Banging Pipes in multiple zones

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Old 02-25-13, 05:19 AM
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Banging Pipes in multiple zones

Slant Fin, gas hot water with 12 zones. Boiler temp set to 180F and running pressure is 18-20. Two air scoops, one for radiant and one for the other zones. When zone opens, there is no noise. If boiler comes on, you hear load banging. None of the baseboard has ability to bleed. As winter started, it was silent but now, it wakes you up from the loud banging. Thoughts?
 
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Old 02-25-13, 05:47 AM
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Are the caps open on the air vents? Have you checked your expansion tank' pressure?
There's a sticky on top with instructions on how the correctly verify the charge.
 
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Old 02-25-13, 05:52 AM
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If you are referring to the air scoops, there are no caps. These are large and when installed had no caps. There is an Amtrol float valve on the boiler which has a twist cap that is open. The expansion tank is also Amtrol and hangs below the return pipe about 2 feet from the boiler. There is no obvious way to check pressure. Silly, but when I tap on it, it does sound empty or at least it has an echo.
 

Last edited by sdente; 02-25-13 at 05:55 AM. Reason: more info
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Old 02-25-13, 05:54 AM
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If boiler comes on, you hear load banging.
Have you gone to the boiler when it is banging to try and localize the noise? To see exactly where the banging is coming from?

Please describe the banging.

Is it a loud metallic hammering noise, repeating rhythmically and continuously?

What type of circulator pump do you have on the system? Is it a big electric motor connected to the pump part?

Like this? (could be another color, but in general...)


image courtesy pexsupply.com

None of the baseboard has ability to bleed.
What do you mean? That you've tried and nothing comes out? or that there are simply no bleeders on the system?
 
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Old 02-25-13, 06:00 AM
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The banging is up in the house, not from the boiler or recirc pumps. It sounds like air in the pipes and you get a loud gurgling and the same banging I used to hear when I had a old steam heat in another home. It comes from various places because there are so many zones. But, it definitely is not from the boiler or pumps.

There is no place to bleed the system. When a zone valve was changed in the past, each zone (12) has purged with a hose to clear the air. Plumbers felt with two air scoops, any air would be purged.
 
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Old 02-25-13, 06:03 AM
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Spirovent looks like this one
 
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Old 02-25-13, 07:30 AM
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As always, one of my first suspicions is the pressure gauge... it sounds as if this is a relatively new installation, so perhaps the gauge is OK, but the OEM gauges really are total crap these days. It wouldn't hurt to verify it. (see sticky post at top of forum).

System has one pump and 12 zone valves?

Is it set up such that the pump is pumping AWAY from the expansion tank connection point?

This is important in that the pump pressure ADDS to the pressure in the system and helps to keep the system air-free.
 
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Old 02-25-13, 07:41 AM
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Actually, house is 11 years old. Last winter we had someone fix the same banging. Auto water feeder valve was changed. New larger expansion tank replaced smaller one. Spirovent replaced a smaller in line vent. Pressure gauge was replaced. All was quiet. Then, this winter, back to the future.

There are 3 zones Radiant with one recirc pump. Those zones are quiet and have it's own Spirovent. The remaining 9 zones are on another recirc pump and yes the expansion tank is on the wrong side. Original plumber is dead so it's hard to get an explanation. New plumber said there is no room to put the expansion tank where it belongs. But, he felt by replacing the smaller in line vent with the Spirovent, it should be OK. It was last year. Now, the noise is back louder than ever. Even the dog cant sleep.
 
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Old 02-25-13, 09:27 AM
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Even the dog cant sleep.
No escape from the music in the whole damn street!

What was the gauge replaced with? Another POS one? or a quality one?

What was the logic behind installing a larger expansion tank, do you recall?

Then, there's always the possibility of a slow leak somewhere in the system that is allowing water to feed continuously... and adding the air dissolved in that water...

You are saying that it was all good for 9 years? Then last year this started? Gotta be something obvious that's being overlooked...
 

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Old 02-25-13, 11:10 AM
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First, you guessed it. Gauge replaced with a brand new POS.

For 9 years, it gurgled like a tea pot. Annoying but tolerable. I had lots of opinions and plumbers tried different solutions but none worked. Then, I spoke to Slant Fin myself and he said the pressure gauge is probably shot (it was) and water feeder probably was therefore not putting in enough water - thus the water was boiling in the pipes. So last year, I got a plumber you did all of what I have already written. Quiet last year - noisy as a brass band now.

Larger expansion tank was suggested because, I was told, the existing one was too small for the size of my system.

No apparent leaks - no water stains, but who knows.
 
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Old 04-08-13, 09:01 AM
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NJ Trooper said find something obvious

Pipes are still banging. I looked for something obvious that changed. There was a zone valve replaced last year so please look at the 2 pictures. One shows the complete line of 8 zones controlled by a Taco 007 pump. The lower pipe is the return line with the feed line just above it. At the left, which is also the end of the line, there is a ball valve. The second picture shows a close up. The valve was closed. Is it supposed to be? If open, it seems that the feed water coming out of the boiler would just quickly loop back. If closed, water couldn't loop back unless it traveled in an open zone and back. Thanks in advance.
 
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Old 04-08-13, 04:23 PM
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The valve was closed. Is it supposed to be? If open, it seems that the feed water coming out of the boiler would just quickly loop back
Hard to say what the intent of the original installer was.

The placing of that valve makes it what we call a 'system bypass' valve.

Yes, if the valve is open, boiler water will in fact circulate back to the boiler. Even with it open you may get enough flow in the zones but with that many zones, perhaps not.

It may have been added as a 'service valve' for the purpose of flushing or re-filling when that was needed.

You won't hurt anything by opening it, so give it a try.

What I would recommend though is consider having a 'differential pressure bypass valve' installed at the bottom of that loop. Although a 007 pump doesn't usually need this type of valve, it may in fact stop the banging.

I'm re-reading the thread to refresh my memory...
 
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Old 04-08-13, 04:29 PM
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OK, I just re-scanned...

I'm still not clear on whether this is a 'water hammer' noise that occurs when one of the zone valves closes, or if this is either expansion noise in the piping, or air bubbles hammering through the system.

If it is possible it would help us to understand the 'big picture'. Can you draw a diagram which shows how the system is laid out and the location of pumps, expansion tank, air scoops, etc?
 
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Old 04-12-13, 02:09 PM
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As requested, I have attached pictures that show the complete system, including the hot water maker that runs off the boiler. Sorry that I could not get the orientation of the pictures right side up.

The noise happens only when the boiler comes on. So, if a zone valve opens, the Taco pumps with no noise anyplace. If the zone opens but needs the boiler to come on, within 15 seconds there is banging. As soon as the boiler shuts down, the noise stops even if the zone is still open.

I spoke to SlantFin and they now think it's scaling. He wants me to disconnect the Taco and start the boiler. If there is noise, there is scaling. Does that make any sense? They still can't explain why there is no noise from the boiler if the problem is in the boiler. All noise is upstairs - you hear nothing standing next to the boiler. This will be a case study.
 
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Old 04-12-13, 02:42 PM
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Good Garsh that is one huge boiler! Let's see, 150K BTUH DOE ... that would heat about 6000 sq ft of home, or, mine and 2 of my neighbors.

The noise happens only when the boiler comes on. So, if a zone valve opens, the Taco pumps with no noise anyplace. If the zone opens but needs the boiler to come on, within 15 seconds there is banging. As soon as the boiler shuts down, the noise stops even if the zone is still open.

I spoke to SlantFin and they now think it's scaling

Does that make any sense?
Yes, it does make sense, and is sorta what I was driving at in my last post... that what first seemed as though you had a water hammer issue now sounds more like what many people call 'kettling'.

Like when ya got a big kettle of tomato gravy simmering on the stove... BLUP! BLUP! etc... but perhaps faster or slower.

I'm not really 'down' with disconnecting the pump as a means of diagnosis though, because this can actually CAUSE kettling in some cases.

I'm wondering if this is a LACK OF FLOW in the boiler? Maybe, perhaps, there is a pump not pumping what it should be?

These sounds can usually be heard at the boiler too... and I don't understand that part either. But what can happen is that the water 'telegraphs' the sound to distant parts of the system.

Have you looked at the pressure gauge when the noise is occuring? Does it jump around?

Let me ask this...

If you were to turn all the t'stats all the way down and turn the control on your Amtrol up (or use a bunch of hot water to cause the boiler to come on to reheat the tank) do you hear any sounds then?


There are chemicals that can be added to the boiler water to clean up the scaling.

Residential Hydronic Radiant | Rhomar Water Management, Inc.

The 9100 formula has recently been used by some posters and they've reported good results.
 
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Old 04-12-13, 02:45 PM
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One more very remote possibility I'd like to entertain...

Name:  sdente pump.jpg
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At any time previous to the onset of the noises was there any work done which might have had a workman remove and reinstall the boiler pump?

I know this might seem unlikely, but if the boiler pump is installed backward (and it's EASY to do so!) you will get all sorts of unpredictable behavior from your boiler.

I'm going to try and piece the pics together in my mind so I can get a mental picture of the system piping, but if it's even remotely possible for you to draw even a crude diagram and post that it would help us to understand how your system is laid out.
 
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Old 04-15-13, 05:45 AM
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Size matters

Yes, the house is big so it's not unusual for at least one zone to be open, causing noise to be very regular.

I know about gravy and it's not that kettling sound. It is banging that is very much like the banging in a steam heat house.

One plumber thought the black Taco (one that control 8 zones) might be failing and offered to replace it and if the noise still occurred, he would put back the old one. But, since when the green Taco (controls 3 radiant zones) comes on, the same banging noise happens, he thought it unlikely that both Tacos are bad at the same time. Never heard from this plumber again.

As I said, the banging is upstairs but you can hear it standing next to the boiler, but it's not coming from the boiler. If you hold the return line, you can feel the vibration and see the gauge jump on the boiler when it bangs.

If the Amtrol comes on and is the only zone open (remember it's 3 feet from the boiler), you hear banging upstairs and not at the boiler. Go figure. There is no water recirculating upstairs, but that's where you hear it.

I have attached a sketch (best I could do) as a Word document. If you can't open, let me know. Also, I answered your email you sent. Thanks in advance for sticking with this.
 
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Old 04-15-13, 06:11 AM
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Pump Direction

And, yes the pump is going in the correct direction. There is an arrow showing direction on the pump and it's going away from the boiler.
 
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Old 04-15-13, 11:00 AM
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sdente,

I have a similar problem and i believe it's scaling that causes "kettling". i hear loud banging on 2 floor (boiler is in the basement) transmitted by the pipes that sounds like tiny explosions. it's actually quieter next to the boiler and it sounds a lot like a kettle on the stove when it's about to boil.

i can see a pressure gauge needle jump a bit with each of this bursts, which makes me believe it's kettling. i have Hyrdo-Solv 9100 cleaner in my system for a month now and I will be flushing it out when heating season is over.

can you check you pressure gauge to see if your jump as well?
 
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Old 04-15-13, 12:12 PM
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Scaling

Thanks for the comment. If you are holding the return line, as you feel the vibration, the pressure needle jumps on the boiler.

I know this is silly, but how do you add the Hydro Solv to the boiler?
 
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Old 04-15-13, 04:16 PM
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i have an answer for you right here
 
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Old 07-12-13, 02:50 PM
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I still have the problem. One zone (hot water) is still banging.
Steve, were you able to get the HydroSolv into the system?

The fact that you can 'feel' vibration and the needle jumps tells me that this is 'probably' a kettling issue, but without being there to see/hear, can't be 100% certain.

You are saying you only hear one zone banging?

(are you actually heating now? or is this one zone the one for the Amtrol?)
 
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Old 07-15-13, 06:57 AM
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No, I didn't attempt adding HydroSolv. The method provided, although I appreciate the suggestion, is well beyond my talent.

A while ago, you had requested a sketch - did you see that?

The one zone is the Amtrol; no other zone is heating.

With only one zone working, the noise is much less and obviously less frequent. It is also not nearly as loud as it was in the winter. You mention "kettling" which is different from "scaling", right? If you re-read back, I had a similar banging and kettling (bubbly noise in the pipes?) before but not nearly as loud as this time. Back then, they replaced the pressure valve that regulated the water going into the system to maintain ~18 pounds pressure. They also replaced the crappy pressure gauge on the Slatfin. All was quiet for 2 years. Can the valve be shot again so soon?
 
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Old 07-15-13, 03:26 PM
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Yep, I saw the diagram and don't see any 'problems' with it.

You mention "kettling" which is different from "scaling", right?
Well, yeah, sorta... kettling can be CAUSED by scaling, and also sediment laying in the bottom of the boiler.

What happens is that with the sediment and scale 'insulating' the cast iron from the water, you get localized overheating of the cast iron and a bubble will form, and 'pop'. This is what you feel in the pipe and see on the gauge.

There's other things that can cause this... really really slow flow can do it... LOW PRESSURE can make the problem worse because it lowers the boiling temperature of the water.

I'm gonna take a WAG here and say that by raising the pressure, the guys who were working on it simply put a 'band-aid' on it. I don't think they 'fixed' it.

IF and ONLY IF it was the same problem at the time.

Maybe they also flushed the system and removed some of the sediment?

Without being there to hear and see, we don't even know for certain that it is in fact kettling!
 
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Old 07-17-13, 04:21 PM
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They didn't flush the system. They drained the zones and the level in the boiler so they could open the system and add the bigger expansion tank. Is there a way to increase the pressure in the system and see if that helps? Any ideas besides ear plugs? Know anyone? Do you make house calls? The only plumbers that have come know how to replace the boiler but either are unwilling or unable to diagnose nor fix the problem.
 
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Old 07-18-13, 03:01 PM
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Is there a way to increase the pressure in the system and see if that helps?
Yes, there is. Whether you want to do it or not is another matter. If you are already at 18 PSI cold, I would not recommend going any higher, although, with that monster expansion tank you MIGHT be able to without opening the relief valve... as long as the expansion tank is properly charged.

Do you make house calls?
Wish I could... and even if I could, my price would be outrageous!

Good help is hard to find!

I really think you should try the HydroSolv. Diver's plan worked for his situation, and it's really not that hard, but if you can 'valve off' the boiler to prevent having to drain the entire system, you should be able to introduce the chemicals where the air vent is on top of the boiler. ( I need to download and flip all your pics upright to view and be sure...)

The process would be to valve off the boiler, hook a hose to the drain valve, drain a gallon or two from the boiler, remove the air vent and bushing, put funnel into pipe and slowly pour chemical in. Replace air vent and bushing, re-pressurize the system, open all valves, and run...
 
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Old 07-18-13, 03:17 PM
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Here's one of your pics flipped and edited:



If you wanted to go the extra step, you could add another tee to that 'stack', 90 elbow up from the side port and reinstall the bushing and air vent there.

Install a pipe plug in the top of the tee. Then, for future use (you will want to add the conditioner after you flush the cleaner out) just remove the plug... a little easier perhaps.
 
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