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I have vented my dryer outside from the basement using 4″ stovepipe. It’s about a 13′ total run with two 90’s and 3′ of flex to accomplish a 1′ vertical offset.
It looks OK but I was wondering if there were any other materials I could have used for the “pipe”. Plastic would be my preference but I remember reading about some meltdown/fires. Any helpful response would be much appreciated. Thanks.
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I'd use alluminum flex hose (4") made for this purpose.
*The smoother the better, with no screws or grilles.
*The single best thing is what you used. 4" galvanized pipe as much as possible with metal flex where necessary. Then seal with aluminum tape.Also, be sure to read and follow your dryer manual. They typically have a callout for maximum vent length and length equivalent for each bend and flex pipe use.Be sure the flapper on the vent termination is working.No plastic or anything else flammable in the vent.
*Eric: Fred's right, you did the best thing. With the possible exception of the 90's. If you could achieve the offset with 45's or less, it would be better. Here's why:13 feet straight run of 4-inch, 2 4-inch 90's, 3 foot of flex equals (approximately) 13 + 2x20 + 6 = 59 feet of equivalent run of straight pipe. 90's cost 60 times their diameter (1/3 of a foot x 60 = 20 feet). And I figure flex is at least twice the resistance of straight pipe.However: 13 feet straight run of 4-inch, 2 4-inch 45's, 3 foot of flex equals 13 + 2x10 + 6 = 39 feet of equivalent run of straight pipe. 45's cost 30 times their diameter (1/3 of a foot x 30 = 10 feet). Either ought to be fine and within the dryer's capabilities. If the manual gives a length limit, hopefully they tell you lengths for different bends in the run. If not, and they say, "40 feet of 4-inch or 10 feet of 3-inch" it's unclear whether they've included an allowance for bends.In general, any reasonable length of 4-inch straight metal duct is going to be fine. But really check carefully if tempted to use 3-inch. It's got to very short and straight. When I've had to go long distances (like 60 feet PLUS bends), I've used 5- or 6-inch and insulated the longer run to reduce condensation during it's longer transit time.-David ThomasKenai, Alaska
*Choosing a vent flapper. For either a dryer vent or a bathroom fan vent where can you get a decent flapper? any home center i've gone to has had only very cheap plastic flappers, which look like they blow open in any crosswind outside the house. There's got to be something better.
*Often times the fires are caused by lint in the line and/or the back of the dryer. Remember to clean those ducts and the back of the dryer once in a while.Just a public service announcement.
*David,You seem to know a lot on this subject so I'll ask my specific question on this topic. I had to move my dryer vent to accomodate a larger backyard deck. I now have about 32 feet of run with two 90 degree bends and a 45. I've noticed that the clothes take almost twice as long to dry. I don't really have any options as far as moving the vent but I can certainly use a larger vent pipe. I also wondered if there is an exhaust fan that would help the dryer "breathe" better. What would you suggest?Thanks in advance.Mark
*Not to steal any of David's thunder; but Get The Manufacturer's Installation Manual. We can give info that is generally true. But, each manufacturer has the inside track on the air flow, pressure and temperature data that is needed to make a good decision on ducting. That is reflected in their duct installation requirements. If your present situation violates them you will either have to accept the increased risk and decreased performance or find another place to vent.As far as a fan in the duct; think about all the lint that goes down that dryer duct. Do you want Anything that could trap lint and cause an obstruction or a fire in that duct?
*Mark -There is a company called FanTech (www.fantech-us.com) that makes high quality inline fans. They make several models that are suitable for dryer duct boosting. These things are not just cheap junk; they are very well made, quiet, and efficient. They make a model for inline use as well as a model for outside mounting. They are specifically designed to pass lint.
*You know I have used fans whose manufacturers said they passed lint. But, guess what, when taking the ducts apart there was the lint. So, it may be conservative but I stick with the no obstruction of any kind in a dryer vent rule.
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I have vented my dryer outside from the basement using 4" stovepipe. It's about a 13' total run with two 90's and 3' of flex to accomplish a 1' vertical offset.
It looks OK but I was wondering if there were any other materials I could have used for the "pipe". Plastic would be my preference but I remember reading about some meltdown/fires. Any helpful response would be much appreciated. Thanks.