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Aluminum heat exchangers

PG2448
PG2448 Member Posts: 5
Our church is installing 2, Weil-McLain 90+ cond aluminum sectional boilers for our old 30+ CI boiler that is a leaker.  Have heard that the aluminum jury is not in yet and the acidic condensate will degrade the water ways in the boiler.  Is this true and should we stick with a 85% Burnham and modulate the high limit to optomize savings without the condensate problems?

Comments

  • TonyS
    TonyS Member Posts: 849
    My opinion

    The boiler companies themselves require stainless al294c stainless pipe on their near condensing boilers . Why? Aluminum tubing would be a lot cheaper. Ever remove a aluminum chimney liner that's been on a outside chimney connected to a gas boiler for a few years. Looks like Swiss cheese. Aluminum has a lot going for it if your a manufacturer.. Inexpensive, easily castable, easily machined, light weight .  Figure the boilers lasting 5 years beyond the warranty...Maybe. There is no payback.
  • Edward A. (Ed) Carey_3
    Edward A. (Ed) Carey_3 Member Posts: 236
    edited August 2009
    To all, Question regarding church boiler

    To all,

     The post regarding questions for the church boiler is by an old friend of mine.  His Name is Paul.

    He was a professional HVAC contractor for many years. He did a lot of larger commercial work. He has since retired from the field to work at a college. He therefore is somewhat outside of the loop of the most current innovations.

    He asked my opinion re the aluminum heat exchangers and I gave him mine. I will reserve that so as not to sway anyone else pro or con. 

    I recommended to Paul that he post here for a good variety of well informed opinions from other pros who work on them. 

    If you have an opinion, I would really appreciate if you would please respond.

    Also, don’t forget to welcome Paul to the wall.

    Thank you my friends,

    Edward A. (Ed) Carey

    E.A. Carey HVAC
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    I await answers to this too.

    I bought a W-M Ultra 3 with an aluminum heat exchanger three months ago, so I very much care about their lifetime. It comes with a 15-year warranty on the heat exchanger, but, on the other hand, in their cost comparison program at their web site, they use a 20 year lifetime for the boiler.



    In their installation manual, they say it should be fine provided that the pH of the water is between 7.0 and 8.5, that the hardness should be less than 7 grains, and the chlorine should be less than 200 ppm.



    I called the water company and they say the pH is between 7.2 and 7.6, that the hardness is about 6 grains, and the chlorine is less than 2 ppm. So that should be OK. I have some pH paper on order. They say the water should be tested annually. I wonder if the pH of the water is expected to change. Anyway, the paper I ordered is shown here:



    http://www.indigo.com/Test-Strips/gph-test-strips/ph-paper-5.5-8.html
  • hot_rod
    hot_rod Member Posts: 21,898
    the key to AL HXers

    is the quality of the fluid inside. This is especially important with glycol use. Seems some of the AL glycols aren't all that AL friendly after all.



    But it is the installers responsibilty to assure the system is properly flushed and cleaned and filled with quality fluid at start up. test that fluid yearly.



    Then the combustion side... There is a lot to know about combustion side design. the size of the HX surface to burner, flame patterns, etc. Sit in on one of Roy Collvers seminars if ever you get a chance. He has a lot of experience with combustion and mod cons.



    The quality of the gas they consume is a big unknown. As you see from another post, more and more natural gas is being imported. Seems to be some questions about what is actually in that imported gas. And in some areas they blend the import with domestic.



    I know in some western states installers had to go around and re-adjust burners when the BTU or calorific content of the blended fuels changes. An array of different colored stickers de-noted which boilers had been adjusted. It may still be going on?



    Sort of like the colored bar graphs for terror threat warning :0
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Devan
    Devan Member Posts: 138
    Keep on waiting!

    In my opinion, time will tell for both stainless steel and aluminum boilers.

    I believe the internal components (sensors, blowers, gas valves, ignitors, etc will need to be replaced long before ANY HX goes bad. Provided that water is tested for PH, proper piping and regular maintainence is followed from maufacturers , again both types.

    Why would any one want a boiler to last 30-40+ years is beyond me. Look were we were 40 years ago, 10 years ago, 10 years from now. I doubt mod/cons would be cutting edge technology by 2025, and we will be moving in another direction.



    As for want it takes for one to cast aluminum, I researched this a little, and it is actually more expensive to smelt and cast vs. stamping stainless. There is an aluminum boiler featured on this website that not only is casted in north america , but also a monolithic, pour. Truly amazing!! But heavy and may be slightly oversized for a small residence, but should fit nicely in a church. Check it out !



    Welcome to HH site Paul !
  • Devan
    Devan Member Posts: 138
    Natural Gas

    HR, my take on the Natural Gas post is that LNG is not yet feasible here in the U.S. because there is not enough infrastructure to process it. Therefore, those countries that want to export it because they don't use much of it is causing a huge surplus.



    Plus the fact that the U.S. has recently found enough domestic gas here to last 100 years! Why import it .



    Sorry to hijack this post on the gas topic.



    http://online.wsj.com/article/SB124104549891270585.html
  • CMadatMe
    CMadatMe Member Posts: 3,086
    Here's the anwser in a nutshell

    I'll leave up to you guys whether you would install this boiler or not. Weil is in the process of changing their heat exchanger in this boiler from alum to stainless. Why? They are beginning to see problems associated with the alum block ie, failures and this comes from a source that knows.

    If it were me I woould be looking at Viessmanns new Vitodens 100 or 200 depending on the application. Why? Strongest stainless heat exchanger on the market. Look at the table of metals nobody elses compares. Also they have a 2 yr warranty on parts and limited liftetime on the exchanger. Nobody else has this type of warranty.

    Also, it you go with the new Vitodens 200. The burner continually looks at gas pressure and gas mixtures and adjusts to fire at its optimum peak. The boiler also condenses like crazy. Your flue gas temp with only be 15 degrees higher than you return water temp. This boiler can also be vented many different ways and to over 200' away.

    I haven't even gotten into the control. I'll leave that up to you. If you would like some info in it, ie, lit and manuals just e-mail me and I will forward them to you. We cannot post PDF files on this site.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    test that fluid yearly.

    Here I go again. What is the procedure to test the pH of the fluid in my system? I just got the pH strips and decided to test the water coming out the tap. The water company said it goes into the pipes at pH 7.2 to pH 7.6. I took a clean glass, let the water flow for a minute and filled the glass. I then tested it with pH paper that goes from pH 5.5 to pH 8.0 in six steps, and the water tests pH 6 which is too sour for my boiler. It does not taste sour, whatever that proves.



    If I remember from freshman chemistry class correctly, tap water is an unbuffered solution so the slightest amount of dissolved stuff in it can make dramatic changes in the measured pH. Now there is CO2 in the air around here, and it can change the pH when it dissolves. On that theory, I tried hot 120F water and the pH rose to 6.5 or maybe slightly more, but not up to pH 7. Do professionals use pH meters or something more accurate than this pH paper?



    I suppose I really should test the water coming out a purge valve on my system, but since it was filled with tap water, I assume it would be pretty much the same as that.
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    Weil is changing their heat exchanger in this boiler to stainless.

    Very interesting. Where did you find this out? I could not find it on the Internet. Perhaps Weil notify dealers and contractors before they notify homeowners. But I would like to read about this if it is publicaly available information.
  • TonyS
    TonyS Member Posts: 849
    I think the Vito uses 316ti

    which is just a variation on 316l. I wouldn't say its the strongest. The ferritic stainless used in the Prestige 439 would be a better choice. Neither is the best and both have their faults. Check here and call the metallurgist in the morning, very friendly people [url=http://www.alleghenyludlum.com/pages/products/products.asp]http://www.alleghenyludlum.com/pages/products/products.asp
  • hot_rod
    hot_rod Member Posts: 21,898
    LNG terminals

    These articles indicate there are 8 terminals, 7 import, 1 export already online. This website tracks who gets the LNG and how much.



    I've heard this gas has made it into the system in some areas, but I don't have that from the "horses mouth"



    http://fossil.energy.gov/programs/gasregulation/analyses/Quarterly_Reports.html#select
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • hot_rod
    hot_rod Member Posts: 21,898
    edited August 2009
    Ph stick meters

    Here is the one I use. This company, Hanna, offers a wide range of Ph test meters. It's the same meter the chemical suppliers around here use to test fluids.I bought mine at Graingers years ago. Under 100 bucks as I recall.hr
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    Thanks for the reference.

    I ordered one of their units. HI 96108. Considerably less than the price you mentioned.



    It will also be useful in my darkroom.
  • EricAune
    EricAune Member Posts: 432
    Hot Rod, PH Strips.

    Ph strips are really only effective/accurate for about one year. 
    "If you don't like change, your going to like irrelevance even less"
  • CMadatMe
    CMadatMe Member Posts: 3,086
    Not publically avail

    nor has it been said to the contractor or wholesalers. While I will not reveal my source it comes for someone inside the industry with knowledge to the change. I'll leave it at that.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    Not publically avail

    I respect that.
  • Leo_G
    Leo_G Member Posts: 89
    The "better" thing

    about the aluminum block exchangers, as explained to moi, is that when the exchanger finally fails (which they all, stainless, alu, cop/alu, etc. will eventually do), the alu should be the easiest (less labour) and least expensive (to purchase), to change out. So another thing to consider, is that if you have change the whole boiler, as is the case with some stainless ones, or just the heat exchanger.



    Either way, we here in North America, are going to have to get used to the idea that mod/cons are only meant to last 12-15 years. About the same amount as a well cared for car.



    Leo G

     
  • Devan
    Devan Member Posts: 138
    edited August 2009
    cool website

    HR,I just browsed through the site. Pretty nifty charts (but in PDF)According to the info LNG imports 1st and 2nd quarter 2009 accounted for 8.46% of all imports of NG. The remaining 91% of imports come to us via Canada (pipeline). Oddly enough we also export gas to Canada.Of the LNG imports, more than half come from Trinidad, and most all of it enter at Everett , Mass. Second terminal that received the most LNG , Elba , Ga. Eygpt and Norway are the other two main LNG importers to us. We export LNG, primarily to Japan, from Alaska.According to the site , LNG impoerts have gone down slightly last year.Most all gas found here is domestically consumed here. And now with large pockets of gas being extracted from shale etc, To me , LNG imports won't increase for decades to come.
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    That is a really nice photograph.

    It reminds me of when I lived in Buffalo, N.Y.



    As far as replacing an aluminum heat exchanger, every 10 or 15 years, that would not necessarily be a bad thing if the price of it were reasonable. I do not know what the cost of a W-M Ultra 3 80K heat exchanger is (and please do not tell me here). But if it is (making up the numbers) $2000, that would be about $133/year or about $0.37/day, less than the price of the gas it burns in the summertime.



    I looked into my boiler and it seems pretty simple in there. My guess is that it would take

    between 1/2 day to a day for an experienced technician to replace it, if it is available.
  • TonyS
    TonyS Member Posts: 849
    In Europe

    these boilers are about 1/3 the cost they are here, check ebay.uk and while you are there check prices on other commodities just to get a idea. I would say the Europeans have it just about right...About a grand for a boiler that last 12 years. No different than a standard power vent water heater here. Im sure everyone here could live with that. I was looking at the new Burnham es2, cast iron with 110 return temps and 85 % eff. w/outdoor reset. This boiler has a much better warranty and will last alot longer. You will never see a payback on these modcons with new boilers like this. There are people out there like you who will buy them just for the enviroment but we live in a country that has 50 million without health insurance and a home is repoed every 30 seconds... that is not the norm.
  • KevinCorr
    KevinCorr Member Posts: 106
    not aluminum

    Lochinvar Knight is one of the best of the new ones.



    My System 2000 is 25 yrs old and still a good choice today.
  • CMadatMe
    CMadatMe Member Posts: 3,086
    I Post This Question

    How often do you trade in the vehicle you drive? Why are some stating that if the boiler was less money,  then the length of time it last would not be an issue. Why is our industry treated so different then the other industries in this country? Would any of you that post on this site go to "appliancehelp.com" or "carhelp.com" or any other industry.com (fictional wen sites) and ask those manufactures to cheap-in the price of their higher end product so it's affordable to you because you don't think it's worth that much. Then why do you want it?

    Why do people that can't afford something feel that it is their right to get it at the price they want to pay? Go to carhelp.com and ask the car manufactures to make a 25k car (the average price of a decent auto) that will last more than 10 years. I hate paying 3 bucks a gallon for gas and with gas I have no choice because everyone charges the same.  Plus or minus a few pennies.

    Let's face it. Certain higher end products are meant for people that can afford it. If you can't afford the higher end product then you don't get it. Whether you think it's worth the price or not is irrelevant. Why? Because you have a choice whether to purchase it or not.

    Few more questions to all the guys that have installed and to those that have mod/cons. How often do you service the piece of equipment you installed or you own? Be honest..Do you do a water test and is a water test done on every installation prior to quoting this type of boiler? ....Be honest....If you answered no to either question guess what......It's the Indian not the arrow...
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    edited August 2009
    to those that have mod/cons

    Few more questions to all the guys that have installed and to those

    that have mod/cons. How often do you service the piece of equipment you

    installed or you own?



    I have had it only 3 months and have not yet had it serveced. According to the manual, I should have it have it serviced at least once a year. The salesman told me that their policy is to do the first annual service free. I will certainly accept that offer. In the past, with my former contractor, I had a service contract that got me an annual service, priority status for emergencies, and a 10% discount on parts.



    Be honest..Do you do a water test



    My contractor did not do a water test at my home. Since all the water around here comes from the same place, he may know how it comes out. I tested my tap water, with which my system was filled, with some old (20 years or more) pH paper (that goes from pH 0 to pH 14, and it comes out at about pH 3. I just got some newer, more sensitive pH stips that go from pH 5.5 to pH 8; Cold, it comes out pH 6 and Hot (about 120F) it comes out pH 6.5+. I just ordered a pH meter suggested by someone here that reads to an accuracy of pH 0.1. We will see. If the meter agrees with the new pH strips, I will need to do something about it. I know I checked with the water company and it goes into the pipes in the range of pH 7.2 to ph 7.6, so it may have dropped at least one pH point. I wonder what one puts into the water to raise the pH that does not harm aluminum. Sodium sulfite?



    I just tested the tap water again as hot as it will come out, 115F as the tank has been cooling off since my morning shower. pH cam out pH 7, which is as close as I can read the chart. I tested it hot to drive off the dissolved gasses, especially CO2, that can make it acid. I may boil some tomorrow and see if that makes a difference. But if so, what temperature should I test it? And ultimately, I should test the water coming out of a purge valve, not my tap water.



    and is a water

    test done on every installation prior to quoting this type of boiler?



    I have no idea what my contractor does. I am supprised that I get such a difference between what the water company puts into the pipes and what comes out in my house. If there really is a difference. But maybe I should not be surprised. My user manual does say the pH should be tested at each service, and I will make sure my contractor does it. I will probably do it myself too, but I do not know how I would adjust the pH of the water in the system. I feel the contractor should do it as part of the annual service, since that is what the service manual says should be done.



    If things are as they seem, the contractor should do a pH test and have some way to adjust the pH each year (if you do not have means to do this, no point testing). And if you cannot fix it, you should probably not call yourself a professional. I do not think the customer should have to buy a multi-gallon tank and a suitable pump to do a system solution transfusion -- but the contractor should.



     ....Be honest....If you answered no to either question guess

    what......It's the Indian not the arrow...
  • CMadatMe
    CMadatMe Member Posts: 3,086
    Water Test

    No matter what the PH coming into your home should be a 7 (neutral) anything else lower and the water becomes acidic. But to fix this problem we have to created another problem. Hard Water. If you find that you PH is low and have to add an acid neutralizer you are going to make the water hard and will have to also add a water softner to the system.

    What we generally do in this type of application is also add a post carbon whole house filter to clean up any residual from either piece of equipment.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    Just thinking out loud here...

    I do not see what good an activated charcoal filter would do in my water supply. If my heating system does not leak fast enough, the makeup water will not enter the system fast enough to correct the acidtiy that builds up (if it builds up). Possibly it would work if installed in the primary loop of the p/s piping inside the system. If the problem is dissolved gasses.



    Also, it seems to me to be necessary to understand why the pH goes down between the water company plant and my house. If it is just dissolving of CO2 in the water, a tiny amount of a suitable base should suffice. Selecting the base may be tricky with aluminum in the system. Sodium hydroxide might be a bad thing because it dissolves aluminum. Maybe not in tiny quantities. We used to etch aluminum by inserting it in a strong solution of sodium hydroxide and water, but it was very basic. In the case of a heating system, we are just returning the fluid from acid to neutral or very slightly basic.



    Also, sodium hydroxide should not harden the water: it is only sodium ions and hydroxyl ions and neither hardens the water. Water softeners replace calcium and magnesium ions in the water with sodium ions, for example.
  • TonyS
    TonyS Member Posts: 849
    You post an interesting question, so heres my opinion

    A boiler is not a car for several reasons, everyone needs a car, from Texas to Maine, it is just an American fact of life. The car is something Americans embellish, we have car museums, movies about cars, drive in movies for cars, When your young your chances of getting" lucky " are directly related to the car you drive. The largest spectator sport in this country is nascar. We drive them around oval tracks, drag race them, jump them, many of us were conceived in them. I can remember every motorcycle I had since I was 12 and every car since I was 16 They each hold a memory of a special time in my life. As much as we all love this trade, it is our trade and very difficult to talk to people about outside of our small group. That's why we are here. Sure, some of us live in affluent areas where radiant heat and Viessman boilers sell much more easily but I for one don't. I live in Reading Pa, A city that was built back in the 1800s and is probably 50% hydronic. People here are suffering as in many places! Sure we sell Modcons and radiant but it is not the mainstay of my business. Boilers are a commodity for most, No more thought about than the roof. What if your roofer told you after installing a new roof...that should be good for 12 years. Even photovoltaic have a 25 year warranty. OK so if they cant afford the high tech, what happens? They buy the low tech and we all just keep on destroying the planet. Also the people that cant afford their fuel are getting Government help which means you get to help pay for their fuel. I wish I could see your question as I'm writing this post, Its one thing I don't care for in the new Wall. I believe you ask if we tested water, Yes I do, I am also in the water treatment business so I make it a point to test water in every home. Lets me ask you, when you have to fill a new boiler and you have 18 grains of calcium and they have no softner, how do you do it. Honestly.
  • TonyS
    TonyS Member Posts: 849
    JD

    Carbon filters are for removing chlorine and radon not for co2. Co2 will be removed from your heating system as soon as you run it up to temp it will exit via the air vent, no need to be concerned. Glycol in a system is what starts the problems if its not maintained, it decomposes into glycolic acid and must be checked every year. Also if you have a auto feed valve, turn it off so if there is a leak somewhere you are aware of it.
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    Carbon filters

    Well, W-M said it was OK to use water with up to 200 ppm of chlorine in it. My water company say their water has less than 2 ppm, so I would guess there is no need to filter that out. I am just concerned with the acidity, because W-M say it should be between pH 7 and pH 8.5, and my limited testing says it is pH 6 cold and pH 7 hot as it comes out of the tap. I have not actually measured the water from a purge valve on my system, but that is the stuff that went into the boiler.



    I was quite surprised that the pH changed so much with temperature, because that raises the question of at what temperature I should measure the pH. I mean I can see that higher temperatures drive off dissolved gasses, including CO2, so that would reduce the measured acidity. But the question remains unanswered.
  • CC.Rob
    CC.Rob Member Posts: 128
    edited August 2009
    car ≠ boiler

    If a boiler is like a car, then I ought to be able to buy one and have it installed in my house with little additional cost, just like I park a newly purchased car in my driveway with little other cost. A car is a commodity item. There are thousands of cars accessible within a short radius of nearly every person in the country at all kinds of price points, with all kinds of features, and total costs of ownership.



    But right now, for most people, a new boiler means full tear-out, new piping, venting, controls, wiring, etc. Dropping $8-15k every 10 years for that is simply not in the cards.



    Perhaps there is a uniquely American expectation that these appliances should last decades. Perhaps that is an unrealistic expectation in the modern boiler era of high tech electronics and cutting edge heat exchangers.



    If boilers are going to be a short-lived commodity item like a car, then the manufacturing industry and the professional hydronics trade needs to standardize as much as possible on piping, venting, wiring, etc. so these commodity items are as close to plug 'n chug as possible.
  • TonyS
    TonyS Member Posts: 849
    edited August 2009
    A car is a different type of commodity

    People will spend 30,000 every 10 years on a car, but a car is more than a machine,its an extension of a persons personality(to many anyway). Could you see Vanna White telling someone that behind curtain number 3 is a brand new......boiler. When people hit the lottery they don't say Yeaaaa now I can get that new boiler. Anyone that says that is braindead or one of us. I don't think asking 30 years out of any large home investment is to much. When I buy a roof I go for the 30 year shingle. New windows have 30 years or better warranty. Solar tubes are 30 years and high tech photovoltaic have a 25 year warranty. I think if solar didn't have a 30 year warranty it would be much harder to sell. When I see a boiler like the new Burnham ES2, that will go 30 years+ at 85% vs 2 modcons in the same time. What advantage was the modcon? Nothing moneywise thats for sure.  i am sure the people in New England states see a payback faster than people in Maryland but even if the modcon is 95% that only 10%. If they spend 2000.00 a year on fuel they save 200 a year for 12 years is 2400.00 dollars...then what. Another 8000.00 to 10,0000 dollar modcon. This is just my opinion, if im missing some angle please tell me. I sell modcons to but im definatley going to start selling the Burnham.
  • CMadatMe
    CMadatMe Member Posts: 3,086
    You and the Post above have

    fallen into the trap....Marketing.......Your educated about the car. A car that was once a luxury item is now a necessity. Who said you had to buy the 30k car. I'll tell you.  Every commerical and magazine with a hot chick and the premise that you could get that hot chick or that you will fell all good inside. The automobile has been marketed as a status symbol and we love that.  We all feel real good inside when we turns heads as we drive down the road or when we pull into the driveway. I have a question for both of you. How much do you spend a year on maintenance of your car? This would include cleaning, oil change and other fixes that you may spend over the year or better yet the life of the car you own. What does your average customer spend a yr or on the life of mainting their heating system?

    As far a the Vanna White analogy. I've sure seen alot of people jumping up and down over getting appliances on game shows.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Leo_G
    Leo_G Member Posts: 89
    edited August 2009
    Tony

    one other "cost" that is not mentioned to often, is the "cost" to the enviroment of mining/refining/producing/shipping of that second mod/con. I still feel in my bones that the total "footprint" of the 2 modcons is not measurably smaller then that one standard boiler with a good  outdoor control when the real "costs" are taken into account.



    Leo G
This discussion has been closed.