W-M Ultra heat exchanger leaking - FYI

Mark Hunt

this is what I got:


>Your search - www.dooyoo.co.uk/archive-house-garden/keston-celsius-25-modulating-domestic-condensing-boiler/433028/www.dooyoo.co.uk/archive-house-garden/keston-celsius-25-modulating-domestic-condensing-boiler/433028/ www.halsteadboilers.co.uk/html/news_article.asp?id=4 - did not match any documents.<

Does the link still work for you? Maybe it was removed????

I hate/love the internet!

Mark H


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bobbyg_2

W-M Ultra heat exchanger leaking

FYI - Ultra 310 installed 3/05 looks like where the condensate pooled and eroded the heat exchanger. It's not really leaking from the water side, it is leaking the condensate. Has anyone seen anything like this?

Paul Rohrs_4

Bobby...

I haven't seen any Ultra installs locally to say definatively.

Questions:

Was the water treated? If glycol'd, did they use the specific glycol recommended by the manufacturer? Is this a snowmelt with low temp water returns?



Regards,

PR

bobbyg_2

Hey Paul,
This is a leak on the flue side. It appears to be a leak from corrosion due to the condensate. The condensate has eroded a spot and leaks out before it can drain out where it should (in the drain outlet). At least it looks like erosion to me. Where the condensate has discolored the area around the hole(leak), it is eroded/thinner there.

But on the water side of the system, it was strictly water and it is a higher temp. system using outdoor reset.

Paul, merry christmas to you and yours. Many thanks for your help in the past! I use your stencils daily!

ALH_4

And

It is also leaking flue gas. Thank you for posting these photos.

Is there any chance of comtaminated combustion air?

If not....

I was starting to think maybe aluminum boilers were ok, but this raises even more question in my mind. There are just too many ways for these boilers to fail, and this is a particularly dangerous one. Aluminum is just too reactive and too far at the end of the galvanic series.

Unknown

interesting.....

Wondering what Weil Mclain saying/doing about this.... I can't believe the national comapny doesn't have a 800 number to help us contractors out....

Steverino

their number:

412-788-9345 & 219-879-6561.
You may want to call the supply house where you purchased the boiler first. Have them call their W/M rep. PLEASE post your results on this thread...a perfect opportunity for all of us to learn.

[Deleted User]

YOWSER...

That is NOT a good thing. Makes me think thrice about the material of choice for a modcon heat exchanger.

Let's see what Weil/Mc says about it though.

Could have been a manufacutring/casting fluke, although the rest of the inside of the boiler ain't that pretty either.

ME

bobbyg_2

I work for a wholesaler, the rep has taken pictures and I will keep you posted on what transpires with Weil-McLain.

L'town radiant

squirelized acid contamination

It is my understanding that due to the extremely poor diet of Hoosier squirels that nest in flu pipes, they produce Squirelized Acid that is extremely corrosive to Weil Mclain aluminum

Seriously though, that's some crazy stuff, was there any damage to the condensate drain line?

Merry Christmas!

Mike T., Swampeast MO

For the sake of everyone with cast aluminum heat exchangers in their mod-cons, I hope that's either a case of severe environmental contamination or a bizarre manufacturing problem that wasn't caught!

Wayco Wayne_2

Not good

The place where the leak is, is supposed to be lined with stainless steel as I recall from a class I took this Summer for the Ultra. The reason for this is that here in the USA we use PVC tubing for the vent pipe. (In Europe they only use stainless steel.) The acidic flu gas combines with the PVC to make a corrosive solution which flows back to that place in the heat exchanger. A stainless steel cup protects the aluminum. This is why the Buderus Mod Con requires a trap to divert the condensate running back the flu p[ipe towards the boiler. They dont want the corrosive condensate/pvc solution back at the boiler. I wonder if the drain clogged up and uverflowed the SS cup. I will watch with interest to the explanation. WW

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Floyd_28

The problem is easy to see...

you can easily see that the casting was defective....the hole ate through a bad spot... the discloration around the hole is different from the rest of the bottom. the metal arouns the hole is much too thin also. There also are other pin holes that show that the metal was not cast properly. So now everyone has one casting that slipped through the QC network and they can point to it with that see I told you so attitude.....and crucify another manufacturer without know any of the facts....

Here we go... any bets on how long this takes to make 100+ posts????

Floyd

dana_3

leaky ultra

was it running on lp or natural gas

lee_7

my old employer had to replace quite a few of these boilers due to the alumminum corroding away. All were covered by warranty as far a know. supposedly had a cating issue.

Maine Ken

Floyd, could you please point out to me that which is so easy to see? I see a hole in the casting, i see what appears to be erosion and staining around that hole. Maybe I am not a metalergist and simply cannot see the obvious. I haven't seen anyone disparage the product...yet...

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Mitch_6

Any Chance

the air inlet was near a source of chlorine or other common item that could have been corrosive.

Leaking bolts, bad sensors, wrong orifices, problems on gas valves, problems on gas manifolds.

Starting to wonder, liked the Ultras Installed a bunch but you do not at least hear of this many problems with Mod Cons.

I like my WM rep and the supply house that sells them but I am starting to wonder.

Mitch S.

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Ted_9

WW

What you say seems to make sense. Let's see what happens.

Massachusetts

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Perry_2

I disagree

What I see is an area where the condesate puddled, and corroded, and a place where it ate through. This is very typical of corrosion failures caused by puddling of a corrodant.

Wayco Wayne below indicates that he beileves that a SS cup was susposed to be lining this area. If so, then this was a defective part from a manufacturing perspective.

The condensate from condensing boilers is known to be corrosive to Aluminium. The design philosphy that I have read for these boilers is that the Aluminium block boiler design is based on making the Aluminium thick enough so that it does not corrode through in a couple of years.

Of course, making the Aluminium that thick eliminates any thermal conductivity advantage over using some form of SS tubing (thermal transmission is a primarily a function of thermal conductivity and thickness).

I have always been skeptical of using Aluminium for this application from the moment I read of the first Aluminium block residential boiler.

There are of course marketing price point reasons to use Aluminium.

Overall - it is what it is.

I will watch with interest the next couple of years related to these boilers.

Perry

Perry_2

Wayco

While I agree that the condensate is known to be corrosive to Aluminium a couple of the items you present here does not sound right:

I do not believe that the condensate is disolving anything significant from the PVC exhaust on Mod/Con boilers.

I do agree that water does condense in the PVC and run back to the boiler in a proper installation. Use of a trap does keep the corrosive water out of the boiler. I'll also bet that the companies that "require" a vent system drain trap also require it on a SS vent system.

I believe that you will find that not all Mod/cons in Europe use SS vent piping. They do not use PVC due to other issues (like is it really suitable temperature wise - as already covered on a long "Wall" thread, not formally rated for exhaust piping, etc); but, Viessmann and some others use another copolymer product as their vent in the co-axial vent products. Of course, SS can be used (and Viessmann does allow its use with the Vitodens).

My understanding of the design philosophy of Aluminium block boiler HX's is that they are to be made thick enough so that they don't corrode through in a couple of years - knowing that the condensate is fairly corrosive to them.

Perry

Uni R_2

Hope

Let's all hope that's not the case, or the whole industry will take a major hit.

Wayco Wayne_2

Hey Perry

thanks for the reply. I'm basing my musings on somethings I learned when I went to the Factory that makes the Prestige boiler in Belgium last April. Their Engineers claimed that the installer in Europe used the stainless steel vents due to the acidic condensate leeching something out of the PVC when it ran back to the boiler. (poly Chloro V..??? What does pvc stand for?) I put together other things myself and could be wrong. I just remember with that information in mind, it made sense to see the stainless steel cup in the Ultra is right where the condensate came back to the HX. I hope this thread fills out my uinderstanding a little more. WW

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MikeB34

PVC

> thanks for the reply. I'm basing my musings on

> somethings I learned when I went to the Factory

> that makes the Prestige boiler in Belgium last

> April. Their Engineers claimed that the installer

> in Europe used the stainless steel vents due to

> the acidic condensate leeching something out of

> the PVC when it ran back to the boiler. (poly

> Chloro V..??? What does pvc stand for?) I put

> together other things myself and could be wrong.

> I just remember with that information in mind, it

> made sense to see the stainless steel cup in the

> Ultra is right where the condensate came back to

> the HX. I hope this thread fills out my

> uinderstanding a little more. WW

>

> _A

> HREF="http://www.heatinghelp.com/getListed.cfm?id=

> 255&Step=30"_To Learn More About This

> Professional, Click Here to Visit Their Ad in

> "Find A Professional"_/A_



V is for vinal (sp?)
Poly vinal chlorinate

MikeB34

PVC

V is for vinal (sp?)
Poly vinal chlorinate

Ted_9

almost

Polyvinyl chloride

Massachusetts

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bobbyg_2

Mitch,
This is a commercial job with (3) Ultra 310 units. It is in an office building mechanical room with no corrosive air contaminants in the room or near the intake air.

"Leaking bolts, bad sensors, wrong orifices, problems on gas valves, problems on gas manifolds"

I believe I know what you mean now.....Are you referring to past issues with Ultras?

Home Depot Employee

This failure is nothing new to us in this area. In fact its nothing new to manufacturers using cast aluminum. They are just beginning to see this and are investigating. I will go on record saying it is just starting and we have an interesting ride ahead of us with regards to cast alum in ModCons. Good thing we have a choice in ModCons, and mine is Stainless Steel.

Perry_2

Thoughts from an Engineering and Marketing Perspective

When I first read of the Aluminum block boiler HX's - I quickly made a multipoint list of "potential material issues" with the use of Aluminum in this application. Issues that all would have to be satisfied before I would consider the material for my home boiler.

So I dug for the answers - only to find that almost every material issue I had listed seemed to be acknowledged by the industry. Water chemistry has to be controlled on the heating circuit side (and all warrantees I reviewed excluded coverage for water chemistry issues). This in a system that most homeowners install and ignore for decades - yikes. Flue gas side was to be designed with enough thickness to prevent several year corroding through; engineered connections of other materials to the HX block; etc...

I then did extensive searching to find out the results in Europe where Aluminum block HX's were first introduced (a lot of searching to find European Heating Contractor and/or boiler review sites). Found out that they had a history of leaking and other problems within a fairly short boiler life. A common theme appears: They are considered a low cost short life boiler - not expected to last more than 10 years (and many failed a lot faster than that - and some failure modes slime up the whole system). A number of contractors refuse to install them. The Aluminum block boiler market share in Europe is only 2% - and is not growing (I saw 3 consecutive years of data on market share of the different base metals for boilers - SS HX's is massively replacing cast iron).

When I was looking at mod/cons I was castigated by a few for not considering the Al block boilers. Some of them, like the Ultra, was a "theoretical" better match than the Vitodens with a lower minimum firing rate (oh yah, I am also skeptical of an effective and long term reliable 5:1 turndown as well).

My real question is why - given what is known about European results are Manufactures in the US introducing Aluminum block HX's.

My conclusion is that in a market where low cost wins market share - that is what they feel they have to do to gain or to not loose market share. I am not sure if the companies are thinking about there long term reputation - and the potential results with that (on the other hand they may know that they can survive that). The companies make money from every boiler they sell. While they may be willing to replace the first few failures (and may call it "casting defects" regardless of the failure mode: Note that I was the ISO 9000 QA manager at a foundry for a few years between power plant jobs - I want them to show me these "casting defects" - and then explain to me how come they were not identified in the foundry). However, if you read the warrantees carefully they are not required to cover this type of failure. Is the failure from a defect in the original Aluminum casting. No (unless they can prove that to me); and I suspect at some point the companies will stop covering the failed HX's (and who pays the contractor for their labor?).

So, in the end - despite the known engineering shortcomings of Aluminum for this application - and known limited life of the material based on experience in Europe. It all comes down to a marketing choice to produce and sell a boiler to capture the low end of the market because a nice SS HX would cost more. Of course the companies will try to do things to make it last longer. Wayco Wayne indicates that one company puts SS cups in this area - and requires condensate drains from the exhaust piping to keep extra acidic condensate from corroding the aluminum block more.

Should the Manufactures claim that they did not know of the various issues - then I suggest that they get more competent engineers and managers.

It seems that the same issues revolve around the use of PVC as a vent material. Cheap; and cheap wins market share. I point out the should Wayco Wayne be correct - and should the condensate leach chlorides from the PVC - that this would be very damaging to 300 series SS mod con HX's as well (chloride induced stress corrosion cracking). Now I was under the impression that PVC was sufficiently stable under modest acid attacks; I will concede that I may be misinformed. That will also be interesting to track. Imagine a contractor not using the required "expensive" venting system and opting to use PVC - and then the SS Boiler failing due to chloride induced stress corrosion cracking; and the boiler contractor being held liable for it (ouch!).

Another common poster likes to use a statement to the effect that marketing will overcome bad engineering; and he is right. In my opinion - use of Aluminum Block HX's for home heating boilers - a product that should last decades - is bad engineering.

Time will tell, and I suspect the next 5 to 10 years will be real interesting; and I am sure glad I have a Vitodens with its concentric vent kit about now. Between this post – and another post about low fire burner problems with the Ultra – both of my key concerns seems to have been right.

In the end - what will Weil McLain and the other Mfr's do? I will watch with interest.

Perry

Perry_2

You might be right...

Wayco:

I am under the impression that PVC is chemically stable enough such that the modest acidic condensate should not break it down. But, what if I am not right about that?

I am very familiar with cloride induced pitting or stress corrosion cracking in metalic materials - and it does not take much cloride to casuse these failure modes in many materials. If the condensate leaches clorides from the PVC - then any 300 series SS HX will likely be quickly destroyed by stress corrosion cracking (and other materials can also be affected). How many contractors will install PVC because it is cheaper than the recomended higher priced concentric vent kits or SS.

I do note that the pictures in this case do not look like cloride pitting or stress corrosion cracking. The pictures of this failure just look like a puddle of corrodant ate through the casting.

So, I am rethinking your comments about leaching of the PVC.

Perry

Mark Hunt

That sounds ominous.

> This failure is nothing new to us in this area.

> In fact its nothing new to manufacturers using

> cast aluminum. They are just beginning to see

> this and are investigating. I will go on record

> saying it is just starting and we have an

> interesting ride ahead of us with regards to cast

> alum in ModCons. Good thing we have a choice in

> ModCons, and mine is Stainless Steel.





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Mark Hunt

That sounds ominous.

> This failure is nothing new to us in this area.

> In fact its nothing new to manufacturers using

> cast aluminum. They are just beginning to see

> this and are investigating. I will go on record

> saying it is just starting and we have an

> interesting ride ahead of us with regards to cast

> alum in ModCons. Good thing we have a choice in

> ModCons, and mine is Stainless Steel.





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Mark Hunt

That sounds ominous.


Do you have any pictures of these failures? Sounds like you've seen quite a few.

Mark H

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Chris_82

I can't resist

The brochures war cry is: "it pays for itself in x number of years," is this justification for the high initial cost of these units? And the multiple times I have heard just put a new one in because they are paying for themselves? Cause I'm tired of hearing it from everyone that sells them versus having to explain to customers and others about the high tech nature of these units. I’m tired of hearing from a rep that is it installed correctly in the first place, as their first question, and it’s not a question? I have WM products that I installed as an apprentice a lo-ng time ago, I still know these people and I no longer pitch the you will same money if we put a this or that in, they are happy with what they have. I have yet to have a customer tell me he wants this or that brand comes replacement time, I’m taking the heat for my poor choice! It seems people get a little crazy with this jump on the energy saving bandwagon, that doesn’t mean we need to buy into this marketing BS. How about a show of hands…who remembers going into every basement and seeing those clothes dryer bypass things that pumped an enormous amount of h20 into homes with the resultant mold and dry rot that they created, all in the name of energy savings? They had great brochures too. The trouble is that that paper is a little to rough to wipe... Anyways I'm startin to spec only what I'm comfortable with, and also giving out my reps and the factories phone number instead of my own, this is as a result of the attidutes I am encountering on a weekly basis. Well I’m the first to save fuel, it that be the case and I find little argument that morally energy savings is a good thing but what of the cost? It makes no sense to purchase a new car for $27,000.00 to save 15 more miles per gallon when the payback period is 44 years! This is what is happening when our customers have to figure in shortened life expectancy, higher replacement costs for parts, and the suggested yearly cleaning by a highly trained plumber or fitter that holds a gas license at a minimum. Those units that have problems are NOT paying for themselves. And there are too many of them in comparison with tried and true materials already out there!
Those pictures look awfully like boat parts that have spent too much time in salt water. Perhaps it's time we start epoxy lining this unit, which was discussed at its inception, btw. Nerveless these units haven’t been around all that long and unlike other manufacturers they have been very responsive in solving growing pain issues. The one igniter assembly problem that we had, WM sent a next day air replacement, even though the local reps warehouse had the part in stock. I hope this responsiveness continues?

Perry_2

Some European References:

Here is some of the links to the European sites that I visisted. I did not keep track of all the sites during my intitial search - and was able to recover these few at a later date when I was asked to provide references.

I will note that I did not find a single site that claimed the AL boilers were long lasting and problem free boilers - or that challanged the statements made on the other sites. Not a single one in many hours of searching.

See the portion labled: "Condensing boilers are less reliable?" at:

www.halsteadboilers.co.uk/html/news_article.asp?id=4


See the paragraph that starts: "Keston have wisely chosen stainless steel" at:

www.dooyoo.co.uk/archive-house-garden/keston-celsius-25-modulating-domestic-condensing-boiler/433028/

An interesting twist on how to prevent the waterside problems (and the problems maintaining proper water chemistry) is under the section most the way down the page "Malvern Condensing Boiler Model Range". See the paragraph that starts with: "The Malvern does not require special inhibitors." at:

www.combi-boilers.com/

Finally, I have attached one of the three annual European market reports from 2003 that I reviewed (and there were other similar ones from other sources), and I have seen this same report for 2004 and 2005.

Too bad I did not keep all the sites or copies of all the annual reports on boiler market share - I could list many many more; and not one European site (excluding Mfr sales brochures) claiming that there were no problems or a long life with Aluminum block HX's.

Any one of you should be able to construct a search that will find these same sites and reports that I found - if you are willing to spend many many hours searching.

Hope this helps,

Perry

Drew_2

Aluminum

Thought I'd put a question out here. Why does'nt the auto industry have the same problems with aluminum?

ALH_4

Harmful contaminants in combustion air

A list I have from somewhere....

These will even cause a stainless HX to corrode.


1. Spray cans containing chloro/fluorocarbons

2. Permanent wave solutions

3. Chlorinated waxes/cleaners

4. Chlorine based swimming pool chemicals

5. Calcium chloride used for thawing

6. Sodium chloride used for water softening

7. Refrigerant leaks

8. Paint or varnish removers

9. Hydrochloric acid/muriatic acid

10. Cements and glues

11. Antistatic fabric softeners used in clothes dryers

12. Chlorine-type bleaches, detergents, and solvents found in household laundry rooms

13. Adhesives used to fasten building products


Are there any dryer vents nearby?

subcooler

The Auto

They run them hotter and do not allow condensate to set..

subcooler

Coatings

Co-Ray-Vac did this in the 70's with quite amazing results..

ALH_4

Chlorides

This is not specifically about venting, but it does relate to PVC and leaching of vinyl chlorides. Is the vent particularly long?

My money would still be on contaminated combustion air, but who knows.

Perry_2

They do..

You just dont notice it and they usually keep it well controlled.

Ever wonder why you need to have your antifreeze "refreshed" every several years. Note that they don't actually replace it: The filter it, treat it, and restore the additives. That is to keep the level of additives necessary to protect the Aluminum in the system.

Ever seen a system that went to long. The Aluminum radiator is the first thing to go (and I have seen some of these leaking and rotted out).

In extreem cases - the some of the Aluminum heads can be affected. Note that the engine block is the heaviest casting and the last to be affected.

The key is that almost every mechanic and service shop knows that the engine cooling system must be flushed every several years and the antifreeze additives restored - and key here: People accept that it needs to be done.

How many boiler techs even know about system chemical cleaners and treatments - much less how to sample, test things, and how much additive to add to restore the systems to where they need to be. Not many.

How many homeowners know that they should be maintaining their heating water circuit chemistry for their new boiler instead of just ignoring it (and how many are willing to pay someone to do it on a routing basis). Not many.

Perry

ALH_4

Aluminum Mufflers

If mufflers were aluminum the same process would occur.

Residential heating systems generally get "maintained" after the failure. In my opinion, this is a good reason to use materials that are as insensitive to water chemistry as possible.