OK so I have read A few threads that touched on this subject but nothing clear enough and its been a while..
1. Return Ducts more then one run on a single system-
A. If there is more then one run lets start with two runs to a single plenum,
Ok so i have been told for best static and air flow it might be best two not only run two seperate ducts to indoor unit but also two separate filters, easily done if you choose to use separate filter bases in ceiling at beginning of run in the home etc
However if you want to use multiple 4-6" media bases to have a better filter and lower static whats the best way(location) to mount these?
let me pain a picture,
I have a fan coil horizontally mounted in an attic apace with a single metal plenum ,
I have to assume you would attach plenum to fan coil/air handler and then cut a hole to size of each filter base you want to mount on each side of the single metal plenum?
If so you would then put filters in and doors on then test static but where would you place static tips once you do this?
If not proper how would you install this in the same situation?
I am again assuming this is only way but lets sub a furnace in instead of a fan coil/air handler ,
would it be easier to install one media filter directly to side cut in furnace and and then the other at natural bottom furnace return opening and attach a plenum to it and then the duct? if you did do this where would you place the static tip and test tesp for return?
I'm assuming you cant really do it this on a fan coil/air handler because the coil is on the return side and blower is ahead of it ? or am i wrong ?
example three which if i did use the single plenum with two filter base mount on each side as example 1 states but had three return runs whats the best placement for the third run??
I have always wondered why this is best using two bases instead of one except media surface area but air is still going through one access provided for return thats why on the furnace i wondered if using one side mount and one horizontal mount is better?
I can use any and all help with some details and ideas on how some of you guys would do this in all examples? remember that space is limited alot of times and putting weird T or L multiple section plenums on a single unit may not work..