Condensation in drip pan---unusual amount

[back2boston]

I have an American Standard a/c system, with air handler located horizontally in the attic. The system has been in place for about 8 years, working fine overall. Underneath, there is of course a drip pan (about 2+ inches high), equipped with an auto-shutoff switch (activated via float).

My a/c shutoff for an extended period recently (an hour plus; unusual when running in its typical on-again/off-again state since hooked up to thermostat of course). So, I went up to check, and sure enough, the float had activated and the pan was nearly full. Glad that works! Would have been a wattery mess to upper floor ceiling.

Anyway, I checked the PVC condensate piping leading away from the air handler and out along the attic floor to the side of the house, direct to gutter/s. I then went out onto the roof to take a look at the end. I can see that there is no blockage visually anyway, where pipe ends at gutter, and at that point I could also see about 1 'drip' out the end of it, per second.

Typically, we see the condensate running more or less at a 'steady' rate (more akin to a trickle) down the gutters/downspouts, when we run the a/c for more than a day straight, so something's not quite right----perhaps there's blockage within the run of PVC piping (for the condensate) from the air handler to its end out at the gutter, and that in turn is backing the flow up all the way back to the pan, or something.

I also noted (visually) that when I inspected the space underneath the air handler's underside, where it sits on hard plastic 'legs' that support it over the drip pan, that the 'sweat'/condensate was constant all over the handler's underside, so it was dripping there as well (yet into the pan; hence the design purpose I guess). Still, I was wondering if it should indeed 'sweat' so much. There is no such visible 'sweat' around the insulated trunks/branches/ductwork coming off of the air handler, which I know would be a bad sign, and the system is otherwise operating just fine, cooling the house nicely during the muggy/hot days. The dew point around here in Boston today is about 70, as it was yesterday, so pretty sweltering lately with temps in the 90's. My attic is pretty toasty, but ridge-vented recently with new roof we had put on, but not 'unusual' I'm sure, for up there.

Do I have a possible blockage in my PVC condensate drain pipe to the gutter? Should I call in a plummer to open that pvc up and snake it, etc? Or can I 'do it myself'? I'm pretty handy (or at least like to think so!). I haven't had the system entirely 'serviced' professionally for over 2 years now, so perhaps it's time for a routine maintenance/inspection, or is that just unnecessary $$$ out the window if I can attempt any such maintenance (if so, what to check/do?) myself. Whaddya think? Thanks.

[hiltontech]

Before calling out a tech I would add a little bleach into the PVC pipe to desolve any slime that may be in the pipe and let it sit for about an hour and then flush with water.
Next I would remove the pump that's sitting in your pan and take it apart and inspect it , if all look ok clean it real good and put it back together then put it back in the pan and see if it took care of your problem, if not I would call some one out to take a look at it for you.
Reason I'm saying to do as I said above I had the same problem just last week at the hotel I work at, the problem was in a large air handler, carpet was all wet in front of the a\h, the problem was the pump wouldn't always work as it should causing the pan to over flow.
Other this this I don't know what else is causing your problem being I'm not there to inspect it.

Let us know if you have other questions, try giving us a little more info, it would help us.

HiltonTech

[Ed Imeduc]

Glad you had the kill float switch in the over flow pan. Here code calls for the kill switch in the P trap on the drain line out of the coil there. That over flow pan under the unit has to have a drain pipe on it to the out side of the home .
It has to come out over a door a window or sidewalk. thats so you see it if it has water in it. Like said use a shop vac and see if you can suck or blow in the drain line. Some clorox helps,check on the pan inside there. You sure the filter is clean ,the coil is clean,the freon charge is ok. Big copper line at the outdoor unit cold and wet???

ED ;)

[back2boston]

Hiltontech said: I would add a little bleach into the PVC pipe to desolve any slime that may be in the pipe and let it sit for about an hour and then flush with water.
Next I would remove the pump that's sitting in your pan and take it apart and inspect it.

Okay, I'll try the bleach-in-the-pipe and see if that clears out any possible clog. There's no pump 'sitting in the pan' --- there's only a single white (1+ inch?) PVC pipe that comes out from the lower corner/side of the handler---so the pump itself that feeds the PVC with the condensate must be 'internal'?


Ed said: That over flow pan under the unit has to have a drain pipe on it to the out side of the home... (and) You sure the filter is clean ,the coil is clean,the freon charge is ok. Big copper line at the outdoor unit cold and wet???

The pan under the unit just has the 1 pvc pipe coming from that lower corner as said, and it 'goes out the home' via a run direct out the side of the house at roofline where gutter is --- it empties directly into the gutter. The gutter is quite clear of debris. If by 'filter' you mean the single return duct's filter, yes, it's clean. Can't speak for any filtration mechanisms INSIDE the air handler---I definitely wouldn't get that adventurous. Likewise, can't speak for the condition of the coil and the freon charge (freon must be okay, right?---if all house registers are blowing cold air?). Regarding the 'big copper line' at the outdoor unit, I just checked it and yes, it's 'cold and wet'. What does that signify? Normal?

[Grady]

You probably do not have a pump. Open the door on the air handler to see if the internal drain pan is full. If it is, you likely have a blockage in the main drain. If it is not full, check for excessive rust. There may be a hole in it or if plastic it could be cracked.