Thank you to all the plumbing professionals who offer their advice and expertise
Welcome to Plbg.com

Over 550,000 Posts in over 160k Threads

Welcome to Plbg.com (aka: PlumbingForum.com) we are the most popular plumbing information sharing, advice, DIY and educational forum on the Web. Ask any toilet, sink, faucet, pump, water quality, and plumbing related questions. Please refrain from asking where to purchase a product, business, pricing, or legal questions, for contractor referrals, or any questions not related to plumbing. Keep all positive and no advertising. This site is free and made possible by:  

Post New
Search
Log In
How to Show Images
Newest Subjects
 How connect condensate drain to PVC drainpipe
Author: jeffw_00

Hi - 4 years ago my FHA furnace was replaced, they ran the condensate hose (pump output) out to a crawlspace. It's now become a watering hole for field mice. I could dig a ditch and fill it with gravel (tricky, it's a low crawlspace), or connect the condensate hose to a drain pipe. I cannot run the condensate hose to a sink or clothes washer drain because the closest one is on the other side of the house through multiple finished rooms. There are no drains of any kind in the basement. However, there are some exposed PVC drainpipes near the basement ceiling, about 30' from the furnace. In fact, the main Iron drainpipe for the house (goes down to septic, goes to roof to vent) is accessible, and I was thinking I could run the condensate drain to the top of a PVC drainpipe that attaches to the main vertical iron drain. I was thinking i could use a dual-nipple connector of the sort used to connect 2 drain hoses to each other. I could drill a hole in the top of the PVC drainpipe, put in the dual nipple, and caulk it in place, and connect the condensate hose to it. Or I could connect it the correct way (is there a correct way)? Or is this a bad idea and I should dig the ditch?

Thanks!
/j

I'm in New England, and on Septic.



Edited 2 times.

Post Reply

 Re: How connect condensate drain to PVC drainpipe
Author: jimmy-o (CA)

You can only connect to a waste drain pipe above a trap, otherwise you will have sewer gas sucked into your hvac system

Post Reply

 Re: How connect condensate drain to PVC drainpipe
Author: hj (AZ)

quote; Or is this a bad idea and I should dig the ditch?

BOTH are bad ideas. Connecting it to the drain line would cause sewer gases to be "sucked" into the system and then blown throughout the house. A "ditch" will still create a wet spot.

Post Reply

 Re: How connect condensate drain to PVC drainpipe
Author: phillyplbg (PA)

Check and see if "unmetered water" is allowed in your sanitary system

Post Reply

 Re: How connect condensate drain to PVC drainpipe
Author: mikdel27 (NY)

Around here most condensing furnaces/boilers drain into a condensate pump, which has a built in check valve on the 3/8" discharge. The 3/8" tubing is then run into the dwv system via a 1.5" trap. I've also seen a barbed adaptor tapped into both cast and PVC. The check valve keeps water in the tube which prevents sewer gas and backflow. Good luck.

Post Reply

 Re: How connect condensate drain to PVC drainpipe
Author: hj (AZ)

That regulation is meant to control rainwater, NOT the miniscule amounts from a condensate line. If they had a condensate pump, it would NOT have had to drain into the crawl space.

Post Reply

 Re: How connect condensate drain to PVC drainpipe
Author: jeffw_00

It is the output of the condensate pump that I'm talking about.

I was thinking that a 8" deep ditch filled with gravel should keep the water from being discovered by the mice.

Problem is - there's no existing drain (or anything with a trap) within reach - I'd have to go through finished space (or over finished ceilings). I guess I could add a trap to one of these PVC drainpipes.....

Post Reply

 Re: How connect condensate drain to PVC drainpipe
Author: mikdel27 (NY)

You don't need a trap, just drill and tap a barbed adaptor into the top of the line. You won't get any sewer gas because of the check valve, the discharge line will always be full of water.

Post Reply

 Re: How connect condensate drain to PVC drainpipe
Author: jeffw_00

Hi Mike - thanks - you're right -because I observe that there's -always- water in the tube (principally in the vertical portion of the tube closest to the pump).

What I'm a little fuzzy on is how to tightly seal the barbed adapter into the PVC drainpipe. Is caulk sufficient? Should I use some sort of glue?

THANKS!
/j

Post Reply

 Re: How connect condensate drain to PVC drainpipe
Author: jblanche (WI)

You won't get any sewer gas because of the check valve, the discharge line will always be full of water.

Except in the spring and fall, and any other time a condensate-producing gas burner or A/C evaporator are not used for extended periods.

Would it be a problem to run it through the wall to outside? OP did not list a location to determine freezing potential.

*******************************
Links to the State of Wisconsin Plumbing Code:
[docs.legis.wisconsin.gov]
*******************************
I am not a plumber.
*******************************

Post Reply

 Re: How connect condensate drain to PVC drainpipe
Author: jblanche (WI)

What I'm a little fuzzy on is how to tightly seal the barbed adapter into the PVC drainpipe. Is caulk sufficient? Should I use some sort of glue?

Just use a saddle tap. They can be cemented in place.

Unless, of course, they are prohibited by code from use on a sanitary sewer system.

When you pick up your plumbing permit ;-) ;-) ask the inspector if this is allowed. Let us know what he (or she) says about that.

*******************************
Links to the State of Wisconsin Plumbing Code:
[docs.legis.wisconsin.gov]
*******************************
I am not a plumber.
*******************************

Post Reply

 Re: How connect condensate drain to PVC drainpipe
Author: jeffw_00

Sorry - I'm in New England. Don't want to drain to the outdoors. There's no A/C on the system, and so water seems to stay in the hose year round. But even if the hose was empty, there's still a check valve on the pump, so where would the sewer gas go?

A saddle tap wouldn't give me a 3/8" connection, I think? and the plumbers seem to hate them - they leak?



Edited 1 times.

Post Reply

 Re: How connect condensate drain to PVC drainpipe
Author: jblanche (WI)

But even if the hose was empty, there's still a check valve on the pump, so where would the sewer gas go?

Do you intend to have an installation that meets code? Neither a saddle nor a check valve would meet code in Wisconsin.

Is that check valve listed and approved to maintain a trap seal? I am not sure if mechanical devices with moving parts are permitted for that purpose.

On the other hand, if you use a dedicated trap, you will have to prime it in the off season, or cap it.

Plumbing codes are usually enforced by states and sometimes other units of government. No one can tell you what is or is not allowed by code in your locale without knowing where you are. "New England" may have prevailing standards, but there is to my knowledge no regional code.

Absent documentation to the contrary, pros are wise to limit their answers to what they know is permitted in the jurisdictions with which they are familiar.

*******************************
Links to the State of Wisconsin Plumbing Code:
[docs.legis.wisconsin.gov]
*******************************
I am not a plumber.
*******************************

Post Reply

 Re: How connect condensate drain to PVC drainpipe
Author: jeffw_00

my guess is that to meet code I need to dig the ditch. However, given that -my- pump keeps water in -my- hose year round, it's tempting to connect it to a drain.....

Post Reply

 Re: How connect condensate drain to PVC drainpipe
Author: Paul48 (CT)

"Sorry - I'm in New England. Don't want to drain to the outdoors".

Me Too....We don't run the A/C in the winter.Why can't you drain it outdoors?

Post Reply

 Re: How connect condensate drain to PVC drainpipe
Author: packy (MA)

paul, he's talking about condensate from a condensing furnace. cabeesh?

Post Reply

 Re: How connect condensate drain to PVC drainpipe
Author: Paul48 (CT)

Oops.....Thanks packy......Guess I should read a little better.

Post Reply

 Re: How connect condensate drain to PVC drainpipe
Author: hj (AZ)

IF you have a condensate pump, i.e., not using gravity, then you do NOT need a trap and can connect it directly to the drain system.

Post Reply

 Re: How connect condensate drain to PVC drainpipe
Author: hj (AZ)

Drill and tap an opening, then screw the adapter into the opening you made.

Post Reply

 Re: How connect condensate drain to PVC drainpipe
Author: hj (AZ)

quote; There's no A/C on the system

Is this condensate from a "condensing furnace"? If not, and there is no AC, then there is also no condensate water.

Post Reply

 Re: How connect condensate drain to PVC drainpipe
Author: hj (AZ)

wHERE did he say THAT, other than by inference when he stated that there was NO A/C?

Post Reply

 Re: How connect condensate drain to PVC drainpipe
Author: jeffw_00

It's a high-efficiency Bryant forced-hot-air furnace without any A/C. It does produce a dribble of condensation which the "Little Giant" pump takes away.

Post Reply

 Re: How connect condensate drain to PVC drainpipe
Author: Paul48 (CT)

I was taught that a furnace was hot air and a boiler was water or steam.Now, I now there is now hybrid systems using a boiler and air handler,but was I taught incorrectly?Nevermind.......My confusion is caused because I keep forgetting that they now get furnaces to condense.Every time I hear the term...I think boiler.



Edited 1 times.

Post Reply

 Re: How connect condensate drain to PVC drainpipe
Author: jeffw_00

Most (all?) high-efficiency furnaces have a condensation runoff.

Post Reply

 Re: How connect condensate drain to PVC drainpipe
Author: Paul48 (CT)

jeff......You're right...I'm just "Old School" about some things.For some reason, furnace and modulating/condensing just doesn't register in this gourd. Sometimes people will post a question about their furnace, and in the next sentence they talk about their radiators.

Post Reply

 Re: How connect condensate drain to PVC drainpipe
Author: jeffw_00

Guys - thanks for all the info. I talked with the wife and we're going to start with the ditch. Seems like lower risk. I understand that connecting into a random drain pipe -can- (or -should- work), but I see the issues people raise about sewer gas, good connection, etc., At least with the ditch there's nothing new to worry about 8-}

I mean, if they made a piece of hardware designed to let me connect in as I proposed, I'd do it, but I save the hack jobs for when I need them 8-]

thanks

Post Reply

 Re: How connect condensate drain to PVC drainpipe
Author: LemonPlumber (FL)

jeff good call.may I suggest a service point of your new french drain end?

Post Reply

 Re: How connect condensate drain to PVC drainpipe
Author: BigReg1500 (CT)

Why can't he cut in a trap & standpipe into his main, then let the condensate pump discharge into the standpipe?

Or - where are your laundry machines? Run the condensate pump over to your washer standpipe and let it dump into there.

Having a ditch filled with gravel and water under a part of the house does not sound like a good idea to me.

Post Reply

 Re: How connect condensate drain to PVC drainpipe
Author: jeffw_00

"a service point of your new french drain end?". I'm sorry, I don't know what this means.

As I mentioned, I have to go through finished space to reach any existing sink, washing machine, or other drains. thanks.

the ditch may not be a great idea, but it's better than what's there now (surface water in the crawl space).

Post Reply

 Re: How connect condensate drain to PVC drainpipe
Author: jblanche (WI)

As I mentioned, I have to go through finished space to reach any existing sink, washing machine, or other drains.

Sorry if I missed something earlier, but what about going up, to a bathroom or the kitchen? Can you replace a tailpiece on one of those basins with a tailpiece that has a barbed branch connection, and plumb your condensate line in there? You will want to the check the acceptable head on your condensate pump to do this.

Again, a dedicated trap will require the trap to be primed or capped in the off-season. A trap shared with a sink would be ideal.

*******************************
Links to the State of Wisconsin Plumbing Code:
[docs.legis.wisconsin.gov]
*******************************
I am not a plumber.
*******************************

Post Reply

 Re: How connect condensate drain to PVC drainpipe
Author: jeffw_00

Furnace is on the left end of the house. All plumbing is in the right half of the house. To get to the right half of the house (other than to the main plumbing wall, as I discussed), requires going through finished space, regardless of direction.

I could access a bathroom sink (other side of the plumbing wall) and attach to the drainpipe above the trap, but again, it's making a connection to a (short) section of PVC and there seems to be no hardware out there designed to connect 3/8" hose to 2" PVC and I don't want to do a hack job (or tear apart what's there).

Post Reply

 Re: How connect condensate drain to PVC drainpipe
Author: jblanche (WI)

I could access a bathroom sink (other side of the plumbing wall) and attach to the drainpipe above the trap, but again, it's making a connection to a (short) section of PVC and there seems to be no hardware out there designed to connect 3/8" hose to 2" PVC and I don't want to do a hack job (or tear apart what's there).

Are you saying you have a bathroom sink with a 2" diameter tailpiece upstream from the trap? That would be unusual.

But if so, and if space allows (or, what does "short" mean), use a barbed nylon 3/8" to 1/2" or 3/4" NPT connector, and then use a 2x2x1-1/2 wye with bushings.

Otherwise if it's a 1-1/2 tailpiece, you can get a dishwasher tailpiece and adapt to that.

I would rather re-do ALL of the PVC under a bathroom sink than dig a trench in a crawl space. If you're concerned about the appearance under the bathroom sink, you can convert from hose to PVC before you go through the wall.

*******************************
Links to the State of Wisconsin Plumbing Code:
[docs.legis.wisconsin.gov]
*******************************
I am not a plumber.
*******************************

Post Reply

 Re: How connect condensate drain to PVC drainpipe
Author: jeffw_00

I'm not 100% sure if the sink drain is 1.5" or 2". It's a conventional sink with a PVC drain and trap. Might be 1.5". I agree that if I rip-out and re-do the PVC under the sink I could connect the drain hose with suitable adapters, but I'm not real comfortable doing PVC, I can use a shovel 8-}, and a shallow ditch filled with gravel will be a penultimate solution.

As I mentioned, the 'draining under the crawlspace" has worked fine since 2007, I just need to move the water under some gravel where the mice can't so easily find it. I'm sure that if that wasn't an option, that with suitable parts and time a plumber could find a way to plumb the drain into my wet wall, but somehow that's now sounding like the higher cost, and possibly higher maintenance route.

best
/j

Post Reply





Please note:
  • Inappropriate messages or blatant advertising will be deleted. We cannot be held responsible for bad or inadequate advice.
  • Plbg.com has no control over external content that may be linked to from messages posted here. Please follow external links with caution.
  • Plbg.com is strictly for the exchange of plumbing related advice and NOT to ask about pricing/costs, nor where to find a product (try Google), nor how to operate or promote a business, nor for ethics (law) and the like questions.
  • Plbg.com is also not a place to ask radiant heating (try HeatingHelp.com), electrical or even general construction type questions. We are exclusively for plumbing questions.

Search for plumbing parts on our sponsor's site:




Special thanks to our sponsor:
Buy plumbing supplies online


Copyright© 2015 Plbg.com. All Rights Reserved.