yesterday that had a 6gpm choke on a 1993 3/4 hp 10gpm 3w Jacuzzi installed by one of our competitors that is still working. It also had wire slack in the well, which tells me it was put on at a later time because the same person that drilled the well couldn't keep it from producing dirty water so they tried raising the pump up first. The 1990 203 wellXtrol had 10psi left in the tank, the complaint was surging.

 

[Valveman]

I don't want to change the subject so I have a quick question to ask. I have heard when using a Dole Valve, they want the dole valve to be sized to at least 50% of what your gpm rate is on the pump and no lower. I haven't seen this stated anywhere from researching, has anyone else came across this?

I had a job yesterday that had a 6gpm choke on a 1993 3/4 hp 10gpm 3w Jacuzzi installed by one of our competitors that is still working. It also had wire slack in the well, which tells me it was put on at a later time because the same person that drilled the well couldn't keep it from producing dirty water so they tried raising the pump up first. The 1990 203 wellXtrol had 10psi left in the tank, the complaint was surging.

That would kind of defeat the purpose of a Dole valve. I have seen 1 and 2 GPM Dole valves on pumps that lasted 20-30 years. So the restriction from a Dole valve is not a problem. But I have also seen 2 GPM Dole valves on pumps that didn't last a year, because they should have had a 1 GPM Dole valve. If the Dole valve isn't small enough you can still pump the well dry. That is the reason for most failures with Dole valves, not the restriction.

 

[PumpMd]

Sch120 1 1/4 drop pipe is rated at 300psi on the threads to throw that out there too. 1" PVC Sch80=320psi, Sch120=360psi

I installed a hydrant next to the well head a few days ago on my buried PSC-35 tank with a 3/4 10gpm Grundfos set at 145', 70' to H2O TD 165' and only one check valve. I am curious to see what a normal Residential pump would see. It was all sandstone on the install so it took me some effort with a rock bar. I keep forgetting about it but I will have a video soon.

 

[Valveman]

I had a question about this besides sensing the water closest to the tank. Couldn't you remove the valve stem and mount the pressure switch on top of the tank on the air side to make it work properly. I have seen this done on an old standard tank before.

See the picture below. I did this back in 1994 as I also thought it was a good idea. And it works fine until you lose the air charge in the tank. Air molecules are smaller than water molecules and will pass right through the rubber diaphragm in the pressure switch. With an old air over water tank or an air compressor, the air lost by the switch is automatically replaced. But air is not automatically replaced in a diaphragm/bladder tank. So I had to go back and remove all the pressure switches I installed on the air side of the pressure tanks.

 

[Valveman]

I installed a hydrant next to the well head a few days ago on my buried PSC-35 tank with a 3/4 10gpm Grundfos set at 145', 70' to H2O TD 165' and only one check valve.

The first video with the faucet open isn't telling much. But that second video is great. See how much less water hammer "pressure surge" there is when you only have the one check valve? The only way to make it even better is to reduce the flow rate before the pump starts or stops as when using a CSV.

 

[PumpMd]

See the picture below. I did this back in 1994 as I also thought it was a good idea. And it works fine until you lose the air charge in the tank. Air molecules are smaller than water molecules and will pass right through the rubber diaphragm in the pressure switch. With an old air over water tank or an air compressor, the air lost by the switch is automatically replaced. But air is not automatically replaced in a diaphragm/bladder tank. So I had to go back and remove all the pressure switches I installed on the air side of the pressure tanks.

View attachment 34214

I am sure you left a Schrader Valve on the mounting of the pressure switch so they can preform Preventive Maintenance on the tank in future. How long did the precharge last before you had to put air back into tank? Expensive system to not have a maintenance guy check on it from time to time.

 

[Valveman]

The air wouldn't last a month with the pressure switch mounted on the tank. As far as I know that system is still running and the air charge in the tank has stayed ever since I removed the pressure switch and put the Schrader core back in.