Since moving into our new house - we've seen our clothes drying times double. The clothes dryer gets very warm, but due to a long duct run to the exterior of the house - airflow is reduced. The duct run is about 30 feet, not including losses due to elbows and fittings. Large loads would take 2 hours to dry.
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| The Fantech DBF4XL Dryer Booster Fan with Pneumatic Sensing Control |
Some research lead to inline dryer duct fans - which improve dryer performance by overcoming the duct loss due to the length of the duct. I have a standard clothes dryer with 4" diameter round ductwork. The ducts were all sheet metal ducts, with only a short length of flexible at the dryer connection, so the ductwork was already optimized by being as smooth and as short as possible to reach the exterior of the house.
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| Fantech DBF4XL - Serial Number Plate - On the Pneumatic Timer Control Box |
I decided to go with a Fantech model with a pneumatic switch that automatically detects the change in air pressure in the dryer duct when the dryer is activiated, then turns on the booster fan in 10 minute timed periods. At the end of the 10 minutes - the booster fan switches itself off - and if the dryer is still operating - the pneumatic control turns the fan back on for another 10 minutes. I found the Fantech DBF4XL on eBay - previously installed but never used - for a good price.
Reading the installation instructions for the fan - they recommend the installation of a secondary lint screen upstream of the fan to help protect the fan from clogging with lint. When I opened my dryer duct - I had plenty of lint in the duct - which indicated that the lint screen in my dryer was passing a lot of lint - more on this later. So - onto eBay where I found a Fantech secondary dryer lint trap for a reasonable price.
Once the secondary lint trap and fan were received, I set to work. My dryer vent line ran through the basement under the first floor where the laundry room is. So - it was a simple matter to cut into the dryer line where it ran under the floor - and duct in the secondary lint trap and the booster fan.
The secondary lint trap has a clear plastic window which helps to show when the filter box needs cleaning. It's a neat looking installation - but would be much more convenient installed directly behind the dryer.
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| Installing the Fantech Secondary Dryer Lint Trap - Note the Laser Line - Simplifies Lining up the Ductwork |
The filter box ending up screwing directly into some wood cross members under the floor - straight through the base of the filter box. Very simple.
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| Fantech Secondary Dryer Lint Trap - Installing the Filter Box with the Cover Removed - Note the Laser Line |
When installing the secondary lint trap and lining up the booster fan - I used a laser level with vertical laser line to line the filter box, fan and ductwork nice and straight - to have a professional looking installation. The laser really facilitates the installation.
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| Installing a wood block to install the Dryer Duct Booster Fan - Four Tapcon Screws into the Elevated Concrete Slab |
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| Secondary Dryer Lint Filter Upsteam of Dryer Booster Fan |
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| Secondary Lint Filter and Dryer Booster Fan Installed |
Very important installation point on the booster fan - the booster fan uses a pneumatic diaphragm switch - the copped colored cylinder in the photo below. The diaphragm needs to be oriented vertically so that gravity does not act on the diaphragm - which would work either for or against the pneumatic pressure and upset the operation of the switch - your switch would either be on all the time, or not activate reliably on duct pressure. It's very simple to rotate the fan on the installation bracket so that the diaphragm is vertical. When installing the bracket - take care not to install the self tapping screws to close to the center of the fan enclosure - you could screw into the fan impellor and block the impellor from turning. It's not as complicated as it sounds - you just need to take care with these points on installation.
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| Fantech Dryer Booster Fan - Note the Orientation of the Copper Colored Pneumatic Switch - This needs to be oriented vertically for it to work properly. |
Conclusion
So - how does it work? Perfectly. It switches on and off automatically as described above. I haven't had any issues with the booster fan turning on when not required, and it recycles automatically in the ten minute intervals without any issue. The secondary lint filter needs to be cleaned once every two dryer loads on average - which is more frequently than what I hoped. It would have been much more convenient to have the secondary filter installed in the laundry room - for easier cleaning - but this wasn't practical in my installation without adding a lot more ductwork. Something for me to consider in the future.
The dryer cycles have been reduced by almost one half, 2 hour dryer loads now dry in about an hour - and the automatic dry cycles now work reasonably well - before - the automatic dry cycles never got the laundry dry.
4 Year Update
Still working 100% reliably after 4 years - at least 6 laundry loads a week. The secondary lint filter is a MUST - it is amazing how much lint misses the dryer lint trap. Super impressed with the performance and durability of this fan - no problems at all.
Sources and Links
I hope you found this post useful. Feel free to ask questions in the comments section below. I answer all questions. If you're interested, you can help support this site by using the following links to Amazon.com in the United States.
