Circulation pump shaking building.


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Old 12-15-09, 08:36 PM
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Circulation pump shaking building.

I live in a 20 unit condominium. I'm an electrician and on the board of directors so I am the person people usually go to with building problems before calling a contractor in.

The building is 2 story, there is a natural gas boiler located in a central basement, then the water pipes run thru the other basements and branch up into the units to convectors inside of metal enclosures underneath the windows.

In some of the basements along the way there are pumps to help circulate the hot water.

First question, I was told these pumps only need to be turned on during the colder days, is this true? Will the water flow thru the impeller when the pump is turned off? Or do the pumps need to be on whenever the heat is on?

Second, one of the pumps located in the basement under my unit is vibrating my stairs and even my living room, and I am on the second floor so I can't imagine how bad it is for the first floor tenant. The pump is held up by a metal strap screwed to the joist, I was told that the vibration is from the way it is mounted. I could see some wood pieces inside the strapping that someone used to help shim it and quiet the noise, I was told that if I get it right it will stop the noise.

Is there any truth to that? If I remount it a certain way, will it stop vibrating? Or is it more likely a worn bearing or air stuck inside it?

I have no problem calling in a professional contractor, but if it's as simple as adding some support for the pump, I would rather save the association some money at this time.

Thanks.
 
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Old 12-15-09, 08:55 PM
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Without being able to see and evaluate this system, it will be difficult to get relevant answers...

As a GENERAL statement though, MOST systems require that the pumps be running with ANY heat call. How will the heated water get to where it needs to go otherwise?

Older (MUCH older) types of systems relied on 'gravity' flow... hot water being more buoyant that cold water would induce flow in these systems without the need of a pump... but chances are almost 100% that you don't have a gravity system... it's possible, but unlikely... how old is the building?

Water pumps shouldn't vibrate terribly... it's very possible that this pump is defective. Perhaps the 'coupler' has bit the biggun.

If you can take some pictures and upload them to a free account at Image hosting, free photo sharing & video sharing at Photobucket and place a link here, we would be glad to take a look and advise...

Keep in mind that many jurisdictions require duly licensed persons to actually do the work... but there's no crime in advising!
 
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Old 12-15-09, 09:11 PM
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Originally Posted by NJ Trooper View Post
As a GENERAL statement though, MOST systems require that the pumps be running with ANY heat call. How will the heated water get to where it needs to go otherwise?
The pumps at the boiler are on whenever the boiler is. I was told that the pumps located further away (like the one underneath my unit) were just to give it a boost when it gets real cold. The heat does work pretty well when these pumps are off.
Older (MUCH older) types of systems relied on 'gravity' flow... hot water being more buoyant that cold water would induce flow in these systems without the need of a pump... but chances are almost 100% that you don't have a gravity system... it's possible, but unlikely... how old is the building?
Built in 1962, originally an oil fired boiler. It is definitely not any type of gravity system, there are pumps.

I'll try to get pictures in the morning.

Adding some type of support or shimming to an installed pump, if needed, does NOT require a license of any type. That was the only work I mentioned that I was willing to do.

So... Can the way a circulation pump is mounted be the cause of vibration?

Second, Can water flow thru the impeller when the pump is turned off?
 
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Old 12-15-09, 09:25 PM
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I spent almost twenty years in charge of the operation and maintenance of a fairly large hot water system. It handled several major buildings, both manufacturing and office spaces and covered an area equivalent to several city blocks square.

The way a pump is mounted can very well determine if it creates noise throughout the building although I suspect that what you have is what is called a three-piece pump. Bell & Gossett is the major manufacturer of these pumps although there are other brands.

The three-piece pumps are as close to bullet proof as you can get but they do require periodic maintenance. One of the things that will cause a lot of noise is a misaligned coupler and if it runs like that very long the coupler will break. The biggest cause of misaligned couplers is over oiling the motor with the excess oil running down onto the resilient rings of the motor mount.

I will wait for the pictures to add further comments.
 
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Old 12-15-09, 09:28 PM
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Alright, I'll get them in the morning, thanks guys.
 
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Old 12-16-09, 06:02 AM
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Here are some pictures of the pump in question, you can see what someone has done to try and quiet it. From what I was told by the old president who has lived here for 35 years, the shimming and the wire hanger have worked to quiet it in the past.







On another note, I find this heating system weird. When it branches out from those main pipes to go to the convectors in the units, it does it it different ways. Sometimes there will be a pipe coming out of the supply main going to the convector, then from the convector back to the return main which seems like the right way. In other instances there will only be one pipe coming out of the supply pipe, that pipe splits into 2 pipes, both going to the same convector (just a loop, no in or out). And I've even seen that same loop type of setup coming out of the return main going to a convector.


ETA: I forgot this forum was in bed with the image hosting corporations. To see the images you can copy and paste the link and insert t i n y p i c . c o m without the spaces.
 

Last edited by VoltageHz; 12-16-09 at 06:19 AM.
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Old 12-16-09, 09:40 AM
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ETA: I forgot this forum was in bed with the image hosting corporations. To see the images you can copy and paste the link and insert t i n y p i c . c o m without the spaces.
C'mon man, that ain't right... nobody in bed with nobody.

Fact is that the way tiny pic manages the database allows the URL's pointing to the images to change from time to time, resulting in broken links... there are other reasons which I won't elaborate on. We recommend our favorites because they work consistently.

Nobody here gets paid, we're all volunteers.
 

Last edited by NJT; 12-16-09 at 02:53 PM.
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Old 12-16-09, 11:01 AM
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I see the make-shift rigging to take weight off the coupling. I would say the coupling is shot. B&G sells a rebuild kit.

I notice a 1992 date marked on the pump.
 
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Old 12-16-09, 02:14 PM
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More: if the pump is allowed to continue to run like a thrashing machine, I fear that more than the coupling will be damaged (if it isn't already).

I'm also not keen on the heavy pump hanging midspan on a horizontal run of copper pipe, seemingly without any pipe hangers located near the pump flanges. Steel pipe might have been OK. I have a hunch, from the vibration you described, that copper pipe (and the pump itself) are bouncing around something fierce.

The jury-rigged coat-hanger slings supporting the pump's weight are not a substitute for properly placed pipe hangers. In addition to pipe hangers, you can add a support stool under the pump.
 

Last edited by Mike Speed 30; 12-16-09 at 02:44 PM.
 

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