Posted: 8/9/2026 4:52:09 PM EDT
[Last Edit: aa777888-2][Edited]
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The backstory I came home yesterday to my central air conditioned house and found it at the proper temperature, but humid and smelling odd. I headed down into the basement and there was water all over the floor coming from the air handler. It was an easy diag., the condensate pump had shit the bed  Of course, what I don't understand is why the high water safety switch did not stop the system  (more on that later).I checked and cleaned the drain line from the evap drip pan, replaced the pump, and tested it with no other problems found (exit line was good to go). I vacuumed the excess water up out of the drip tray and the plenum below it, and the floor, and put the system back in service. It is working normally. The big issue, a wet plenum liner The plenum at the bottom of the assembly got wet, which means the plenum liner got soaked as well. I did remove as much water as I could with the shop vac, and since the system has been running since yesterday it has dried out some but not completely. Two photos appear below. With the plenum in question at the bottom of the air handler assembly I am not going to try to remove it!!! The questions I don't know much about plenum liner or replacing it. I'm not sure what brand or type it is. It has a facing on it, is 1/2" thick, and is held on with 1/2" weld pins (no adhesive at all). So: - Should I just let it dry out? - Should I rip it out and be done with it? - Should I rip it out and replace it? If so, with what product, and with what adhesive, since I have no way to do weld pins? All any any advice would be most appreciated.  P.S. More on the high water safety switch: the switch in the old, failed unit worked perfectly when I tested it. I can only assume the original installer did not wire it correctly inside the air handler. I will have to investigate further  P.P.S. I have also found that the drip tray does not completely drain. Standing water remains on the side opposite from the existing drain to the condensate pump. I did check that the unit is level. Even lifting it a bit on the "wet" side is not enough to cause it to drain. I am planning to add another drain line in order to eliminate this standing water. The appropriate fitting is there, I just have to cut an access hole in the cover on that side. Attached File Attached File |
"Cogito, ergo armatum sum."
| It should eventually dry out. I would spray something like a Lysol product on it until it is completely dry to prevent any type of growth. Don't soak it, just a light spray occasionally. If you have to end up replacing it, go with a foil faced insulation, easier to clean if ever the need. |
Matthew 5:9 Blessed are the peacemakers,
for they will be called children of God.
for they will be called children of God.
| Hose it well and HVAC companies make a product to disinfect also. There are also UC like products out there that can be used to coat and seal trays and plenum bottoms if needed. There should always be a SLIGHT tilt of the system so as to direct any water to the drain, settling and/or poor installation can make drainage problematic at best. |
Liberals are a curious mix of communism and fascism, they want to destroy you but want to use your own money to do it.
I'm getting down to the last box, the others have all been destroyed...
I'm getting down to the last box, the others have all been destroyed...
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Originally Posted By aa777888-2: Thanks, guy! Can you recommend any sanitizer that won't make the entire house smell for days? How about mounting a UV light in that plenum? Any benefits to that? They work if done right but need to be on continuously on and not just when the blower is sent power. However, they do need to be replaced yearly because even if they do still work, their ability to actually kill bacteria and such is diminished with use. Some will go longer but scheduled maintenance and replacement is best. They will add a bit of cost to your utility bill depending on your KW prices. [say 60 or so watts continuously] |
Liberals are a curious mix of communism and fascism, they want to destroy you but want to use your own money to do it.
I'm getting down to the last box, the others have all been destroyed...
I'm getting down to the last box, the others have all been destroyed...
|
Update: The plenum liner dried out pretty quick. Duty cycles, indoor humidity, and air quality (odors) are back to normal. The high water safety switch does work and is wired correctly. At this point I have to assume a dry or clogged trap (P trap) was the culprit (the drain is on the suction side of the fan). I think the installer plumbed the wrong side of the drip tray. I've ordered one of those clear U traps with cleanouts, cleaning brush, and built-in high water safety switch from Amazon which will get installed on the proper (lower) side of the drip tray. I'm also going to use a PVC spigot-to-barb adapter and some 3/4" clear tubing to go into the condensate pump. That way I can visually inspect the entire system. |
"Cogito, ergo armatum sum."