Filters In Fan Powered Boxes

[rains612]

I have had some Mechanical contractors tell me that it is not necessary to have a filter on a fan powered box if it does not have a cooling coil. The boxes do have electric reheat coils and cooling air is delivered from (2)115 ton Trane Intellipak units that share a common plenum. The units on the roof do have filters in them. The return is open plenum as well and the FPB are Trane. My argument is that I still see filters build up a lot of dust on the fan powered boxes especially in heating season. When the fan powered boxes are calling for heat, the fan kicks on and still picks up a certain ammount of dust particles from the return. I would think that not having a filter would cause some indoor air quality problems and would cause dust to get on the mechanical components such as the heating coil, fan motor, fan assembly and capacitor. I just would like to see what peoples opinions are on what is a better practice, to have a filter on the FPB or not.

[dandyme]

you would be well advised to have filters in those boxes, the dust & what ever else is above that ceiling will make it's way out of the supply diffusers.

your contractor could tolerate some education.

[maxster]

if the filters are matted up that is leftover from the heating season filtering the return are in the ceilings.no air is drwn thru in the cooling modes on the boxes and have no effect on the rooftop...BUT if they have resistance heaters could smoke the room if the space over cools and the fan powered runs...so do the filter or have then sign off on no filter changes $$$$$. popping tiles on overtime... so you cover your A**