Well, Pump and Tank Questions

[Dave Schwabauer]

We purchased our home about 2 1/2 years ago. We have well water which obviously means a well, pump and tank configuration. Our home is very well insulated so we rarely hear the pump when it starts. For about the last 2-3 months we have noticed that we can now hear the well/pump when it kicks in and when it turns off after pressurizing the tank. The turn off has been getting louder and when it turns off it sounds like it is rattling the pipes pretty violently.

Our tank for our well is in a separate room at the end of our finished basement. The room is approximately 5 ft deep by about 10 feel long. I have some shelves on the far end away from the tank where I store various things, including some light fixtures that we replaced with ceiling fans. About a week ago I did a pretty routine check to make sure everything was fine in the pump room and there was no water leaks...but interestingly the vibration is so bad when the well turns off that it actually shook 2 of the light fixtures off the shelf which shattered on the floor. Any idea what might cause that kind of vibration when the tank shuts off? It appears to be pressurizing OK...up to about 30 pounds on the gauge and the tank seems to hold pressure...we have had no issues with water pressure when showering or any other water flow...

Is this possibly a sign that the tank is becoming water-logged and needs to be replaced? I know very little about pumps and well systems, so after searching the internet and finding your site, I thought I would give you a shot. Please let me know what you think.

Thanks so much in advance.

Dave

 

[Reach4]

t appears to be pressurizing OK...up to about 30 pounds on the gauge and the tank seems to hold pressure...we have had no issues with water pressure when showering or any other water flow...

Is this possibly a sign that the tank is becoming water-logged and needs to be replaced?

1. How long does the pump run, at a minimum?
2. What pressure does the pump turn on at and what pressure does the pump turn off at? Is there a piece that may be a check valve before the pressure tank in line with the pipe from the pump? If in doubt, post a picture of the area including the stuff before the pressure tank.

 

[Sponsor]

 

[Dave Schwabauer]

The pump usually only runs for a minute or two...have not timed it, but not unusually long at all. Not sure on the other questions and I am at work today...a 12 hour shift...and tomorrow too. I will try to find the answers to all of your questions and, if I can, post some pictures as well. Thanks for the response...

 

[Reach4]

The pump usually only runs for a minute or two...have not timed it, but not unusually long at all.

A minute or more would seem to say the pressure tank is OK, presuming your minute or two number is still in effect. So checking for that possible check valve would be next.

 

[Valveman]

We purchased our home about 2 1/2 years ago. We have well water which obviously means a well, pump and tank configuration. Our home is very well insulated so we rarely hear the pump when it starts. For about the last 2-3 months we have noticed that we can now hear the well/pump when it kicks in and when it turns off after pressurizing the tank. The turn off has been getting louder and when it turns off it sounds like it is rattling the pipes pretty violently.

Our tank for our well is in a separate room at the end of our finished basement. The room is approximately 5 ft deep by about 10 feel long. I have some shelves on the far end away from the tank where I store various things, including some light fixtures that we replaced with ceiling fans. About a week ago I did a pretty routine check to make sure everything was fine in the pump room and there was no water leaks...but interestingly the vibration is so bad when the well turns off that it actually shook 2 of the light fixtures off the shelf which shattered on the floor. Any idea what might cause that kind of vibration when the tank shuts off? It appears to be pressurizing OK...up to about 30 pounds on the gauge and the tank seems to hold pressure...we have had no issues with water pressure when showering or any other water flow...

Is this possibly a sign that the tank is becoming water-logged and needs to be replaced? I know very little about pumps and well systems, so after searching the internet and finding your site, I thought I would give you a shot. Please let me know what you think.

Thanks so much in advance.

Dave

That is what happens when you have more than one check valve in the system. Remove the check valve that is above ground and all the hammering should go away. However, the extra check valve maybe masking the fact that the lower check valve is leaking back. If after removing the upper check the pressure still drains off when no one is using water, or there is still a hammer on pump shut off, the lower check will need to be replaced.

Some people think multiple check valves help eliminate water hammer. In reality, multiple check valves cause water hammer. The only check valve you want in the system is the one attached to the pump. The only time a check valve is even used is when the pump is cycling on and off. If you eliminate or at least reduce the cycling on/off the check valve will not wear out like it has.

If the pump is running for a minute, your tank is still good. The tank is just not large enough to reduce the cycling as needed. And even if you have a larger pressure tank the check valve will still slam from the wide open position each time the pump stops, which causes check valve wear and water hammer. Having a CSV would eliminate the need for a large tank, and creates a mechanical soft stop that keeps the check valve from slamming when the pump shuts off.

 

[PumpMd]

Some people think multiple check valves help eliminate water hammer. In reality, multiple check valves cause water hammer. The only check valve you want in the system is the one attached to the pump. The only time a check valve is even used is when the pump is cycling on and off. If you eliminate or at least reduce the cycling on/off the check valve will not wear out like it has.

That's because it's a proven fact that using multiple check valves in the well takes out water hammer and using one above ground just causes problems with no water column above them and why I see swigging check valves lasting along time above ground and where a spring loaded check valve is terrible for above ground.

We don't use above ground check valve because no way for the water to back up to our frost free hydrants out in the field and for our sprinkler systems but we always install extra check valves in the well every 200ft to eliminate water hammer.

Not using extra checks in the well when having 200ft of water above your check valve, you will have water hammer in your system causing short life to everything in the well. Unless you have a soft start and a soft stop system, where using only one check valve in the well is fine.

 

[Valveman]

That's because it's a proven fact that using multiple check valves in the well takes out water hammer and using one above ground just causes problems with no water column above them and why I see swigging check valves lasting along time above ground and where a spring loaded check valve is terrible for above ground.

We don't use above ground check valve because no way for the water to back up to our frost free hydrants out in the field and for our sprinkler systems but we always install extra check valves in the well every 200ft to eliminate water hammer.

Not using extra checks in the well when having 200ft of water above your check valve, you will have water hammer in your system causing short life to everything in the well. Unless you have a soft start and a soft stop system, where using only one check valve in the well is fine.

Come on man! I know you have not been reading these forums or helping people with this problem for very long, but anymore than one check valve in a pump system is just asking for water hammer problems. Go back and read about 10 years worth of these forums and you will find many many posts where people have removed the extra check valves and the water hammer goes away instantly. It doesn't matter if the extra check valve is 20' above the pump, 200' above the pump, or above ground, they will all cause water hammer, it is just a matter of when.

I would never recommend a flapper check valve in a pump system. But you think they work better above ground, because they close slower than the spring loaded bottom check, which means they really are not doing anything.

You cannot have an electronic soft stop on a submersible pump, because of the wear on the thrust bearing when running lower than 1800 RPM. And electronic soft starts don't help much either. This is because of the loss of head produced by the square of the pumps speed. The pump isn't really moving any water until it gets to about 90% of full speed. This doesn't leave much room for a soft start to do anything.

Dave has water hammer so bad it is knocking stuff off the shelf. When he removes the un-needed extra check valve, this problem will completely go away.

You have problems with check valves, and you think extra check valves are needed, because you let your systems cycle thousands and thousands of times. It is cycling that wears out your check valves, causes water hammer, and shortens the life of everything else as well.

Now a "mechanical soft start/soft stop", as with a CSV, has nothing to do with the Affinity law and losing head by the square of the speed. The CSV makes sure the pump is only producing 1 GPM when the pump shuts off, which takes out all the water hammer and causes the check valve to close from a very short distance instead of slamming closed from the wide open position as it does when you just let pump systems cycle on/off at full flow, as when not using a CSV.

 

[PumpMd]

You are correct that haven't been but my uncle has for over 50yrs on eliminating water hammer by using multiple check vavles in the well like the engineers tell you too, so stop tring to prove them wrong.

 

[Valveman]

You are correct that haven't been but my uncle has for over 50yrs on eliminating water hammer by using multiple check vavles in the well like the engineers tell you too, so stop tring to prove them wrong.

I teach classes on this subject to the people who wrote the book that says "add an extra check valve every 200'." They were proved wrong a long time ago. People who do not understand water hammer just keep adding extra check valves. They do not understand that water has to have something to crash into to cause water hammer, and every extra check valve added just gives the water another place to crash into.

 

[PumpMd]

All your taking about is a failed check valve for the water to crash into from pump start that will cause water hammer, as long as they are installed correctly and woking properly, it will eliminate water hammer from pump stop, that's it's way of telling you that you have check valve failure, if you have water hammer from pump start.

 

[Craigpump]

I typically use 2 check valves and sometimes an additional pump check right on the pump, I never have water hammer issues. I've seen guys run 800'+ of steel in the ground with 4 checks and have to pull it out because of water hammer. I've also seen where there isn't any hammer with multiple checks, but why take the chance?

And the BS about the checks taking the weight off the bottom check is just dumb. If the pump won't lift the load, all the checks in the world won't help.

 

[Reach4]

I typically use 2 check valves and sometimes an additional pump check right on the pump

Why do you use 2 or 3 check valves?

 

[Valveman]

woking properly

Working properly is certainly the key. When there are multiple check valves in a system, they ALL have to work PERFECTLY to keep from being the CAUSE of water hammer. If they all open and close at EXACTLY the same time, there is nothing to crash into. It only takes a few days of too much cycling to cause one check valve to start leaking a bit or closing slower than the other check valve(s). Then as the water comes up from the well, it crashes into every extra check valve on the way out, causing water hammer that knocks stuff off the shelves.

You would not have any failed check valves to start with if you didn't let them fly open on pump start, slam shut on pump stop, and repeat this process hundreds of times per day because of all the cycling. It is the all those failed check valves from too much cycling that makes you think multiple check valves are needed in the first place.

I typically use 2 check valves and sometimes an additional pump check right on the pump, I never have water hammer issues. I've seen guys run 800'+ of steel in the ground with 4 checks and have to pull it out because of water hammer. I've also seen where there isn't any hammer with multiple checks, but why take the chance?

And the BS about the checks taking the weight off the bottom check is just dumb. If the pump won't lift the load, all the checks in the world won't help.

Yes you can use multiple check valves as long as they all work perfectly. You are not really taking a chance that there will be a problem, it is just a matter of when the problem will start. And when it does start causing water hammer, you have to replace every check valve, because they all have to work perfectly.

Plastic pipe absorbs a lot of water hammer shock. That is why the problem is worse with steel pipe. Using plastic pipe with small pumps, you may not notice the hammer, but it is still happening. The only way it works on 800' of steel pipe is if the upper check valves have weaker springs than the bottom check, and every connection has to be drip tight. A slight leak between any 2 check valves will cause violent water hammer. And if it happens on 800' of steel pipe with 4 checks, it is also happening on 300' of plastic pipe with 2 check valves, it is just not as violent and noticible.

 

[Valveman]

I am working with several municipalities in south Texas right now that are having major water hammer problems. These are booster pumps above ground. They are typically 100 to 300 GPM pumps with 3, 4, and 6" check valves and 20,000+ gallon hydro tanks. The pumps cycle every 2 minutes or so, and the water hammer is so bad it shakes the entire building. Then every 6 months on every pump they have to replace the worn out check valves. These are about 1500 a pop to replace, not to mention the damage in the rest of the system from all that water hammer.

Multiple check valves didn't help. Soft starters didn't help. Surge arrestors and pressure relief valves didn't help. So after years of engineers trying to Band Aid the problem they finally called me and we will solve the problem with a CSV on each pump.

 

[PumpMd]

You guys are answering your own problems (above ground check valve) and why we don't have those problems.

You don't take the load off the bottom check valve, you take the load off the top check valve to give longer life and to the rest of the check valves below it.

Feeding 800ft away with 4 check valves inline, the pressure tank would've got installed right out of the well, so don't have above ground CV's to cause problems later.

 

[Boycedrilling]

One of the factors that create water hammer is the velocity or speed of the water inside the pipe. The old rule of thumb in pipeline sizing is to keep the velocity of the water below 5 feet per second. Many times we have a much higher velocity in the drop pipe in a well. When the pump stops the water doesn't stop moving instantaneously. It decelerates, then stops, then it try's to reverse direction. That's the purpose of a check valve, is to keep the water from reversing direction.

The CSV or other control valve eliminate water hammer because they slow the velocity of the water at startup and shutdown of the pump.

30 plus years ago I installed a project that was pumping 4500 gpm in a 16" pipeline up a hill. We had 3 300 hp turbines at the river. Three more at an intermediate reservoir and two more 300 hp turbines at a second reservoir. All the pumps had Cla-Val pump control valves on them. At first startup, the pump control valves had to be adjusted. Everything went fine at the river station and we filled the first reservoir up the hill. We went to the the first reservoir and brought the pumps on line to pump up to the next reservoir. We had about 100 psi pipeline pressure at the pumps. The Cla-Val's weren't adjusted correctly yet. When we shut the pump down the pressure gauge went from 100 psi, down to about 60 psi, from the water continuing to move. Then the gauge spiked to 150 psi. The 16" ductile iron pipe line turned a 45 degree angle just after leaving the reservoir. The pressure surge moved the thrust block poured behind the 45 elbow and blew the pipeline apart. If the pipe hadn't of blown apart, you would have seen the pressure gauge go up and down in pressure 3 or 4 times before everything settled down.
There are 665 square inches in a 16" circle. 100 psi creates 66,500 lbs of push. That 90 psi water hammer had right at 60,000 lbs of impact. That's why water hammer can blow pipelines apart.

 

[Craigpump]

Why do you use 2 or 3 check valves?

There's one in the pump discharge, depending on water quality (sand, sediment) we'll sometimes use a pump check right above the pump. Standard practice (and maybe code) here in CT is a check valve on the tank T.

Works for us.

 

[Valveman]

You guys are answering your own problems (above ground check valve) and why we don't have those problems.

Oh you have those problems like everyone else, you just don't realize it. The small pumps don't cause as much water hammer, the plastic pipe absorbs most of that, and you think stuck check valves are just a normal everyday problem.

You don't take the load off the bottom check valve, you take the load off the top check valve to give longer life and to the rest of the check valves below it.

What ???

Feeding 800ft away with 4 check valves inline, the pressure tank would've got installed right out of the well, so don't have above ground CV's to cause problems later.

Don't need an above ground check valve to cause problems when you already have 4 problems (check valves) waiting to happen down hole.

 

[Reach4]

Standard practice (and maybe code) here in CT is a check valve on the tank T.

If it is CT code/law to have a check valve at the pressure tank, would you support changing that code/law?

 

[Valveman]

One of the factors that create water hammer is the velocity or speed of the water inside the pipe. The old rule of thumb in pipeline sizing is to keep the velocity of the water below 5 feet per second. Many times we have a much higher velocity in the drop pipe in a well. When the pump stops the water doesn't stop moving instantaneously. It decelerates, then stops, then it try's to reverse direction. That's the purpose of a check valve, is to keep the water from reversing direction.

The CSV or other control valve eliminate water hammer because they slow the velocity of the water at startup and shutdown of the pump.

Velocity in the drop pipe needs to be higher than horizontal pipe. If the velocity in the well is not high enough the sand and debris never make it out of the well. But of course I am preaching to the choir here.

30 plus years ago I installed a project that was pumping 4500 gpm in a 16" pipeline up a hill. We had 3 300 hp turbines at the river. Three more at an intermediate reservoir and two more 300 hp turbines at a second reservoir. All the pumps had Cla-Val pump control valves on them. At first startup, the pump control valves had to be adjusted. Everything went fine at the river station and we filled the first reservoir up the hill. We went to the the first reservoir and brought the pumps on line to pump up to the next reservoir. We had about 100 psi pipeline pressure at the pumps. The Cla-Val's weren't adjusted correctly yet. When we shut the pump down the pressure gauge went from 100 psi, down to about 60 psi, from the water continuing to move. Then the gauge spiked to 150 psi. The 16" ductile iron pipe line turned a 45 degree angle just after leaving the reservoir. The pressure surge moved the thrust block poured behind the 45 elbow and blew the pipeline apart. If the pipe hadn't of blown apart, you would have seen the pressure gauge go up and down in pressure 3 or 4 times before everything settled down.
There are 665 square inches in a 16" circle. 100 psi creates 66,500 lbs of push. That 90 psi water hammer had right at 60,000 lbs of impact. That's why water hammer can blow pipelines apart.

Good story! I have a similar one. 11 mile pipeline going downhill. Well field at the start and ground storage tanks at the end of the line. There is an 8" Cla-Val at the bottom end that shuts off when the storage tanks are full. The Cla-Val and two operators where in a manhole outside the storage tanks. On startup the Cla-Val speed control knob needed adjustment. Water was coming down hill, the valve was signaled to close, and the operator turned the speed control knob the wrong way. The Cla-Val closed to rapidly and blew the valve off at an MJ fitting. It filled the manhole with water instantly and squirted the two operators out the top onto the ground. Lucky no one and nothing was hurt except for both of there cell phones being destroyed. To this day neither one of those guys will touch a Cla-Val. They call and make me do it. LOL