Aluminum Heat Exchangers

Perry_5

Not a problem.

I was using this as an example to argue against the people who seem to think that having to replace a boiler every decade or so should be the thing. I also argued against it back in 2006 when I was previously most active on this forum.

It makes no sense for there to be short lived boilers - they are just too expensive to buy and too expensive to install.

For the record. I had to replace that boiler in 2006 as it was no longer healthy to have around. I looked at all the options available then. I installed a Vitodens 200 with hot water. It was not cheap.. But, it has the potential to last decades - and the more I study the details the more I am convinced that Viessmann at least tried to addressed many of the longevity issues.

I will look at the design of the Ray. However, you cannot get away from the fact that the condensation will corrode a cast iron material. You can of course make it thick to provide a corrosion allowance. You could also provide for replaceable corrosion plates for some design concepts (I have no idea if they did that or not). But, you cannot stop the corrosion. Of course, Cast Iron (or Carbon Steel) is immune to other issues that affect stainless steel.

Have a great day,

Perry

Dave Behrens

Share Practical Information

I am interested in hearing the experiences of the installers here with reference to aluminum heat exchangers used in mod con boilers.

Two areas specific to aluminum HX are:

1. Use of pH buffering, anti-oxidation, and anti-freeze additives in the heat delivery system. Are they necessary? If so, what brands work best? Any noticeable difference in heat delivery in systems utilizing these additives?

2. Is it possible to control the low pH of the condensate discharged from mod con boilers? Does that low pH condensate act detrimentally on the aluminum HX? Are pH neutralization systems necessary for the mod con boiler condensate? What effect, if any, does this slightly acidic condensate have on septic systems?

hot_rod

yes

It is very important that aluminum heat exchangers are cleaned properly, with an aluminum friendly cleaner. Then flushed, and filled with a top quality AL glycol or aluminum inhibitor.

The warranty is usually very clear about the use of chemicals, types and sometimes brands.

I have seen pictures of aluminum heat exchangers that were destroyed in less than a years time from poor water quality. It is a soft, and sensitive material, but a great conductor.

The condensate from the drain must be conditioned before heading down the drain. It is very aggressive to concrete (septic tanks) cast iron (floor drains) and just about any other material, other than plastic, that it contacts.

It is very simple to build a condensate neautrilizer with some PVC and marble or limestone chips.

hr

Brad White_203

Exactly...

Dave, you are hitting on an area that has yet to be reconciled in my mind.

The aspects that never did add up are, "If one has to maintain the pH of the water-side of the equation at above 7.0 (usually in the 8.0 to 9.0 range), then why is the combustion side, at a pH of 3.8 to 4.5 and at higher temperatures, not an issue?"

Some of the reasoning I was given is that the aluminum is indeed sacrificial but the wall thicknesses take that into account.

The second half of this is that there have been "eat-through" perforations (leaks) from the condensate side, but this had, (unconfirmed beyond my source) a root cause in chloride formation out of PVC venting. In other words, metallic venting would have prevented this, if that source is correct.

My conservative side says that there is not enough empirical evidence to sway me conclusively to use aluminum when stainless steel is available. Certain aluminum boilers, such as Buderus, are fine products with a loyal following but the timeline and specific conditions over that time is not known to me yet. So for me, it remains stainless as the default.

Now, on the water side, if the manufacturer recommends a certain fluid, I would follow that to the letter. Noble (the "No-Burst" folks), has a formulation specifically for aluminum boilers. Drew at Noble is and has been a terrific resource in that area.

On condensate neutralization, yes, please do this. Untreated the condensate is somewhere in the range of vinegar and orange juice and will eat iron and to a lesser extent, copper. It is fine in PVC and CPVC and PP drain piping as far as I know, but one does not know if the iron pipe starts right after the plastic drops below the floor...

A simple neutralizer can be made using PVC pipe and fittings. I use a 1.5" drum trap for mine, but have made them out of 3" PVC pipe, a pair of 3x1.5 tees and end plugs to change out the marble chip fill. Yes, regular garden-variety marble chips.

Dave Behrens

To Soon To Tell

The empirical evidence is not readily available, YET.

Could this be a profit center...like money in the bank...when all those AL HX in mod con units start to leak?

How many years has Buderus been making AL HX mod cons? What is the oldest AL unit out there?

Dwight (Rhomar Water Mgt.)

Aluminum HX

In regards to the water-side of an aluminum boiler, maintaining a pH in the range of 7.0 - 8.5 is critical. The problem with this is most inhibited glycols are formulated to produce a pH of 8.5 and higher. The Rhomar RhoGard glycol is approved by most aluminum boiler manufacturers for use in their boilers and will produce a pH in the proper range and has inhibitors for all of the metals.

If you don't need freeze protection, you can add Rhomar's Pro-Tek 922 inhibitor. With a variety of metals that are typically present in modern high efficiency hydronic systems, it's important to add a multi-metal inhibitor.

Dwight

Perry_5

The oldest AL HX mod/cons were

in Europe where this concept originated.

My research through European websites several years ago indicated that they were a dismal failure...

Here is a direct quote from someone's posting on a blog back then in Europe: "Aluminium heat exchangers have a tendency to rot away with time and leave a slimy mess for the service engineer."

Here was another one:

"One of the major concerns held by many homeowners is that condensing boilers are a 'new' technology and that they are not as reliable as the conventional type of gas boiler. In some cases they are right to be concerned. Some local authorities that have been fitting gas condensing boilers for the last few years have been forced to replace the boilers within just three years.

This is all down to the construction of the boiler. Many boilers feature aluminium heat exchangers which, when they come into contact with the condensate produced by condensing boilers, will corrode and eventually fail."

-----

Many of the links from that search are no longer valid. I saved a few of the web pages on my computer.

Of course, they are cheap to build...


Perry

Andrew Hagen_2

Amen

I am not convinced aluminum will provide the service life that homeowners expect because of pH issues on the condensate side of the heat exchanger. That is not to say that I think aluminum boilers are constructed poorly. I just question the material's ability to last 20 years.

Perry_5

Additional Inhibitor issues - Warranty Issues

Yes, you can protect the waterside of a Aluminum Boiler HX via use of a good corrosion inhibitor package.

Unfotunately, this is not a one time thing. You have to sample every year or two, have a lab analysis done, and then retreat the system to bring the corrosion inhibitors up to snuff.

That means a lot more service calls. Who is going to do it? who is going to pay for it? Who is going to pay for the lab analysis?

Once those inhibitors break down... so does the Aluminum HX.

Of course, on the fireside the condensate slowly eats away. Yes the Mfrs have made the HXs thick so that they should last at least "X" years.... I assure you that "X" is not 15, 20, 30, etc. Of course, if your boiler has heavy use - or bad natural gas/propane trace elements then the AL HX will dissolve faster than "X".

What a system. Guaranteed new business on an average of every "X" years (assuming that the waterside inhibitor package was appropriately maintained).

As far as the warranties go... Look at all the exclusions. Last time I looked (in 2006) and if my memory is correct - all of the AL boiler warranties in the US essentially excluded HX failure due to corrosion. Why don't you read the fine print on the warranties yourself.

A little checking on my part indicates that:

Weil-McLain does not list their Ultra warranty on their site. I thought they used to.

If you read the Buderus Warranty; I am left with the impression that they are only responsible if they mismanufactured the HX (perhaps did not machine it correctly). Is that not what a "defect in workmanship
of materials" means. It certainly does not mean a defect in the choice of materials.

Please read all of their exclusions. Exclusion 9 covers corrosion although they hide behind fancy words as corrosion is an "electrochemical reaction" (this is the chemistry definition of corrosion). Note also the exclusion from damage from water and air impurities; as if we all have ultrapure water and ultrapure air...

9) Damage to the Residential Cast Aluminum
Boiler or any of its original components or
parts caused by excessive temperatures or
pressures fuel or gas explosion, electrochemical
reaction, water and air impurities,
electrical failures, riots, insurrection or acts
of God.

I suggest you then read their cast iron boiler warranty to see the differences.

Perry

Darrell_5

From the service perspective...

Every aluminum block boiler that I have opened for service has been "tracked" meaning that the condensate flow path has eaten away the aluminum...not by much...but material is gone.

Every aluminum block boiler that I have opened for service has a blocked drain...blocked with aluminum sludge.

Almost nobody balances or maintains the water side chemistry.

The oversized ones are far worse.

Seems like unions wuld be a good idea.

Put the thing where it can be easily bagged, tagged and carried away.

So far, none of the SS block boilers that I see have any of THESE issues.

Just my hundred and five dollars worth.

Ross_7

Well,

We should see if we can test Brad's theory, of which I heard the same thing at a Triangle Tube seminar. About the the leaching of the PVC venting into the condensate. We should ask people here on the Wall, as to what they are finding on the boilers such as the Crown Bimini & Burnham Freedom, of which are only approved with stainless venting or Polypropylene. This would support the theory of the chlorides causing aluminum heat exchanger depletion.

Ross

Perry_5

Ya know.... Thats an interesting theory, especially for

300 series SS boilers.

If the vent system condensation runs back through the HX to drain - chlorides leaching from PVC venting would be a great explanation as to many of the reported SS HX failures in another thread.

However, I do not buy that this is "the problem" with Aluminum HXs. They will dissolve regardless of the chlorides (although the chlorides may speed the process up a bit - I'm not sure and would have to do some research on that).

Perry

Perry_5

Duplicate Posting - Sorry

Sometimes my finger taps twice....

Perry

Brad White_203

I agree, Perry

the leaching and dissolution happens regardless of material but is accelerated by chlorides as we all know.


But aluminum starts out at a disadvantage, having specific "care and feeding" information going in.

The TT uses a 400 series stainless, 439 I think. I would be interested to hear your thoughts on that versus the 316L, 316Ti and other 300 series stainless steels.

Perry_5

There are I believe 5 classifications of mod/con boilers now

Brad:

Actually, leaching and dissolution does not have to happen and is not always accelerated by chlorides.

Right now there are in my mind 5 general classifications of mod/con boiler/water heaters HXs out there:

1) Copper (Multiple Companies)

2) Aluminum (Multiple Companies)

3) 316/316L SS (Multiple Companies - fabricated mainly by Giannoni in France)

4) 316Ti SS (Viessmann)

5) 439 SS (Triangle Tube)

Without going into details right now I cannot consider the first 3 as long life options (expect 20 years of life - or heck - even 10).

The last two might be - if some other things are done right (but both 316Ti and 439 could be affected by some issues).

There are materials out there that would likely perform much much better - but I have just confirmed that they have workability issues (not saying it can't be done - just tricky and would likely need R&D just to come up with a fabrication method).

I am planning to start a thread on mod/con boiler life (are they - can they be long life) where I will discuss the issues I see facing a home mod/con boiler - and what can be done to minimize issues.

Given the cost of installing a boiler (any boiler)... Is a mod/con even worth it unless it can be a long lived appliance (a lot of issues/variabilities there; but a valid question to ask).

This may take some time to write. But I hope to have it up by Sunday.

Perry

Brad White_203

Hi Perry

I would add the Mestek KN and Ray boilers, cast iron condensing, to that array by the way. They use a thicker casting and a downward path so as to avoid re-evaporation, the concentration of salts being the thing to avoid.

The notion that dissolution occurs is something I will stand by. All metals erode, none are perfect, but certainly we agree that SS holds up better than Al or Fe.

As a physics professor once drilled into us, even water is a universal solvent, if you are patient enough..

Perry_5

Yo Brad...

Dissolution and eroding are two different phenomena.

I will add Cast Iron to the list - but like Aluminum I question if it can really be a long life material because as you know it readily corrodes in the acidic environment of a condensing boiler.

Also, while you can make a general statement that "All Metals Dissolve" - that is only true if you are free to change the environment.

If I can control the chemistry of the environment - I can give you metals that will not dissolve.

Gold is a classic example of a metal that will not dissolve in the natural environment. We have items that were covered with gold leaf a thousand years ago - and the gold leaf is still intact. We have intricately carved solid gold many thousands of years old - with no signs of dissolution.

Copper and silver also has been found in excellent shape even after thousands of years. One of the plans for burying nuclear waste in a certain part of Europe is to encase the waste billets in copper and bury them in a soil/ground condition that is known to have preserved copper for thousands of years with no detectable corrosion (this ground/rock is naturally basic).

Of course though... we do know what chemicals will dissolve gold, copper, and silver. So you cannot say that gold will not dissolve; all you can say is that gold will not dissolve in most environments.

Erosion is a mechanical process (and gold is highly susceptible to it), and there is a mid ground where errosion and corrosion combine to create faster material loss than either would by itself: Flow Accelerated Corrosion (FAC) - which has been responsible for some of the worst power plant/oil refinery/chemical plant disasters (in loss of life) in the world.

My point being: From a practical - and even likely a theoretical standpoint: I do not see why we should accept a metal that corrodes in a mod/con boiler. Certainly, if you are going to have a long life condensing boiler HX you wish to minimize this to the maximum extent available (if you cannot eliminate it). From a practical standpoint - such material for this environment appear to exist - and are widely used in the worldwide HX industry (i.e - they are readily available materials; unlike 316Ti which has to be special ordered on a full batch quantity).

The problems with the materials that I am thinking of is that they are difficult (and potentially very difficult) to fabricate into anything other than a round tube at this time (and it took a lot of work to figure out how to make round tubes from the materials).

Perry

Leo G_101

nice to see

that more people are now starting to look at ALL costs associated in boiler replacements, not just the "35 - 60% savings in fuel usage from the old boiler".

I started talking about this "life-cycle" cost 4-5 years ago, and was roundly poo-pooed. Also on the green side, what is the enviromental cost to manufacture 3-4 high-eff. boilers, when 1 cast or industrial steel boiler will last 35-50 years?

Because of these thoughts, I have in the past couple of years i have decided to only install mod-cons, that I feel have a chance of lasting 20-25 years, and are engineered in a way that allows for the yearly service to be done in as efficient a way as possible, helping the customer to actually put some of their fuel savings into their own wallet.

The other thing that drives me crazy, is that we have a lot of companies that do installs, but not service. So it seems that every year I have to carry more OEM parts for boilers brands that I don't install. The cost of this is ridiculous! At least with the "old" boilers, they all used basically the same control parts, so they are cheaper to work on. Maybe these boiler companies should have a council of Nacine, and hammer out a strategy so that most parts are usable on whomevers' mod-con, thus saving the customer and service gys some cash!


One thing to remember, which does predujice my thinking very strongly, where I do most of my work, we have a very real problem with our N/G. There seems to be a lot more crud in our systems then even 20-30 miles further up the valley.

Leo G

Brad White_203

I *think* we agree!

Hi Perry-

Yes, I did use the terms interchangeably (and incorrectly in so doing). But speaking specifically, all metals will dissolve in time by one process or the other. I do not mean necessarily in our lifetimes.

True, the distinction between dissolution and erosion (chemical versus mechanical) could have been better stated, but in many mod-cons, the two follow one-another. There is an alumina slurry I call it, that develops in some aluminum mod-cons. Slime actually.

Lead-lined coffins are one instance- normally fairly resistant to many acids, butyric acid (from decomposition) pin-holes the stuff. Everything has it's foil.

Yes, gold is an element and will be worn away and is not compoundable at the atomic/molecular level (in any way that I know at least!).

Aluminum is dissolved in TSP, among other things. A common system cleaner (and de-facto pH adjuster), will eat away aluminum especially at higher temperatures, even though the pH is in the 7+ range.


Even stainless steel rusts, we know that, just some hold up better than others. Copper- I have seen copper flashings and gutters erode/corrode away over several decades, especially where tannic acid from oak leaves dominates.

So, I think in principle, we agree!

Dave Behrens

SS Heat Exchangers

I have serviced two old Weil-Mclain Model VHE condensing (not modulating) boilers from the mid 1980's. The starting systems on these two are really problematic, and require yearly maintenance. They are both sectional cast iron, with SS secondary heat exchangers. These old models, when they start (if they start!) push out lots of condensate; their 3" single wall SS vents are comfortable to hold firmly while firing. No problem.

Viessmann HX (Vitodens 200) are works of art in SS. They will long outlast me, for sure. Will they outlast their control systems? Shouldn't they last only long enough till the next iteration of control system, whatever that will be?

Erich_3

System 2000

Maybe a mod-con is not the way to go. The same or better real world efficiency can be obtained with a System 2000. Certainly a lower life-cycle cost.

Mark Eatherton

Buderus' effort to avoid Chloride attack from PVC...

There is a requirement for a drip tee on the exhaust, immediately after the boiler. I think this is probably their effort to avoid chlorides back feeding in to their HXer.

Inasmuch as the PVC appears to be holding up OK under the thermal stress issues, maybe it would be a good idea to put a drip tee on every condensing boiler to keep the chlorides out of the HXer.

Obviously, certain plastic pipe manufacturers (think Canada) are taking advantage of the fact that they are a sole source supplier of an approved venting system... That in and of it$elf $hould be con$idered unethical...

ME

Leo G_101

Prof

we finally have a second approved manufacture. of course we can't mix and match, but hopefully a bit of competition will help with the prices. Also, only the CPVC version is allowed on boiler venting, even if only radiant is being installed. worried about a high temp zone being added in the future, good call in my opinion.

Leo G

Perry_5

Not really so...

I would not say this is another "approved" manufacturer at all.

This is still an Aluminum HX - and it still will be dissolved by the acidic condensation within the boiler (even if the Mfr is attempting to protect it from additional chlorides - and I'm not sure that is the case here as there are other reasons you may want to drain the vent system water outside of the HX).

In addition, as my Dec 24 post above points out. The Mfr specifically exempts corrosion of the HX from their warranty coverage. So a failed HX due to the normal corrosion of the material is not covered at all as part of their HX replacement policy.

Right now I see only two boiler HXs that have really tried to address the vulnerabilities: Triangle Tube and Viessmann.

However, the Triangle Tube has at least 2 flaws that could lead to early death and I am not sure that Viessmann has adequately protected the Vitodens HX for all applications from some of its vulnerabilities. I do believe that the Vitodens with either the Viessmann supplied Coaxial vent system (polypropylene) or AL 29-C4 systems is the best protected boiler from pitting & Cracking problems.

I can also see the Vitodens and its venting system is so expensive. These are specially produced materials just for Viessmann. But more on that in the post I am working on concerning the life and times (and expected value) of mod/con boiler HXs.

Also, I am not convinced at all that CPVC is really an adequate venting material either - if you are looking for a Boiler HX that will last decades.

Perry

singh

I thought the Aluminum HX concept orginated in Korea. In 1988 Kyung Dong partnered with Nefit from the Netherlands, then of course Buderus bought Nefit around 2000, which then was bought by Bosh.
Kyung Dong Boiler Inc. also has a very large amount of units in China and Russia.
Navien is also part of Kyung Dong.

I have installed Buderus , and Ultra, also Triangle Tubes, I just stay away from Viessmann, I heard they had some o-ring problems. The devil is in the details.

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

Steve Ebels_3

Heating appliance life span

We boiler people are used to having our products last for multiple decades. Walking into a house and finding a 30-40 year old CI boiler chugging merrily along (at 60% efficiency) is not at all uncommon. We have come to expect that length of service to be normal and a lot of homeowners have also.
The large majority of M/C (high efficiency type) boilers are not cut from the same cloth from what I can see. I would guess design life to be in the 10-15 year range for most of them and consumers will have to get used to it. This "news" comes as a shock to a lot of boiler contractors and homeowners but they may as well get over it. The two exceptions that I see on the market may be the TT Prestige and the Vitodens from Viessmann.
I still have a couple question marks on the TT lifespan due to the material used but it looks like a good design. 400 series stainless has excellent corrosion resistance but is more susceptible to metal fatigue related failures than 300 series metals are as a rule. The round shape of the HX and pressure vessel will help with the cracking issues.

We as an industry have to do the best we can to educate our customers about the expected service life of the products we sell because so much has changed in the last 5-6 years in the boiler business. The new one they buy is not going to last for 30-40 years like the old one did. The forced air side of the business has already gone through this and a huge number of customers have found out the hard way that the new furnace in their basement takes more care and will last about 1/2 as long as the old standing pilot behemoth did. I recall a statement in a F/A industry trade magazine claiming that average life for a condensing furnace was only in the 11-12 year range. I would agree 100%. We have replaced many that are only 8-10 years old and this goes across all brands. It seems to be a fact of life for high efficiency heating appliances. They are exposed to a much harsher operating environment and more stress than the old stuff ever was and it shows. We and our customers may as well get used to that type of life span because it seems to be the rule and not the exception. High efficiency comes at a price but future energy costs dictate that price will be a good investment.

Of at least as great a concern as the construction of a M/C boiler is expertise of the installer and the maintenance the boiler receives over its service life. A poor installation will make a mess out of even a Viessmann whereas a correct installation and good upkeep will wring the last possible minute of life out of a Munchkin. I have been trying to help a young family with a M/C boiler that suffered a very poor installation. The boiler has multiple failures under its belt even though the unit is only 4 years old. Improper venting has led to failure of the draft inducer motor and severe corrosion of all the electrical connections in the enclosure. The piping integrity is poor with multiple small drips and leaks causing constant fresh water makeup. It's a sad looking piece of work to say the least. Is it the boilers fault? By no means. Probably all of the lockouts and failures they have had with this piece of equipment have been installer related. I doubt if this one will make 10 years before it expires.

Ross_7

I agree 100% with you S-Ebels

Sometime it's real hard sell to the customer also. Especially, when you're standing next to that existing 30 year old boiler, and trying to tell them that for the "exuberant price" that about to pay for the new equipment will only last 15 years if your lucky. However, they seem to have no problem buying a $30,000 truck every 4 to 5 years, without blinking. But "you're a no good S.O.B. for charging me that much!", for a new heating necessity. JMHO

Steve Ebels_3

Yah

I see that all the time too. They pay $600 per month for the vehicle plus upkeep and maintenance costs and the thing is worth next to nothing 5 years down the road. The car companies have done a pretty good job of marketing their product. That fact lends some credibility to what Ken Secor used to say about good marketing overcoming a bad product or something to that effect

Andrew Hagen_4

Status

I think it's about image and status. Everyone sees the car you drive. No one sees your boiler. The ability to consume more than your neighbor is still a symbol of status. I doubt we will ever see people bragging that their Prius uses less fuel than their neighbor's Civic. ;-)

I hear anecdotal evidence that aluminum boiler have been failing on the combustion side of their heat exchangers. I haven't seen it first hand other than the photos of the Ultra that were posted here a while back.

I hope that mod/cons can provide at least 20 years of service, particularly given that any advances in efficiency will be small in the future. I'm not sure aluminum boilers will make that mark, but I do believe stainless boilers will.

I prefer to use materials that have the least possibility of failure from normal operation. Why use anything less?

klaus

fuel savings = $$$ saved

At some point, maybe 5-6 years or so, down the road, the fuel saved pays for the new boiler. Maybe not all the additional work done to set the system up right, but most likely enough to cover the cost of a new boiler.

Lets say a AL mod-con boiler only lasted 10-15 years. This means that for more than 1/2 the boiler life, it is a direct payback in savings to the owner. Still a good investment. Yes if would be nice to see improvements to the AL and see it last longer, but to be fair we need to look at the overall savings, you presently get by upgrading a system.

Another fact.... more fuel saved in the USA means less support for present and future terrorists. Its just not an enviromental issue.

Andrew Hagen_4

But...

Payback compared to what? Will the next boiler pay for itself when compared to the mod/con it is replacing? I doubt it. We are making great efficiency strides at this point in history. These strides will never be made again.

I absolutely agree on the national security implications of energy conservation. I feel this is the biggest reason we need to start promoting alternative energy production as quickly as possible.

The boiler we put in today to replace the aging cast iron boiler is the one that pays for itself quickly and has to last as long as possible because the next boiler will not have a payback....unless supplemented with solar.

D107

modcon replacement'd need much less re-piping, yes?

Just to amplify your post (Eayrs)....even if, in 10 years a replacement was needed, and assuming a Pro install was done for the first mod-con, wouldn't a replacement need only minor re-piping even for a different model? Assuming primary secondary, neat zone circ/ZV setups, supply/return manifolds etc, indirect HWH piping--aren't these a MAJOR cost of the initial upgrades to mod-con of the old haphazardly-piped CI systems always pictured on the Wall?

Thanks,

David

CC.Rob_11

how about...

We place an emphasis on reducing home heating loads? Not trying to be a smartass here, but let's not forget that getting the heat loss down is the first place to start.

Andrew makes an excellent point about the savings of the second modcon compared to the savings of the first.

Dave Behrens

I agree

Andrew Hagen and CC Rob have very good points.

The replacement for the mod con you install today will have no 'payback' incentive in the form of dramatically increased efficiency in itself. Incorporating future solar devices may provide that incentive, although I'm not smart enough to imagine how those devices will work.

Conservation, in the form of additional insulation or upgraded millwork, is something I hit upon when installing a boiler. People think their $800/month fuel bill will disappear when the shiny new toy is installed. I tell them 'you will be heating your neighborhood much more efficiently.' Most of them don't get it.

Jed_2

You might

think of it as a delayed service "part" replacement(think expensive)from a "system replacement" perspective. But, where is the energy savings ROI for that "part" replacement. There is already a high efficiency appliance that's been amortized. Think of it as Life Cycle Service Cost.

That's why I am so high on the KN and rAy boilers from Mestek. And they back it with a Lifetime Warranty!

Jed

http://www.knowsomethingmore.com/downloads/Ray_Case_Study.pdf

Perry_5

Furnace Vs Boiler Lifespan Vs Cost of Equipment

Steve:

I disagree with the concept that the homeowner needs to accept the fact that their new boilers will only last on the order of 10 years or so (just like they do on a Furnace).

Compare the cost of the equipment and replacement.

A furnace typically cost a fraction of what a boiler cost (1/3 to 1/2 within the quality/efficiency range). They also cost less to install.

So, it is one thing for a homeowner to have to face about a two thousand dollar installation about every 10 years.

Its another thing to tell them that they will be facing a $6000 - $10,000 installation every 10 years.

Hello....

My heating contractor told me he could retrofit a Furnace and run ducting and hoses for half the cost of a "plain" replacement boiler. Just a plain low 80's% replacement boiler was quoted at about $6000 in 2006. Sealed combustion and vented out the side of the house at about $7000 (and gain a few %).

The expected life of the plain 80's% boiler would be decades - and be very easy to service and fix.

So instead I opted for a mod/con - at an additional cost of about $4000 (and a much cheaper mod con would have been at about $2000 more).

As a homeowner we chose to build with hot water heat and pay a premium for it - but in part because the equipment is known to last decades. We can pay a premium for replacing a boiler if they last decades as well.

If all the equipment is going to last is a decade or so... the pecieved advantages of hot water heat quickly evaporate due to the 2X - 3X cost of the system (and its maintenance).

So the real question is.... Is the cost of a mod/con worth it over a conventional non-condensing boiler.

If I had opted for the plain boiler I still would have seen significant fuel reductions. Just not as much as I got with my Vitodens 200.

In reality - the efficiency difference between a properly sized decent non-condensing boiler and a decent mod/con is about 10%. My heating bill is currently about $800 per year: If I had a conventional non-condensing boiler it would probably be in the range of $880 (and perhapd $900).

Does the extra several thousand dollar cost of a mod/con offset an estimated savings of $80 - $100 per year.

What happens to the savings if the mod/con has to be replaced every 10 years at a cost of about $6000 and the conventional boiler lasts 30 years?

What savings.

I - and many people - can only long term justify the cost of mod/cons - even given the value of reducing energy usage - if they last for decades.

I suspect that a lot of people will want to switch back to conventional boilers if mod/cons cannot last.

Perry

Jed_2

Perry!

Read my Post. I also take exception to your claim that a furnace will only have a life expenctancy of 10 years. Maybe in your part of the world, and when the system design is faulty from the get go(of course, there is also the chronic lack of service issue). there are many furnace systems lasting 20 years or more.

So, why do they need to face mod/con replacement every 10 years? "Is the cost of a mod/con worth it over a non-condensing boiler." YES! If they buy the right boiler. And, yes, the Mestek rAy boiler only became available within the last year. But, it is here now, and makes mince meat out of most, if not all, the service/longevity issues raised in this thread (it's only drawback is weight and can't be wall mounted). You questioned someplace else about cast iron being an appropriate material for modulating/condensing boiler design. Have you explored the design/application of the rAy/KN boiler? Please do so.

And the replacement cost of $6000.00 in 10 years; sorry, that's your cross to bear(and probably thousands of others) for buying the marketing.

No, I think a lot of people will learn to switch back to cast iron modulating condensing boilers like the rAy! Then watch the ROI numbers jump. And, yes, the efficiency will jump more than 10% if these systems could only be mechanically/hydronically designed to do so, which they can.

In your assumptive scenario of a mod/con lasting only 10 years or so, then; from a life cycle cost analysis, it (the boiler) should be considered a replacement service "part", and factored into the cost. And you're right, how do you explain that to the prospective buyer?

I have in the past critcised Smith Boiler Company for not keeping up with the times. Now, I am pleased to say their time is now. The rAy will last for decades.

Jed

Steve Ebels_3

Hi Perry

How's things across the pond? Looking forward to our hapless Lions completing the NFL's first 0-16 season at the hands of the Packers tomorrow.

Regarding the subject to life expectancy; I wasn't insinuating that people should expect and accept 10-15 year life spans from their F/A or hydronic condensing appliances in any way. To me, that type of service life is unacceptable. Period. I think that consumers should raise a mighty hue and cry directly to the manufacturer's when they have an appliance that suffers an early and unwarranted death.

What I was saying is that sadly, it seems to be the case more often than not in the field and I think it happens for two main reasons. The first is that condensing equipment needs more attention than an old standing pilot non-condensing piece of equipment. As a rule, I find that people are either unwilling to accept this fact or else they just plain don't think about their equipment until it breaks. When a piece of condensing equipment fails you add up a lot of dollars very quickly for either a furnace or a boiler. There are simply many more things and pieces to break on a condenser than an old type appliance. That's the cost of efficiency. Today's fuel injected vehicle costs a lot more to repair than Henry's Model T did and it's the same with boilers and furnaces.

The second reason goes a bit more toward our discussion and that is planned obsolescence on the part of the manufacturer of a given piece of equipment. They know very well the design limitations of their product and make decisions at the corporate level to market it or not. Many times the equipment itself is not all that bad, it's just that the manufacturer decides to produce a certain boiler or furnace that obviously has no built in margin for error, field variables or lack of maintenance.

In the F/A side of the business we saw a host of problems with the first generation condensing equipment produced by nearly all the manufacturer's. There are still some that seem to have recurring problems with product design. IE: Carrier's secondary HX issue as witnessed by the class action lawsuit they lost. Many of the issues with the F/A side were installer related as are some of the failures with boilers. I am at present trying to resurrect........yah, that's a fitting term.......a T-50 Munchkin for a young single mom with no money for very expensive parts which have been basically dissolved by recirculation of exhaust gases. This is somewhat due to a questionable design but more so due to improper venting by the original installer. This unit was installed in early 2005 and requires repairs totaling over $1,000 in just parts. That is not acceptable to me and obviously places her in a great hardship.

Again, I feel that consumers should demand more and better service life from their equipment and take their complaints directly to the manufacturer. That more than anything else will drive product quality.

Perry_7

I think you only see part of the problem

First, the Packers aren't doing so hot either. Perhaps we should get together and comiserate over a first rate meal somewhere....

Second: I believe that you only see part of what the Mfrs are getting away with. Not only are they designing for short design lives - they are not designing to handle common issues that can come up from poor installs (you think the Mfrs don't know that many vendors won't install their stuff as per the manual - of course they do). Without knowing the details.... I'll bet that problems you are currently having were entirely forseeable; and should have been designed to not have occured (or not have occured to the costly extent they did).

The reason for that is several fold.

A) Many Americans default to the cheapest product - regardless of quality. Thus some Mfrs are focused on building the absolutely cheapest thing they can.

Most Mfrs are not willing to pay to seak out knowlege on their planned designs. A common theme at a lot of companies is that they have young design engineers... who often have no practical experience or institutional knowlege on issues. They are doing the best job they know how... but miss the dangest things. Expert consultants and old designers are out there... but cost $$$$.

In both the begining and in the end: You do not know what you don't know; and what you don't know can be very significant. Hence - why a lot of suff dosn't last.

For something as significant as a heating boiler - I personally think that the actions of some of the boiler Mfrs actually is neglagance.

As an Engineer who's been arround the block on some issues - there is no way I would have approved the design of some of these boilers. This is not to say that you do not compromise when designing most things. Of course you do - but you ensure that the product will still work well with the compromises you accept.

Perry

singh

Enertopia

If a car was designed to get 100mpg with maybe a technology such as lithium bateries, but every 8-10 years those batteries needed to be replaced. At $10,000 a pop. Would the automobile be a worthwhile venture.
I think so.
I look at mod/cons the same way. This linear thinking, that a appliance has to last 30+ years has to change, and a new pardigm of thought need to take root. Efficiency over longevity.
And as for SS vs.CI.vs AL , in reality what will not last long on ANY of these appliances are the individual components that make the units, such as fans,ingnitors,sensors,solenoids,gas valves,condensate traps, control boards, and yes even o-rings. Already many of these are needing replacements now, fans seem the most vulnerable and I doubt more than 5 years should be expected.

Just my thoughts.

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Gordy

Interesting thread

Been following this one in silence for a while.

It would seem the mind set of "some" is that the boiler is really a commodity like a computer has become over the years.

I tend to agree with Perry on his point of view on what the longevity of a mod/con should, and can be if some serious R/D are applied.

The mind set that a boiler is an expendable component of a heating system is unexceptable. Even in the name of being green, or an attempt to minimize your carbon foot print.

No it does not make sense to me to buy a car that gets 100 mpg with a lithium ion battery bank that needs be replaced every 8 to 10 years for 10 grand which is an understatement. I know this is just an example thrown out there,but it is unexceptable as a consumer to be at the mercy of costly technology.

I for one think the shortivity of a product is in the name of sales for the company. Why do you think nothing reasonably priced does not last anymore.

Gordy