Venting Clothes Dryer and DC Together?

[Craig Summers]

since we are discussing dryer vents and the like, let me ask how u would set this up. my current setup is 4" ridgid pipe. it is in my basement and has to exhaust thru the sideboard right above the concrete block. i have about 10' straight. I added a garage bay to the outside and now it vents into new bay. (I know poor planning). Approximately how many elbows and such can i have before i need to get a dryer vent booster fan. Has anyone installed one of these? i think i have about 12' w/ some elbows currently. Maybe that length is why it takes clothes so long to dry...any help would be appreciated...

I installed a dryer booster fan when i bought this house. The dryer was supposed to be vented to the roof, but the vent was lying on the attic floor. So i installed new smooth metal pipe, taped all the seams with the metal tape, it goes out the back of the dryer, 1.5 ft then elbows up about 9' into the attic, then elbows over across the attic, about a 20-24' run to daylight. I put in the booster fan about 5' after the elbow in the attic.

I bought a Fantech unit, cannot recall the model number though. Works very well, its has a pressure sensor that automatically turns the fan on when the dryer is running, and cycles every 20 minutes or so

According to the Fantech website, they reccomend a booster:

When to boost a dryer.
Typical residential dryers are rated at 160cfm. However, boosting is generally needed in order to maintain a minimum airflow of 100cfm as duct length increases and bends are introduced in the duct line.
Based on surveying the recommendations from dryer manufacturers, and local building codes in selected areas, dryer boosting is typically required when the duct length exceeds the following:
Maximum duct
length with:
No bends 25'
1 bend 20'
2 bends 15'
3 bends 10'

Craig

[Mike SoRelle]

since we are discussing dryer vents and the like, let me ask how u would set this up. my current setup is 4" ridgid pipe. it is in my basement and has to exhaust thru the sideboard right above the concrete block. i have about 10' straight. I added a garage bay to the outside and now it vents into new bay. (I know poor planning). Approximately how many elbows and such can i have before i need to get a dryer vent booster fan. Has anyone installed one of these? i think i have about 12' w/ some elbows currently. Maybe that length is why it takes clothes so long to dry...any help would be appreciated...

I've had to replace the motor in my dryer twice in the last 10 years, the first time was after around 4 years living in a townhome that had roughly a 35 foot run (up a wall, across a great room and out) and most recently the replaced motor died a few months after we sold one house and moved into an apartment that had a similar long run. The poor airflow is what's responsible for the long dry times, you can also get water damage in the ceiling along the run as the moisture condenses in the run and escapes through seams and the like.

In the new house, it's on a 2 foot run (up and out) and it's back to drying in one cycle instead of 2 or 3 (or more for towels and jeans).

The long run also does a terrible job of removing any lint that makes it past the screen, so it's advisable to clean out the long ducts periodically and really important to open the dryer cabinet and clean it out. I found a pretty serious fire hazard inside during the first replacement. Now I take the shop vac to mine annually.

The lint trapped in the long lines coupled with the condensate can also make for some wonderful mold/mildew smells