[Greenbuilding] a better boiler

kaa-ajk at sonic.net kaa-ajk at sonic.net
Wed Apr 13 17:19:21 PDT 2011


John,
  I've had a parallel experience.
  I kept a hydro-pulse high-efficiency boiler going for 20 years, took a
lot of attention to clearing the condensate drain from the chamber, and
then the chamber plugged up with debris/rust so much I couldn't any
longer open the condensate drain.  I replaced it with the same model (no
longer available).

  But what I realized as I pulled things apart for the replacement was
that much if not most all of the condensate was coming not from the
boiler chamber but the (20' in this case) up-sloping PVC exhaust.  In
the replacement I put a trap in the exhaust, with a condensate drain
from the foot of the trap.
  After that the same continuous light flow of condensate came not from
the boiler but the trap in the exhaust.  I'm convinced that if that had
been done originally the original boiler would still be going.

  I have incomplete data, but tend to agree that most boilers are
installed poorly.

  In our new abode I'm in the middle of installing a Triangle Tube
high-efficiency boiler.  I would have used another hydro-pulse, but
since it's no longer available I searched a bit through high efficiency
boilers.  The Triangle-tube looks good to me (& I'm an engineer) - we'll
see after it's put to use for a while.
  This time I arranged for the exhaust to be under 2' right out the wall
the boiler is mounted on.

Joe


> Hello John,
>
>
>
> I replaced a Weil-Mclain CGA-4 boiler (77000 BTU gas boiler) that was only
> 10 years old in CHICAGO in JANUARY.
>
> The HVAC contractor who installed the boiler 10 years ago said that the
> chimney was not venting properly (
>
> Maybe debris) and caused the boiler to build-up carbon in the combustion
> chamber therefore rendering it
>
> Irreparable.  He wanted $4700 to replace with a higher efficiency Weil
> -Mclain boiler that he would not have to fix
>
> The chimney venting problem because he could vent directly out the side of
> building. I did not feel comfortable
>
> Giving the same contractor another $4700 to install another boiler when
> the first one should have lasted 25 to 30  years.
>
> The building is a 1910 brick “2 flat” rental property consisting of 2
> small apartments (700sq. ft each) with unevenly heated cast iron
> radiators.  This boiler was used to heat both apartments.
>
>
>
> To make a long story short … I decided to determine what the actual
> problem was and proceeded to
>
> Diagnose and solve the problem myself.
>
>
>
> My conclusion:
>
> The chimney was not clogged however one side faced the arctic cold
>
> Of Chicago and therefore caused condensation buildup inside the chimney
> because the air cooled off before
>
> Exiting out the top of chimney . The condensation ran down the chimney
> into the boiler vent pipe and into the boiler. This is what caused the
> boiler to fail early … 10 years of condensation
>
> Dripping down into the boiler eventually causing a carbon/rust buildup and
> also rusting out the bottom half of the boiler.  This was one source of
> condensation. The installation manual recommends a vertical and horizontal
> drip vent
>
> Installed to eliminate this issues. This was not done in the original
> installation.  If my conclusion is incorrect I welcome anyone on the list
> to help me understand the error in this conclusion?
>
>
>
> After talking to Weil-Mclain support engineers they confirmed another
> source of condensation within the boiler.
>
> And that would be low temperature return water coming back into boiler
> causing condensation. This is corrected
>
> With primary / secondary bypass piping that was not done in the original
> installation.
>
>
>
> Important Considerations that I learned the hard way in a cold snowy
> Chicago 2011 winter  in a cold apartment with very patient cold tenants.
>
>
>
> #1. 30 year supply house veteran who helped me diagnose issues said his
> experience is “Most
>
> Boilers are not installed correctly”. (Scary and I hope he is wrong.)
>
>
>
> #2. Sizing of boiler should be calculated  with an estimate of Heating
> load. This would include an accurate assessment of building parameters and
> radiator sizing. See attached installation guide.
>
>
>
> #3. Venting calculation is very important using venting tables based on
> configuration of boiler location, chimney
>
> And relative locations.
>
>
>
> As to your thoughts on a better solution for the same price …
>
> Some ideas maybe worth pursuing ?
>
> 1.       Recently someone posted an idea about solar preheating to a
> boiler (maybe too expensive).
>
> 2.       Convert to gas and use a tankless boiler. (Does anyone on list
> have experience with this technology?)
>
> John … If interested I can send you documents related to my research and
> installation of a Weil-Mclain (CGA-3 50000BTU) used for one of the 700 SF
> apartments. Works fine in Chicago.
>
>
>
>
>
> Sincerely,
>
>
>
> Bob Jakaitis aka "Jake"
> NC General Contractor | B.S.E.E.  Illinois Institue of Technology
>
> Air Sealing and Energy Saving Services
> Jake at the Lake Development Inc.
> Tel: 704-236-3574
> Email: jake at jakeatthelake.com
>
>




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