Hmmmm Low Delta T?????????

Can’t even imagine why???

Ran into a similar situation last week. After moving a dead rat in a huge trap out of the way I saw where he had eaten thru the covering, the insulation and the inner duct to build a nest in a nice, cool section of the flex duct. You can’t really see it in this photo but 50-70% of the conditioned air from that duct was being lost to the attic of this 1936 home.


Did you check the temps of the cooled air before it moved past these points with deteriorated plastic covering. My thinking is that if the insulation was still fully intact with the inner air-carrying duct being air tight, the delta T still may be low from poorly operating/serviced AC unit.

I had pretty much written off the HVAC before I got into the attic Brian, this was just one more nail in the coffin. Unit was original circa 1985. :smiley:

Michael, what are you doing moving personal property?:smiley:

I hate to start this but BK here goes anyway David A. is on vacation so let her rip take my pics of 72 degrees within the home and 55 degrees on the supply and move the delta T to 85 within the home and 67 degrees on the supply. What would you say about the system then???

Nice try Charley, but not enough info. :mrgreen:

But if it has not been serviced in the last year, they better have a HVAC contractor out there to check it out.

I do not like the dirty rusty registers either. :wink:

Working good Charley----:lol:

Yep…you’re damn lucky David is on vacation----:lol:------------:-&

For what?-----](*,)------------:lol:

Oh my, you and OUR court system seem to have you gun-shy----:lol:—:lol:

Me too, actually-------:lol:

Come on Wuss what more do you need put those temps on any unit that you have looked at.

Ah therein lies the rub Charley, I haven’t looked at that unit now have I? :smiley:

And the register is still dirty and rusty. :mrgreen:

You got that right I am sure I will catch hell for this;-)

Don’t want to rub you and don’t care about the dirt and rust you are avoiding the subject:D :smiley: :smiley:

…this is unhealthful to my delicate psyche

Based on my limited knowledge & training I would let the system run for 12-15 minutes and if the room temp was coming down to say 82 or so then to 80 I would call the system operating properly with a delta T of around 18°. Now, I’m sure that’s the wrong answer so feel free to berate me and inform me of my shortcomings…maybe we will all learn something. :wink:

Mike I don’t berate anyone just trying to draw old BK out on his Delta T and he just clammed up;-)

You were right in your assumptions if left running long enough in my example that unit would have drawn the house down to the low 70’s


Excellent…I suspected there was something with your example that would have demonstrated the inadequacy of using a delta T to judge a system but I guess not. I do wish there was a better way, short of gauges.

Too easy. :wink:

:smiley: :smiley: :smiley: :smiley: :smiley: :smiley: Ya its a bag of worms on this BB

Wanna see an extreme Delta-T…guess what caused this: