Re: OT- HVAC questions

Posted by draire on December 01, 2004 at 05:45:57 from (141.214.17.5):

In Reply to: OT- HVAC questions posted by Gary-MN on November 30, 2004 at 13:48:05:

If you are installing a dedicated Fan Coil Unit(combo furnace/ac), as a general rule, size the blower for 0.5 cfm per square foot of basement space.

The size of the heater and the a/c coil obviously depends upon where you live.

To keep duct noise down select the duct velocity in both the Mains and Branch Ducts around 1000 feet/minute.

Keep in mind that the 'effective area' of a rectangular duct does not match the mathematical cross sectional area.

For example, a 8" Round duct (.35 sf) moves 350 cfm @ 1000 fpm; whereas, it takes a 14" x 4" Rectangular duct (.38 sf) to do the same.

In the HVAC professional world a mechanical Calculator, called a "Ductulator" is used to select the proper size duct.

However, assuming that you don't have one, and you don't need great accuracy, assume that the 'effective area' of a rectangular duct is only 90% of the mathematical area.

As the flow into the Branch ducts gets smaller so does the duct to keep the velocity around 1000 fpm.

Hope this helps.

Follow Ups:

• Re: OT- HVAC questions Gary-MN 09:24:17 12/01/04 (1)
  • Re: OT- HVAC questions draire 05:25:01 12/02/04 (0)

Post a Followup Name: E-Mail: Subject: Comments: Optional Link URL: Link Title: Optional Image URL: Email Notification: If you check this box, email will be sent to you whenever someone replies to this message. Your email address must be entered above to receive notification. This notification will be cancelled automatically after 2 weeks.

TRACTOR PARTS	TRACTOR MANUALS

We sell tractor parts!  We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today. [ About Us ]