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A draft inducing blower defect


mgbinspect
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Download Attachment: icon_photo.gif Cracked Draft inducing fan.jpg

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Keep an eye out for this black plastic draft inducing fan. When these units are found on a furnace that is in unconditioned space about 40% of them with any age on them will be cracked as this one is at the bottom center. In the early stages it will simply show as a hair line crack with efflorescence along it. It's about a $350.00 replacement.

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Interesting! Thanks for the input, John. So far I've only seen them on furnaces in crawlspaces, attics or eaves.

I bounced it off an HVAC tech on one of my inspections and he had mentioned that the extremes of going from cooler outside temps to heating exhaust proved to be too much for the material. He's the one that offered the replacement cost.

At any rate, I've mentioned to several of my fellow home inspectors who were not aware of the problem, so.. here it is.

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We have found, and reported abt 300 of these. Has nothing to do with where installed. Think improper material and cross vibration. How they are attached to cabinet - maybe no washer or groumet on older models. typically find them between 4 and 8 o'clock when mounted with throat up.

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Another thought. We've all seen furnaces in unconditioned areas that are more trapezoidal than rectangular 'cause the things were hefted through tiny scuttleholes. That plastic isn't very flexible. I'll bet some of the draft-inducer housings wind up having small cracks in them before the furnace is even fired.

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Hi,

I think, but am not certain, that most of these are made by the same manufacturer. A few years ago, I did a bunch of google searches on all sorts of fan references while looking for something on ventilation on google. I came across a manufacturer of these devices that had issued a recall. I remember something in the recall that listed all of the different furnace manufacturers that had the device and telling myself at the time to go back and bookmark that section so that I could look into it further. Well, I forgot about it. By the time I did remember it, I didn't have the energy to find it again. Every time I see one of these cracks I remember that site and curse myself for not bookmarking it.

ONE TEAM - ONE FIGHT!!!

Mike

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  • 4 years later...

Just found another one today, that's three this month alone. Newbys, if you see a black plastic draft inducing blower, scrutinize the heck out of it, because it's most likely cracked. Todays had little tiny almost invisible cracks only tipped off by a rusty residue of escaping moisture and minerals? This one is indeed a Windjammer. So far, about 25% to 33% of the ones I see are cracked, and it's about a $400.00 + replacement. Be careful!

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If the furnace in the OP is in an unconditioned space then it must use nothing but B-vent instead of single walled connector and it must run uphill. This appears to be running severely downhill with offsets. Looks like the pic is rotated 90 degrees. More pics?

Reference? I believe that the code changed a few years ago and now double-walled vents are only required in climates where the winter temps are consistently below a certain average. Don't have time to look it up right now but the change has been a royal pain in my keester for the past few years.

ONE TEAM - ONE FIGHT!!!

Mike

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2009 IRC G2427.10.2.2 Vent connectors located in unconditioned areas. Where the vent connector used for an appliance having a draft hood or a Category I appliance is located in or passes through attics, crawl spaces or other unconditioned spaces, that portion of the vent connector shall be listed Type B, Type L or listed vent material having equivalent properties.

Exception: Single walled metal pipe located within the exterior walls of the building in areas having a local 99 percent winter design temperture of 5degrees F(-15C) or higher shall be permitted to be used in unconditioned spaces other than attics and crawl spaces.

HTH,

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