Basement sump drain questions

[Whisk(e)y]

Hello, I’m new to the forum and looking for some advice. Two days ago, I walked into my basement and heard that sound that everyone dreads, drip, drip drip. Our basement bedroom had water pooling in the ceiling and then running down onto the floor. After pulling out the sheet rock, it looks as if someone at some point used a rubber flex coupling on the discharge line for the basement sump. One side of this had either loosened or was never installed properly and water was leaking around the coupling. When I touched it, a jet of water shot out into the wall cavity, and I later realized it was because 25 feet of 11/2 inch pvc was completely full of water And had to drain through that small hole. I plan on replacing the flex coupling with a true glue in coupling.

Here’s my question, just past that flexible coupling, about a foot before the PVC stubs to the outside of the house. There are two PVC 45’s glued back to back, causing the drain to rise 3-4ish inches from the horizontal run before it exits the house. Because of this rise the 25ft horizontal run stays full of water. I can’t figure out why this was done, unless it was to create a solid water column for the pump to push upon when it kicks in. To me, with my little plumbing knowledge, it seems that this would be better if the horizontal run was sloped with the 45s removed so that the water would completely drain from the pipe.

What started all this was the outside drain froze solid with the temperatures we’ve been having. I’m assuming that caused excess pressure in the drain line when the pump kicked on. I plan on remedying that by putting an air gap outside and draining it into a 4 inch pipe so I will at least be able to see it in the future if it starts to freeze.

Thanks for any advise, input, or wisdom you can provide.

-Adam

This is the riser from the check up, about 9ft from the top of sump pit.

This is the coupling and rise in the pipe.

Horizontal run going back to the sump.

 

[CT18]

You dont want that water draining back to sump, that will cause short cycling. I believe you have a check valve just above the sump on the discharge so it doesn't drain back. It looks like they missed the hole and jumped up to hit it. The line freezing is what caused the issue. You are on the right track with the overflow outside.

 

[Whisk(e)y]

You dont want that water draining back to sump, that will cause short cycling. I believe you have a check valve just above the sump on the discharge so it doesn't drain back. It looks like they missed the hole and jumped up to hit it. The line freezing is what caused the issue. You are on the right track with the overflow outside.

Thanks. There is a check valve so I’m too worried about water draining back. Am I correct that if I slope the pipe 1/4inch per foot and then stub out a new hole that the outflow will drain completely back to the riser? My biggest worry is there being some kind of airlock forming in the pipe and making the pump work that much harder. Is there any issue with the pump pushing the water initially angainst air rather than a solid column of water?

 

[MicEd69]

What started all this was the outside drain froze solid with the temperatures we’ve been having. I’m assuming that caused excess pressure in the drain line when the pump kicked on.

Actually, the freezing alone is the likely cause. That line is full of water and the end of the line froze. The pressure of the water between your check valves and the ice plug increased as the ice continued to freeze upstream in the line. The weakest point was the one side of that rubber coupling.

As you have to run a rather long distance to get to the outside, that line needs to slope towards the exterior wall all the way from the vertical pump discharge line. To do that in your case, it looks like you will need to drill another hole in your rim joist and siding.

I would not glue in a PVC coupling as it will not fix your problem. Using a rubber coupling there is not a problem once the elevation issue is fixed.

 

[breplum]

Sloping for full drainage of the horiz. pipe to the outdoors is better.
As long as the vertical riser has water in it, no worries about the horizontal being fully drained via gravity.
The most-preferred no-hub couplings are the "shielded" ones with stainless steel band covering the rubber. For real protection is sensitive spaces like over food prep, we like the 'Husky' four band shielded couplings. No-hub couplings should be torqued to the mfr's spec. There are T-torquer tools that we use to get it tightened as per spec. Proper tightening is essential.

 

[MicEd69]

Thanks. There is a check valve so I’m too worried about water draining back. Am I correct that if I slope the pipe 1/4inch per foot and then stub out a new hole that the outflow will drain completely back to the riser? My biggest worry is there being some kind of airlock forming in the pipe and making the pump work that much harder. Is there any issue with the pump pushing the water initially angainst air rather than a solid column of water?

Read this after posting my answer. There is no problem at all with the pump starting with air in the line. There is no way for a sump pump like yours to "air lock".

And yes, a 1/4" per foot to the outside is fine. Just don't confuse the word riser, which normally refers to the "riser" from the pump.

 

[Whisk(e)y]

I would not glue in a PVC coupling as it will not fix your problem. Using a rubber coupling there is not a problem once the elevation issue is fixed.

Is there a reason for not using the PVC coupling? I’m going to have to disconnect there anyway to slope the discharge line and bore a new hole to the outside. I could easily glue in a new coupling then.

 

[Whisk(e)y]

Thanks again, everyone. I appreciate the help. I worked as electrician for 8 years but all I ever really learned about plumbing was there was always a water line where I needed to put a recess can.

 

[MicEd69]

Is there a reason for not using the PVC coupling? I’m going to have to disconnect there anyway to slope the discharge line and bore a new hole to the outside. I could easily glue in a new coupling then.

Not at all, a hard coupling would be just fine. I just didn't want you to do that now thinking that was one of the issues. But often, removable couplings are used for easy access and unplugging lines like these. But you can always just cut the line and add a new hard coupling if there is a problem.

 

[Whisk(e)y]

Ok one more time. After looking at this from a little further away I realized that the 1.5ft section of pipe (circled in black) that is on the other side of the elbows slopes downward so it should drain completely every time the sump runs. That means the pipe circled in red would remain full of water and the last portion past the elbows would be dry. I’m considering leaving it this way for 2 reasons 1. It’s worked for the 23yrs the house has been here until we had these sub zero temps for a week and 2. To properly slope the discharge pipe I’d have to tear out Sheetrock in the other half of the room as well as a bathroom and I don’t really want to get into all that. The other, I’m not sure about option, would be to just turn the elbows around so that they would be dropping down instead of rising and allowing the water to drain that way. I’m just worried that if I flipped the elbows it would allow a trickle of water out making the possibility of freezing worse. Thoughts?

 

[MicEd69]

From the picture in your first post, it wasn't clear how long that pipe was. As long as the water can easily flow out without restriction or anything that impedes flow, you should be good. If the pipe is open ended, cold air might be able to migrate into the pipe a bit and freeze the water at the first 45. But if this has not been a problem for 23 years, and if this is the first time subzero weather has plagued you for several days, you are probably not in too much danger. the water in the horizontal section will not increase the head on you pump more than a few inches.