high velocity - do they like it

[hottubbrad]

I recently have been thinking about using high velocity on an install. There is a flush 25' long and 21" high laminate beam running in the center of the basement. It runs right up to the sub-floor. My wholesaler tells me to run 2 supply and 2 returns on each side of the beam. This sounds OK, but I am new to this HV stuff and don't want to screw it up..

Does anyone have any good or bad feedback from customers concerning HV?

ie ...windy...noisy etc.

[jacob perkins]

Originally posted by hottubbrad
There is a flush 25' long and 21" high laminate beam running in the center of the basement. It runs right up to the sub-floor.
Does anyone have any good or bad feedback from customers concerning HV?

That first part didnt make any sense to me,but I am not there to look at it so I will take your word on that.

As for feedback,follow the manufacturers instructions and you should have happy customers.Deviate from instruction and you wont.

[hottubbrad]

Instead of running the floor joists from one foundation wall to the other, the joists are basically cut in half with joist hangers on the beam in the center of the basement. The beam goes flush up to the plywood subfloor which means that you can't run the vent pipes over the beam.

[berad]

One of the nicest things about hv systems is that is doesn't need return to pull air around for mixing or throw purposes. A given room will have a certain amount of heat gain, you add the number of supplies to that room to get your btu of cooling. It doesn't matter where you put them as fair as air mixture goes, the velocity will mix for you. Just locate them so they will not blow directly on occupants or you'll get complaints when uncle willies toupe blows off his head. As far as return goes, One central return located about anywhere is fine. Again the return is not for mixung purposes. I love high velocity, since it's your first one they should help you design it and size the number of supplies to each room etc.

[sean88]

With high velocity (over 800 FPM for residential systems)you run the risk of a noisy system. Another thing to consider is the length of duct run, with high velocity your static pressure increases and most residential type air handlers can barely handle a 1/2" total static.

With that said, use your ductulator (if you don't have one get one, Trane makes the best one I've used) to properly size the ductwork. If you want a quiet system size duct work below 500 fpm.

[berad]

Originally posted by sean88
With high velocity (over 800 FPM for residential systems)you run the risk of a noisy system. Another thing to consider is the length of duct run, with high velocity your static pressure increases and most residential type air handlers can barely handle a 1/2" total static.

With that said, use your ductulator (if you don't have one get one, Trane makes the best one I've used) to properly size the ductwork. If you want a quiet system size duct work below 500 fpm.

When I'm talking high velocity I mean on purpose. Unico air handlers anr made to move at 1000 fpm. Throw the ductilator away on this one, the hv systems have their own rules which the dealer will be glad to tell you. By the by, they move 250 cfm/ton and at 1,000 fpm at the supply. However the diffusers and supply duct are made specificly for sound reduction. The las few feet of the supply run are a particular piece called the attenuator. It muffles sound.

[Black Adder]

Where can I guy find more information on High Velocity. Sounds like a cure for a lot of situations I am called on to solve. We don't seem to have anybody dealing it in our area.

[berad]

http://www.unicosystem.com

[berad]

also another brand http://www.spacepak.com

[casturbo]

HV system require, I think, 6 outlets per ton of cooling. That's 18 holes for the feeds and one monster return grill somewhere in a house for a typical 3 ton system. IMO, having 1/2 the register total using a conventional system is more visually pleasing. Plus, don't HV systems compromise SEER? Now I fully admit I do not install nor service these systems, so this is what I know.

[berad]

Yes you do lose some seer, you can only max out at around 11 seer. However at 250 cfm per ton the dehumidification (latent heat removal) makes up for it.

[i b cool]

If they r designed and installed properly they are not noisy and work execellent.They also usually dont have to be balanced either. Make sure you use the proper amount of sound attenuator duct on supply runs and noise will not be an issue.

[beenthere]

HV has its place. You may lose a seer point, but the lower humidity also allows the HO to set the stat a little higher and be more comfortable.

Installed properly, they are not loud, cut some corners, and you can call it a jet pac.

Follow the instructions and they are great.