Iced Furnance Air Intake

Dear All,
Outside winter temperature often reached -30 C. The fresh air intake iced up resulting in furnace shut down. The furnace is 1 year old, high efficiency, forced air furnace.
The intake is a 2.5" OD black PVC pipe.
The cloth dryer's exhaust vent is about 6' below and 3' displaced from the furnace air intake.
Other than moving the clothing exhaust vent elsewhere, any suggestion to avoid having to remove the loose ice from the air intake?
No problem when the cloth dryer is not running.
Thanks, MC
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up
efficiency,
Heat it? You can get electrical pipe heating tape to prevent outside pipes freezing... http://www.doityourself.com/invt/1462068 ... but I don't know if they are powerful enough. ...check it's rated for outdoor/wet use
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On Mon, 3 Sep 2007 22:24:41 +0100, "CWatters"

I'd be reluctant to recommend that as the pipe is PVC, and that may present a safety problem.
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Possibly but I don't think the heating tapes get that hot. Would have to try it I guess.
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My first thought is that you should consider whether it is possible to recycle the dryer exhaust and use that heat (and moisture) in the building...
Other than that, extend the dryer exhaust above the furnace intake, or more the furnace intake down below the drier?
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on 9/3/2007 2:37 PM MC said the following:

I'm not a furnace expert, but what does the dryer vent have to do with the furnace fresh air intake? Are they connected? Where does the furnace air intake draw the air from?
--

Bill
In Hamptonburgh, NY
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The point is that the dryer vent is exhausting warm, moist air; as the exhaust cools to ambient below freezing temperature, some of the moisture condenses out and freezes. Since this is all happening near the furnace intake, some of that ice ends up at the furnace intake vent or in the intake pipe; over time it can build up and restrict the pipe enough to cause a problem.
Cheers, Wayne
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on 9/4/2007 12:19 PM Wayne Whitney said the following:

I'm still at a loss. Shouldn't the clothes dryer have an exhaust vent to the outside? Is it exhausting into the room? Is this the same guy that's over in alt.home.repair that complains of having to clean lint out of his bathroom fan once a month? :-)
--

Bill
In Hamptonburgh, NY
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This is a sealed combution furnace, so its air intake is outside.
Wayne
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To Group,
I seem to get two suggestions so far: 1) Heat traced it. 2) Heat trace not suitable because the pipe is plastic.
Questions: a) How hot can the heat trace wire get to? Can the PVC pipe (the kind one can buy from any construction outfit) take the heat safely? b) If it is safe, how shall one proceed to heat trace it. The loose ice accumulates near the entrance grill only. The body of the pipe is never plug. It is the accumulation of loose ice from the moisture of the dryer vent at the intake grill that will eventually restrict the air intake so much that the safety mechanism of the furnace shuts down the heating cycle.
Thanks in advance, MC
wrote:

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BloodCoder had written this in response to http://www.thestuccocompany.com/construction/Re-Iced-Furnance-Air-Intake-Heat-Tracing-OK-10669-.htm : In my first house we had a dryer vent about 5 feet away from the air intake for our furnace and didn't have any problems. At our new house we just got our furnace replaced and have a electric dryer vent about 4 feet away. Will this cause any problems?
------------------------------------- MC wrote:

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If you paid to have the furnace installed, contact the seller and ask him to make the necessary changes (I believe that you are supposed to maintain 6' from a dryer exhaust for just this problem). If not, it appears you have two choices. One is to install an elbow and run the intake to a higher level. The second is to close off the existing inlet and route a new one to a different location. (Or perhaps you could reroute the dryer. But do not terminate the dryer exhaust inside the home. The additional moister load will cause untold problems inside the walls.)

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