Can you "hear" your water flowing into storage?..

[Pat53]

Just curious, for those who have storage, do you hear your water flowing into the tank? Mine makes a steady sort of hissing sound as it flows into the tank. I have a diffuser pipe inside the tank, and I'm wondering if that is why I hear the hissing sound. I would think without that pipe you shouldn't really hear any sound from the flow?

thx, Pat

 

[jebatty]

The only sound I hear is from the circulator. Might you have air in your lines or tank? I think that could result in a sound of running water. If the tank is pressurized, there really is very little if anything to hear.

 

[Pat53]

The only sound I hear is from the circulator. Might you have air in your lines or tank? I think that could result in a sound of running water. If the tank is pressurized, there really is very little if anything to hear.

Jeb, the only sound I hear is from the 500 gallon tank in my garage. As you may have read, I am having a problem with "kettling" in my HX in the boiler and I'm trying to figure out what the problem is. I made a diffuser pipe for the inlet into my storage tank, and I'm wondering if it is causing too much back pressure and a lack of flow thru my HX. As I mentioned the other day, when I get a hot fire going the HX will start banging/gurgling at about 375F stack temp when I have the circulator on high speed. ironically, when I slow the circulator down to low speed the banging doesn't start until about 420F stack temp. I'm wondering if I'm getting too much head pressure and actually slowing the flow down on a higher circulator speed setting? I read another thread that someone posted about getting higher heat transfer to storage with a lower circulator speed as opposed to a higher speed setting.

The sound in the storage tank is no doubt the water flowing out of the diffuser pipe, and I'm thinking if the flow wasn't restricted, that I probably shouldn't be hearing it? I can put a different pipe on that will just send the supply water directly into the top of the tank, and I'm thinking of trying that and see what happens. My circulator is plenty big to move the water thru the HX, but something seems to be preventing it from doing so. My piping is all 1.25" black and only a short 40' run with only a few fittings.

Pat

 

[in hot water]

It may be the sound of excessive velocity. What pump are you running? Pipe size? Often times folks use a high head circ in an attempt to get more GPM through a boiler or tank. If the boiler has a big wide open flow, as most wood boilers do, you want a high flow (gpm) low head circ to avoid those velocity noises.

A good rule of thumb is 2- 4 FPS (feet per second) in hydronic piping. Above that you may get noise and un-wanted wear in the pie and fittings.

Air is another possibility, but it is typically more of a gurgle or slow stream noise. A tough call to troubleshoot via the www.

hr

 

[Pat53]

It may be the sound of excessive velocity. What pump are you running? Pipe size? Often times folks use a high head circ in an attempt to get more GPM through a boiler or tank. If the boiler has a big wide open flow, as most wood boilers do, you want a high flow (gpm) low head circ to avoid those velocity noises.

A good rule of thumb is 2- 4 FPS (feet per second) in hydronic piping. Above that you may get noise and un-wanted wear in the pie and fittings.

Air is another possibility, but it is typically more of a gurgle or slow stream noise. A tough call to troubleshoot via the www.

hr

hr, I don't have any other noise coming from any of the lines to or from the storage and boiler. Just the noise from the diffuser. No gurgling or trickling noises from any piping or the storage tank. My pump is a Grundfos 26-99.

 

[stee6043]

I have zero noise from the movement of water in my system. The only things I can hear are the circs running (very quitely) and the draft fan.

 

[Singed Eyebrows]

The Laddomat pumped flow is quiet, even on high speed. This is low flow & designed for tank charging. I'm running 1 1/2" pipe into the top of a vertical tank, no diffuser, Randy

 

[Pat53]

I actually called Fred Seton and talked to him about it, and he said that the only time he has ever had a "kettling" situation in any boiler, it was the result of too slow of flow thru the system. He also thinks that the diffuser pipe is probably the problem. I can change the supply line into the storage tank to go directly into the top of the tank, but it is going to mess up the stratification, but I can fix that next year with a deflector plate welded inside the port. For now, i would just like to be able to burn full out without the HX gulgling and banging. Better get the pipe wrenches out and redirect the supply and see what happens. LOL

Pat

 

[2.beans]

id move the pipe and see if the noise goes away. it might not bother the stratification at all.

 

[in hot water]

A hissing sound is generally a flow reduction noise, like a partially opened valve or other restriction. Kink over a flowing garden hose to get an idea of this sound. It's actually a form of cavitation. This could be caused by the restriction on your dip tube.

Banging, thumping, clanging is often a sign of in-adequate flow through the boiler. A boiler that is scaled up on the inside can make a similar noise, but more like a tea pot perculation sound or sometimes a howl.

Make sure your circ is actually moving fluid. It could have a broken shaft or debris in the vanes of the impeller presenting slow, or no-flow. It could also be air locked if it is at a high point. Crack open the flange bolts to release any air in the volute, carefully if it is hot.

The system should be noise free when you get it all dialed in.

hr

 

[Pat53]

A hissing sound is generally a flow reduction noise, like a partially opened valve or other restriction. Kink over a flowing garden hose to get an idea of this sound. It's actually a form of cavitation. This could be caused by the restriction on your dip tube.

Banging, thumping, clanging is often a sign of in-adequate flow through the boiler. A boiler that is scaled up on the inside can make a similar noise, but more like a tea pot perculation sound or sometimes a howl.

Make sure your circ is actually moving fluid. It could have a broken shaft or debris in the vanes of the impeller presenting slow, or no-flow. It could also be air locked if it is at a high point. Crack open the flange bolts to release any air in the volute, carefully if it is hot.

The system should be noise free when you get it all dialed in.

hr

Hr, I am topping off the storage tank right now. I was able to dislodge the diffuser pipe and remove it from the tank. So now I have unrestricted flow from the boiler to the tank. The 1 1/4" pipe flows into a 2" port on the tank, so I'm hoping it will keep the tank somewhat stratified, but I can correct that in the off season. I'm anxious to fire it up and see what happens.

I agree that the hissing noise was probably inadequate flow thru the diffuser pipe. everything looked good inside. The water was pretty clear and the inside of the pipe and fittings had no rust on them at all.

The circulator is working well. I checked it after disconnecting the supply to the tank, and it was pumping water like crazy out of the system. The pump is at a relatively low point in the system and runs very quiet, and I'm confident that air in the system is not an issue. I'll report back this afternoon.... keeping my fingers crossed here ! LOL

Pat

 

[Pat53]

Well, sadly, the removal of the diffuser pipe has failed to stop the kettling. However, it takes about 425F stack temp now before it starts thumping, whereas before it was about 370F.

And once again, for whatever reason, if I set the circulator on high speed the banging starts sooner than if I run the circulator on slow speed. If I drop the circulator speed to low, the banging stops until the stack temps get up to about 440F. The faster I move the water thru the HX the more it bangs at a given stack temp. Just the opposite of what you would think....strange.

I guess the only other option now is to take out the HX and see if something is plugged? I can think of no other reason for this to be happening. But I'm not doing that now, it will have to stay like it is till spring.

And I still hear the "hissing" sound of the water entering the storage tank, but not quite as loud as before.

If anyone has any other opinions on what could be causing the kettling, I'm all ears ! LOL

 

[RobC]

With the slowing down of circulator giving you better performance that would point toward water needing longer time in HX to adsorb BTU's.
If that is the case would you possibly need a bigger HX ?
Besides the stack temp, do you have a supply out temp ? Is that temp going up as you slow circulator ?

 

[Singed Eyebrows]

Well, sadly, the removal of the diffuser pipe has failed to stop the kettling. However, it takes about 425F stack temp now before it starts thumping, whereas before it was about 370F.

And once again, for whatever reason, if I set the circulator on high speed the banging starts sooner than if I run the circulator on slow speed. If I drop the circulator speed to low, the banging stops until the stack temps get up to about 440F. The faster I move the water thru the HX the more it bangs at a given stack temp. Just the opposite of what you would think....strange.

I guess the only other option now is to take out the HX and see if something is plugged? I can think of no other reason for this to be happening. But I'm not doing that now, it will have to stay like it is till spring.

And I still hear the "hissing" sound of the water entering the storage tank, but not quite as loud as before.

If anyone has any other opinions on what could be causing the kettling, I'm all ears ! LOL

I'm wondering if your water tube exchanger is coated with mineral on the inside. The instant gas hot water heaters are known for this. They were tested by someone & found to only have the very high efficiency for a short time(till the exchanger got coated). Only other thing might be an imbalance in the exchanger manifolds although this is not too likely. This would cause poor flow to some tubes & kettleing, Randy

 

[Singed Eyebrows]

Can you get a cheap IR gun on the exchanger when it is more or less idle? This might pinpoint problems in individual tubes etc if that is the fault. Harbor Freight has some that are reasonable in price, Randy/ Tubes that are problematic would probably read a higher temperature.

 

[Pat53]

With the slowing down of circulator giving you better performance that would point toward water needing longer time in HX to adsorb BTU's.
If that is the case would you possibly need a bigger HX ?
Besides the stack temp, do you have a supply out temp ? Is that temp going up as you slow circulator ?

Hi Rob, I'm not sure I would call slowing the circulator down better performance. And yes, when I slow the circulator down, the outlet temp rises faster, when I speed up the circulator the outlet temp will fall, indicating that the flow is definitely speeding up thru the HX on the higher pump speed setting, yet the HX will do more banging on the higher speed and higher flow rate. That is whats so strange about this. If the banging were being caused by too slow of flow, why would a slower flow rate result in less noise? Weird.

At about 400F stack temp I'm getting about a 25-30 degree delta T accross the HX when the pump is on high, and that seems too high to me, especially with a Grundfos 26-99.

 

[Pat53]

Well, sadly, the removal of the diffuser pipe has failed to stop the kettling. However, it takes about 425F stack temp now before it starts thumping, whereas before it was about 370F.

And once again, for whatever reason, if I set the circulator on high speed the banging starts sooner than if I run the circulator on slow speed. If I drop the circulator speed to low, the banging stops until the stack temps get up to about 440F. The faster I move the water thru the HX the more it bangs at a given stack temp. Just the opposite of what you would think....strange.

I guess the only other option now is to take out the HX and see if something is plugged? I can think of no other reason for this to be happening. But I'm not doing that now, it will have to stay like it is till spring.

And I still hear the "hissing" sound of the water entering the storage tank, but not quite as loud as before.

If anyone has any other opinions on what could be causing the kettling, I'm all ears ! LOL

I'm wondering if your water tube exchanger is coated with mineral on the inside. The instant gas hot water heaters are known for this. They were tested by someone & found to only have the very high efficiency for a short time(till the exchanger got coated). Only other thing might be an imbalance in the exchanger manifolds although this is not too likely. This would cause poor flow to some tubes & kettleing, Randy

Well, at this point I have no idea what the problem might be. I can't think of anything that could be "coating" the HX. My propane boiler in the house works fine.

I'm not sure if it would be significant or not, but last spring I emptied the HX to change out some plumbing and I know that the HX had water left in it on the bottom of the header manifolds, because the water tubes are located in the center of the manifold and would not have drained all the water out of that header. The gulgling/kettling noise seems to be coming from the header manifold directly below the outlet pipe. I'm wondering if there is some kind of rust build-up there that is causing the problem ? But I just can't see how that could be causing the problem.

The other thing that I've noticed is that the noise starts whenever the flames from the wood are high and really hitting the HX. After the flames die down, even with a 400+F stack temp, that banging stops.

I do have an IR heat gun and I will check the tubes in the morning during an idle period just for the heck of it, but once again you would think that if one of the tubes was plugged, or partially plugged, that a slower circulator speed would cause the problem to get worse, not better. This is very frustrating to say the least !

Pat

 

[RobC]

If you run a circulator at to high a speed. IE: Water moving at a high a rate, feet per second you will not be as efficient at removing heat from HX as you would with a lower feet per second. That is why you get the opposite effect than one might think with circulator setting. Just one possibility.

 

[Piker]

Do you have several tubes in the boiler? IF they are piped in parallel but have different flow rates through them because of different lengths, friction loss, etc... this might be causing the problem? The small thermo control units that we carry with the water heating tubes inside the firebox have to have the tubes piped in series in order to keep them from banging and knocking.

Just a thought... not all that experienced with this type of boiler. Will be interested to see how this pans out...

cheers

 

[Pat53]

Do you have several tubes in the boiler? IF they are piped in parallel but have different flow rates through them because of different lengths, friction loss, etc... this might be causing the problem? The small thermo control units that we carry with the water heating tubes inside the firebox have to have the tubes piped in series in order to keep them from banging and knocking.

Just a thought... not all that experienced with this type of boiler. Will be interested to see how this pans out...

cheers

The Seton 130 has a 34" 4" X 4" header on the inlet and outlet of the HX with 29 water tubes inbetween. They are all 3/4" and are all about the same length. the inner row of tubes is just slightly shorter than the outer tubes.

Last year, i had no storage and the system worked fine, no noise at all, even with 500F stack temps and a firebox full of red oak splits that burn HOT. The burn times were obviously shorter, but that thing would really rip for about 15-20 minutes before going into idle, and never once had any issues with kettling. There are sveral guys who post here who have Setons or GW's and only 1 other guy has a kettling problem that I know of. I am actually thinking of trying a smaller circulator on it just for the heck of it and see what happens ?

Pat

 

[Pat53]

If you run a circulator at to high a speed. IE: Water moving at a high a rate, feet per second you will not be as efficient at removing heat from HX as you would with a lower feet per second. That is why you get the opposite effect than one might think with circulator setting. Just one possibility.

Yeah, I understand that part, but what I don't understand is how that would cause the kettling in the HX?

Pat

 

[Singed Eyebrows]

If you run a circulator at to high a speed. IE: Water moving at a high a rate, feet per second you will not be as efficient at removing heat from HX as you would with a lower feet per second. That is why you get the opposite effect than one might think with circulator setting. Just one possibility.

Yeah, I understand that part, but what I don't understand is how that would cause the kettling in the HX?

Pat

I think you got some hot tubes in the exchanger & we''ll see as you check this. Your exchanger can coat on the inside from lime calcium etc in the water & a water tube boiler is going to be much more susceptible to this. Is your inlet water going into one side of the lower header? If so, having dual inlets(each side) would probably solve the whole mess. Yes, maybe it shouldn't need this, it shouldn't kettle either, Randy

 

[Pat53]

Randy, the inlet and outlet are both 1.25" pipe and they are right in the center of the headers. I definitely agree that it shouldn't be kettling, but if there is a flow problem in one or more of the tubes, why does it get worse with a higher flow rate? I can't think of any reason it would do that with more flow.

As far as some kind of deposit in the HX, I really don't know. My water is not really hard and I've never had any other problems with the propane boiler that has been in the system for 11 years.

Pat

 

[in hot water]

You might try a dose of hydronic cleaner. Copper tube boilers are especially prone to noise when the tubes got a small layer of deposit. I have seen, or herd, it in cast iron block boilers also. Generally this happened when the boilers kept taking on make up water, from a small leak in the radiant tubes.

This company www.chemicalspec.com sells some excellent cleaners and chelates for scale problems. It might be worth a try before you start disassembling or repiping. If the problem started without any other changes to the system it could be a scaling issue.

hr

 

[Pat53]

You might try a dose of hydronic cleaner. Copper tube boilers are especially prone to noise when the tubes got a small layer of deposit. I have seen, or herd, it in cast iron block boilers also. Generally this happened when the boilers kept taking on make up water, from a small leak in the radiant tubes.

This company www.chemicalspec.com sells some excellent cleaners and chelates for scale problems. It might be worth a try before you start disassembling or repiping. If the problem started without any other changes to the system it could be a scaling issue.

hr

At this point I am willing to try just about anything LOL . This is not a copper tube unit tho, the HX is all black iron.

thx, Pat