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We have an older home (circa 1965) on a concrete slab (not big news for TX). The Heater/AC unit is in a central closet. The PVC condensation pipe goes down the side and into a larger pipe into the slab. That larger pipe must be backing up and leaking as it is a bit wet where it enters the slab, but much wetter about a foot forward outside the closet under the rug. It's happened before, but quite a while ago.

I believe last time the plumber blew the line out from the closet end. However, in viewing videos online, there is supposed to be an outside pipe that you can suction to clear the line. Trouble is there are no pipes out by my compressor or any I have seen in the 15 years I have lived here. Is it possible it just connects to the main sewer line under the slab? I know there are tablets, or bleach you can pour in to help clear the clogging (I put some bleach in tonight) and turned the a/c way up so it would shut off for a while. The missus used to help out in Apt. maintenance when she worked at a complex, and she said they just turned the units off for a bit and put in the tablets.

In any case, I'm open to any and all advice as to the best way to handle this, short of calling a plumber. I had to fix a slab leak this year and it wasn't cheap, so if I can avoid a plumber it would be nice. Thanks.

G26ster wrote:I believe last time the plumber blew the line out from the closet end. However, in viewing videos online, there is supposed to be an outside pipe that you can suction to clear the line. Trouble is there are no pipes out by my compressor or any I have seen in the 15 years I have lived here. Is it possible it just connects to the main sewer line under the slab?

It's possible it connects into a normal drain line somewhere downstream. Mine drains into the same pipe as the sinks in the master bathroom. I bought a snake (drain pipe auger) at Home Depot for ten bucks or so. Fortunately, only the sinks were clogged/slow - not the shower or toilet.

Good luck. That a/c sludge is some nasty stuff.

apostate wrote:

G26ster wrote:I believe last time the plumber blew the line out from the closet end. However, in viewing videos online, there is supposed to be an outside pipe that you can suction to clear the line. Trouble is there are no pipes out by my compressor or any I have seen in the 15 years I have lived here. Is it possible it just connects to the main sewer line under the slab?

It's possible it connects into a normal drain line somewhere downstream. Mine drains into the same pipe as the sinks in the master bathroom. I bought a snake (drain pipe auger) at Home Depot for ten bucks or so. Fortunately, only the sinks were clogged/slow - not the shower or commode.

Good luck. That a/c sludge is some nasty stuff.

Nothing else is clogged, so I guess I need a plumber or heating/AC tech, as there is no way to get a snake down that tall skinny pvc pipe in the a/c closet. Don't remember which I called years ago. I believe they have to blow it out with compressed air. Thanks.

G26ster wrote:

apostate wrote:

G26ster wrote:I believe last time the plumber blew the line out from the closet end. However, in viewing videos online, there is supposed to be an outside pipe that you can suction to clear the line. Trouble is there are no pipes out by my compressor or any I have seen in the 15 years I have lived here. Is it possible it just connects to the main sewer line under the slab?

It's possible it connects into a normal drain line somewhere downstream. Mine drains into the same pipe as the sinks in the master bathroom. I bought a snake (drain pipe auger) at Home Depot for ten bucks or so. Fortunately, only the sinks were clogged/slow - not the shower or commode.

Good luck. That a/c sludge is some nasty stuff.

Nothing else is clogged, so I guess I need a plumber or heating/AC tech, as there is no way to get a snake down that tall skinny pvc pipe in the a/c closet. Don't remember which I called years ago. I believe they have to blow it out with compressed air. Thanks.

Might try to run a smaller version of the plumbers snake through the line, look in the electrical department for a steel fish tape.

...cut the pvc pipe about 6" above where it goes into the larger pipe...measure the inside of the larger pipe that goes into the slab...buy at Home Dippy or Lowes a black rubber bulb that goes on the end of your garden hose...when you put that down into the larger pipe...(get the right size range i.e. 1"-3"),,,hold it in place about 1' in...have someone turn the water on...as the pressure builds, the bulb will swell and seal...the pressure will blow out the drain, which, if it's gone larger than where it comes out of the pan under the AC coils, does drain into a house drain...let it run a minute or two then cut off the water and remove it...pour water from the hose down the big pipe to be sure it's open......then use the augur 1/4" in a spin housing of plastic...less than $20 to clean the smaller pipe...from the top where you pour in the bleach monthly, if you can make all the turns...or from where you cut it...messier...get a plastic coupling and push the smaller pvc into it and wrap it with black tape...you'll prolly have to do it again sometime so don't glue it...

...put a day on the calendar in red each month to pour about a cup of bleach down the small tube from an opening which should be at the top of it...

speedsix wrote:...cut the pvc pipe about 6" above where it goes into the larger pipe...measure the inside of the larger pipe that goes into the slab...buy at Home Dippy or Lowes a black rubber bulb that goes on the end of your garden hose...when you put that down into the larger pipe...(get the right size range i.e. 1"-3"),,,hold it in place about 1' in...have someone turn the water on...as the pressure builds, the bulb will swell and seal...the pressure will blow out the drain, which, if it's gone larger than where it comes out of the pan under the AC coils, does drain into a house drain...let it run a minute or two then cut off the water and remove it...pour water from the hose down the big pipe to be sure it's open......then use the augur 1/4" in a spin housing of plastic...less than $20 to clean the smaller pipe...from the top where you pour in the bleach monthly, if you can make all the turns...or from where you cut it...messier...get a plastic coupling and push the smaller pvc into it and wrap it with black tape...you'll prolly have to do it again sometime so don't glue it...

...put a day on the calendar in red each month to pour about a cup of bleach down the small tube from an opening which should be at the top of it...

Due to the way my ancient system is designed and installed, it is not possible to do as you suggest, but thanks for the input. I guess it's plumber time $$$.

Is it possible the leak is coming from another place and running to where you see it?
That was the problem I had Saturday night. It turned out the drain was clogged at the unit. The condensation found the next place to come out, and leaked enough to pass under a wall into the wife's closet.
I blew it out with a natural low-pressure air pump. Yep. By mouth.
I need to put in a backup drain, in place of one of the two plastic plugs provided.
BTW, my drain goes into a funnel, which feeds the same drain that the washing machine uses.

G26ster wrote:We have an older home (circa 1965) on a concrete slab (not big news for TX). The Heater/AC unit is in a central closet. The PVC condensation pipe goes down the side and into a larger pipe into the slab. That larger pipe must be backing up and leaking as it is a bit wet where it enters the slab, but much wetter about a foot forward outside the closet under the rug. It's happened before, but quite a while ago.

I believe last time the plumber blew the line out from the closet end. However, in viewing videos online, there is supposed to be an outside pipe that you can suction to clear the line. Trouble is there are no pipes out by my compressor or any I have seen in the 15 years I have lived here. Is it possible it just connects to the main sewer line under the slab? I know there are tablets, or bleach you can pour in to help clear the clogging (I put some bleach in tonight) and turned the a/c way up so it would shut off for a while. The missus used to help out in Apt. maintenance when she worked at a complex, and she said they just turned the units off for a bit and put in the tablets.

In any case, I'm open to any and all advice as to the best way to handle this, short of calling a plumber. I had to fix a slab leak this year and it wasn't cheap, so if I can avoid a plumber it would be nice. Thanks.

Is it possible it just connects to the main sewer line under the slab?
Present building codes (in most jurisdictions) require the primary condensation drain to be connected to a trapped sanitary drain...I don't know what code allowed when your house was built (1965)

I know there are tablets, or bleach you can pour in to help clear the clogging (I put some bleach in tonight)Be careful with the bleach...you should really use a non-oxidizing biocide. Bleach will rust your evaporator coil frame, and drain pan (if it's metal). If you use bleach, dilute it and minimize contact with metal surfaces.

Good luck!

Do you have an air compressor? I may be possible to get blow it out.

Thanks all. Plumbers cleared the drain and rerouted the 3/4" PVC to make it better than the "circus of hoses and pipes" I had in hard to access areas that led to the main drain. I think I had cleared the blockage with the bleach and hot water anyway, but snaking the pipe was insurance I guess. All in all cost me about $100, but at least I have a reasonable setup now. This unit is at least 20 years old, so at some point soon, a new system will need to go in.

G26ster wrote:Thanks all. Plumbers cleared the drain and rerouted the 3/4" PVC to make it better than the "circus of hoses and pipes" I had in hard to access areas that led to the main drain. I think I had cleared the blockage with the bleach and hot water anyway, but snaking the pipe was insurance I guess. All in all cost me about $100, but at least I have a reasonable setup now. This unit is at least 20 years old, so at some point soon, a new system will need to go in.

Getting a plumber to come out and do anything for <$100 is a not bad, and if they do a good job, then even better. Mind sharing who the company was? It might be helpful to someone else on the forum who needs a reasonable plumbing company.

Keith B wrote:

G26ster wrote:Thanks all. Plumbers cleared the drain and rerouted the 3/4" PVC to make it better than the "circus of hoses and pipes" I had in hard to access areas that led to the main drain. I think I had cleared the blockage with the bleach and hot water anyway, but snaking the pipe was insurance I guess. All in all cost me about $100, but at least I have a reasonable setup now. This unit is at least 20 years old, so at some point soon, a new system will need to go in.

Getting a plumber to come out and do anything for <$100 is a not bad, and if they do a good job, then even better. Mind sharing who the company was? It might be helpful to someone else on the forum who needs a reasonable plumbing company.

Strain Plumbing Co. in Hurst. (817) 284-8009. I've used them for years.

My central AC is located pretty much in the middle of the house, and the drain actually connects to the sink drain on the bathroom behind it. Last time it got clogged, it was blown out with an air compressor, which solved the problem but necessitated an hour worth of cleanup in the bathroom as the sink in there turned into a dirt volcano!