leaking plenum
#1
05-09-15, 08:15 PM
leaking plenum
I have a relatively new AC installation in our Houston, Tx home. Its a 3 ton 13 SEER 410A system installed by a licensed AC company meeting all pertinent city codes. When our weather began to stay in the 80's day and night (common for these parts), the AC began to cycle on a daily basis. A week ago, I noticed water dripping from the ceiling underneath the AC unit. I went into the attic to see what the trouble was. The condensate lines are clear and draining properly and there was no moisture in the overflow pan under the evap case. But under the plenum was another story. I cleaned everything up, put towels under the plenum, then pulled the side cover off the case coil. the moisture is draining well and flowing down the edge of the pan to the case drain and down into the ptrap. Even though the case coil is level in both planes, I decided to tip up the farthest corner from the drain just to see if it made any difference. No change. Thinking that maybe the plastic catch pan under the A coil itself might be cracked, I took the bottom edge screws loose from the coil case to see if any water went into the overflow pan. And again, no change. So....??? Any other ideas before I call service ??
#2
05-09-15, 10:18 PM
Group Moderator
Welcome to the forums.'
It sounds like your plenum is not insulated properly. Any place where you see metal ductwork will sweat and drip water.
It would appear that some insulation is in order.
It sounds like your plenum is not insulated properly. Any place where you see metal ductwork will sweat and drip water.
It would appear that some insulation is in order.
#4
05-10-15, 06:19 AM
the plenum is made out of high quality duct board. it is stapled and taped per code. mastic is applied to all seams from the air handler out to the actual ducts.
#5
05-10-15, 09:25 AM
also...
I should have been clearer.....the water is coming from inside the plenum....when i pulled the service panel off the evap coil and point a light down the plenum, you can clearly see the water soaked fiber board in the area closest to the evap coil. The water runs like a plume about halfway down the plenum where it fades away. So it looks as if water is blowing past the coil into the plenum.
#6
05-10-15, 10:42 AM
Group Moderator
That is a completely different matter. Call your installer back. They may have forgotten to put in air seals to keep water from being drawn out of the drain pan. There are certain steps they need to follow based on position of air handler.
#7
05-11-15, 07:52 AM
more....
Ok...so...I sat on my bucket next to the coil access panel and watched the unit operate. What I'm seeing is that as the airhandler blows the return air through the furnace and then through the coil, the moisture coming off the coil sometimes sprays beyond the plastic drain pan and into the plenum. I didn't have the manual for the coil at the time, so I went online and I see that the units Goodman makes have a condensate lip that extends beyond the drain pan into the plenum several inches to catch the spray and let it fall back to the pan. There is no such lip on my cased coil. Should there be such a lip? Or is the air velocity too high causing this spray effect?
#8
05-11-15, 11:31 AM
Group Moderator
There is no such lip on my cased coil. Should there be such a lip?
