What is the correct amount of slope for an AC condensate line

[Tidybuoy]

I need to re-route my AC condensate line. The installer has it coming out of the side of my house (at attic height) which I agreed to, but it puts out so much water that my patio is very wet.

I'm going to re-route this to under the house and exiting out of a lower vent. The run is about 65' and I need to determine the amount of slope.

Any suggestions as to the amount of slope I should be doing for this 65' long PVC pipe? I'm also going to look for another exit and possibly shorten the run. I may also be able to plumb this into a sewer vent, but my neighbor is telling me not to do this.

Thanks

[908/930]

Can you "T" it into your house drain vent? If you have a pipe or tube straight down from your attic I'm pretty sure you can run the lower section under the house horizontal, could freeze in winter though. 1/8"/foot will drain.

[look 171]

When I install these thing, I go big because the 3/4" line will clog. It isn't if but when. There are lots of damaged ceilings due to these things clogging. We always dump it in the drain like 908 suggest. There's a Y fitting for a vanity drain right before the p-trap. I go 1.5" then narrow it back up at the Y under the sink.

[Tidybuoy]

Thanks Guys!

Since I am building a bathroom directly underneath, I have the walls framed but still open and I am going to route a PVC pipe down the wall. From that point, I am going to see how I can tap into the sewer line which is directly below this bathroom. If I can't tap in, I will run the line to a vent under the house.

The original A/C condensate was plumbed directly to the sewer line but I have now replaced the old cast iron with ABS. I feel like I can drill into the ABS and add a pvc fitting to it.

And, thanks for the heads up on 3/4 size. I think I will go with 1"

The A/C installer installed two pvc outputs: 1) condensate line, and 2) drip pan under the A/C. I will leave the drip pan line exiting the house where I can see it. If anything coming out, it means a leak.

[Zeke]

PVC won't attach to ABS chemically. You'll have to mechanically attach it. You may find a saddle.

However, this is a bad idea for many reasons. Sewer gas is one.

Jeff, I'm surprised you do it the way you do. You aren't getting that inspected I assume.

908 has the right idea even though it isn't allowed here. Dump it into the vent stack.

Edit: I was mistaken about the vent stack. Apparently as long as the vent is a dry vent it is acceptable to dump condensate into the stack. This provision provides that in no way will the HVAC drain line be open in any way, including the tailpiece of a sink drain before the trap, that terminates within the living space. I suspect that it must not be covered an any way just as an electrical splice.

[A930Rocket]

1/4” per foot.

Don’t tie into the vent line, etc. I can’t remember if that’s code, but you could get potential sewer gas.

[look 171]

Originally Posted by Zeke

PVC won't attach to ABS chemically. You'll have to mechanically attach it. You may find a saddle.

However, this is a bad idea for many reasons. Sewer gas is one.

Jeff, I'm surprised you do it the way you do. You aren't getting that inspected I assume.

908 has the right idea even though it isn't allowed here. Dump it into the vent stack.

You mean before the P trap or the larger line?

[look 171]

goes in right under the sink

https://www.amazon.com/Westbrass-D432-RAW-1-1-Slip-Joint-Unfinished/dp/B07BB56HCR/ref=asc_df_B07BB56HCR/?tag=hyprod-20&linkCode=df0&hvadid=693463571983&hvpos=&hvnetw=g&hvrand=10958217182422083965&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9030984&hvtargid=pla-799280197152&mcid=9bca6fa0095f32c583ac61af12f45d78&gad_source=1&th=1

[red-beard]

Originally Posted by Zeke

PVC won't attach to ABS chemically. You'll have to mechanically attach it. You may find a saddle.

However, this is a bad idea for many reasons. Sewer gas is one.

Jeff, I'm surprised you do it the way you do. You aren't getting that inspected I assume.

908 has the right idea even though it isn't allowed here. Dump it into the vent stack.

Almost all of the evaporator drains in this area drain into a bathroom sink line. It is connected with an angled line in before the P trap. The only issue is the dust in the water eventually clogs the lines. You have to pour chemicals down the line every 6 months to keep it clear.

[Zeke]

All I said was code in my AHJ prohibits draining condensate into DWV plumbing. We require a dry sump outside of the foundation. I thought L.A. and the county were the same.

This is what I go by:

2021 CODE: 307.2.

Condensate drains shall not directly connect to any plumbing drain, waste or vent pipe. Condensate drains shall not discharge into a plumbing fixture other than a [exceptions] floor sink, floor drain, trench drain, mop sink, hub drain, standpipe, utility sink or laundry sink.

My take is that the discharge must enter free air before being collected. e.g., no closed direct to pipe connection. It's a health thing in case you can't figure that out.

I should have never brought this up. Do what you want.

Edit: A dry sump as determined by the local mechanical code is a 2 foot deep by something like 18" in diameter and filled with 3/4' stone/rock. This is a perfect breeding ground for the Aedes aegypti and Aedes albopictus mosquitos that invaded L.A. about 3-4 years ago and are a real health threat not to mention day biters. This goes to show you that building codes officials have always had their head up their ass when it comes to logic and reasoning. And why I dropped my licence and haven't pursued a permit for any work in 20 years. I go by the book when it makes sense but I don't deal with inspectors. Most are failed contractors and suck the hind tit.

[908/930]

Where does your clothes washer dump into? Can you get it to drain over there?

[red 928]

Originally Posted by look 171

When I install these thing, I go big because the 3/4" line will clog. It isn't if but when. There are lots of damaged ceilings due to these things clogging. We always dump it in the drain like 908 suggest. There's a Y fitting for a vanity drain right before the p-trap. I go 1.5" then narrow it back up at the Y under the sink.

Isn't that taking forced air and venting it directly to the
outside through the DWV?
Seems like a big leak.
For every Cu. Ft. of air that is pumped to the outside,
another ft. of unconditioned air is trying to come in and replace it.
LOL reminds me of what my dad used to ask:
"are you trying to air condition the whole neighborhood?"

My condensate drain line is only 1/2" diameter and drains
to the flower bed outside and I've experienced a
clogged drain line once in several decades.
After that I started taking a shop vac to the outside end of
the line every spring with no problems since.


it's probably fine to do so but I'd be a little nervous tying
directly into a drain (waste) pipe.
If get it that it's on the vent side but seems like it
could still get odors over time.

[look 171]

Out here, there's a secondary drain line that must be place or drain over a window so when that starts to drip, it is a warning that the primary line is clogged. I have seen them placed over on the interior of a shower in condos. I believe the code specify that it is acceptable if it drains over a drain or exterior.

[look 171]

Originally Posted by Zeke

All I said was code in my AHJ prohibits draining condensate into DWV plumbing. We require a dry sump outside of the foundation. I thought L.A. and the county were the same.

This is what I go by:

2021 CODE: 307.2.

Condensate drains shall not directly connect to any plumbing drain, waste or vent pipe. Condensate drains shall not discharge into a plumbing fixture other than a [exceptions] floor sink, floor drain, trench drain, mop sink, hub drain, standpipe, utility sink or laundry sink.

My take is that the discharge must enter free air before being collected. e.g., no closed direct to pipe connection. It's a health thing in case you can't figure that out.

I should have never brought this up. Do what you want.

Edit: A dry sump as determined by the local mechanical code is a 2 foot deep by something like 18" in diameter and filled with 3/4' stone/rock. This is a perfect breeding ground for the Aedes aegypti and Aedes albopictus mosquitos that invaded L.A. about 3-4 years ago and are a real health threat not to mention day biters. This goes to show you that building codes officials have always had their head up their ass when it comes to logic and reasoning. And why I dropped my licence and haven't pursued a permit for any work in 20 years. I go by the book when it makes sense but I don't deal with inspectors. Most are failed contractors and suck the hind tit.

I am sure you are correct about code, b ut I have never had any inspector call us on draining it through under the sink. My HVAC installer have done it that way for a very time. We try and run it over a flower bed.

[Zeke]

The vent stack is at atmospheric pressure at all times. There are vents that would not be appropriate but terminating into the and main vent should satisfy the need for the condensate to fall freely into air. There is a trap (or should be) at the evaporator unit preventing ambient sewer gasses from entering whatever space the thing occupies. Some are in a hall closet, others in the garage and some in the attic. All of the above have the potential to be in a closed place if not in a conditioned air space.

Getting the condensate out of any contained space doesn't have to be hard. But since there are many bozos installing HVAC, our code is what it is in order to prevent them from becoming creative and not understanding the requirement. All it has to do is run free of the pipe into normal atmospheric condition. By gravity, even if you have a pump at the evaporator.

The potential for methane build up is minimal, but it is there. Methane is lighter than air.

[dad911]

What Look said. Some localities, like where I am in Florida, not allowed to run condensate into sanitary sewer. However, in other areas (NJ) we run the condensate line into a trap that will not dry, like the laundry. If there is a pan under the unit, again, as look said, we run these drains (because they should never actually run) to a visible location. We also put a float switch in the pan that will shut down the unit if that pan fills(the secondary drain fails).

Main condensate line should have a trap. I really like these: https://a.co/d/c1rC9CT Visible with clear trap, has ports to pour in cleaning fluid(vinegar) and easy to clean.

[Tidybuoy]

Originally Posted by look 171

Out here, there's a secondary drain line that must be place or drain over a window so when that starts to drip, it is a warning that the primary line is clogged. I have seen them placed over on the interior of a shower in condos. I believe the code specify that it is acceptable if it drains over a drain or exterior.

That is what my A/C contractor installed. The secondary line will remain as is and that would alert me if it were dripping - indicating a problem. However, the primary line is pumping out too much water for it to be all over my patio and so I am relocating that line.

[look 171]

Originally Posted by Tidybuoy

That is what my A/C contractor installed. The secondary line will remain as is and that would alert me if it were dripping - indicating a problem. However, the primary line is pumping out too much water for it to be all over my patio and so I am relocating that line.

Its just water, just dump it into the garden is what most do or the drain above the p trap way to keep sewer gases out of the building or do what Milt suggest, a well with gravel. In the summer months, its Africa hot so it will evaporate in no time.

[A930Rocket]

Originally Posted by Tidybuoy

That is what my A/C contractor installed. The secondary line will remain as is and that would alert me if it were dripping - indicating a problem. However, the primary line is pumping out too much water for it to be all over my patio and so I am relocating that line.

We always install the secondary drain from the air handler pan and discharge it over a window. I always tell the buyers what it is and if they see water coming out, to call the HVAC company.

I got a voicemail from this one crazy lady saying that she saw water coming out of the drain. It was a torrential downpour of rain that she was seeing.🤪😂