Semenars misconception on combustion eff vs system eff

clammy

Wondering what other thoughts are on this subject.I recently went to a semenar for a european wall hung boiler and listen as the instructor went on about how eff there boiler was and every one there listened in amazment i myself was very skepital knowning better espically when he claimed 97 to 98.5 eff for there wall hung and went on to explain how they get there numbers .The gentleman claimed that they isolate the boiler from the system and with the use of 2 boiler drains piped on the suply and return of the boiler they run a hose and just run cold city water through the boiler and dump it in a sink or floor drain.I personally though that this was very misleading espically since most there had never installed a mod con nor designed a system to take use of the condensing tech.I called the guy on the issue that doing the combustion test under those condition was only showing the boilers combustion eff under conditions that they would probalby never see in the real world baseboard system that most in the room would be installing these wall hung to serve.the guy did not get upset with me at all and then stated that what i was saying was true and then that you could get these eff # if you where running low temp system .Most in the room had a Holiday glazed ham look on there faces as myself and the instructor talked about design and layout of a low temp systemand using there outdoor reset which i know most of the plumbers in the room would never do cause they don't want any call backs to rest the urve or not enough heat calls.Do you think that when these guys do these semairs they should make these claims with these hi eff # or just tell the truth .I found it very strange being i have gone to semairs for alot of differnt wall hung mod cons and most touch over the fact that these system work best with low temp .While other do not say one word about .Do you think this is misleading or is it that they realize most of these guys have no clue .Also they stated that after the install that you can go 2 to 3 years before doing cleaning .I also called the guy on that subject also being this boiler using a giaconni heat exchanger and i am some what familar with this design and would not let one go 2 or 3 years before servicing .Maybe 2 years after the first year check up if the system was low temp and the condition was very clean after the first year using it as a gauge .I really found the way they get those # misleadinng espically tell the guys to piping it that way so they could combustion testing on the job easier with out the unit cycling .To me it seems like it would not be a true eff test yes combustion eff test but not waht the unit is really doinfg as it is installed in the HO site .Whats your thoughts ?Sorry for the long rant  peace and good luck clammy

Wayco Wayne_2

I know

what you mean Clammy. It doesnt seem right to set it up that way. I bet the saleman also sells vinyl siding in his spare time. You might get those efficiencies on a snow melt but not for a heating system. Also you know and I know that style heat exchanger needs to be cleaned. How often is more a metter of how much dust and particulate are pulled in with the combustion air. Remember the Old Glowcore with the cartrige air filter on the intake air? There was a reason they thought of doing that. I hope they had a good lunch for you. WW

Jamie Hall

and if you believe all that stuff, Clammy,

I have a nice, slightly used bridge on the east side of Manhattan I'd like to sell you...



Rant away, sir.  Folks like that drive me bats.

EddieG

I agree

The statement about service only needing to be done every 3 years, is what got a lot of units out there a bad rap. All the sudden when the HX is shot in about 6 years because of no maintenance. The condensate backs up and destroys these things. Along with gas pressure issues, flue issues, etc, etc. These things need to be serviced, probably more so than the older style systems.



On the efficiency thing, that is misleading. But we really need to revamp the whole AFUE thing anyway. As far as these plumbers who disable the ODR, why bother with a Mod/Con if you aren't going to use ODR. A waste of money as far as I am concerned. Just install a conventional system.

clammy

gotta agree

Wayne it was a dinner deal pizza and all things Italian ,this supply house which is independent only 1 location always does free training and  seminars  and always a very good food spread but for me i never eat at them instead i am there for knowledge and answers and usually leave mind hungry i can eat at home but most of the guys are shoveling that free  food down as if it was there last meal  it is very dishearten to me personally being most of them don't have even a clue .The whole comedy thing is most of these guys i known some what and none of them have either a digital manometer ,multi meter nor combustion analyzer and have no clue how to properly install ,set up or pipe them properly  using some easy P/S piping but i know they are all very very good at writing a bill and chargeing they are also even better at IDing  a custermers phone # and then remenbering it so they do not answer it by mistake .Really sad yet very true .As for servicing them i had realized that need upon the first one i installed and later i realized that before even installing it you should pull the burner out so you an check the back refactory this way you an get a new one under warranty instead of buying one the first time you pull it apart to clean .I had it happen 3 times that the rear target wall was damaged from rough  transport before i installed it now i take the 5 minutes and pull it apart so i can get the new non damaged 1 for free instead of paying a year later .Don't get me wrong i love the mod cons but i think they are getting mis applied alot and i see myself waving more towards CI boilers when it comes to replacement stuff It makes like much easier  .If the custermer has there heart set on it ok but i am real up front about service ,maintance and the costs that come with that pride of ownership .I also tell them where or not it is worth it with the type of system they have .I have a honest buddy who has me look at his tough promlem jobs and he always advises the HO that they should not be present unless they have some  kleanx napkins being i usually will make them cry but i am just telling it like it is being i don't like to lie cause it is easier to remeneber the truth over remenbering lie plus my memory sucks and the truth is the truth it does not change cause it is the truth .If we only could see some truth beyond salemanship HAHA now i am doing comedy peace and good luck clammy

Brad White

Theory versus reality

Reminds me of an old joke, about the son doing his homework and the question was "What is the difference between Theory and Reality". (Fill in punchline here. If you do not know it, e-mail me off-line



The highest efficiencies, theoretically, peak at 98% but that is with very cold water returning or rather, being introduced. Condensing boiler efficiencies indeed are entirely dependent on the incoming water temperature, coupled with the firing rate.  *Some* manufacturers have gone so far as to state 108% efficiency with some reference to absolute temperatures, total enthalpy and then some miracle happens. I may have missed something.



The colder the water and lower the fire brings out the best efficiency, but one cannot always couple that to an existing radiation system in a way that resembles comfort. At least not on a cold day.



So, Clammy- you get an "A" for asking and not just nodding.

Jean-David Beyer

Theory

I do not know the reality, but I have read that stuff.  As I understand it, efficiencies over 100% are the efficiencies obtained by condensing. I.e., 100% would be the most you could get, in theory, from a non-condensing boiler, and greater is the result of the condensing. If it were possible to condense all the water vapor into water, you could get an efficiency, rated this way of 110.1%. But this should not be thought the same as an AFUE rating.



It is confusing that two efficiency ratings are used. When I used to be interested in cars, I came up with the idea of "advertizing horsepower" as contrasted to horsepower delivered to the wheels. The current systems may not be misleading if the speaker is clear what efficiency is being used. But as has been said, figures do not lie, but liars sure can figure.

Tim McElwain

Gents the truth is

that is not a seminar you are attending it is a sales meeting. When reps come to do a class at my center I tell them I do not want to hear a sales pitch.



Present the product, tell us how to install it, vent it, etc. Then what problems I may expect to have and how to program and troubleshoot. If there product is every thing they want to tell you it is then it will sell itself.

clammy

A bit of both Tim

Yeah it was a bit of both but not much of a sales show .The gentleman discussed all the basic stuff proper flue piping and supporting ,gas piping sizing and other issues especially the higher output durning domestic hot water production which is not really in the output rating and must be considered when sizing the gas pipe being the instruction do not glaze over this kinda funny not ,The guy glazed over  things like the necessary things like multimeter , manometer and combustion analyzer and a tiny screw driver basic stuff as i am concerned.But all in all it did not seem like a hard core sales show that i have experienced in the past .It seems to me most of them cover the same basic stuff and could use to update the shows to help guys out when they have issues but it is what it is .Peace and good luck clammy