Hello, We bought a house and just moved in and noticed that the
propaine gas fired Boiler is vented horizontally out from basement to
the outside with pipe and terminating on the outside a few feet from
the ground level. The house is a 1 story ranch and the pipe terminates
on the side of the house where the eaves are. The problem is that it
is causing condensation up under the eaves and frost is forming on the
rafters in crawlspace above house. The system is 7 years old.
Obviously this was vented wrong needs to be vented elsewhere. The
previous owners did not use the boiler that often and used wood.
There is exsisting chimney that is close to the boiler that was
used by the previous owner for an add on wood boiler that is no
longer there. The chimney is not in use now and and we have no plans
for using it. The chimney is centrally located in the building The
flue is tile. Can the boiler be vented into this exsiting chimney?
The Boiler is a Weil-McLain High- Efficiency Gas Boiler. (HE II 5)
Here is a quote from the Venting directions. "The HE II boiler may be
vented directly through an outside wall or through the roof using
standard 3-inch galvanized vent pipe. In addition, the boiler may be
vented into a chimney inside the building with or without other gas
appliances, using single-wall galvaized vent pipe. For extended runs
through cold area-or when venting into a chimney on an outside wall-
Type 304 or 316 stainlss steel vent pipe must be used. Whne venting
into an outside chimney, the stainless vent pipe must run through the
ntire lengh of the chimney." Any advice will be appreciated Thank
I would think that the chimney could be used. I would check with a heating
proffesional to be sure. Sealing the entry might be tricky. As a dodge until
you find out, why not extend the vent so that it does not rise into the
eves. Just a suggestion
Thanks for the suggestion. We looked at he pieces of gas vent pipe.
The eaves stick out quite a way. At the building supply store we
bought an 18 inch piece of gas vent pipe and it looks like that will
bring it out farther but not comepletly out past the eaves. It was
dark when we got home so we didn't have a chance to try it. It was
only $5 so if it doesn't matter if it doesn't work. How far out would
it be safe to extend pipe? But I suppose any extention of it will help
untill we get a professional here or at least talk to one.
Please explain what you mean by "sealing the entry might be tricky".
We are planning on getting a professional here but we would just like
some advice/ideas before they come. Thanks for your advice.
The code has changed since that manual was written. This is a Type
III appliance. It requires stainless steel vent pipe regardless of
how you vent it. Galvanized was inadvertently allowed for a few
As far as venting in the chimney you're very likely to have
Is frost forming in other areas of the attic or just in the area when
the vent is?
On 13 Dec 2003 07:19:11 -0800, firstname.lastname@example.org (Karen) wrote:
'3 kinds of people: those who can
count & those who can't.'
Obviously your local code official thought it was ok...it DOES have a record
of a permit being pulled for the installation does it not?
Nope. Not unless you line it.
And even then, you need to know if the run from the gas unit to the flue
will exceed code.
Not any more. Galvanized is a no no.
Well...thats old code...if you change it now, you need to follow new code,
and your local guy that is going to be doing the work for you should have a
copy of the International Mechanical Code and the Fuel Gas Code that state
what you need to know.
In other words, what the OLD book said was legal then, its not now.
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