Spider system duct

[sols]

Spider system under a house with flex trunk lines.
Iknow a tapered box will work but I would like to know
if I make a square box and off set the collars in the
end of the box would this work as well and be quiter
or does someone have a better Idea With a design of
a box that will work.

[dash]

Spider system is,equipment near the center of home,one plenum,with each branch duct running from the plenum,to the register/grille.

Boxes are usually in flex systems,plenum with a run to a box ,then to grilles and possibly another box and so on.


Which do you have??

[tinner73]

why are you replacing? poor airflow? infestation? flex just deteriorated?

[sols]

What I am trying to find out is the best way to make a
pressure box for a flex trunk line. And would a peice
of pipe with a reducer work or will the air flow move
by to fast.

[tinner73]

call a contractor that does this for a living.

[sols]

We are hvac contractors trying to find a better duct system
that is cheaper to install but still a good system

[tinner73]

fill out your profile. you are a hvac contractor and you don't know this? do your customer a favor and put all that flex in the garbage. install a metal graduated trunkline with round metal runouts, so they won't have to replace it again. that would be cheapest in the long run.

[dash]

Originally posted by sols
We are hvac contractors trying to find a better duct system
that is cheaper to install but still a good system


Spider or radial duct system,generally has relativly low total equivalnt feet compared to others.

If you follow ACCA's Manual J ,you'll be fine.

Since it's likely you aren't using Manual J,the branch runs are probably undersized,if you are having poor air flow.

What do you mean"trying to find a better duct system"??

What type return duct system are you using?

What Friction Rate,on the ductolator for suizing supply and what for sizing returns?

What type of box or boot at the supply register/grille?

What size return grilees for what tonnage?

What model indoor unit on a typical install??

[tinner73]

How often do the animals eat through the flex?