[Greenbuilding] power vs. direct venting on the Buderus G115 oilboiler

[Drew A. Gillett P.E.]

----- Original Message ----- 
From: "Irina Golfman" <irina at inera.com>
To: <greenbuilding at listserv.repp.org>
Sent: Tuesday, February 06, 2007 9:49 PM
Subject: [Greenbuilding] power vs. direct venting on the Buderus G115 
oilboiler


> Dear Greenbuilders,
>
> We just had a Buderus G115 oil fired boiler installed. It provides heat 
> via
> the cast iron radiators and baseboard, and indirect DHW. The system has
> been running for about a month and a half and we still have a very strong
> smell of oil in the boiler room and all adjacent rooms.
>
> The G115 is a direct vent system. Our exhaust pipe is a galvanized pipe,
> about 15 feet long with three elbows (much longer than what Buderus
> recommends), it has many unsealed seams that are already covered with 
> soot.
> Two separate companies have suggested that the smell is due to the
> incorrect venting and recommended that we power vent the boiler.
>
> One company suggested that we have an additional issue of the oil being 
> too
> cold (the oil tank is outside about 50 feet from the boiler with the new
> two pipe underground oil line) which prevents the burner from working
> efficiently and suggested that we switch from the 2 pipe system to the
> "tiger loop".
>
> My questions are these:
>
> 1. Do people have experience with power venting the G115?
yes
> 2. Is it considered OK to power vent the boiler that's designed to be
> direct vented?
yes, look for the least power and most externally located powervent.  those 
by exhausto are nice. measure and control the draft to be that specified for 
the direct vent version.  be sure to not have a barometric stack draft 
damper ( these are relics of the 50's to reduce the draft of warm chimney)

> 3. How loud are the power vents? Do you hear them when the doors and
> windows are closed?
that's why you put them oudoors. varys with installation, you can adjust the 
speed (noise) on some. yes, but not worse than the typical refrigierator is 
the goal.
> 4. Does the power vent run all the time or only when the boiler is 
> running?
no on ly when running and pre and post purge. however, some smells can 
backflow during off cycle.  one of the nice things about conventioal 
chimneys is they did provide a continuous flow to remove smell when off.
> 5. What are the draw backs of power venting (other than the use of
> electricity and noise pollution)?
you guessed them.  maintenance, cost , an additonal switch in the startup 
sequence to fail, looks, vibration, space use, etc.
> 6. Does anyone have any suggestions regarding switching from the 2 line
> system to the "Tiger loop"?
tiger loop is merely an indoor version of the 2-pipe.  .   you might also 
look at nozzle line preheaters. they also improve startup performance 
reduce soot and increase efficiency.
>
> Any other thoughts on this issue would be very much appreciated.
burn biofuel or B20 for a sweeter smell.
>
> Thank you very much for the help.
>
> Irina Golfman Rosenblum
> -------------------------------------------------
> Belmont, MA
>
>
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