[Greenbuilding] Dryer vent backdraft solutions

Bob Klahn Home-NRG at dnaco.net
Sat Sep 24 10:55:13 CDT 2011


Sacie,

I don't suppose that you have any pictures of the installation but if 
you do, I'd like to see one.  There must have been something that 
allowed the wind to product enough lift to raise the cap.  If it was 
counter-balanced with a spring as, I described in another email, perhaps 
the spring lift needed to be adjusted; a straight, 4' duct run may have 
required less help to lift the cap and the cap may have been too close 
to dead neutral.  The displacement of the fan you used would be another 
key factor.

The need for site adjustment of the spring, which I assumed, was one 
reason I never tried very hard to sell the idea to a client.
Bob Klahn

On 9/21/2011 3:40 PM, Sacie Lambertson wrote:
> Interesting about this Heartland duct.  I bought one some years ago 
> from our local electric coop to use in conjunction with a exhaust fan 
> in a bathroom.  The connecting pipe is less than four feet and 
> straight.  Every time we get a blowing hard rain the thing leaks like 
> a sieve through the exhaust screen in the bathroom.  It's a real 
> mystery to us since it looks like no water can enter the vent and we 
> find no cracks around the outside where it is connected to the house 
> wall.  If the thing is highly recommended I suspect there is something 
> unique to our situation that I don't observe.
>
> sacie
>
> On Wed, Sep 21, 2011 at 12:34 PM, Bob Klahn <Home-NRG at dnaco.net 
> <mailto:Home-NRG at dnaco.net>> wrote:
>
>     Rob,
>
>     I've used and recommended the Heartland for years.  IMHO, it's the
>     only outside dryer fixture with even a hope of preventing
>     backdrafts - and it does that reliably.
>
>     It's also provides the easiest access for clean-out of the duct of
>     any system I've seen or tried.
>
>     Most clients love it, once they get past the "mushroom" appearance.
>
>      I have only heard of one complaint.  A friend, not a client, said
>     that when he tried one, his dryer took longer to work.   I haven't
>     seen his system and he didn't provide more detail, but this is
>     completely at odds with other feedback.
>
>     I suspect that his duct run may be the real problem - too many
>     elbows and/or a long flexible duct run - but I have not had an
>     opportunity to check further.   I believe he mentioned that the
>     cup never rose fully; also odd.  However, it was a chance comment
>     on meeting in the street, so details and my memory are sketchy.
>
>     If you install one, I recommend making sure the connecting duct is
>     - or converting your current exhaust run to - straight, smooth
>     pipe; sealed and with the minimum length and fewest turns
>     possible.  Where possible, use two 45's in place of a 90 degree
>     elbow.  Make sure the pipe seals to the dryer discharge and the
>     outside vent.  If a short, straight run is not practical, change
>     the duct to 6" (most installations I see are usually 4"), with a
>     reducer at the dryer if necessary.  The Heartland is set up to
>     accommodate a 6" duct for a reason.
>
>     If the run is long, or convoluted, consider adding a clean-out
>     access at a point that will let you sweep the full length.  (Lint
>     build-up could be another of my friend's problems, and a fire
>     hazard to boot.)
>
>     I hope this is useful,
>     Bob Klahn
>
>
>
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