Quieting Pump Roar

Constantin

... nevermind, I actually have a pressing issue with respect to my heating system.

As you may all recall, it's all radiant fed by Grundfos 15-58FC's three speed, flow-check pumps. Initially, the roar was quite objectionable, but since reducing the pump speeds to "low" the beasts have been tamed somewhat.

However, the noise isn't quite gone and I wonder if we cannot remedy the noise once and for all by doing some supplementary work on the primary manifold.

Below is a picture of the unfinished manifold. As some of you have pointed out, such a manifold/pump combination will always be prone to cavitation, noise due to turbulence in the water. One recommendation called for allowing at least 12" between the manifold and the Grundfoss pumps. Is the 12" a minimum or could we get away with as little as 6" or so?

The reason I ask is that moving a primary loop is a pain in the rear. I'd rather not have to re-sweat the copper lines above either. So here then my idea:

Install B&G Isolation Flanges above and below the pump, but as high as possible from the primary manifold. I might get 6" of 1" diameter pipe out of this... would that be enough? Or, do we best start over and drop the primary manifold 6"?

As it is, we have to undo a big part of the primary manifold because one of the connections near the boiler is leaking. I'd prefer isolation flanges above and below the circulators... Plus, we'll have to bleed the whole system anyway due to the Rhomar cleaner and conditioner retrofits in the future.

hr

I'm not convinced

the short pipe section on the intake side of the pump is causing the noise? Look at the Danfoss ZCP, the Wirsbo ProPanels, or the Watts HydroControls. Not uncommon to see pumps close coupled like that.

Yes, ideally you would have more straight section...

Also I just iso valve the suction side of the circs. I've found the intergral checks in the Super Brutes allow a motor change out without needing additional, discharge side, valves. The volutes hardly ever fail

I'd still spent time, and money, on isolating the noise (wherever it's generated) from the wall of the structure. With that much pumping going on it will never be completly noiseless.

It doesn't take much debris to make a pump noisey. A ball of solder, even a copper reamed chip will throw them off balance and cause noise. Pull each one and check the vanes of the impeller for crude.

Here is a Super Brute with a pebble lodged in the impeller. It was a wall shaker

A Y strainer would have prevented this, my fault and a no charge callback:(

The only, and the quickest, way I can tell if a Super Brute is running is with one of these spinners.

hot rod

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Constantin

Food for thought... Thanks Hot Rod!

In the current system, the only iso flanges are on the discharge side of the pump. I.e. not the side that you seem to like to isolate.

I recall that you had a preferred means of "vising" the manifolds and whatnot to prevent them from vibrating. What method worked best for you? Any brands you can point me to?

Another question I'm asking myself is whether all these pumps are necessary?

Presently, each 15-58FC is handling approximately 700 ft² of zone with 3/8" tubing installed in Quick-Trak (it's a beta application of the larger tubing, I'm told). Each tubing circuit is about 150' long, on 8 or 9" centers, so that's about 1 circuit per 100 ft².

When I fire up HDS, it would appear that a 15-58FC could easily handle two zones, i.e. 14 circuits, or a whole floor without breaking a sweat on the lowest pump speed setting. However, perhaps I'm not using the HDS correctly?

The design-day heat loss is about 23 BTU/sq ft/hr, and HDS indicates about 2300 BTU/run of tubing using their 8" OC setting. But can I translate 2300 BTU from PEX in the floor into 2300 BTU in the room, even if I have R13 insulation below? Assuming we have no losses from tubing to the exterior (and we shouldn't the manifolds are central to the house)...

Our manifolds are at max 100' long, 1" Dia Cu, with minimal bends. What I'm getting at is that perhaps we're better served by having each floor on one pump, two zone valves plus differential bypass? As always, your thoughts are appreciated.

Lastly, lest someone think this is a criticism of my installers work, it isn't. I'm very impressed overall with their level of craftsmanship, etc. I'm simply looking how to make something good even better.

hr

Choices

for noise and vibration isolation. Unistrut clamps are available from many manufactures. These are mainly for refrigeration noise isolation, and work fine for hydronics.

On the right is a Mupro brand. much meatier rubber component, many styles available. this is a threaded rod style hanger.

I tend to zone with pumps for the reasons you listed. One or two, small wet rotor pumps, can generally handle a good sized home, regardless of the number of zones. Use PAV's if you have more than 4 or 5 ZVs on one pump.

If you care to be a pioneer, looks like WILCO is introducing some delta P pumps soon, to the NA market.

hot rod

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Weezbo

i'd like to second that opinion Constantin. *~/:)

hot rod, due to my enigmatic means of communicating would you explain Fighting pumps to constantin?

bob_44

4-way

Constantin, If I remember your system has a 4-way valve. The photos that I have seen don't give enough info to draw a schematic of the whole system. With your air elimination all on the boiler side of the 4-way I wonder if you might have some air on the system side that never gets back to the air eliminator. Also have you tried throttling the pumps back with the ball valve on the discharge. Just some random thoughts. bob

S Ebels

Was wondering the same Bob

Getting all the air out of system with a 4-way in it can be difficult. We nearly always set them up with the capabiliity to isolate and purge each zone.

Darin Cook_3

I have had some noise issues also

The constant circulation systems seem to be worst. If you are mounting multiple circs against the wall, rest assured you will get a fair amount of harmonics resonating through the immediate structure. One thing in paticular I have seen or should I say heard is a low key chattering of the integral flow check on the 15-42 and 15-58 when I use them on constant circ systems. I have had two panel rad jobs where this has happened. I ended up removing the flow check. Being that the other zone is a indirect with a thermostatic valve on it I didn't worry about scalding issues. I have used the unistrut clamps that HR showed and does help to a degree. I have kicked around the idea of taking a whole sheet of red rubber and putting it behind the pump panel, basically isolating everything from the wall. I don't know how much noise the screws would transmit into the studs. Worth a try I guess.








Darin

steve gates

hr could it be

that the panels use copper vs. pipe.
to much eddy efect? Thus turbulence?

Constantin

Thanks Bob!

Here is the diagram you ordered. I took me a while to recreate all the symbols, I hope I have them right.

All the pumps are Grundfos 15-58FC's, all zones are radiant 3/8" ID 1st floor and up, the basement is 1/2" ID.

After taking my wife to brunch, I'll try and draw up what I think would be an improvement and see what you guys think. I am happy to hear that the FC in the 15-58 is removable... more later... thanks!

Constantin

Gentlemen, how did I do?

Here is my first attempt at sketching a new layout. Note several changes:

1. As the vitola has a built-in air scoop, I moved the air sep to the other side of the 4-way valve. I also attched a purge-water ballvalve and backflow preventer for zone purging.
2. The expansion tank and auto-feeder moved to the location that Viessmann prefers in their installation diagrams. Seems reasonable.
3. All pumps get iso-flanges as I believe it's good practice to use them. The B&G's look pretty nifty.

Hopefully this setup would purge most, if not all, air and be servicable to boot. What do you guys think?

I also like the idea of sound insulation via large rubber mats. This could work, particularly if you can find a way to mount a heavy plate to said rubber to give the system more mass to excite.

Constantin

Here is another approach...

... as it appears that the pumps may be oversized WRT their loads, it may make sense to reduce the number of pumps and resort to zone valves.

The below approach is a reflection of that. Your comments are welcome, as always. Cheers!

hr

Or it could be

Constantin's low " engineered" tolerance for noise Those pumps generally are very quiet, it may be some tiny air bubbles yet?

Iron pipe may help for the same reason plumbers use cast iron drainage and waste stacks in custom homes. It really deadens the noise of running water.

In this case it is probably more of a vibration or frequency thing.

Mount everything to the concrete floor and unistrut rack up from there would do it

hot rod

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