Reducing Noise From an Old Water Pump

Sounds like a pump shaft bearing problem. A bearing replacement or a new pump is what you are looking at.

Carlos, what are the sounds the pump is making? Please describe in as great of detail as possible.

Mike

Hi Mike, the sound starts like an boat engine, at the very beginning you could hear a click and then just a regular engine sound like. If you listen close to the wall from my room, you could hear like water running smoothly. That's pretty much what I listen, and also you could feel a vibration inside my room.

hope this helps

Try using marine acoustic insulation, as might be used inside the engine compartment of a boat, near the pump. It will reduce the noise though not eliminate it.

Some solutions treat the symptom and not the problem.

At last, you could always put a lawyer to solve this engineering problem.... Just kidding.

The quicker way of doing that is to encapsulate the two pumps with insulation, and install some insulated duct to allow air circulation to each pump motor and exhaust far away from your home. A good insulation around the pump would really help a lot, but check if the noise is not comming from the water flow in the pipes. If so, it's gonna be necessary to spend more work to solve the problem. Maybe turn the pumps and reservoir room an entire insulated room. Does not solve completely, but really helps.

thanks for the advice, what material will do the best work for insulation this time? and what about the base of the pumps? like you could check on the pictures, they are place onto the floor, if I add some rubber and glass fiber, would it help too?

It may be easier to go next door and throw the disconnect switch for the pump in the "off" position. By the sounds of it, no pun intended, that pump isn't going to last much longer and the picture of the fate that awaits it is right next to it. If you insulate an enclosure around the pumps and provide alittle cross flow, you can probably kill that pump alot faster. I think we may be on to something here. Humor is good sometimes when there seems to be no end in sight.

Hola Carlos, Felize ano nuevo, short of having your landlord insulate the walls or gluing or screwing the styrofoam insulation sheets such as is used to insulate concrete foundations to your walls not much.

It seems that the motor is not fixed to the floor and might be hanging on the pipe. the motor actually vibrate on the floor. The piece of material to keep the motor down will act as a sound box.

solution : cut short pieces of garden hose and insert under motor and bolt down.

it might also help to insert adjustable pipe couplings using rubber rings to seal on the discharge side.

If everything else fails uses the switch and bucet method.

I see in the photos that the pumps are attached to the wall. Good point regarding the pumps are transmitting vibration to the adjacent construction.

Replaceing the pumps by newer and quieter ones of course is the best, but i'm affraid they'll not spend 3000 US bucks only because our colleague cant sleep. As I wrote before, maybe a task for lawyers...

Insulate the room. Install vibration isolators in the pump mounts and pipe connections, replace and/or overhaul the pumps. As you can see in the forum, those are the solutions. Better take them all in count.

I agree that the better material for insulation is that marine type, they have a range of thicknesses and densities. You better look for a local supplier. THey are all good, if installed correclty.

To us with means Carlos' problem seems a farce. Replacing the pump is the obvious answer. Deadening the sound by any means seems temporary at best. Carlos, you seem to have access to the pump room, what is the owner's response? Finally, I can say after 20 years and a few thousand experiences analyzing pumps, there is a chance the fan gaurd on that TEFC motor is bent and the fan blades arre making the noise as they bang inside the gaurd. That is a fix you can remedy with a screw driver and a hammer. In case you were wondering my guess is that those are Scott Motor Pumps about 15 HP and they retail for about 1500.00 U.S. If the fan gaurd is not the problem then the pump needs replacing.

Good Luck.

JT

• Change to a small Monoblock Centrifugal pump 1/2 horsepower NB 25 flexible piping. Mount pump on a rubber foam block.These normally cannot be HEARD.
• Change the 1 minute ON,4 minute OFF cycle-- to a rational 1/2 hour on,2 hour OFF cycle using 2 float switches and 3rd world controls(if nothing better is available in your town.)

Your little son won't be jerked out of his sleep every 4 minutes and you will soon forget all about the (killer) thought-provoking pump/s.

Don't you have a local(Noise)pollution control authority working?

This would be one of the crappiest pump installations It's easier to list what is correct rather then wrong so here is what is right;

ASOLUTELY BLOODY NOTHING!

No seriously though there are two glaring mistakes here. Firstly the pump plenums are mounted directly on the ground and the pipes connect directly to the pumps. It should look something like this.

Note how the pump frame is not in direct contact with the concrete floor and the flexible joints between the fixed piping and the pumps.

The flexible joints should look something like this.

The pumps look heavily corroded and the impellers are probably poorly balanced an this will increase the vibration and noise the pumps make as well as shortening their life.

The whole installation needs to be done properly and anything else is just band aid engineering. You could install vibration dampers under the pump mounts but this will raise the pumps up and the fixed piping will not line up any more. This could be fixed with the flexible couplings I referred to earlier but, as I said, this is all band aid engineering. Keep in mind the pumps look like they are on their last legs and are probably long over due for replacement so any work you do may well be wasted when the pumps ultimately fail.

My suggestion is convince the owner that the pumps need replacing and when they are replaced make sure they install flexible couplings to the fixed piping and vibration arrestors between the pump mounting frames and floor of the pump room. Failing this try and get the owner of the pumps to upgrade the installation to include the devices I have mentioned and set it up so that the pumps can easily be replaced when they later fail.

When you say the pump starts for every one minute and stops 4 minutes and goes on the whole day - this means propably the pump is being used to supply the whole building's requirement like a boosting system normally used in commercial buildings in my country where there are no overhead tanks. You might not be having overhead tank and on the slightest use of water by any one in your apartment/building the pump has no option but to start.There will be a pressure swich somewhere signalling the pump to start/stop.

Now with your problem:

1. Residential builings ought to have overhead tanks. In this case the pump runs for an hour or so and fills up the overhead tanks. After that the pump stops to be mauannly started the next day.

2. The pump shown in the photograph is very drastically undersized 1"x1" . I've this pump in my house but for an apartment this seems undersized therefore needs to operate frequently. Flow is on gpm the lesser the more the pump operation.

3 . Every stoppage time there is a banging or clanking sound. This is water hammer. There must be a non return valve at the discharge. This must be disc type to cushion the sound.

4.The waterhammering every minute has damaged the balance of the empeller with the shaft hence the noise.

5. There is no buffer vessel after the pump (pressure boosting system)or the vessel is very small maybe 12"dia x 24".The Vessel being small does not give the pump rest enough so it operates every minute. The Vessels are normally 3"dia x 6' height and these are normally designed on volume Vs time, I'd not like to go into this .

If you introduce a vessel or increase the size this will do only good by delaying the pump operation time but the sound stays.

6.Similarly if there is a pressure switch you can go and increase the pressure subtractive differentiial .Then again it will only delay the pump starting time.

Summarizing :

You need to replace the pump with a bigger capacity pump.Installing a disc check valve on the outlet with 2 rubber bellows (one at inlet & outlet) to minimize vibrations.Try fabricating an overhead tank to get rid of all these type of problems.

Put a canopy on the pump to further reduce motor noise.

I strongly agree with the last two posts. Isolating the pump in a proper installation is the best option. Also, consider a pressure tank (like a bladder style tank, not too expensive) to hold the pressure if the last post is correct. The pump cycles would go down. These guys sell them online in many sizes:

http://www.watertanks.com/category/48/

I have one of these in my basement. My pump comes from a well and feeds this tank. I have the rubber floor mounts, but not the flex lines on the pipe. You can still hear the pump vibration through the pipe, but it is not too bad and the pump only comes on for about 10 minutes every 4 or 5 hours. You have to size the tank to match how many users you have.

I just installed one of these for a big casino client that was 2,500 gallons!! That one was expensive, but it works the same.

I hope that helps,

Stephan

It's not good engineering practice to place an elbow in the piping near the pump inlet. In the "upper" pump you have two of them. This is most likely the source of the noise. Killing that pump will probably afford you some sleep. If you can't kill the pump you could install a flow straightening device, counter-rotating vane or, re-pipe to eliminate elbows within 10 pipe diameters of the pump inlet.

All the points Ducon has put forward are quite valid and reinforce what I said about there being nothing good about this installation.

However the longer I think about it the more I come to believe that the single biggest problem is that the pump frame being mounted directly on the floor. If it were up to me I would find some way to install vibration suppressing mounts between the pump frame and the floor then reassess the situation. The second step could be any of the other things that have been mentioned but I feel that all of these combined will not make as much difference as mounting the pump frame on vibration pads.

The more I look at the photograph the worse it gets and to date I have not been able to locate a single thing that has been done properly. Like I said this is one smeging awful, poorly thought out, appallingly feeble installation, done by somebody that either didn't have a clue or was so intent on reducing the cost that they cut every corner possible.

I may be wrong, but from what I see, I suspect the pump(s) is/are transferring their operating noise directly to the plumbing and possibly at a resonant frequency, greatly aggravating the problem.

I agree that the pumps appear to be well into their service life, the seal seems to be leaking on one for sure.

Properly installed, the tenant should never hear them. They aren't even in the adjacent room, but the next room 3M away. The pump room appears to be very narrow, by the picture, barely more than half again the length of the pumps. This may limit the ease of curing the problem.

Even if the pumps can not be isolated from the floor, I agree that your suggestion of isolation by flex couplings to the plumbing will be key, that was my first thought. If there is insufficient room for the styles you have illustrated, there is a style that will slide over a straight cut pipe end with a compression seal.

As others have suggested, longer cycle time would make more sense as well. Longer cycle times can only be more efficient too, avoiding the ~300% current draw on startup as often as possible.

I hope our guest has some influence to effect a cure to this unfortunate situation.

This is a classic example of how a poorly engineered and installed items can have far reaching and unpredictable effects.

Treat this as a lesson on how it is important for all engineers to strive to do the best possible job at all times regardless of the size and budget of the project. It is our responsibility as engineers to not only build things for a cost but to make sure that we have taken into account ALL the parameters and to make sure that we understand ALL the consequences of our actions.

thanks everybody for your suggestions, I did check and the pumps are not fixed to the ground properly, they are only put onto some metal base fixed to the floor directly, and the vibration through the main pipeline is really bad, so I think vibration is the number 1 reason why I hear all this noise in my room. I'm going to put some rubber pieces down to the pumps (between the pump and the ground), then the next step will be cut a little piece of pipe and replace it with a rubber hose (high presure one) in order to cut vibration. There are other problems that I'm working on, because pumps belongs to a 60 years old building that has 70 apartments (can you believe that!) and the administrator of the building is an old guy who is not very friendly. I have local police on my side because of noise regulations, but it's still hard to make all the things I would like to try.

Hope this works, I will let you know how it goes.

and yes, please all you Civil Engineers (I'm an Industrial Engineer) and Arquitects just be careful when you design or construct buildings.

Thanks again for your help

Carlos

Hi Carlos you did not mentioned who is the owner of the old building next to your wall and who is the owner of the pumps. If you can get to the owner of boths, ask him to solve the problems for you if not refer him to the authorities for nuisanaces caused.

I just noticed something in the photograph of the pumps that it looks like at one stage there were flexible couplings at least on the vertical discharge lines. Note the piece of pile that joins the pump to the building's plumbing. It looks suspiciously like an afterthought or patch repair. I have a sneaking suspicion that there once was a flexible coupling here and that over time it required replacing and instead of replacing it with the appropriate new item a short piece of pipe has been used instead.

MASU is very observant. My take is that these pumps are not the original pumps. The frame on which they sit looks similar to frames that are used for flexible coupled pumps, where pumps and motors are separated by a coupling, rather than the close coupled pumps shown. If indeed these are pressure boosting pumps for the building, then they are handling potable water. If that is the case, by all means use a stainless steel flexible connction, approved for potable water, on both the suction and discharge of the pumps, see pictures in previous posting. Also, use galvanized water pipe if you need to replace or add any pipe. Small pieces of old auto tires make good isolators for mounting the pumps on the frame. Isolating the pumps from the building will prevent vibration and accompaning noise, however I suspect these pumps are 3600 (sync) rpm, and if so, the noise from the motors may very well carry through the piping, at least for a short distance.

Operating 1 minute out of every 5 minutes sounds like "short cycling". If it's adjustable, the differential on the pressure switch should be increased so that there is a longer draw down period on the tank before the pump is energized.

I don't know,........ maybe MASU is right, but looking at the paint job, I'm just a little suspicious that the long nipple to union was the original means of installation. I guess the top portion of pipe would have had to have been removed to be threaded, and then the paint would have gone on after, but it just looks too much like it went together this way on day one. Sorry, I'm not trying to be CSI here, just stating my observation.

If only one pump is in operation, do you suppose the other is closed out by valves? Or, perhaps they don't feed a pressure tank upstairs, just a cistern, not that that is important to the problem.

OR,..... if the second pump is still in the loop, might it contribute to system pressure loss increasing the required frequency of pumping cycles?

If you are right about these being 3600RPM, that would really help conduct noise to the pipes with the lack of dampening, and isolation.

I wasn't going to say this, but now I will, MASU is right........This is the crappiest installation I've seen.......If this was engineered, the engineer should lose his license. The more I look at the photo and ponder, the less sense this whole thing makes. Pressurization systems are more than just a couple of pumps. They encompass a piping system with controls and valving to maintain constant pressure in the system.......IF, THIS IS A DOMESTIC (POTABLE) WATER SYTEM!........ The tank, which stays full, being in the floor, according to Carlos, could be a break tank. Some cities do not permit pumps to be tied directly to the water mains, hence a break tank to draw water from. Some cities allow the tank to be used as a "fire water" tank, with fire pumps and separate risers to the fire protection system.

If this system has a pressure tank with the pump operating as Carlos stated, perhaps the tank has become water logged and needs have some water drained and replaced with air. Over a period of time, water will absorb the air and the tank will become water logged.This condition reults in short cycling the pumps. "Bladder" tanks prevent water logging.

I'm not surprised if only one pump is running. The pump with the 2 ells on the suction side could not possibly pump water without causing the impeller and wear ring to prematurily fail, plus the possibility of cavitating which would certainly destroy the impeller in short order.

My vote is to replace the "pump system".

We need a sound button and by the looks of it even a smell button next to the green camera !

The pump and system should be replaced or the use of earplugs should be compulsory.

I agree the vibration isolation of this pump is extremely poor seeing there isn't any. Here is another point to be considered. The noise could also be a bad shaft bearing, or a damaged impeller. All the vibration isolation in the world may have no effect on the noise, and we could be treating the symptom of the noise and not the actual problem is a possibility. When pumps go, there are usually three ways. A bad shaft bearing, the impeller is damaged, or the motor itself is fried. The shaft on the other pump in the picture looks seized. What does anyone think about this possibility?

You may be right about the shaft being seized, one of the pumps is out of service. But I don't think I can see enough from the picture to draw the same conclusion.

A bad bearing or impeller may well be a possibility.

Carlos is an Industrial Engineer, so I think he might well be able to detect by ear if the pump sounds to be in pain. A mechanics stethoscope, or an old broomstick against ones head & rested on various portions of the operating motor or pump should give clues to any source of unusual noise emission.

I think we have all come to the conclusion that the pump in the foreground is the operational pump. Does anyone feel that it's apparent smaller size might be a clue? I realize with no scale that I can't tell size any better than noise, smell, or tightness, but I'm going to venture a guess that we are looking at a 1" NPT out vs. maybe 1½" on the other pump.

To me the lines coming in from the wall do look like 1-1/2" returns and 1" supply discharges. Probably cavatating like a %^&ch causing all that noise lol!