My self Install HVAC system

[Brandon Whitmore]

I've got a 1500 sq. ft ranch house that I'm installing a forced air system in (conversion from radiant ceiling heat). The living room, entry, and dining room are all basically one large area in the center of the house. The hallway of course leads back to the three bedrooms and full bath. On the other end of the home, there is a kitchen and family room.

I have a 4x10 register with a 7" duct hooked up in the family room, and a 4x10 register with a 6" duct run to the kitchen.

I am installing a 16x16 return air grille with a 12" duct in the hallway, and a 12x12 return air grille with a 10" duct in the family room to pull warm air from the woodstove.

I'm tempted to place this secondary return air close to the woodstove so I can pull the heat out of the room quicker. On the other hand, I am thinking that it would be safer to stick it a min. of 10' from the stove as would be required if it were the primary return air.

With a well balanced system, would it be just as safe to place the return air closer to the woodstove?

[Jim Katen]

I don't know duct design very well but I have learned some things from experience.

Having many returns is always better than having fewer returns. Many returns are quieter and improve circulation.

If you have many returns, and an adequate supply register nearby, there's nothing wrong with placing a return grille near the woodstove.

If you want to exploit the heat from the woodstove, place the return air grille above it, not to one side of it, or below it. Woodstoves radiate heat equally in all directions, but they also create a plume of hot air. You can't suck up radiant heat with a return grille, but you can suck up hot air.

- Jim Katen, Oregon

[Brandon Whitmore]

If you want to exploit the heat from the woodstove, place the return air grille above it, not to one side of it, or below it. Woodstoves radiate heat equally in all directions, but they also create a plume of hot air. You can't suck up radiant heat with a return grille, but you can suck up hot air

One concern I have with installing the grille directly above the stove is that the duct I purchased for this return is flex duct, which has a max. operating temp. rating of 140 deg. I could take a stick of my hard pipe and start off with that, as I've got plenty of 12" hard pipe I could reduce. Capturing the convective heat would be good. No matter what, I will be purchasing more CO detectors for the home.

hmmmmmm

[Brandon Whitmore]

Having many returns is always better than having fewer returns. Many returns are quieter and improve circulation.

I considered installing jumper ducts in the bedrooms, but cutting more holes than I have to through the radiant heat wires is getting old, and is slightly damaging the ceiling in areas. I could install grilles in the walls or doors, but may just undercut my doors more and leave it at that.

Some may find this interesting (duct design): http://www.toolbase.org/PDF/DesignGuide ... design.pdf

[Terence McCann]

A great tool to have:

http://www.bookmarki.com/Trane_Ductulat ... neduct.htm

Used it all the time when I was in the trades.

This looks interesting:

http://unicosystem.com/Portals/0/Videos ... 20(2009-05).pdf

I was just using Google to try and find some "how to" web sites regarding using the Trane Ductulator for those that have never used one.

[esch]

Make sure you dont put any ducts on the END of the main trunk, return or distribution, or you will have severe unequal suction/blowing. See this to many times.

[Brandon Whitmore]

That Trane device does look interesting. For that price, I may have to purchase one and play with it.

I originally intended on designing my own system. After looking at the price of all of the design manuals, and deciding I was in over my head for a quick project, I decided to hire a heating contractor to design a system. That way, I could install the majority of it myself, while having the HVAC guy hook up the furnace so that I could retain the product warranty.

Once I had purchased all of my materials, I looked over all of the supplies, went back through the drawings, and decided the system did not make any sense. I ended up pulling a favor from another HVAC guy. He dropped by on Sat., looked at my system, and told me I would not be happy with that design. He basically said the entire design was crap, without using those exact words. He was sure curious as to who designed the original system. This threw me for a loop, considering I was planning on installing all of the ductwork over the weekend. He ended up re- drawing an entire system using the majority of the materials I had on- site on Sat. He then showed up on Sunday to get me started, and dropped off missing materials that I would need pulled directly from his shop and truck.

So thanks to Bob with Thomas Sheetmetal & HVAC.