Air flow assist blower location in system

[chopped]

I would like anyone opinion on this. .I have a forced hot air heater, and have two 6 inch runs at the end of the main trunk.One of the runs goes about 14 feet and then a 90 degree and exits. The other one used to dot he same but Ive 're-routed' it to another room.
My problem is this line is some 36 feet from the wood furnace.Thus the install of the booster blower. OK Consider this the pipe is 12 foot long with a 90 degree upward and then another 90 degree and runs in a 3 foot section of square duck and then naturally exits up at another 90 degree.
so its really trying to make 3 90 degree turns after the straight length of 12 foot.
Now the question. in the 12 foot length where would the blower work best ?
At the beginning so it will be pushing air more
or on the far end where it would move it directly thought the 90 bends?
Or even in the middle?
Possibly it wont matter at all LOL.
Any input is appreciated. thanks:thumbsup:

 

[arsenix2001]

I would like anyone opinion on this. .I have a forced hot air heater, and have two 6 inch runs at the end of the main trunk.One of the runs goes about 14 feet and then a 90 degree and exits. The other one used to dot he same but Ive 're-routed' it to another room.
My problem is this line is some 36 feet from the wood furnace.Thus the install of the booster blower. OK Consider this the pipe is 12 foot long with a 90 degree upward and then another 90 degree and runs in a 3 foot section of square duck and then naturally exits up at another 90 degree.
so its really trying to make 3 90 degree turns after the straight length of 12 foot.
Now the question. in the 12 foot length where would the blower work best ?
At the beginning so it will be pushing air more
or on the far end where it would move it directly thought the 90 bends?
Or even in the middle?
Possibly it wont matter at all LOL.
Any input is appreciated. thanks:thumbsup:

I would *think* that if your ductwork is air tight, placing the booster twards the outlet would be a better idea as it will be easier to draw through the bends than to attemp to pressurize them. Just place it back far enough your not hearing fan noise. I dunno just my uneducated guess.

 

[chopped]

Thanks that makes sense and is how I was thinking And that part. (round piepes) are tight they hold duck tape very well.And that brings up another thought lol I saw on a TV show there is some sort og gobblie goo that you paint on the joints instead of the duck tape. I'm going to research that some more.Id like something real cheap .On the plenum I used a couple tubes of liquid steel. and it sealed it very nicely..But would be way expensive to use for all the joints..lol
Thanks for your thoughts...

 

[vwnotrunning]

Best location depends on type of fan blade and fan configuration. Most fans are more efficient at pushing air. Actual temperature of the air may effect the availabilty of the fan being in the duct work. Location will also increase or decrease fan noise.

 

[chopped]

Good points. I have a blower like this
TJERNLUND DB-2 AIR- FLOW DUCT BOOSTER FAN - USED | eBay
I used it on my sisters house for awile. but now will use it here. It sort of just 'scoots'( technical term) the air along. also had a new one of these
6 in. In-Line Duct Booster Fan-DB206 at The Home Depot
Brand new cut the pipe etc and nutting . never would have thought it was new so should work but it didn't so I returned it.
these outside ones are better built the motor certainly is better.

 

[vwnotrunning]

You may need a fan similar to this one, depending on how many CFM you are wanting to move.

In-Line Fan, 6 In, 2 Spd, 115 V, 293 CFM - Inline Duct Fans - Fans - 3CGA6 : Grainger Industrial Supply

Most likely much cheaper places to buy it, but Graingers ships nearly everywhere.

Most of the induction or cheap booster fans make little to no difference in air flow. You can try and 8" to 12" cheap fan and put transition fittings on each end and may provide sufficient air flow for what you are wanting.

If you go with an in-line fan like above you may want to install it with 2-3 feet of flexible duct work on the ends to minimize the sound transmission.

 

[slowzuki]

Inline fans operate at such low pressures it really doesn't matter. Farther from the room would help some with the noise.

 

[chopped]

Thanks for all the opinions. Its installed and working fine I decided to go in the middle.,And its boosting the flow well. I had never given much thought to the noise level. but I can hear it if im really ''listening''. but I supect if it were closer tot he outlet it would be more noisy.Thanks for the help everyone.