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Viessmann Vitodens Venting

But I heard there's 10 or 12 foundation guys and carpenters who worked on the new Secor Chalet all wearing size 14 boots with the logos mysteriously cut off . It must've been fun watching them work on the house with their new jackets too - sorta like a swarm of worker bees with the gold and black motif :)

Thanks for your picks of best mod-cons .

Comments

  • What's the deal with Viessmann Venting?

    I have installed a number of 6-24/8-32 boilers recently, often in basement/below grade situations. Their venting guidelines are somewhat onerous and I'm wondering what this might be due to.

    To recap: They allow 20'DL horizontal with their cocentric or up to 45'? vertical with 3" or 4" single wall vent, drawing combustion air from the mechanical room. Thats it.

    Just for kicks I ran a 3" single wall about 18' to a horizontal termination and checked performance on the 8-32. It performed just as it should on low fire/high fire etc.

    Boilers like the Trinity I sell as my "good" boiler as opposed to the Vitodens which I sell as my "best". But I sure love the Trinity's ability to vent via PVC just about anywhere you need to go.

    What's the story? Is the Vitodens venting restrictions due to Canadian building codes (I know this is the case with PVC) or truly low blower strength, or is it something else?

    What's wrong with a nice say, 20' sidewall termination via SS single wall vent? (other than it is not allowed in the literature?)

    Comments?


    Happy_Jake

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  • Ken_40
    Ken_40 Member Posts: 1,320
    The...

    "Best engineers europe has to offer" don't have a clue!

    But they sure as hell know how to overcome product short-alls with marketing, don't they?

    The venting instructions are so confusing, written in euro-speak, a hybrid of German/techno-babble/English, is "intended" to be confusing. The reason this is so?

    It allows the claim that you did not follow the instructions, thereby avoiding any shortfalls of inferior designs.

    You don't want me to post my euro-marketing over substance caveat yet again, do you (;-o)
  • Constantin
    Constantin Member Posts: 3,796
    Hmmm...

    Having co-developed an outdoor gas water heater, I can tell you that there are a lot of issues involved in building a vent/intake system that is ΔP-neutral. A zero ΔP under all wind/wall conditions is pretty hard to achieve on a atmospheric burner but essential for clean combustion.

    If the blower motor on the Vitodens is not oversized and responsive enough to deal with gusts of wind, then a ΔP could cause a lot of trouble and prevent clean combustion.

    It is conceivable that the Viessmann guidelines are intentionally strict to prevent such ΔP's from developing inside their concentric vent/intake kits. Hence also the large concentric intake/exhaust, which should be pretty pressure-neutral.

    Another theory could be that their blower cannot overcome the friction of long intake / exhaust vents, restricting the boiler to a narrower range of input than it was designed for.

    Either way, I have a lot more confidence in the venting system that Viessmann uses than the PVC recommended by other manufacturers. Besides featuring a metal inner flue liner, the exterior flue material is made of polypropylene, which has a melting temperature about 2x of PVC. Whether this added margin of safety is either necessary, cost-effective, etc. is for the market to decide.
  • J.C.A._3
    J.C.A._3 Member Posts: 2,980
    What they're trying to say....

    > Having co-developed an outdoor gas water heater,

    > I can tell you that there are a lot of issues

    > involved in building a vent/intake system that is

    > ΔP-neutral. A zero ΔP under all

    > wind/wall conditions is pretty hard to achieve on

    > a atmospheric burner but essential for clean

    > combustion.

    >

    > If the blower motor on the

    > Vitodens is not oversized and responsive enough

    > to deal with gusts of wind, then a ΔP could

    > cause a lot of trouble and prevent clean

    > combustion.

    >

    > It is conceivable that the

    > Viessmann guidelines are intentionally strict to

    > prevent such ΔP's from developing inside

    > their concentric vent/intake kits. Hence also the

    > large concentric intake/exhaust, which should be

    > pretty pressure-neutral.

    >

    > Another theory could

    > be that their blower cannot overcome the friction

    > of long intake / exhaust vents, restricting the

    > boiler to a narrower range of input than it was

    > designed for.

    >

    > Either way, I have a lot more

    > confidence in the venting system that Viessmann

    > uses than the PVC recommended by other

    > manufacturers. Besides featuring a metal inner

    > flue liner, the exterior flue material is made of

    > polypropylene, which has a melting temperature

    > about 2x of PVC. Whether this added margin of

    > safety is either necessary, cost-effective, etc.

    > is for the market to decide.



  • J.C.A._3
    J.C.A._3 Member Posts: 2,980
    What they're trying to say.

    > Having co-developed an outdoor gas water heater,

    > I can tell you that there are a lot of issues

    > involved in building a vent/intake system that is

    > ΔP-neutral. A zero ΔP under all

    > wind/wall conditions is pretty hard to achieve on

    > a atmospheric burner but essential for clean

    > combustion.

    >

    > If the blower motor on the

    > Vitodens is not oversized and responsive enough

    > to deal with gusts of wind, then a ΔP could

    > cause a lot of trouble and prevent clean

    > combustion.

    >

    > It is conceivable that the

    > Viessmann guidelines are intentionally strict to

    > prevent such ΔP's from developing inside

    > their concentric vent/intake kits. Hence also the

    > large concentric intake/exhaust, which should be

    > pretty pressure-neutral.

    >

    > Another theory could

    > be that their blower cannot overcome the friction

    > of long intake / exhaust vents, restricting the

    > boiler to a narrower range of input than it was

    > designed for.

    >

    > Either way, I have a lot more

    > confidence in the venting system that Viessmann

    > uses than the PVC recommended by other

    > manufacturers. Besides featuring a metal inner

    > flue liner, the exterior flue material is made of

    > polypropylene, which has a melting temperature

    > about 2x of PVC. Whether this added margin of

    > safety is either necessary, cost-effective, etc.

    > is for the market to decide.



  • Paul Pollets
    Paul Pollets Member Posts: 3,663
    Off Base Comments

    Ken, for someone who has installed only one Vitodens (and had problems with the particular venting of that project), I suggest you leave the bias at the front door.

    This boiler has particular venting requirements, both for the co-pipe application or single-wall stainless, which removes the sealed combustion feature.

    The venting issues can be carefully explained by the Viessmann tech help, either in Waterloo, Ont. or Rhode Isl.

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  • ALH_4
    ALH_4 Member Posts: 1,790
    SS

    We had some trouble with achieving a water-tight seal in horizontal runs with stainless single wall. The stainless steel vent pipe was gasketed and installed with great care. Maybe Viessmann is uncomfortable with guaranteeing that horizontal stainless pipe will not develop sagging issues and therefore potential leaking of condensate. I am guessing at this, but it does make some sense from what I have seen.

    PVC is not vent material, and is not rated as such. I am surprised that other manufacturers recommend PVC for vent pipe. Does this not open them to liability in the event of a failure?

    -Andrew
  • Ragu_5
    Ragu_5 Member Posts: 315
    Interesting Points...

    I will be installing my first Vitodens soon and am reading the manuals over and over, especially regarding the venting.

    I agree that the PVC venting issue of other brands may and probably will come to a head with a liability problem in the future. Do you remember the grey plastic vent piping made by one of the major chemical companies that was taken off the market and a class action suit brought about 8 years ago? Seems like a precedent.

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  • Ken_40
    Ken_40 Member Posts: 1,320
    So, now

    my critism of a first-hand experience with Viessmann is the result of bias? Not experience?

    I still service some Viessmann's that were installed when you were in diapers lad and they just made great boilers - without the marketing perversion.

    And when they would not return calls and the homeowner had to write on The Wall to get any response, THAT was bias as well?

    You don't suppose your relationship and selling nothing else but Viessmann has any basis of a bias now do you? How many installs were the resutl of factory/rep leads?

    Let's not go there... I respect you too much and the "jingle" Viessmann has directly put in your pocket as a result of you being their poster-boy, is the stuff bias was made from..

    Shalom



  • I seem to remember ...

    And correct me if I'm wrong Ken , that you were very critical of Viessmann products before the troubled install happened . I remember specifically asking why you would install equipment you have an issue with . I forgot the answer ?

  • Paul Pollets
    Paul Pollets Member Posts: 3,663
    Bias vs. Experience

    I was hardly in diapers when Viessmann started their West coast operation. And I'm hardly their poster boy. I've never appeared in any of their advertisements,nor paid to endorse their products. Are you sure you don't have me confused with Richard Trethewy, eh?

    In 9 years, I've received one developable lead from the local rep that resulted in a sale. That was in Aug. of this year. The 'jingle' I've managed to put in my pocket is the result of my work and marketing, not Viessmann's.

    I still feel this company offers the highest quality equipment and technical services...which so happens to suit my particular market. Even on the West coast, where the hydronics industry is geographically challenged.

    Back to the topic...all wall-hung boilers available have their own vent requirements. These requirements need to be determined when the system is designed. There is some flexibility running (2) 2" PVC pipes rather than one. BUT, I'd rather run one larger co-vent, than 2 pipes. If installing the co-pipe was a show-stopper, I'd spec another boiler.


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  • Constantin
    Constantin Member Posts: 3,796
    Plexvent?

    Wasn't that the stuff on the boiler in NH that killed a couple of students via CO poisoning?
  • Constantin
    Constantin Member Posts: 3,796
    Time will tell...

    ... under the right conditions, PVC may be seen as a material that is adequate for the job.

    Thousands of installs across the nation over the last couple of years appear to be problem-free... and if your quest is to find a "vent" material that is cheap, universally available, acid-resistant, and easy to assemble, PVC looks like a pretty good choice, as long as you take the care to protect it from excess flue gas temps, etc.

    Hopefully, all the manufacturers were able to anticipate the various failure modes that a boiler can experience without causing a bad hair day inside the boiler to become a bad hair day for the house as well.
  • I'm with you

    I'm with you. I sell Viessmann because I believe that they are the best -- period.

    As I also believe that my outfit is the best there is in my local area -- we are a perfect match.

    When I no longer see the value in the price tag I will spec something else.

    That being said. I would sure love to vent the damn thing through a side wall using the SS single wall vent...!

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  • Ken_40
    Ken_40 Member Posts: 1,320
    Who's got more hair?

    You, or Tretheway?

    Let us know when the endorsement check arrives. We'd like our cut. After all, without us...
  • Solarstar
    Solarstar Member Posts: 82
    Viessmann venting article

    please read and comment!! See attachment its a large file
  • Ken_40
    Ken_40 Member Posts: 1,320
    I was told,

    in no uncertain terms, that the client, who was acting as his own GC, said, "It Will be a Viessmann." It was apparent that he knew something. When I asked, "Why not save some money and look at a few options that would be as efficienct but better at the venting nightmare potential, and he said, "Make it work."

    When asked point blank why the Viessmann, he said, "Because it is perceived to be the best boiler in the world and some of my frinds think it is overpriced and got another brand. "I wanted to see the look on their faces when they saw what I had in my building..."

    He followed that comment with a, "I know its overpriced goods, but it has appeal to those who don't really know, but want to be thought of as such, nonetheless.
  • Paul Pollets
    Paul Pollets Member Posts: 3,663
    Hairy Scary

    I have more hair, at least this weekend....but his feet are much bigger.

    Without you Ken, My life would be terribly boring.

    Your favorite Kuchlefel...

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  • Mark Hunt
    Mark Hunt Member Posts: 4,908
    Ultra-vent


    was the grey stuff. Plex-vent was either and amber color or black.

    Both products were recalled due to failure and SS replacement kits were available through the Corrective Action Program.

    Mark H

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  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928


    Nice article Paul. Thanks.

    Some will probably think it techno-babble and marketing hype...

    If the goal is to carefully balance combustion air with fuel to both reduce emissions and maintain efficiency, then that "non-mechanical, proportional pneumatic link" would sure seem preferrable to, at best, a fixed adjustment based on static restriction in the venting.

    With such adaption, there must be some reserve capacity in the blower motor to deal with unusual conditions (wind, ice, etc.) that may require a higher blower speed to maintain enough air to ensure full output in any conditions. I suspect that Vitodens venting instructions are particular and length restrictions fairly tight for this very reason. Even "uncompromising" designs require attention to detail to ensure the best performance...
  • Constantin
    Constantin Member Posts: 3,796
    Thanks for the article, Paul!

    It makes for interesting reading and a number of my thoughts re: why Viessmann is so restrictive with its venting seems to be confirmed.

    Using a differential air pressure sensor is but one way to figure out how hard to drive the electric motor. Cars frequently use mass-air-flow sensors that meter air very accurately to achieve good combustion and high output. Yet MAF's are expensive and can be troublesome, so a differential pressure sensor will probably be a much better match for a low-flow application like a boiler.

    Also note how their graph on the last page of the article for flue pipe lengths vs. output goes well beyond the 10 meter mark, suggesting that the Viessmann venting system installation requirements are, by design, very conservative. On the other hand, "babying" their DC blower motor like this may achieve the kind of longevity that some other boiler blowers have had issues with.
  • I'd like to know

    if Ken has reaped any benefits from touting the Weil Mclain line of products ?

    And I'd also like to know what brand mod-con Ken believes is the best , and why ?

    Thanks .



  • Ken_40
    Ken_40 Member Posts: 1,320
    I mailed all the checks to

    you! Didn't you retire on that money yet?

    Don't tell me you didn't get them... You at the same mailing address?

    For small stuff, I like the Munchkin. For bigger, I like the Aerco. For bigger yet, we like the C/B. We also use W/M , Viessmann (if the client has bought the absurd marketing claims and chooses not to listen to logic), and a smidgen of anyone else who makes a mod-con, based a lot on area of the state we are working in if not near our basic three suppliers.

    Why? Both made in the U.S., both priced so as to meet the "best bang for the buck" criteria most of us appreciate and love. Neither has much of a marketing budget, (at least not like Viessmann's) allowing all the costs to go into the product's quality, rather than an office of suits and wannabe "experts." Installation and service instructions in real English. Three competing wholesalers near the center area of work, all of them "stocking parts." Lots of generic components that we can pick up almost anyhwere. Unrivalled efficiency. Low water content and simple to connect PVC venting. No real restriction sas to venting. Great reliability track record so far. Small size relative to BTU firing rate. Stainless steel HX. Standard MPT not some gypsy euro-style. Very low firing rate capabilities. Large turn-down ratios. Both companies been around for a long time. Learning curve for installs and service remarkably fast. No absurd claims of superiority over their competition. Excellent on-site training, if desired. No preferred competitors (of mine) being fed leads from corporate networks. Excellent inventories. Few if any, negative comments on The Wall about either. Huge selection of input ranges. Neutral color cabinetry. No "attitude" from any aspect of the distribution chain. No stupid trips, trade shows or fishing trips offerred for "being in their pocket, or one of their fair-haired goombas/goons." Extreme reliability to perform as promised. No waiting for parts from overseas. No ego issues, just decent stuff priced fairly: probably because they know how to manage overhead.

    They also have Chuck Shaw. I saw the factory. Was very impressed by HTP workers and work ethic, especially when compared to Viessmann's in Germany! Like night and day!

    Hope this helps?
  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928


    Ken:

    Do the o-rings used in the HX of the Munchkin bother you as much as those used in press fittings? Sorry, but I couldn't resist asking.
  • ALH_4
    ALH_4 Member Posts: 1,790
    Certainly

    If I had to choose between a Munchkin and a Vitodens simply based on quality of construction.............

    I guess the Munckin is at least assembled by Americans for an American company. How many components are American made? Really my biggest beef with the Munchkin is the cheap plastic jacket and the way the heat exchanger just lays on a fiberglass batt. There is also a huge difference in the construction of the heat exchanger between the Vitodens and the Munchkin. I buy American whenever I can, but not when it means a sacrifice in quality of that magnitude.

    Is it true the Utica condensing boiler hx is cast here? That's what I want to see. Real American manufacturing capability, not the ability to source components from all over the world and piece them together here. Burnham can do better than the Revolution II. I want Burnham to do better than the Rev II, and do it here.

    -Andrew
  • Ken_40
    Ken_40 Member Posts: 1,320
    I would always prefer

    a jont that can handle expansion and contraction the best. Metal on metal therefore, would not be my first choice.

    But then, the same euros that developed the press fit", also developed the Viega EPDM as well. Talk about contradictions! The euros are so prone to speaking out of both sides of their mouths...
  • ALH_4
    ALH_4 Member Posts: 1,790
    O-Rings

    Yeah, I can attest to the longevity of o-rings in the heat exchangers in Raypak boilers. No thanks, I'd rather have a weld.

    -Andrew
This discussion has been closed.