[kp2171]

Well my wife didn't shed a tear when our dryer went caput. Meant she could finally get the front loading whirlpool he washer dryer combo shed wanted for a few years.

Yesterday they were delivered. Our old dryer was connected by a flexible, expandable connection that runs to the heavy metal venting that goes up and out of the house.

I noticed the dryer manual pretty much says do not do this. To use only heavy metal, rigid connections to vent the dryer. The deliv and sales guys all said the flex connection is OK.

I usually clean my dryer vent line out once in the spring and check again in the fall before its cold. Usually nominal buildup, but I can see where the rigid probably gives less suface area and irregularities for lint to catch.

Any thoughts here by people who do this work? I'm probably going to buy the few pieces I need, since it won't break the bank, but I've got to move everything and then rebalance... do-able but id rather not.

Thoughts on the flex connections?

[RickJ]

Rigid dryer vent?? I've never heard of it and never seen it in use.

I have, though, switched from using the flexible plastic to the flexible metal as the plastic ones can catch fire under some circumstances.

[kp2171]

Well its just the same thick metal venting that runs the upward course to the outside... but instead of using flex metal run at the bottom, you'd need to install a fixed angle turn, run to the machine, turn toward the machine and in.

The problem being its inconvenient to not have the flex line. The space where the washer and dryer are is tight, so I either need to use flex line, or I need to do the rigid, requiring me to remove the washer out. Something I'm not wanting to do since its in place, leveled, and hooked up.

The manual just threatens a fire hazard if you use anything but the rigid metal ductwork.

[RickJ]

Metal is metal. I can't for the life of me imagine how a rigid metal vent would be less of a fire hazard than flexible metal.

We've had flexible metal in our apartment laundry rooms for years and never had a service person recommend otherwise.

[kp2171]

Metal is metal. I can't for the life of me imagine how a rigid metal vent would be less of a fire hazard than flexible metal.

Well... I guess I disagree with you a little on both points... and that's why I'm hoping an hvac guy can straighten me out or agree.

Steel has a higher melting point than aluminum, so I don't agree that metal is metal. If there was a fire and I had a choice of what wall would protect me, id say that a thicker steel would do a better job of containing a fire than a thinner aluminum barrier.

But... I've always used the flex metal and not had a problem.

Also, knowing what I know from physics and fluid/air flow, I can see how the accordion style venting would create eddy currents and reduce laminar flow... meaning more lint catching on the increased surface area and the machine needing to work harder to pump out the air.

But... again... I've always used the flex metal.

This just reminds me of the person who always fueled their car in the winter with it running and the person getting in and out... not a problem until that one time the static electricity sparks the thing.

So basically my mind says to change it out, but I want an hvac guy to say its overblown and with regular cleaning its fine.

I'm going to have to go look at the manual to see if the warranty is voided with the flex metal. If so, I'm going to lay into the retailer who said its fine to use.

[RickJ]

OK... I stuck my neck out, so I did some surfing...

Here's a good article. Very informative.

He points out "The American Household Appliance Manufacturers Association (AHAM)recommends the use of either rigid aluminum or steel duct or spiral-wound aluminum flex hose" of course because the main cause of a fire is built up lint that catches on fire. The article goes on to list other UL approved vents.

The article author does recommend rigid (aluminum) over flexible but not due to increased fire resistance but due to it's being easier to run a vent brush through it to keep it clear. He recommends once a year, but I do it 2-3 times a year as we've got a household of 8.

I can't think of any other cause of fire in the vent other than built up lint, so I'd think that keeping it clear and using other than plastic should give you the peace of mind you're looking for.

Now, would an HVAC guy please pipe in here on this one too? :D