Fear and Loathing in Cambridge...

Constantin

As you may all remember, I'm having some issues with the noise in my house whenever the heating system pumps are running. A number of good suggestions were made, and I hope to summarize it all for my heating contractor.

Enclosed below is a diagram for the revised system. It's a reflection of what Viessmann recommends re: boiler fill and some of the tips that have been given to me by the good people of the Wall.

As air entrainment may be causing some of the noise it was suggested we move the B&G air-sep up to the supply-side of the 4-way valve. I also think that may be a good location for a purge location to be piped in. Do you think we ought to buy a second air-sep or is it good enough to rely on the built-in air sep that comes as part of the Vitola boiler? For that matter, how effective are the vents built into the ends of Stadler manifolds?

Are there any strong feelings regarding the use of the bottom drain in the Vitola as a location for a water feeder and expansion tank?

I am also planning to ask for the B&G check-trol flanges and have the internal flow-checks in the 15-58's removed to reduce flow noises further. Seem reasonable? The current shut-off is only on the discharge side, so it's not possible to really isolate parts of the system.

Lastly, I'm definitely going to go for the Müpro rubber-lined flanges, as I can feel the entire pri-sec manifold shaking with vibration right now. A couple of rails with the uni-struts should add a lot of mass to the system and hence reduce oscillation a great deal.

I presume that the contractor will shake his head, but as I'm willing to pay for his time and materials, I hope he won't refuse to do the work. What do you all think. Am I nuts or does it seem reasonable?

hr

OK

I'd use the Spirovent or the B&G knock off, not that big cast iron B&G

The B&G check iso valve, which I love will only move the check about 1/2" further from the pump discharge, then where it is in the Grundie's volute. Not sure it is worth the hassle. The checks themself look near identical.

hot rod

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Constantin

Fair enough...

.... I had a similar thought but think that the B&G iso-valve/flange combos make a lot of sense. So we'll get them w/o the flow-check. With no heavy-duty repiping, we should be able to achieve about 6" of straight pipe ahead of the circulator, which should help.

In the picture below, you can see the back of the boiler while it was being installed. Note the drain/fill location on the underside, the vent at the top of the boiler, and the B&G vent on the piping on the way to the 4-way valve.

To make the air-sep work as shown above, we'd have to move the 4-valve a bit towards the back of the boiler. We have the room... I suspect a PITA in the making, however. All that steel is likely hard to undo... What do you think?

hr

Why not leave

the current purger where it is and add another to the 4 way. I've added them to the return side and they catch air just as well

Personally I would do this... Use two large ball valves on either side of the 4 way. This is plenty close to isolate the bottom of all the circs, and the internal checks would isolate the discharge side. Keep the iso's valves at the discharge side so you can purge one zone at a time.

Of course leave the inlet side iso's in since they are already there My one valve on the inlet side is just an example of a simpler, less valve intensive way to accomplish the same function. The purge cock allows you to bleed off fluid to change out a circ without getting squirted in the face

On the return from the heating zones add another large ball valve with a purge cock just upstream. The additional air purger (to be added) will work fine on the return from the zones as long as you establish flow. The bubbles really don't care where they get captured. in your current system all the bubbles may never get back to that purger location. Two purgers are ALWAYS better than one with 4 ways and injection mixing piping, for this reason.

Trust me this will work and minimize a lot of repipe work.

hot rod

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ScottMP

Somthings not right ?

You allready own the largest air trap possible, its big and silver and comes with an air vent. I am confused as to why you are getting so much air. I mean HOW many vents do you need ?

I have installed systems like your and never had this type of air elimination problem. I owuld look more to the piping layout and less towards adding more vents.

Scott



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Constantin

Very good points, Scott & Hot Rod!

I am going to try and take a gradual approach towards eliminating noise from the distribution system. Currently, there is a good amount of white noise anywhere near the core of the building where the manifold pipes are running. Perhaps I'm very sensitve towards noise, but the sound is similar in magnitude to a well-installed AC system operating.

It was subsequently suggested that there may be some sort of air entrainment causing the noise. This may or may not be the case.

Having said all that, in the interest of preserving my pocketbook and the sanity of my heating installer, I think I will approach quieting the system in a layered manner.

First, we'll try to use the Müpro clamps to fix the system in the basement. The whole manifold assy vibrates now as few of the Uni-struts that were installed way back when have been tightened yet, etc. There is a good chance that installing the Rubber-lined clamps will solve the noise issue.

I'm also going to shy away from moving the expansion tank and water feeder from their present location. They seem to work fine there.

However, I do think that having check-trol-style Iso-flanges on either side with a bit of straight pipe ahead of the 15-58's will not only reduce cavitation a bit but will also help me with any replacements in future (Wilo ΔP pumps?)

Since we have yet to clean, stabilize the system using the Rhomar Hydrosolv, etc. I'd like to think that the above changes won't be too disruptive. As always, any further comments or thoughts would delight me.

Leo G_99

C, 2 things

make sure that that 4-way is installed correctly. The V 4-way is very particular to which port goes where. If it is wrong, you may have to reconfigure the paddle. Also, from your drawing, I cannot tell if you have flow controls on your pumped zones. Could velocity be an issue?

Leo G

Constantin

Thanks Leo!

The 4-way is installed correctly... I've had to verify that to be sure. I'm not sure what you're referring to re: flow controls beyond the flow-checks built into the circulators and the ball valves we could crack a bit closed to reduce flow speeds.

I ran the numbers for the system by HDS. As best as I can tell, velocity should be acceptable, as it doesn't even come close to the 4ft/s speeds indicated by HDS as being problematic. Those manifolds are pretty large (1") and the zones are pretty small (700 ft² being served by 6-7x 150' long, 3/8" ID PEX tubing).

J.C.A._3

Constantin,

If memory serves me...(No guarentees here brother,) the piping diagram for the Vitola, IN THE INSTRUCTIONS!!!!, shows the feed for the boiler and the feed for the expansion right on a tee where the boiler drain is on the lower bottom.

It has been about a year since my lst Vitola install, but this seems to stick in my memory pretty well as I would normally have pipied it the way you have. I think I was thrown back a bit on reading this, but I ain't gonna second guess the big cheeses at Vie$$man. A warranty is more important than the "way I have been taught", and with the Benz of the heating field, I wasn't taking any chances.

NIN....You VILL do it our VAY!! Chris

Constantin

Yes Chris, you are right.

Hence, my diagram at top shows the waterfeeder and the expansion tank at the bottom of the Vitola, rather than in the boiler-loop as is presently the case. This was one my original questions (see top parent post), though I suspect it is one of the less controversial ones.

Would you ask your installer to repipe according to manufacturers specs? They are enclosed below (so you can compare them to my drawing...)

Constantin

Latest Revision

Below is a revision to the above drawing. Note the additional valves and drains. I still have the optional B&G air sep on the suction side of the pumps because we have more straight accessible pipe there to squeeze it into. Whether we need it or not will be determined by the extent to which the Müpro clamps quiet the system down.

How strongly do the Viessmann luminaries feel about the expansion tank and water feeder location. Is the below strictly preferable to the two feeding into a B&G Airsep on the boiler supply leg of the 4-way valve?

J.C.A._3

O.K. Here goes,

I'm thinking there should be a pump on the system feed side of the boiler TO the 4-way just to make sure the volume of water is available to it.

On a minimum call, the extra will just bypass the 4-way and return to the boiler. On a call from all of the zones,there will be sufficient flow to not cause any "scavenging" and cavitation. Maybe I missed something, but I swear I read this in one of Dan's books.

I think I would go with the feed and expansion tank on the bottom because of the size,flow design and volume of the vessel. The flow pattern makes it purge through the "Christmas tree" tee/branch provided. The other purger you've installed won't hurt, but feeding into it with this particular boiler MAY not be the way to go. Chris

Ernie

JCA

What you described is in Dans book Hydronic Radiant Heating,page 175. Hope this helps.

J.C.A._3

Thanks Ernie!

I knew I saw it somewhere. Chris

Unknown

You're a good listener too?

I think the expansion tank and feed water inlet should go on the bottom of the Vitola as shown in their suggested piping schematic. The "big silver" air trap should be quite enough for even well beaund your motorized 4-way. "You VILL do it our VAY!!." It VILL VERK VELL!!

I don't much like HR's idea about adding the ball valves on both sides of the 4 way as a best option. It is a smart solution and although it's close enough to isolate the bottom of all your circs, and the internal checks (should) isolate the discharge sides. However, if a circulator flange seal needs to be changed out (they all do some day) I'd prefer to have the iso-flanges (less checks) instead and stick with the internal 15-58's checks. This will also isolate the IFC's should you decide to remove/play with them.

Your heating contractor may have one heck of a time changing out the existing strut setup to Mupro's Sonic clamp style. The Dammgulast™ sound insulation takes up quite a bit more room under the tubing and you may have dimensional differences in the MPC support channels as compared to the typical Uni-strut™ I mostly find around here.

RE: noise. Are the supply & return lines to your remote manifolds run in copper? I haven't heard your system but, I don't see how this could be air. Seems more likely to be velocity related IMO. Another thing that may (or may not) be the problem; You might want to inquire of the contractor if he reamed all his copper & steel pipe work? Hard drawn tubing that is cut with tubing cutters and not reamed within a distribution system can (sometimes) experience what you refer to as "white noise" due to turbulence created by un-reamed tubing. I always try to remember and ream all my pipes but, this is quite an unpopular practice among lots of plumbers & fitters because it takes much more time. Typically this is not a problem but when someone like you can audibly hear and be disturbed by turbulence, I'd be looking there first.


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Dave Stroman

I assume the there is a pump in the boiler that is not shown in your drawing. With the 4way valve in the postion you have drawn, the boiler pump flow is added to the zone pumps flow. If all the zone pumps are calling, the water can be really zinging through the 4way. And the flow can vary through the boiler depending on how many zones are calling and the postion of the 4way. Is there not a minimum flow through the boiler? In this drawing, the flow through the boiler does not change ever. And the zone pumps and 4way can operate without any influnce from the boiler pump.

Dave in Denver

Constantin

No pump... and further research...

Gentlemen,

Many thanks for your thoughts, insights, and drawings regarding the 4-loop on this boiler. There is no pump built into the Vitola, it's just a very large-mass (31 gallons!), low temp boiler. Here is where I think some of the confusion with Dans excellent Radiant manual is concerned:

Dan wrote the manual as a general guide without stopping to recount all the exceptions to the rules that one can encounter in the field. In our case, the Vitola doesn't care about low temperature water returning to the boiler as the design is condensation and thermally shock-proof. Dan's two caveats on pages 176 and 177 specifically only mention condensation and shock as a reason for a pri-sec setup with 4-way valves.

His proper concern is that a 4-way motorized valve that doesn't have pumps on both sides can lead to lead to the valve acting like a 3-way valve rather than a 4-way valve in terms of boiler return water temperatures. On a regular boiler, this is very bad, on our Vitola it should be great since it'll boost the AFUE by about 3% (IIRC, right, Scott?).

So, no, there isn't minimum flow through the boiler... I presume this has to do with the fact that the boiler has a ton of mass and that any of the zone pumps can push something on the order of 4GPM through the boiler if the 4-way opens all the way to one side. Considering that the current system is performing admirably despite the lack of some windows speaks for itself.

As I stated above, my main issue with the system as installed vs. as I would like it to be has to do with noise and maintainability. The former is likely to subside somewhat as not all the zones will be calling for heat 100% of the time (we're currently running all pumps on Low speed continuously) and the Müpro clamps take their toll on pipe vibration. The airsep on the pump side of the 4-way would simply become additional insurance that the system has minimal of air in it.

Along the way of researching pump roar, I became aware of how the fill system on the boiler deviated from the Viessmann instructions. I think I will ask for a re-pipe when they have to open the system up to repair a leaking joint.

Constantin

Oh dear...

Well, at least I can hope that the pipes were reamed. Plus, I doubt its flow velocity, simply because (what I think are) 1" pipes should be perfectly capable of handling 3.6GPM of fluid flow... see my HDS print-out below.

For every manifold I have up to 7 circuits, about 140' ea, of 3/8"ID tubing with 100' of 1" Cu Pipe going to and from with a couple of bends. If I'm using HDS correctly, 3.6GPM through 1" Cu is 1.3ft/s... while it's 2.3 ft/s though 3/4" pipe.. But I could be wrong.

One thing in favor of my heating specialist is that his supply manifold is a good 6" off the backing board. He should have no trouble installing just about anything to hold those pipes. In fact, I'm willing to bet that once we restrain the manifold properly that the noise issue will be reduced significantly. Right now, I can feel the primary and secondary manifolds vibrate...

I wondered why he chose to use Cu to run the secondary piping since PEX is cheaper and just as good for the job. I guess he's wedded to his torch... If improper or no reaming is the issue, then it's going to become hairy to resolve. Either I learn to live with the noise or we'll have to figure out some sort of agreement re: the substantial cost of opening walls and fixing bad pipes.

Jed_2

Well Constantin

Hi. Sorry to here about the anomaly in your system; you have put so much time and enrgy into it. But, I don't think the HDS parallel system module applies in your case ( I know you understand the difference between a single pumped system vs. a multi-pumped parallel system). Flow rate/velocity capacity with reference to line size may apply, but differential pressure definitely does not. Are all the circs the same size? I might have missed it if you gave their sizes, but; in a parallel pumped system, you could be have some wild differential pressures with different sizes of circs, or different circuit resistance and same size circs. Just a thought.

Jed

Constantin

Interesting Points...

The circulators are all the same, Grundfos 15-58FC's, currently all running on a low-speed setting.

The manifolds that are attached to them each have between 6-7x 140' long, 3/8"ID PEX tube runs attached to them. The only manifold that differs from this is the basement manifold, which features 6x 300' long ½" ID PEX loops in cement.

Thus, for the most part, the individual circuits not only have pretty much the same head pressure, but they have matched pumps also. No zone valves, bypasses, etc. in this system.

The picture above was just a reference re: how much water that pump should be capable of pumping. Naturally, when all pumps are running at the same time, there are going to be some pretty high velocities going through the 2" primary loop.

If I were to multiply the 3.6 GPM by 5 circuits, and add 4.5 GPM for the basement circuit, that would turn into something like 22.5GPM, well below the "trouble" speed for the 2" manifold, it would appear.

Lastly, two of the 6 mainfold loops in the basement are likely to be shut off permanently as the utility room and one storage room are unlikely to ever need heat. That brings the head pressure on the basement loop up to about the same pressure (+/- ½psi) as the other manifolds throughout the house.

Larry Weingarten

a silly thought

It might not be productive, but have you considered using an ultrasonic detector with a tube on the receiver to try to pinpoint the source of the noise? Your ears get all the noise and what you want is just the source. An ultrasonic detector can be adjusted to get only the highest volume... It may work or it may be a waste of a few minutes time.

Yours, Larry

hr

He's got too many circs

plain and simple Noise happens. The more noisemakers you install the more potential for a noisy system.

Zone valves rule

hot rod

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Paul Pollets

I agree...

I'd be piping with one pump and zone valves, with a PBD to protect the pump.

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Leo G_99

same here

I'm a definite ZV kinda guy.

Leo G