New dryer vent duct


  #1  
Old 08-29-09, 11:05 AM
W
Member
Thread Starter
Join Date: Nov 2002
Location: WA
Posts: 36
Received 0 Votes on 0 Posts
New dryer vent duct

Hello,

I just finished re-doing my dryer vent and would like to get some input on the new installation.

Quick background: Previous vent system was simply one of those foil hoses running straight up about 2.5' to a regular thru the wall vent flapper thingy. This worked fine until I put a new larger deck on the back of the house and the vent would spew lint all over that area of the deck, and it would get wet and make a mess.

Washer and dryer are in the garage which is on slab. The dryer is flanked on one side by the washer and on the other side with some built-in cabinets. Because of this the dryer needs to be able to be pulled away from the wall in order to access the back to clean behind the dryer and clean/replace the vent hose when required.

I decided to move the vent location such that it would be dumping the lint on the gravel walkway instead of the deck. I did this by running a horizontal run of rigid alum vent tube down the wall through the cabinets to a new exit point to go through the exterior wall. The run is about 5' in length. Clamps are used with foil tape over the clamp/joint and I put all the crimped ends going in the air flow direction.

My first concern is the foil hose I'm using between the dryer and the 90 elbow at the beginning of the rigid run wants to have a bit of a sag in it. However, I'm not sure what can be done because as I mentioned the dryer has to be pulled out from the wall so I don't think I can have a rigid run all the way to the dryer connection? Please take a look at the pictures and tell me if you think this sag is going to be a problem.





My second concern is the heat put off by the vent tubing where it runs through the 4.25" hole in the 1/4 or 1/2" (can't remember if it is 1/4 or 1/2) plywood in two places inside the cabinets. I let the dryer run awhile and then checked temps. They varied from about 80 degrees at the bottom of the tube to 125 degrees max at the top of the tube in some places. Can these temps cause the plywood to catch on fire?

I also wonder about the vent tube that goes through the exterior wall. I assume this tube gets just as hot and it is inside the wall with insulation and such? Yet everyone I've seen is installed this way so what about the heat?

Please view the pictures below and advise if I should do something different?





I'm not that concerned about cleaning the rigid 5' part of the installation as I can clean from both ends with the duct cleaning brush kit and then vac it out or blow it out with compressed air.
Thanks
 
  #2  
Old 08-29-09, 01:01 PM
M
Banned. Rule And/Or Policy Violation
Join Date: Dec 2007
Location: Chicago
Posts: 1,011
Received 0 Votes on 0 Posts
Per the IRC (M1502.4) that foil duct is not allowed anywhere in a dryer duct, the only flexible duct allowed is a single piece of "flexible transition duct" connected at one end to the dryer, 8 feet or less in length, and listed and labeled per UL 2158A. One source for the parts you need is: Dryer Venting Accessories
 
  #3  
Old 08-29-09, 01:21 PM
W
Member
Thread Starter
Join Date: Nov 2002
Location: WA
Posts: 36
Received 0 Votes on 0 Posts
Originally Posted by Michael Thomas View Post
Per the IRC (M1502.4) that foil duct is not allowed anywhere in a dryer duct, the only flexible duct allowed is a single piece of "flexible transition duct" connected at one end to the dryer, 8 feet or less in length, and listed and labeled per UL 2158A. One source for the parts you need is: Dryer Venting Accessories
Thanks for the reply.

I have the rotating close elbow on the dryer outlet already and can replace the foil duct with the flexible transition duct. I assume that is the kind of semi-rigid flexible duct I've seen in the stores. Does this type of duct work ok in situations where the dryer needs to be pulled away from the wall for access?

Edited to add: Actually now that I think about this, if I install one of those rotating close elbows where the foil duct currently connects to the straight rigid piece instead of the 90 that I currently have there, it would probably rotate as I pulled the dryer away from the wall.

And, what about the heat from the rigid duct that passes through the two holes in the cabinets? I'm just trying to ascertain if this is a problem or not. Yet it seems that rigid dryer duct is run inside walls for some installations is it not? And the short duct section that passes through the exterior wall must get just as hot and it passes through the interior wallboard and the exterior wallboard, and of course there may be insulation inside the wall as well.

Thanks
 
  #4  
Old 08-29-09, 01:27 PM
Gunguy45's Avatar
Super Moderator
Join Date: Dec 2007
Location: USA
Posts: 21,112
Received 4 Votes on 4 Posts
The semi rigid duct is fine for a couple of pull outs..then it might need replaced. Just gotta watch out it doesn't get crushed.

If plywood caught on fire (or even close) at 125...my roof would burn off every day from about May until Oct...lol. No worries there.
 
  #5  
Old 08-29-09, 04:17 PM
W
Member
Thread Starter
Join Date: Nov 2002
Location: WA
Posts: 36
Received 0 Votes on 0 Posts
Originally Posted by Gunguy45 View Post
The semi rigid duct is fine for a couple of pull outs..then it might need replaced. Just gotta watch out it doesn't get crushed.

If plywood caught on fire (or even close) at 125...my roof would burn off every day from about May until Oct...lol. No worries there.
Ok, thank you. I realize I'm probably being kind of anal about this but just want it to be a safe installation. I will replace the foil duct with the semi-rigid and keep it all cleaned on a regular basis.
 
  #6  
Old 10-16-09, 03:59 PM
W
Member
Thread Starter
Join Date: Nov 2002
Location: WA
Posts: 36
Received 0 Votes on 0 Posts
Ok! Installed the semi-rigid. Looks better?

 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: