Dryer Exhaust

1. How can I reduce the risk of my client's dryer catching fire?

Some solutions include the following:

Clear all lint traps in the system on a consistent basis.
Keep ducting to outside clear of lint as needed.
Use a Dryer Exhaust Duct Power Ventilator (DEDPV) on long length duct runs (length varies by regulation) to boost dryer performance and to significantly reduce lint and moisture buildup.

Check out the video “Only YOU can prevent dryer fires” to learn more about how our DEDPV-705 can help keep the home safe from a dryer fire.

2. Why is a DEDPV necessary?

According to some dryer installation instructions and local building codes, adding fans listed to the DEDPV standard are a requirement when the length of the duct run exceeds 35 linear feet. With an existing system, you may find that drying times are far longer than the dryer manufacturer’s instructions give. This issue may indicate that you have a duct run longer and more restrictive than your dryer can handle. Installing a Fantech DEDPV can assist the dryer in overcoming the added restrictions to allow the dryer to operate as designed.

3. How does the DEDPV work?

When the dryer is on, if the pressure switch senses positive pressure in the duct, the Fantech DEDPV turns on 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. Once the switch detects no positive pressure, the DEDPV will continue to extract air for a few minutes to keep temperatures reduced.

4. What is the maximum length of duct that can be used with a DEDPV?

The DEDPV-705 is effective for up to 125 linear feet of 4” rigid duct.

5. How do I calculate my duct run?

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 2.5–5 linear feet to your total duct run calculations (or as required by local codes).

Diagram of where a DEDPV can be installed in the duct line

6. Where in the duct line can I install my DEDPV?

Fantech recommends installing the DEDPV at least 5 linear feet from the dryer and up to 35 linear feet from the initial 5 linear feet. Refer to the figure below for a visual representation.

7. Can I mount the DEDPV-705 horizontally?

Yes, as long as the air flow direction is correct and the pressure switch is vertical, you can mount the Fantech DEDPV in any orientation.

8. I am adding a DEDPV-705 to my existing dryer duct line because my duct run is too long for my dryer to operate efficiently. Do I have to do anything special before I install the fan?

Ensure the duct is clean and free of lint buildup, 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 that will block airflow and eventually stop the fan.

9. What maintenance does my DEDPV-705 require?

Fantech seals and lubricates the fan bearings for life, meaning no additional maintenance necessary. Over time, the fan impeller may accumulate some lint. Perform an annual inspection to ensure the fan impeller is free from obstruction or loaded with lint. To help minimize lint accumulation in the ductwork, Fantech recommends installing the DBLT 4W, Secondary Lint Trap. To remove lint from the RVF 4XL wall mount fan, disconnect power to the fan, remove the fan cover, clean the lint (if any) from the impeller, reinstall the cover, and reconnect power to the fan. After maintenance or cleaning, check the operation of the fan.

10. How can I tell if my DEDPV-705 is working?

With the dryer operating, open the dryer door. The fan on the dryer will stop but you should still hear air pulling through the dryer from the DEDPV. Fantech's DEDPV-705 features 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.