Replies

1. 
   [email protected] | Apr 18, 2011 01:59pm | #1

   Relay?

   So long as the wire is properly sized for the load, it is probably better to have a longer switched run, that minimizes the length of charged run.  You will still probably need a dedicated outlet or junction box near the booster fan though. 

   You might also consider just a 120-volt relay at the drier that would energize and close, any time the drier is on, as opposed to a pressure switch.  I think they are more reliable. 

   And, with the remote pressure switch you have the possibliity of getting into a feedback loop kind of scenario, where: the booster fan cuts in, causing the back pressure to drop and kill the fan; which then causes the back pressure to build up and start the fan; causing the back pressure to drop and kill the fan...... 

1. 
   richardi | Apr 18, 2011 04:10pm | #2

   Relay Vs. Pressure Switch

   Thanks for the response!

   First, it looks like the fan has its own terminal box.

   Secondly, I think the feeback loop scenario is how the pressure switch works - per their website:  

   DB10 Pressure Switch

   Automatic pressure switch allows for fully automatic operation of RVF4XL dryer booster fan. Fan runs for 10 minutes when positive pressure is sensed in the duct then shuts off and turns on again as needed. Switch suitable for 115 volt supply. 2 amp rating.

   But, I'm open for suggestions. Please explain the 120-volt relay option.

   Thanks agin,

2. 
   rdesigns | Apr 19, 2011 04:21pm | #3

   A booster fan should prove to be running before the dryer turns on. Otherwise, when the booster fails for whatever reason, it actually becomes an obstruction to airflow.

   It may be that you don't really need one.

   How long is the existing vent?

   How many 90's in it?

   What's it made of? (smooth metal duct with no screws of other lint-catching features?)

   What style of backdraft damper is there at the termination?

   Adding 8-10 feet with one 90 is equivalent to about 15 more feet of straight, smooth metal duct--not much for today's dryers, many of which are capable of venting with 60 feet of straight duct and 3 or 4 90's. Granted--short and straight is always better, but check the manufacturer's specs on this before you go to the trouble of adding a booster.

3. 
   Geoffrey | May 11, 2011 03:59am | #4

   Yup!

   Rich, the model # you are using is NOT a dryer booster fan, you need a model DBF-110,

   which comes with a pressure switch already installed, it cycles every 10 mins. when the dryer is on, and it has a j-box on it  and you just need to run power to the j-box. This is an in-line booster fan and should be mounted 15' from the dryer. simply exhaust to the exterior via a standard dryer vent. There's also a model DBF-4XL, that is a galvy housing, but the 110 model has a plastic housing which should be just fine for basement or attic use, the 4XL also comes with a pressure switch attached. Follow the link below to EFI for more info (product code for EFI is 5501.391(DBF4XL)  or 5501.39(DBF-110).

   Fan-tech is an excellent product, I've used them before and would recommend them to anyone, also EFI is a great supplier as well, I've dealt with them for more than 10 years.

   Good Luck,

                                          Geoff

   http://www.efi.org/wholesale/wholesale_catalog.pdfhttp://www.efi.org/wholesale/wholesale_catalog.pdf

4. 
   seeyou | May 13, 2011 07:49am | #5

   Had basically the same situation. Used a Fantech booster for about 7 years. Worked flawlessly. Finally got the vent moved to a better location, so I took the booster out of service.