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Thread: Please clear something up
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09-18-2005, 11:40 PM #1
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I had an HVAC guy out last week (had to check my system due to Katrina). Anyhow I showed him the duct work in the attic and he said it's fine that all connections to the supply registers make 90 degree angles? I was under the impression that a smooth transition is generally the prefered method?
Thanks for the help
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09-19-2005, 12:07 AM #2
Generally preferred and practical are two very distinct animals. Are you having any air flow issues? The ducting must make turns.
Government is a disease......masquerading as its own cure…Ecclesiastes 10:2 NIV
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09-19-2005, 12:23 AM #3
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Yes, having some airflow problems to the back rooms. He was doing a general check as I got some water in the attic. Bascially the supply lines come off and lay on the rafters, bend up slightly and then make a 90 degree turn onto the vent.
Thanks
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09-19-2005, 12:40 AM #4
The ducting sounds normal.
Government is a disease......masquerading as its own cure…Ecclesiastes 10:2 NIV
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09-19-2005, 12:42 AM #5
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Sounds normal from here.
If this is an air-flow issue and EVERY run makes the same 90 degree turn... your problem is somewhere else!
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09-19-2005, 01:04 AM #6
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Since the attic should be level, I am ruling out water in the end ductwork and I am leaning towards lower blower output as a possible cause. Dirty blower wheels or blocked ductwork will cause reduced output and this wil be most noticeable at the rooms furtherst from the blower.
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09-19-2005, 04:55 AM #7
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Checking
Did his "general check" include measuringOriginally posted by justahomeowner
Yes, having some airflow problems to the back rooms.
He was doing a general check as I got some water in the attic.
Bascially the supply lines come off and lay on the rafters, bend up slightly and then make a 90 degree turn onto the vent.
just Two blower variables:
___ 1. the overall Air Flow ( C F M)
and 2. the External Static Pressure (E.S.P.)?Designer Dan
It's Not Rocket Science, But It is SCIENCE with "Some Art".

Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities
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09-19-2005, 09:20 AM #8
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He took NO measurements, just made sure nothing was damaged in the storm.
With my hand I can tell a difference in output at the front of the house closest to the supply trunk.
I will have him check the blower wheel, etc and go from there..
Air temp gets down to 72 with no problem. However when I walk down the hallway, I feel a temp change at the doorways of each bedroom and inside the bedroom.
This is a 1k square foot home with a 2.5 ton unit.
1 return of 16x24 and 6 supply lines
Thanks
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09-19-2005, 10:55 AM #9
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one more reason for variable speed units with a full time fan on low. Help to even out temperatures throughout the home. System will have to be balanced as it is to acheive more uniform airflow to each room. Also if ductwork is run in the attic the further from the unit the more heat gain so it is a simple rule of nature that air furthest from the unit will be warmer. Check over the insulation on ducting and fix any leaks, then use dampers to balance the system.
"Go big or Go Home"
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09-19-2005, 09:35 PM #10Well, you are better then any of us on this forum...we need to use instrumentation to tell air flow differencesOriginally posted by justahomeowner
With my hand I can tell a difference in output at the front of the house closest to the supply trunk.

I'm not trying to be a smartass, but there are many variables that can really trick your "hand" measuring data.Government is a disease......masquerading as its own cure…Ecclesiastes 10:2 NIV
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09-20-2005, 08:13 PM #11
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Cablibration July, 2005
RoBo,Originally posted by RoBoTeq
Well, you are better then any of us on this forum...we need to use instrumentation to tell air flow differencesOriginally posted by justahomeowner
With my hand I can tell a difference in output at the front of the house closest to the supply trunk.

I'm not trying to be a smartass, but there are many variables that can really trick your "hand" measuring data.
I am prettty sure that 'Justa HomeOwner' was
using his Calibrated Hand.Designer Dan
It's Not Rocket Science, But It is SCIENCE with "Some Art".

Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities
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09-20-2005, 08:18 PM #12
OH! Sorry...my bad
Government is a disease......masquerading as its own cure…Ecclesiastes 10:2 NIV
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09-21-2005, 09:22 AM #13
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Originally posted by justahomeowner
He took NO measurements, just made sure nothing was damaged in the storm.
With my hand I can tell a difference in output at the front of the house closest to the supply trunk.
I will have him check the blower wheel, etc and go from there..
Air temp gets down to 72 with no problem. However when I walk down the hallway, I feel a temp change at the doorways of each bedroom and inside the bedroom.
This is a 1k square foot home with a 2.5 ton unit.
1 return of 16x24 and 6 supply lines
Thanks
What size duct ,to the 6 supplies??6 sounds a little light,unless they are large enough.


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