According to some dryer installation instructions and local building codes, booster fans should be added in the dryer duct run when the length of duct exceeds 25 feet with no bends, 20 feet with one bend or 15 feet with 2 bends. With an existing system you may find that drying times are far longer than the dryer manufacturers instructions give, this may indicate that you have an duct run longer and more restrictive than your dryer can handle. Installing a Fantech dryer booster in the duct line will relieve the excess pressure in the duct allowing the dryer to operate as designed.
The DEDPV-705 and RVF 4XL (with DB10 pressure switch) are effective for up to 130 equivalent feet of 4” hard duct. The DBF 110 is effective up to 108 equivalent feet of 4” hard duct. At these lengths the booster fans will maintain a velocity 1,200 feet per minute which will keep lint particles airborne guarding against build up in the duct.
To calculate the length of your planned duct run, measure from the dryer to the external venting point in the roof or wall. For each bend or elbow add 5-7 feet to your total duct run calculations (or as required by local codes).
When the dryer is on, the patented pressure switch senses positive pressure in the duct and turns on the booster fan for a pre-determined time, at the end of the timer cycle the switch checks for positive pressure in the duct, if there is pressure in the duct the cycle continues.
Fantech recommends that the dryer exhauster be installed as close to the end of the duct run as possible with a minimum of 5 linear feet between the outlet of the dryer and the inlet of the fan.
As long as the air flow direction is correct and the pressure switch is vertical, the Fantech inline dryer booster fan can be mounted in any orientation.
Ensure the duct is clean and free of lint build up, this may require the services of a professional duct cleaning company or chimney sweep. Otherwise on start up the fan may pull lint into the impeller blocking the airflow and stopping the fan.
Since the fan bearings are sealed for life and provided with an internal lubricant no additional lubrication is necessary. Over time the fan impeller may accumulate somee lint. Periodic inspection, based upon dryer usage, should be performed to ensure the fan impeller is not obstructed or loaded with lint. Under normal conditions, the fan should be inspected annually. To help minimize lint accumulation in the ductwork, we reccomend to install DBLT 4W, Secondary Lint Trap.
For the RVF 4XL wall mount fan, disconnect the power to the fan, remove the fan cover and clean the lint (if any) from the impeller reinstall the cover and apply power to the fan. e. After maintenance or cleaning check the operation of the fan.
With the dryer operating, open the dryer door. The fan on the dryer will stop but you should still hear air being pulled through the dryer from the booster fan. Fantech's DBF 4XLT and DEDPV-705 feature a wall-mount indicator panel that mounts in the wall near the dryer. An LED light on the indicator panel lets the user know that the fan is operating correctly.
Fantech makes air quality control easy thanks to decades of research, development, and refinement that continue to push the industry forward. Learn which Fantech solution is the best fit in your next project today.