Condensate not draining properly

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  #1  
Old 07-11-04, 08:52 PM
maromagosa
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Condensate not draining properly

I am in a 1200 sq. ft. condo in W. Palm Beach, FL. I have an 18 year old Trane system. I am having a leaking problem. The PVC line that runs from the drain pan to the wall (and then supposedly outside) continues to hold water, even after being blown out and vaccuumed with a shop vac. When I run the AC, the water backs up into the drain pan and then flows out a relief valve on the side of the air handler, where it then spills out onto the floor.

One thing that is confusing to me is that I am not sure where my outside drain pipe is. My outside unit sits next to my upstairs neighbor's unit. However, there is only one visible outside drain pipe (upside down L), and I assumed it was my neigbor's (drips regularly while his unit is on). Would we share this outside pipe? (I walked around my building and all of the outside units are in pairs with only one visible outside pipe per pair). With a shop vac, I have blown and sucked and listened from both ends of the pipe and I am getting no sure sign of detecting the whereabouts of my outside pipe. Could it be so clogged that I am just not able to detect it? What if it is that clogged? Solutions?

Another weird thing is that after I had vaccuumed out the section of pipe from the inside (just before the trap), and the AC had been shut off for several hours, I was getting water coming backwards in the pipe (back toward the AC). It wasn't exactly flowing, but sure enough it would slowly overflow out the section of PVC I had cut to vaccuum out the pipe. Just to double check, I vaccuumed it out again, and again it slowly backed up. While the AC is still off, once I re-connect the PVC, it doesn't seem to flow back into my unit because it is not dripping. I had a service guy tell me that the outside pipe (upside down L-shape) acts like a trap, and that a trap at my inside unit would not be necessary (if indeed my neighbor and I shared the outside pipe) as it would slow down flow too much. Unfortunately, the service guy couldn't really get a definitive answer on where my outside pipe was either.

I realize this is a long post and I apologize. I was trying to anticipate questions.

Thanks for any assistance you can provide.
 
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Old 07-12-04, 05:50 AM
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Did you try the shop-vac outside on the one pipe you saw or did you just try it from the inside where you disconnected it? If you are sharing a condensate drain when you vac from your unit the vacuum gets broken where the other unit ties in and you just pull air from their unit.
 
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Old 07-12-04, 11:23 AM
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Wink

Hey west palm who knows????? Take and block the line in side by your unit . Then blow in from that line outside . See if that helps. 18 years on a unit down here is very good with the power we get from FPL. 15 years is the life of a AC and thats up north where they dont run as much

ED
 
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Old 07-12-04, 04:05 PM
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if there is a tee before the trap. cap it.

in your case the coil is probably before the blower, creating negative pressure on the drain.

it must flow into a trap right out of the unit before any air vent.

with no trap or an air vent before the trap, air is pulled into the coil through the drain and prevents the water from draining properly. when the fan cycles off, the water in the drainpan then flows properly, as negative pressure is gone

this would explain "water back to the a/c"

can you remove the coil cover and check that nothing is in the way of the pan outlet?
 
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Old 07-12-04, 08:04 PM
maromagosa
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I tried the shop vac from both ends. So if I am only pulling air from my neighbor's unit, how do attempt to pull air from the drain pipe? Maybe go back outside and try the shop vac again?

Originally Posted by mattison
Did you try the shop-vac outside on the one pipe you saw or did you just try it from the inside where you disconnected it? If you are sharing a condensate drain when you vac from your unit the vacuum gets broken where the other unit ties in and you just pull air from their unit.
 
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Old 07-12-04, 08:22 PM
maromagosa
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Ed, thanks for the reply. I will try what you suggested tomorrow (since it's now too late for me to run my shop vac - will wake the neighbors). If I plug my line, then will I just be sending air to my neighbor's unit? I'm not really understanding, but I will give it a try nonetheless. Yes, I know given the age of my AC I should probably be asking you where to buy a new one and not how to fix this one. I guess I'm just hoping to delay the inevitable. Thanks again.

Originally Posted by Ed Imeduc
Hey west palm who knows????? Take and block the line in side by your unit . Then blow in from that line outside . See if that helps. 18 years on a unit down here is very good with the power we get from FPL. 15 years is the life of a AC and thats up north where they dont run as much

ED
 
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Old 07-12-04, 10:08 PM
maromagosa
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No tee before the trap. As the condensate leaves the drain pan it flows directly into a trap, then from the trap to the wall. I don't have any air vents in the drain line.

You mentioned getting negative pressure that causes backflow of the condensate into the coil. The weird thing is that I noticed some backflow when I had the AC completely off and the drain pipe separated (at the trap) to use the shop vac. This backflow was slow, but I would suck all the water out of the trap and a few minutes later, it would be filled again, without ever having hooked it back up to the drain pan.

I looked at the coil cover and it doesn't look like I can remove it very easily. However, I was able to hook the shop vac up to the drain pan outlet. I assumed that I was able to clear any obstructions that may be in the drain pan or the drain pan outlet.

Originally Posted by hvac4u
if there is a tee before the trap. cap it.

in your case the coil is probably before the blower, creating negative pressure on the drain.

it must flow into a trap right out of the unit before any air vent.

with no trap or an air vent before the trap, air is pulled into the coil through the drain and prevents the water from draining properly. when the fan cycles off, the water in the drainpan then flows properly, as negative pressure is gone

this would explain "water back to the a/c"

can you remove the coil cover and check that nothing is in the way of the pan outlet?
 
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Old 07-13-04, 05:00 AM
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Are you getting a good seal around the vac hose?
If you've sucked from both ends and it's still not clean somethings not right. How many condos could be on this drain line?
Is it possible there's another drain line somewhere you're not seeing?
Maybe buried under mulch?
 
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Old 07-14-04, 03:42 PM
maromagosa
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I used the shop vac on both ends yesterday, both sucking and blowing, and with good seals. I also confirmed with my downstairs neighbor that I share the outside drain pipe with my upstairs neighbor. (He mentioned that he and his upstairs neighbor have worked together to keep their line clear). So there are two units draining into this one pipe. I also tried plugging my line at the AC and blew from the outside drain. Nothing has worked. My gut is telling me that when I use the shop vac on the line, I am just blowing air into or sucking air from my upstairs neighbor's AC because of a clog in my portion of the line. Could this be? If this is the case, what do I do? Ask my neighbor to plug his drain too? Will I need to use some sort of pipe snake or other mechanical device to unclog it?
Thanks
Originally Posted by mattison
Are you getting a good seal around the vac hose?
If you've sucked from both ends and it's still not clean somethings not right. How many condos could be on this drain line?
Is it possible there's another drain line somewhere you're not seeing?
Maybe buried under mulch?
 
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Old 07-14-04, 03:49 PM
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Wink

I take it that the line is PVC cut it close to your unit an then blow in it also look into your drain at the coil. you can put the line back with just a coupling.


ED
 
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Old 07-15-04, 10:12 PM
maromagosa
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The line is PVC. The line is separated just after the 90 degree elbow joint which is connected to a 3" length of PVC coming out of the drain pan. This separation is where I have been blowing into the line. The line is joined back together with a coupler.

Because the line is cut after the elbow joint it is not possible for me to look into the drain at the coil. The 3" PVC line coming out of the drain is glued into the drain outlet built on the pan.

Originally Posted by Ed Imeduc
I take it that the line is PVC cut it close to your unit an then blow in it also look into your drain at the coil. you can put the line back with just a coupling.


ED
 
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Old 07-16-04, 04:54 AM
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I've got to admit. If you've blown into it just after your unit and it blows free and you've sucked from the outside I'm at a loss. Sounds like your drain goes so far then someone elses ties in then the clog then another may tie in before exiting the building. That way when you blow into yours it's feeding back through the next persons unit and when you do it from the outside it's feeding through the persons unit after the clog.The only way to clear it is for everone on this line to block their drains at their unit and only leave yours open. Then suck it out from the outside.

Is there any way to run a new line to your utility room maybe and have your own dedicated condensate drain?
 
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