Home project: noise insulating a pump while keeping cooling

[DaveC426913]

Please move to appropriate forum if necessary.

I need some help. Attached is a pic of my standard 1/4hp Hayward pool pump. I want to enclose it to make it quieter. (The sound is being transmitted by air rather than by physical contact.)

As a "proof of concept" I stuffed it in a storage bin packed with a couch cushion, and it was a great improvement, so I know it is possible. Of course the couch cushion will not work in the long run because of heat buildup.

I'd like a more viable solution, one that doesn't cost too much but addresses the issues:

- noise silencing
- cooling
- vibrational damping in the base
- drainage (pump will spill lots of water when being primed etc. can't have it filling up with water)
- easy access to filter lid
- easy access to on/off toggle
- two pipes exit the container

What cooling is good/easy? A fan, blowing air? Coils, circulating pool water?

If air, how will I allow circulation of air without cutting holes in the container that will vent sound?

Help?

 

[NateTG]

What is it resting on in that picture?

 

[Danger]

Hi, Dave;
It looks as if you should be able to drill a few holes in that base plate (if they aren't already there; it's hard to tell). I'd start by bolting, clamping or screwing it to the top of a rubber block or large coil spring. Even though the sound is propogating through the air primarily, that plate vibrating against the ground probably causes a lot of it. I'd put some similar sort of support under the filter canister to even out the gravity load and further dampen vibrations.
For an enclosure, I think that a simple plywood box lined with some sort of foam insulation should be plenty. You can cut hinged access panels wherever you want. Since you'll need a cooling system anyhow, that shouldn't cause a problem.
While any kind of forced air would be helpful, I think that you hit on a really good idea about circulating the water. Divert your incoming supply through a few turns of copper or aluminum tubing coiled around the pump before it enters. Maybe some heat-sink compound would be helpful in that application. The conductance of the tubing should transfer a fair bit of heat to the water, which will carry it off to the pool and make room for more cold water. Since you only need the cooling while the pump is running, it'll be self-regulating. Just to be safe, put a thermal cut-off switch in the power line. That would also protect the pump if it happened to run dry (if sensitive enough).

 

[DaveC426913]

Hi, Dave;
It looks as if you should be able to drill a few holes in that base plate (if they aren't already there; it's hard to tell).

The hilit/muted portions of the pic differenitate between the actual pump itself and the base it attaches to (with 4 bolts). The base is simply crummy plastic, designed to hold it to the filter cannister behind. It serves very little use.

I'd start by bolting, clamping or screwing it to the top of a rubber block or large coil spring. Even though the sound is propogating through the air primarily, that plate vibrating against the ground probably causes a lot of it.

The pump is sitting on 2x6s, which are on a ½”x2’x2’ rubber mat, which is, in turn on a 2” thick concrete tile.


The noise is high-pitched and “breathy”, rather than thrumming or vibrating. And it virtually disappears whenever I get the pump serviced and lubed (shop job, not user-serviceable).

I'd put some similar sort of support under the filter canister to even out the gravity load and further dampen vibrations.
For an enclosure, I think that a simple plywood box lined with some sort of foam insulation should be plenty. You can cut hinged access panels wherever you want. Since you'll need a cooling system anyhow, that shouldn't cause a problem.
While any kind of forced air would be helpful, I think that you hit on a really good idea about circulating the water. Divert your incoming supply through a few turns of copper or aluminum tubing coiled around the pump before it enters. Maybe some heat-sink compound would be helpful in that application. The conductance of the tubing should transfer a fair bit of heat to the water, which will carry it off to the pool and make room for more cold water. Since you only need the cooling while the pump is running, it'll be self-regulating.

Yes, it would be great, especially since I have a heck of a time keeping the pool warm enough to use.

But I have a feeling that

a] wrapping the pump in coils of tubing will not make it very serviceable. I’d have to make it close-fitting enough to transfer heat, yet make it removeable so I can take the pump out when necessary.

b] it might be beyond my engineering skills.

Just to be safe, put a thermal cut-off switch in the power line. That would also protect the pump if it happened to run dry (if sensitive enough).

Huh. Didn’t know there was such a thing. I’ll look into it. Where might I pick one of those up? And are they easy to configure?

 

[FredGarvin]

Usually thermal cutoffs are integral to the windings of the motor. If you wanted to protect against running dry, I would suggest a simple pressure switch in stead in the pressure (output) line.

There's a lot of conversation going on here, but I did notice that you mentioned a high pitch screetch. Is this the core of the reason why you are looking into this or is it the continual operating noise? What is the situation surrounding the noise?

Just to get my feet wet (pun intended) on this topic, here are a couple of thoughts, questions:

- The pump-motor is not a TEFC housing (totally enclosed fan cooled) so it is a fair assumption that it will run well at elevated temperatures. If you can pull a model number off of it, we should be able to find a max operating temperature for the motor. You may not have to worry too much about the heat build up. These things have to survive in very hot climates.

- Since you mentioned high frequency noise that happens after it is lubed, I would look at replacing the motor bearings if feasable. If we had the ability to record the sound and put it through a spectrum analyzer we could nail down if it were a bearing issue. Misalignment of the pump is always a first thing to look at if your bearings are constantly being maintained/repaired.

- Are you certain that the noise is not flow related? Could it happen only after the pump loses prime? If so, is there a way to ensure a constantly flooded inlet?

-Since the motor is not rigidly attached to anything, that may be a factor in the noise generation. Even if the motor is attached to an absorbing platform, it should be mounted especially during start up and shutdown. The inrush torque is just going to get transferred to the case and the attaching piping in it's current state.

 

[DaveC426913]

Couple of quick questions: if I reroute some of the flow to the coils, I don't want to reroute it ALL, right? To do so would require more throughput than the cooling mechanism could manage, as well as reducing the max flow through the filter. So, I'd insert a T connector to reroute only a % of water through the cooling, right?

I'd put the T-connector on the pump outflow. Where would I reconnect? I suppose if I reconnected AFTER the filter, then that would accomplish two things:
1] The pressure differential across the filter would ensure that I get good flow through the cooling pipes. (If there’s no pressure diff, then my cooling system would be stagnant, right?)
2] A minor side effect is that all the heat would go straight into the pool and not be dissipated through the filter and circ piping.

 

[DaveC426913]

Usually thermal cutoffs are integral to the windings of the motor. If you wanted to protect against running dry, I would suggest a simple pressure switch in stead in the pressure (output) line.

Indeed, the label says thermally-protected.

There's a lot of conversation going on here, but I did notice that you mentioned a high pitch screetch. Is this the core of the reason why you are looking into this or is it the continual operating noise? What is the situation surrounding the noise?

Definitely bearings, flow, etc. As mentioned, when the pump has just been serviced, it is fairly quiet.

- The pump-motor is not a TEFC housing (totally enclosed fan cooled) so it is a fair assumption that it will run well at elevated temperatures. If you can pull a model number off of it, we should be able to find a max operating temperature for the motor. You may not have to worry too much about the heat build up. These things have to survive in very hot climates.

Hayward SP2075X10CSA
1HP
11.6A

http://www.poolsaz.com/Hayward-1-0-HP-Power-Flo-II-High-Performance-Pump-p/sp1780.htm"

- Since you mentioned high frequency noise that happens after it is lubed,

No, it goes away after lubing. I just can't afford to do that every year.

- Are you certain that the noise is not flow related? Could it happen only after the pump loses prime? If so, is there a way to ensure a constantly flooded inlet?

No, I am very familiar with noises from losing prime. (It is a total pain it the *** to prime because the pre-filter basket lid is extremely hard to open/close due to friction – I need a foot long wrench. In fact, I would say this is the pump's biggest headache).

This is a normal-operation noise.

 

[RVBuckeye]

Hello Dave,
A concern I have is it being a 1/4 HP pump. That seems a little low for a pool. I used to own an above ground pool, (which it appears this is what we're dealing with from your photo) and never had to get it serviced.

I do recall it getting a little "whiney" when I didn't backwash the sand filter often enough, and that usually solved the problem. My thinking is that as the sand gets clogged, it's making the pump work harder, hence the whinning. Not sure if I would call it "breathy" though so I could be wrong in your case.

Just a thought, but a more powerful pump might be what's needed. Don't know how much you plan to spend, but it might save you long term by eliminating the servicing. Anyway, good luck.

 

[DaveC426913]

Hello Dave,
A concern I have is it being a 1/4 HP pump. That seems a little low for a pool. I used to own an above ground pool, (which it appears this is what we're dealing with from your photo) and never had to get it serviced.

I do recall it getting a little "whiney" when I didn't backwash the sand filter often enough, and that usually solved the problem. My thinking is that as the sand gets clogged, it's making the pump work harder, hence the whinning. Not sure if I would call it "breathy" though so I could be wrong in your case.

Just a thought, but a more powerful pump might be what's needed. Don't know how much you plan to spend, but it might save you long term by eliminating the servicing. Anyway, good luck.

Apologies. I just checked. It's 1HP.

Backwashing does not help.

 

[RVBuckeye]

I know this might sound odd but if you want a cheap solution. Put it underground. Let it rest on it's base but don't bolt it to it. When you have to clean the filter, just pull it back out of the hole (it's flexible tubing isn't it) A piece of plywood over top and there you go. Sound dampening, cooling, and cheap.

 

[Danger]

I think that RV's idea about the hole sounds the most practical. And if the motor ever dies on you, it's already buried. Wish that I'd thought of it.
When I mentioned the coiled heat exchanger, I actually meant to run the entire incoming flow through it. Comparing them with the size of the power cord in the picture, I'm estimating that those hoses are about 1.5" OD. To keep with the specifications of the pump, you'd probably want to make the coils the same inside diameter. More effectively, but also more complicatedly, you could run a lot of sub-sized tubes in parallel. Your flow rate would stay the same, but the surface contact area would go way up. The coils could be easily removeable from the pump if needed; they should just slide on and off like a sleeve. I'll have to get into Illustrator tonight and post a diagram of the set-up that I'm envisioning. By the way, I can't tell from the picture... is the filter on the inlet side?
That all is moot, of course, if the motor will indeed handle elevated temperatures.

 

[FredGarvin]

I'm sure you've looked here:http://www.haywardnet.com/owners/troubleshooting/pumps.html#noise

My pump is noisy
♠

This may be normal since they produce water flow. The motor has a cooling fan internally which can be heard to a certain degree. It is advisable not to locate any pool pump under someone's bedroom window. The pump's sounds can be caused by vibrations between the pump base and the base or concrete pad it is sitting on. A piece of old carpet or rubber between the pump and base may quiet the sound.

The bearings may be noisy due to normal wear. Feeding high concentrations of chemical tablets in the skimmer will cause corrosive damage to the pump seal, which can leak and damage the motor bearings. It is recommended to get the bearings replaced by a qualified motor repair shop. Also, cavitation due to improper suction line sizing, leaks in the piping, a blockage in the suction line, or a low level of pool water will cause higher than normal sound.

 

[DaveC426913]

Actually, I'm really liking the water-cooling idea, since that will solve another problem with my pool - the fact that it is rarely warm enough.

When I mentioned the coiled heat exchanger, I actually meant to run the entire incoming flow through it. Comparing them with the size of the power cord in the picture, I'm estimating that those hoses are about 1.5" OD. To keep with the specifications of the pump, you'd probably want to make the coils the same inside diameter.

Wrap my pump in 1 1/2" pipe?? The heat exchange would be abyssmal wouldn't it? Especially since the tubing material is 1/8" rubber.

OTOH, it would drastically simplify construction.

More effectively, but also more complicatedly, you could run a lot of sub-sized tubes in parallel. Your flow rate would stay the same, but the surface contact area would go way up.

That's what I was thinking, yes. I'll need to look for parts. I imagine some sort of brass gang valve to have f4 or so 1/4 copper pipes off the main offshoot.

The coils could be easily removeable from the pump if needed; they should just slide on and off like a sleeve. I'll have to get into Illustrator tonight and post a diagram of the set-up that I'm envisioning. By the way, I can't tell from the picture... is the filter on the inlet side?
That all is moot, of course, if the motor will indeed handle elevated temperatures.

 

[RVBuckeye]

Don't take this the wrong way, but...

Actually, I'm really liking the water-cooling idea, since that will solve another problem with my pool - the fact that it is rarely warm enough.

...that's hilarious.:rofl: :rofl:
How much heat do you think is going to make it back into you pool?
I see many wasted dollars in your future. Good luck.

 

[Moonbear]

Not to be too flippant, but the only way I know to avoid the noise of a pool filter is to run the pipes underground for some distance and place the filter far enough away you don't hear it, or far enough away that you can house it in a small shed.

Are you just interested in muffling the sound somewhat? Completely blocking all sound might not be very feasible, but to muffle it, why not just build a plywood box? On the side with all the pipes, just cut holes large enough for the pipes to fit through and leave that side permanently in place as the back of the box. Then, construct the remaining sides attached to the top, and use hinges to attach the top to the back. A couple of latches near the bottom to connect the two sides to the back will make it easy to open and close by lifting the entire box up by the hinge. Paint the plywood with several coats of a good outdoor paint, and if needed, add some foam insulation along the interior of the box.

If you're worried about the motor overheating, you can put a vent on the side of the box nearest to the motor, but that'll of course reduce the amount of sound blocked.

Edit: I've attached a figure to give you a rough idea what I mean, though I think it's a simple enough concept you probably don't need it (I always prefer pictures for clarity).

 

[DaveC426913]

Don't take this the wrong way, but...

...that's hilarious.:rofl: :rofl:
How much heat do you think is going to make it back into you pool?
I see many wasted dollars in your future. Good luck.

Glad I could amuse.

Since you are clairvoyant, you can also see the size of my pool (4000gal) and the amount I'd like to raise the temp by (1C).

Not as ridiculous as you might think, Kreskin.

 

[DaveC426913]

Are you just interested in muffling the sound somewhat? Completely blocking all sound might not be very feasible, but to muffle it, why not just build a plywood box? On the side with all the pipes, just cut holes large enough for the pipes to fit through and leave that side permanently in place as the back of the box.
...
If you're worried about the motor overheating, you can put a vent on the side of the box nearest to the motor, but that'll of course reduce the amount of sound blocked.

Edit: I've attached a figure to give you a rough idea what I mean, though I think it's a simple enough concept you probably don't need it (I always prefer pictures for clarity).

I appreciate the input, but if you follow the thread you'll find that

1] cooling is my major concern. A hole in the side of the box won't be enough. And yes, it would drastically reduce the sound dampening.

2] I do not have a choice where the pipes exit. One of them goes straight up.

 

[RVBuckeye]

Glad I could amuse.

Since you are clairvoyant, you can also see the size of my pool (4000gal) and the amount I'd like to raise the temp by (1C).

Not as ridiculous as you might think, Kreskin.

Relax...I was just kidding. We're all friends here. Witty reply as well.

I was just envisioning what it would be like if it was me. With my wife saying, "I told you it wouldn't work!" And me shelling out a couple hundred dollars on a new pump, on top of what I just spent on that "contraption". (which I should have done in the first place). A couple of similar experiences and I'm a firm believer in...
K.I.S.S.

 

[Danger]

Crap! I did up a sketch this morning (didn't have time last night), threw it on a disk, and planned to post it from work. Unfortunately, I didn't realize that ImageShack doesn't take PDF's. :grumpy:
I'll have to do it tonight from home, so it might be near midnight.

edit: Somebody better check my math here; this seems weird. My figuring says that if we divide the flow into 6 sub-tubes, each one would have to be .75" inside diameter to approximate the flow rate through one 1.25" ID hose (1.5" OD w/ .125 wall thickness as indicated). That wouldn't be tremendously helpful.

 

[turbo]

Since the noise goes away when the pump is lubed, it is likely the bearings in the pump head itself making the noise, which is being trasmitted to the air by the vibration of the pump head and rigid piping attached. If this is true, I would start by cutting some flexible closed-cell foam to fit (neoprene would be good), and duct-taping it to make a cover around the pump head and at least the first few feet of rigidly-attached piping. The pump will be self-cooling (via the pool water running through it) and the motor will stay cool.

 

[DaveC426913]

Relax...I was just kidding. We're all friends here. Witty reply as well.

I was just envisioning what it would be like if it was me. With my wife saying, "I told you it wouldn't work!" And me shelling out a couple hundred dollars on a new pump, on top of what I just spent on that "contraption". (which I should have done in the first place). A couple of similar experiences and I'm a firm believer in...
K.I.S.S.

You've no idea how accurate you are! :rofl: Except I was unlucky enough for it to have been her FIRST husband.

[ digression ]
Her first husband (I'll call him Scott) thought it would be great to heat their house from the fireplace and a heat exchange system: a coil of pipies under the fire grill, and out into the room to a radiating panel.

Great idea, right? But forget those puny little 1/4 inch pipes in the heat exchanger, bigger pipes mean more heat, right? So let's go with one inch diameter pipes, yeah! (Say... why is the water coming out of the fieplace still cool? Hm...)

She still talks about it to this day, and if catches any hint of me "contraptionizing" anything, she drags this story out and beats it with a stick. :rofl:
[ /digression ]

 

[DaveC426913]

Since the noise goes away when the pump is lubed, it is likely the bearings in the pump head itself making the noise, which is being trasmitted to the air by the vibration of the pump head and rigid piping attached. If this is true, I would start by cutting some flexible closed-cell foam to fit (neoprene would be good), and duct-taping it to make a cover around the pump head and at least the first few feet of rigidly-attached piping. The pump will be self-cooling (via the pool water running through it) and the motor will stay cool.

This is actually good idea. I hadn't though of baffling only a portion of the pump - the part that doesn't get hot.

RV's idea of burying it is good too. It would by far be the most effective an silencing the noise.


If only I hadn't hit on the idea of taking advantage of all that wasted heat to warm my pool...I'd be all set.

 

[RVBuckeye]

You've no idea how accurate you are! :rofl: Except I was unlucky enough for it to have been her FIRST husband.

[ digression ]
Her first husband (I'll call him Scott) thought it would be great to heat their house from the fireplace and a heat exchange system: a coil of pipies under the fire grill, and out into the room to a radiating panel.

Great idea, right? But forget those puny little 1/4 inch pipes in the heat exchanger, bigger pipes mean more heat, right? So let's go with one inch diameter pipes, yeah! (Say... why is the water coming out of the fieplace still cool? Hm...)

She still talks about it to this day, and if catches any hint of me "contraptionizing" anything, she drags this story out and beats it with a stick. :rofl:
[ /digression ]

:rofl: :rofl: :rofl:

I feel for you. As someone who's pretty handy around the house, if you attempt enough stuff, you're bound to become the character of one of you wife's stories.:rofl:

I actually installed my pool myself. Took a week off from work, cut up the sod, leveled the ground, set the concrete blocks for the uprights. Had someone help me unrolling the sides. Turned out perfect except...

I put the pump right below our bedroom window. (and only realized it after I filled it )
I piped it underground using pvc instead of the flexible hose.
Aboveground pools were also against our association rules, unbeknownst to me, and I had to take it out. Luckily I moved shortly thereafter.

 

[Artman]

Dig a trench a few feet deep to a pit below your pump location. Put a piece of 6" PVC thinwall pipe in the trench with an elbow up and another elbow above ground to keep the rain out (the longer and deeper the trench, the quieter the operation and cooler the air will be). Build an insulated box over the pump and pit with the pump supported above the incoming 6" pipe. Take another piece of 6" thinwall and a 90 deg elbow. connect it to a hole in the top of the box over the motor with the elbow acting as a sound deadener and gooseneck. The heat in the box will rise and draw cold air in from the pipe below ground. Gadgety yes, but it would work.

 

[Moonbear]

2] I do not have a choice where the pipes exit. One of them goes straight up.

Oh, you're only looking to cover the pump itself, not the entire pump/filter assembly? I was thinking more along the lines of something that covers the entire thing. There should be plenty of space inside for it not to overheat (pool pumps are designed to be run in the blazing hot sun, and if you're having trouble keeping your pool water warm enough, it doesn't sound like you're in a climate where you're getting blazing hot sun on the filter pump). Here's a picture of an actual product along the lines of what I was thinking (though seems to be for sale in Australia), though that particular one wouldn't give easy access to the pump cover that you'd need to be able to open to clean the filter out. http://www.shedman.com.au/pricelist/Colorbond.htm#a1015 It's in the middle of the page.

But, yeah, if you weren't thinking of something that big, then nevermind. I had the impression from your original post when you talked about wrapping an entire mattress around it that you were going for something to cover everything, not just the pump itself.

 

[Gokul43201]

edit: Somebody better check my math here; this seems weird. My figuring says that if we divide the flow into 6 sub-tubes, each one would have to be .75" inside diameter to approximate the flow rate through one 1.25" ID hose (1.5" OD w/ .125 wall thickness as indicated). That wouldn't be tremendously helpful.

Checked and confirmed. 5 would come up a little short; 6 would make it; 7 would be safe for turbulent flows.

(haven't read most of the discussion here so this may likely be redundant or just wrong) If it's just the bearings going noisy with time, you might think of wrapping the pump in Ethafoam. As for the pipes, use a length of flexible pipe and run it through a larger diameter sand-filled pipe. You could also just make a sand-filled double-walled plywood box to house the pump.

 

[DaveC426913]

I have decided that a heat exchanger system would result in too much flow loss due to friction to make it practical. While it might heat the water, problems with throughput (important to keep the pool clean) could leave me worse off than before. I may do it someday, not not just yet.

So -

I have enclosed the pump in a rubbermaid tub, lined with foam, and supported on rubber and wood pilings. The foam-lined lid has resulted in a promising drop in the higher-pitched noises.


There's an ironic twist to the story. Once I had put all the plumbing back together and was cleaning up, I noticed the filter making a surprising amount of noise, as were other parts. I worried that perhaps I had jigged something, and was now getting unwanted side-effect noises due to the new construction.

After some checking and testing, I concluded that these were not new noises at all; they had been there all along but I had not noticed, as they were masked by the loud pump. Overall, it's quieter.

 

[FredGarvin]

That's cool. I would be really interested in characterizing the noise from the pump. Is it flow noise, mechanical noise or something else? Anyways, glad it worked out.

 

[DaveC426913]

That's cool. I would be really interested in characterizing the noise from the pump. Is it flow noise, mechanical noise or something else? Anyways, glad it worked out.

http://www.davesbrain.ca/miscpix/PF060619pumpnoise.wav" .

00-08 pump plus high-pitched, "breathy" wail
09-15 pump turned off
16-28 pump comes back on, begins priming itself, we hear ONLY PUMP ( it may not be obvious from this clip, but the pump sound doesn't carry NEARLY as far as the high-pitched wail)
29-38 as pump primes we hear the high-pitched wail return in fits and starts
30-38 I close the lid of my container, wail is reduced and mostly you can only hear the pump

 

[FredGarvin]

Cool. Let me see if I can get this into the spectrum analyzer sometime today.

 

[Danger]

A WAV file

I must say, lad... that's quite annoying.