Sizing ducts for forced hot air system

HB

Thanks for the info. The problem I'm having is that some short runs (20 feet or so) use a combination of 4 by 10 rectangular ducts and 8 inch circular ducts. Some Longer Runs (30-40 feet) use rounded rectangular ducts (3 x 8)and only 6 inch diameter round ducts.

One of the three returns is about 4 feet from the furnace and is a 2x2.5 foot grate leading into a plenum directly above the furnace, the other two are at the ends of 6 inch round ducts about 15 feet long. One of the returns happens to be about 3 feet away from a supply line.

In general I get the feeling that the system is a bit of a mess. I'm needing to revamp it, and place new ducts as we slowly renovate the house and open up more areas to everyday living.

Thanks again for the tips on the websites and manuals to investigate.

Thanks!

HB

HB

Sizing Ducts for forced hot air system

Howdy folks. Could you point me in the direction of an online site or book that offers information about sizing ductwork for a forced hot air heating system?

I have an old house with a hot air system, and it seems like the previous owner installed 8 inch ducts to everything on the first floor and 6 inch ducts to everything on the second floor.

I've fidddled with what dampers were installed in the lines to attempt to balance the system, but I think I'm really just going to have to re-duct the whole thing.

I guess that I'm ultimately looking for a design guide.

Thanks.

HB

Empire_2

ACCA.COM

This sight has everything you need to size your duct system.

Weezbo

There is a Tin Knocker *~/:)

Who likes to stop by every now and again. he has a site i think it is called the Tin Knockers Workshop. he would likely be a great source for cfm take offs, sizing ,zoning ,plenums, controls,supply and return locations. and maybe some professional help if you prefer not to drag out a variety of tools.

Eugene Silberstein 3

There are three great references for residential

duct sizing. They are:

1 - Manual D from ACCA

2 - Manual D from ACCA

3 - Manual D from ACCA

(do you think I'm partial to Manual D?)

Empire_2

I'm sorry

ACCA.org is the sight. I should have checked before I sent you on a blind hunt:)

Steve_35

What symptom(s) are you experiencing?