Replies

1. 
   Charles_Moore | May 13, 2000 05:48am | #5

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   you are right to be worried about back flow to other units, the ideas posted about central units are good. if they don't sound feasible -- then think in terms of using 4" duct for each fan and not joining any together for as long as practical. join them with wyes not tees and put two fours into a six and then the third 4" and the six into a 7" unless there are more than two els needed in the seven -- if so use eight inch. You will need to go to a good sheet metal house to get the good wyes and they will be able to make or provide "check valve" flaps to be installed just before the wyes. ======== now comes the important part -- what is your comment about 20 feet or more OUTSIDE ?? the house ???? Remember that bathroom exhaust is very moist at shower time!! You are setting up a guarenteed condensing situation which I have seem ice up so badly as to close of the duct !!! if any of this system is in freezing space it must be pitched to the outside vent cap or you will have water dripping out of the fan units!!!!!! You have to go straight up out of the fan far enough immediately then "all down hill from there " !! good luck.

2. 
   Guest_ | May 13, 2000 05:48am | #6

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   Is it possible to join the exhaust vents of 3 fans together and run them out just one pipe/hose outlet? We're doing a timberframe house which is a bit challenging when it comes to mechanicals and where to route them. My thought is to take all 3 bathroom fans and merge the exhausts all together
   and then run them out of the house.

   Would this cause problems with air bleeding into another fan while one of the others is on? I know the fans have a spring flap that closes when not in use, but I don't think the thing is air-tight. Maybe a minor issue.

   Also, are there some rules of thumb on length of exhaust pipe/hose. The route I plan to run this might be 20-30' in length once it exits the house.

   Thanks for the input,

   Matt

1. 
   Guest_ | May 10, 2000 06:12pm | #1

   *I believe there are now fan units that exhaust the whole house. All vents feed to a trunk that contains the fan so it does not force air down into the other vent lines. I believe there is some sort of switch and gate system that keeps air from being drawn from all locations each time the unit is on.The other benefit is that they are very quiet. I don't remember where I saw it, seems like it was on TV. It also seemed pricey, but that would not appear to be a concern in your application. My recollection was that it was made by one of the usual manufacturers, like Braun or Nutone.Wish I could be more help.Bill

1. 
   Guest_ | May 11, 2000 03:57am | #2

   *Go to the Grainger Catalog, they have a couple 3 and 4 unit fans which connect to a manifold, and then has a single exhaust.

1. 
   Guest_ | May 11, 2000 06:06am | #3

   *Here's a place that specializes in the type of exhaust system you are looking for:POWER VENTILATION

1. 
   A_Gribble | May 11, 2000 10:12pm | #4

   *Have you looked at Fantech? What about the wiring?