Giannoni heat exchanger

Derheatmeister

I am confused about the plate between the exchanger and also is this Mild steel in a corrosive environment?

Supply House Rick

modcon boiler

Looking for informed opinions. Unit is 3 years old.

troy_8

WoW

I've never seen one that abused. It looks like it was overfired.

tim smith

I would say combustion was way off on that unit, that's not

flue gas recirculation......

Mark Eatherton

The plate...

is the divider between the primary and secondary heat exchanger.

Looks like a natural gas appliance that had LP applied to it, bit you can't use that in court :-)

Did the vent pipe melt off? If it did, you had "The Perfect Storm" of redundant control failures. They usually cover it.

ME

Unknown

Due to the discolorazation

you have had flourinated hydrocarbons being brought in somehow with air for combustion along with a poor flame condition. Their also maybe some cross contamination. What is the venting setup on this unit? How do you get air for combustion and what is the equipment this is located in?

Unknown

I enjoy your opinion Tim,

"Due to the discolorazation you have had flourinated hydrocarbons being brought in somehow with air for combustion along with a poor flame condition"
But you can diagnose this from one picture?
Perhaps a gas-can was set-down by the intake, how would you know?

Dave

Perry_5

Thats one possibility.... I can think of others...

There are a number of chemicals that in trace amounts could affect the metal to the point that it would deteriorate like that. I find the cracks most intriguing myself.

I'd love to be able to see it up close and send it in for a metallurgical failure analysis....

Of course, it could just be an improper burner was installed (or a grossly misadjusted burner).

Perry

Supply House Rick

Thanks for your interest. Here are a few more pics. It's nat. gas and gets combustion air from the top of a ten storey bldg. No contaminants I'm aware of. Damage was behind ceramic divider plate insulation.

Perry_5

At least 1 design issue + Something else

Thanks Ken; those pictures put the whole thing in perspective.

I see at least one design issue, and then there is a degradation issue of the ceramic insulator plate, and possibly other issues.

If you look at the pictures you will see that the area with the worst damage on the lower left also corresponds with degraded and missing ceramic liner plate.

Also - if you look at the ceramic insulation plate picture on the upper right you will also notice that there is an uncovered gap associated with the location of the large crack in that area.

Concerning the cracks: Both the Lower left and upper right areas indicate a sizable crack that extends towards the center of the divider plate. Those two cracks are thermal fatigue cracks caused by the edges of the divider plate heating up in those areas and then cooling down while the rest of the plate is not subject to uniform heating and expansion/contraction.

At a minimum there is a poorly fitting insulation plate - and it was likely damaged on the lower left during installation. This speaks of a quality control issue (which may affect design, supplied parts, and installation).

I further question the design concept of just putting this divider plate between 2 rube sections without a thermal break. A far better design would have had a refractory plate extending the full diameter of this plate and extending between the tubes.

There is general heat discoloration (high temp oxidation) around much of the plate. It is likely that some trace elements in the Natural gas or inlet air may have aided in the high temp oxidation; however, I doubt that those trace elements were a significant reason for this failure. These trace elements are just there - and you have to prevent them from affecting the metal as part of the design.

The extensive degradation on the lower left may just be thermal fatigue related - it may be from trace element accelerated thermal corrosion - or a combination of the two.

Overall my conclusion is that the extent of the degradation is from a poorly fitting and damaged insulation plate.

The thermal fatigue cracking is from a design problem by not providing a full thermal break for the divider plate (i.e.; having an refractory plate that extends between the tubes along with the divider plate. I would expect that you will see similar thermal fatigue cracking even with better fitting refractory plates as the edges will always see higher temps than the center area of the plate.

AFDM (A few dollars more) would have eliminate the problem entirely, Better QA of the basic existing design would have prevented the apparent major degradation (but that cost $ too).

I suspect the same issues can occur on the back plates of the other HXs that this company makes if they are insulating the back plate the same way.

Perry

Unknown

Years of experience

in looking into thousands of combustion chambers (50 years in the gas business). A similar type situation I ran into caused by a deteriorization of roofing materials and the chemical being drawn into the air intake on a piece of equipment. On that job a relocation of the air intake solved the problem. I am sure compared to Perry my answer seems somewhat to the point but then I am only a lowly service technician/teacher so I bow to his much more knowlegeable answers.

I do agree that combustion reaction is part of the problem. It would help on many of these problems presented here on the wall to be able to see the actual job location. I am a very hands on type of technician.

Mark Eatherton

You may think you're not drawing contaminants in...

If the air intake pipe is anywhere near a plumbing vent stack, you are probably drawing residuals of clorox (chlorine) in to the combustion process, and it leaves a residue just like that.

In my experience, the "laundry stack" is typically fairly close to the mechanical room riser stack....

I think we need to pay more attention to these details, manufacturers....

Got pictures of the roof? As Dan says, the fix is NEVER in the same room as the problem.

ME

Supply House Rick

more pictures

Perry, here are a couple more pictures of the burner and divider plate. Note on the lower right in the small ellipse, the divider plate is overlapped. Also this is the first one I've seen of about 10 where there is what appears to be writing from a felt marker (outlined by the two large ellipses). Will get a shot of the roof and post it later to satisfy those concerned about the air intake. The next shot is higher definition so you should be able to blow it up for a good look. The last shot is of a boiler the same size in service since August 04 taken in Dec 08 when it was serviced. The ceramic disc is new and there does not appear to be any degradation of the SS divider plate. Unfortunately I did not take a pic of that.

As for the cracked and holed plate, the manufacturer claims this is not a warranty issue because it was caused by lack of servicing and I quote "This failure is a result of inadequate service of the heat exchanger; at least judging by the buildup. The excessive buildup in the chamber has resulted in high combustion chamber pressures and has thus resulted in flue gases being forced, at excessive flow rates, through the spaces between the tubes near the target wall"

After a bit of pressing, I got this reply "As described previously, this failure is clearly due to a lack of, or
inadequate, heat exchanger service (i.e., cleaning and inspection). This is evident from the pictures of the obvious excessive build-up. Regardless of how often or recent you have cleaned this unit, it is clear that it has not been often or recent enough, judging by the build-up currently present on and in-between the heat exchanger tubes."

After you digest all that I'll send more pictures.

Ken

Supply House Rick

Roof

Mark, here are pictures of the roof. The B vent next to the one with the white cone on top(condensing boiler) is for a standby gas fired hot water tank that only runs if the condensing boiler cannot keep up, for sure now with the boiler broken down. The large B vent is for a 2 million BTU boiler used for space heating. The plumbing vents you were concerned about are visible in the foreground to the right and left of the picture. I also looked over the side of the building just in case, nothing there. Ken

TimS

WOW NICE VIEW

the concentric vent had to been modified lengthened I believe thats not approved also venting TDL is probably way too long.

Perry_5

Typical

Ken:

I see no evidence that the writing caused a problem. There is no reason to think that it would as long as the Mfr uses the right markers and paint sticks (there is a well established market for non-problem trace element free markers and paint sticks for use on 300 series SS).

As far as the Mfr response.... Typical. While the boiler may not be sparkly clean - the failures evident has nothing to do with the problem they cite from the unclean boiler. If the failure was related to erosion of the tubes due to high velocity gas due to pluggage they would have something - but would not necessarily escape responsibility (see below).

The heat damage to the end plate is obvious due to the discoloration. The major cracking is also obvious - and proceeds in the direction you would expect from thermal fatigue related to edge heating. I also note that the 300 series of SS is well known for thermal fatigue cracking. I wish I could post a report I did at work on the thermal fatigue failure of a $1/2 Million HX set (and it will cost another Million or so for the labor to replace them) - and we have had a small production loss for the last 9 months while these HXs are out of service (in this case we have an backup system that is not as efficient).

I have seen similar Mfr responses as well related to home heating boilers. A couple of years ago had a series of pictures from a corroded AL HX. The Mfr replaced it as obviously a "casting flaw." I used to be the ISO 9000 QA manager for a foundry (between HX & power industry jobs). I could not see any evidence of a casting flaw in the detailed pictures - and I'd like to see them make that claim to a bunch of foundry people....

The problem you and others face is that to do a formal failure analysis and bring in people like me is in the range of $5000 - $10,000 (and could be more). It would likely be several times that if you went to trial.

The Mfr knows you can't do it (I note that I don't think the Mfrs are really doing proper failure analysis themselves either). When you move to larger industrial plants where failures can cost a company tens of thousands to millions of dollars in direct expenses and lost production we can afford to pay for analysis and experts like that. The Mfrs respond totally differently.

I also point out that a basic legal claim that can be made for a consumer product (like a home boiler) is that the item must be suitable for its intended function. If the Mfr recommends annual cleaning - and you do it; then the Mfr cannot claim that it failed because you did not clean it enough as long as you were using fuel within specifications of what the Mfr rated as suitable. So - even if the Mfrs explanation was correct and this HX did fail due to HX fouling - they would likely loose on the suitability for its intended function argument in court.

However, until there are a series of such failures - with such picture documentation - and someone can turn it into a class action lawsuit; I doubt that anyone will individually put up the $$$$$$$ to begin a lawsuit on suitability for its intended function (and related issues). Unless of course you and your client are looking for a fast way to go broke - with the hope that you can get class action status.

I actually think that one specific Mfr is very likely to be on the receiving end of such a class action lawsuit. Of course, I'm not sure that they will be around that much longer either as people stop using their high failure rate product while warranty claims keep coming in - leading to financial failure of the company (you cannot afford to support a high rate of warranty claims on declining sales). Thus, any such lawsuit may be pointless.


Perry

Derheatmeister

Acid?

Mark soo this looks like another Hydro chloric acid deterioration situation?

Is that a dryer vent stack next to the concentric. any "Commercial" or "community" Washer/Dryer setup in the Building ?

Perry_5

For those who suggest that this is a form of chemical attack...

Could it be fluorocarbons... Could it be hydrochloric acid attack... Could it be - Whatever.

All of those items can indeed attack the metals involved.

Please consider why it did not attack the tubes as well.

It seems to me - that anything that would have pitted, cracked, or dissolved the endplate would also have done the same to the tubes. They should have been leaking long ago.

I note that in my analysis above that I mention that something like this could be a contributor; but, that I did not consider it to be the main reason for the failure.

Perry

Mark Eatherton

It did degrade the exterior of the tubes...

In all the combustion chambers I've stared in to, only those exposed to chlorides looked oxidized like that. I've seen cast iron boiler dissolved from this same attack (no floor drain trap seal), I've watched water heaters fail ANNUAL from the attack of CFC's (prior to their being banned as a propellent in laundry spray aids) etc.

I see a down turned vent to the lower left of the roof photograph. That isn't a blow off from a refrigerant (R22) chilled water system is it? Also, are there any swimming pools anywhere near this roof top installation? Can you smell chlorine on the roof?

Gotta be coming from somewhere. I've seen completely neglected boilers under extremely stressful conditions that looked better than this. This is NOT a normal failure mode. It is absolutely chemically induced failure. In any case, I don't believe the manufacturer has any liability in the situation, but that is just my humble opinion looking from the outside in.

ME

Derheatmeister

Materials used

Does anyone have the data of the grade of SS materials that are used for the Plate vs the exchanger?(From the Manufacturer: HTP ? )

tim smith

I think it's the delamification by the stratrification of

the combustionization. (right out of in living color)

Supply House Rick

Thanks Tim

You sound like the manufacturer's rep.

Ken

Supply House Rick

Mark

The turned down vent comes from a gas meter just below. No swimming for blocks around. No chlorine smell either.

Ken

Supply House Rick

Hi Perry

The reason I mentioned the markings on the plate was because the thought crossed my mind that cracks may have been noticed in the manufacturing process and it was just never pulled off the line.

I suggested to the manufacturer that the cracks came first, opened to the point where the gases no longer had to pass between the tubes allowing the spaces to become clogged. This too was poo-pooed. He says clogged first, then divider plate damage. I've had much difficulty getting the boilers to light under good conditions on some units, so have to wonder how it would run until this kind of failure.

Thanks, Ken

Supply House Rick

TDL of the vent around ten feet.

Ken

Perry_5

Please explain how the cumbustion gasses stratify...

I can't imagine any scenario where the combustion gasses stratify in a boiler like this... So can you explain it to me?

Also, what is delaminating that is causing the cracks...



Perry

[Deleted User]

chemicals

If this is a 10 story building. Id there a cooilg tower or Air cooled chiller on the roof? The chemicals used to clean those type of units may be a factor? Coil cleaner is very caustic and may have been sucked into the air intake. I have seen this happen in other buildings.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Supply House Rick

That's the vent for a 250 MBTU gas hot water tank.

Ken

Supply House Rick

Mike

Check the roof.jpg in the reply to Mark above. There is a chiller in the area below the fireplace vents to the left side of the photo.

I will contact building engineers and see if anything of that sort was used.

Thanks, Ken

Derheatmeister

In which City?

How is the air there?

No wonder people have respiratory problems if this is what is happening with die boilers due to die intaken sie Luft..

jeest kidding ?

tim smith

Perry, you had to have seen the show In Living Color to get

this. Tim

Perry_5

Really?

I have probably spent more hours watching the burning patterns inside boilers than I can even estimate. That comes from spending decades working with industrial to power plant size boilers. At that size there are actual observation ports. Many power plant boilers now have cameras in them so you can watch from the control room - and often from different angles (the first plant with cameras in the boiler that I worked at was in 1983).

I've also spent a lot of time inside furnaces and boilers since I was a teenager as well: starting with cleaning and repair of coal fired furnaces and boilers, the occasional cleaning job of an oil burner, and of course Navy ship boilers and industrial & power plant boilers.

So what is it I havn't seen?

The terms you use don't even make sense to me. I'm an engineer who has made a carrer out of the operation and maintenance of industrial steam and power plants - my current specialty is Heat Exchangers.

While there are burner and flame patterns - and gas flow patterns. I am not aware of any way that there could be any kind of stratification.

I don't even recognize the "words" you used. Can you provide links to combustion industry literature and sources that use those words to describe combustion or combustion issues? Or, are they just impressive sounding words invented to baffle people who know nothing about combustion (and perhaps you've just picked them up as they sound good to you).

Perry

Perry_5

In this case I agree with the Mfr

Ken:

Lots of plates have lots of writing on them in fabrication shops. I am sure that if the steel was obviously defective it would not have been used (they might have dented it and used it, but not these kinds of defects).

The amount of combustion gasses that could leak from these cracks are minor compared to the space between the tubes - at least initially. The hole that ultimately developed is a different matter and might provide enough bypass to be noticed.

Have a great day,

Perry

Mark Eatherton

Perry, It's a JOKE...

Relax...You're taking life WAY too seriously.

No one I am aware of is questioning your credentials nor experience.

Go out and RENT the movie, "In Living Color" and laugh a ilttle, willl ya?

ME

Mark Eatherton

When you talk to the building engineers..

ask them if they've had any refrigerant loss (that they'd admit to...).

Also, see what they use as bacteriacides and fungicides for the tower. Where is the tower in relation to this termination.

It doesn't take much chlorine gas to turn metal in to dust when mixed with the combustion process. It SUPER oxidizes ferritic metals.

ME

Ted G

RE: In Living Color Referance.

LOL.

tim smith

Thanks Mark, I was just about to enlighten Perry on this.

I was gigging Tim mcelwain on the reply I did regarding his first reply to this thread. I loved in living color. Thought it was one of the funniest shows ever in first few years. Totally un PC, just the way I like it. Tim

" I did not mean to exacerbate or pontificate on this threadicate, please excuseacate the blabicating".

Supply House Rick

Giannoni sampler

This is a quiz, pick out the boiler with the biggest problem.

File name has months in service before being opened up.

Sorry, no prize involved.

Ken

Dave Stroman

Yikes! Where do you find these things? I have to say that in this part of the country (CO), I have never seen things this bad. Are all of these from the same area? Could there be some common thread? Air quality, gas content, water quality, piping issues, something? Those big heavy cast iron boilers look more attractive the more I read.

Dave Stroman

Derheatmeister

Analyze This!

I Think that it is time for a Investigation in what the Debris are that are accumulating in the boiler i.e. simple Lab test in the consistency for the materials/ Mineral/ Chemicals maybe some science teacher in your local high school can point you in the direction may make a Project for his Students or just take it to a laboratory otherwise you will always be Guessing.

Analyze it with the proper tool

Just think of it this way it kinda like adjusting a high efficient boiler without the proper tools...

Larry (from OSHA)

some comparison

All those pics are quite amazing. Have to wonder about the installs and any owner involvement - like even looking in the boiler room at least once in a while.

These are pics of mine at one year in service for space heat (3 zones baseboard) and DHW. About 9300 hours of power on and 3750 total hours of run time.

Larry