Any Pro's great at troubleshooting this broken pipe? Why?

Hey all! So this past weekend has been sheer hell for us as Friday nights storm (Chicago land/NWI area), brought us to find a leaking window in dining room, flooded window well with water in basement, and finally...a broken sump discharge line inside the wall of our fully finished basement in a house we've lived in for less than a year!!!
Turns out my discharge line is 1.5" for the entire run out of the house and buried in ground for about 40ft to end of yard. Could this be why the pipe in house burst? See pics

Are those lines on the pipe and elbow, in the first photo, fractures ? If so then my guess is that that is where it froze last winter.

Steve123 said:

Are those lines on the pipe and elbow, in the first photo, fractures ? If so then my guess is that that is where it froze last winter.

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Yes they are fractures but only in that spot. I figured the 1 1/2" line may of played a role in that too

I'm not so sure about pipe diameter, but it looks like household PVC. Might not be rated for that kind of use. Also if the pipe is not buried deeply, the whole line could have frozen. Especially if some critter filled the end full of acorns.

slownsteady said:

I'm not so sure about pipe diameter, but it looks like household PVC. Might not be rated for that kind of use. Also if the pipe is not buried deeply, the whole line could have frozen. Especially if some critter filled the end full of acorns.

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Yeah my plumber buddy said it looks like cheap PVC. I think I should replace the riser as well?

Billbill84 said:

Yeah my plumber buddy said it looks like cheap PVC.

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Please ask him how cheap PVC pipe looks different from expensive PVC pipe. I would be really interested.

Pvc only breaks like that when its frozen. Looks more like a poor installation then pipe.

Out side it should have changed to a bigger pipe to relieve pressure. there should be a bypass outside in case of freezing and it should be on a down hill slope where it goes thru the exterior wall so water is not left to freeze when the check valve stops the water.

nealtw said:

Out side it should have changed to a bigger pipe to relieve pressure. there should be a bypass outside in case of freezing and it should be on a down hill slope where it goes thru the exterior wall so water is not left to freeze when the check valve stops the water.

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Great point! I think that poor installation with no slope as it passed thru rim joist combined with the fact that they had a 1.5" cheap corrugated line buried for some 50ft to the end of yard was destined to have a pressure issue, freeze and fail!

First off, by cheap he must have meant it was DWV rather than schedule 40 PVC. DWV is for gravity drainage and not pressure rated as Sch 40 would be. (It's likely marked on the pipe and that exterior screwed joint, I believe, is an indication of a DWV type pipe.

Secondly I doubt very much if you could develop enough pressure(with the average sump pump) to fracture that pipe even if it was blocked somewhere.

So that leaves freeze up. Of course that pipe remains full of water from the pumps check all the way to the elevation where it exits the house. From there on it would likely empty by gravity. Or at least empty to the highest point of the buried pipe.

EDIT: I wouldn't arbitrarily increase the size of that pipe without first looking at the pumps flow characteristics(flow vs pressure) and subsequent pressure loss due to distance and bends. I doubt very much if the average sump pump could build up much more pressure than about 25 psi or so.
If it turned out that there was excessive pressure loss due to pipe size it would only reduce the rate of flow.

Diehard said:

First off, by cheap he must have meant it was DWV rather than schedule 40 PVC. DWV is for gravity drainage and not pressure rated as Sch 40 would be. (It's likely marked on the pipe and that exterior screwed joint, I believe, is an indication of a DWV type pipe.

Secondly I doubt very much if you could develop enough pressure(with the average sump pump) to fracture that pipe even if it was blocked somewhere.

So that leaves freeze up. Of course that pipe remains full of water from the pumps check all the way to the elevation where it exits the house. From there on it would likely empty by gravity. Or at least empty to the highest point of the buried pipe.

EDIT: I wouldn't arbitrarily increase the size of that pipe without first looking at the pumps flow characteristics(flow vs pressure) and subsequent pressure loss due to distance and bends. I doubt very much if the average sump pump could build up much more pressure than about 25 psi or so.
If it turned out that there was excessive pressure loss due to pipe size it would only reduce the rate of flow.

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Thanks for your input. My pump is a champ she dumps the entire normal size pit in about 6 seconds. I was that the pressure is increased due to such a long run of 1.5" discharge line and if it were frozen, that non pressure rated pipe would fail. Or if the line was frozen out side, close to where it goes underground, the frozen pipe could be acting like it's own check valve which would not allow for the water to completely drain from the pipe as it leaves the house (area that broke that runs through rim joist). Gravity then could not let it run empty and so it froze and broke. Weird thing is that I didn't see any fractures in any part of PVC that was on the exterior portion AND the part that did fail is inside a fully finished basement which happens to be thee warmest spot in the house during winter.

Champ?
Normal size pit?
The pressure can only increase to the point on a pumps performance curve where there is no flow. Referred to as the shut off head. Here's an example of a typical sump pump performance curve.
Note: 35 feet head = about 15 psi.

A pump can ONLY operate at a point on it's performance curve. Meaning as an example, if any one of these curves represented your pump and if it was putting out say 50 GPM(that's 5 gallons per 6 seconds), it would be putting out a pressure(at the pump) at the corresponding Head(pressure)to the left. As friction loss increased due to smaller pipe, longer pipe, higher elevation to pump against or a restriction, it would simply climb up that curve to a point of no flow and the corresponding pressure. My point is that the pump cannot build up any more pressure than that, regardless of whatever takes place downstream.

EDIT: If that pipe I see was on the other side of that insulation, it was insulated from the warmth of the living quarters and froze. Better off leaving the insulation off.

Diehard said:

Champ?
Normal size pit?
The pressure can only increase to the point on a pumps performance curve where there is no flow. Referred to as the shut off head. Here's an example of a typical sump pump performance curve.
Note: 35 feet head = about 15 psi.

A pump can ONLY operate at a point on it's performance curve. Meaning as an example, if any one of these curves represented your pump and if it was putting out say 50 GPM(that's 5 gallons per 6 seconds), it would be putting out a pressure(at the pump) at the corresponding Head(pressure)to the left. As friction loss increased due to smaller pipe, longer pipe, higher elevation to pump against or a restriction, it would simply climb up that curve to a point of no flow and the corresponding pressure. My point is that the pump cannot build up any more pressure than that, regardless of whatever takes place downstream.
View attachment 22672
EDIT: If that pipe I see was on the other side of that insulation, it was insulated from the warmth of the living quarters and froze. Better off leaving the insulation off.

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I see! Thanks I was unaware of that performance curve. You're right about the insulation preventing the warm air from "conditioning" the pipes. One thing that's a concern is that the discharge riser is clamped directly to the concrete foundation so the insulation was masking it indefinitely but the area that failed had some insulation behind it if u look closely in the initial pics from my first post. Here is some more pics but can't see the riser it's behind that stud. I'm thinking I should just insulate the hell out of the rim joist behind the horizontal portion as it leaves house and just leave that wall open or move the discharge riser off the concrete and remount it on the inside of that stud?

The other thing you can do to help freeze proof the pipe is to make sure when then the pipe makes its last turn to go through the rim joist, make sure the section of pipe going outside has fall to the exterior on it. That will keep the first place the pipe has water in it farther from the cold air. Then as you suggest, insulate the hell out of things between the outside wall and the vertical pipe. I realize Chicago had a record setting winter so I am assuming that is why there had not been a problem before now.

I also agree with nealtw. If I were installing the pipe headed through the back yard it would have been 3" drainage pipe with an elbow and a short section of pipe standing straight up at the house. The 1&1/2" feeding into it would then create and air gap allowing the 3" to overflow if it became plugged or frozen. When plumbed that way the sump pump would keep moving water out of the house.

I also agree that that pump would not have broken that pipe even if it was DVW pipe. Having said that, always use Schedule 40 where pressure will be applied to the pipe. Also, the fittings used are not pressure fittings. The pipe failed due to freezing but, I have seen poorly glued non-pressure fittings fail on sump pump lines.

I totally agree that slopping that section of pipe as it penetrates the exterior wall would prevent that standing water at the point it froze.

I do not think changing that long buried pipeline is really worth it. I believe it's safe to say that the line currently empties itself from that exterior elbow downstream. At any point that can be confirmed by simply disconnecting thatvscrewed connection.
So we are just talking in case it got plugged up. Much less chance of a small pump discharge line getting plugged up than a larger gravity line.
In other words, in general I think that's overkill.
EDIT: For that matter, if you want to see when/if it ever backed up due to a plug, a piece of clear see-thru pipe could be added above grade.

Out of curiosity, do you use the sump pump during the winter, when it would be subject to freezing?

Yes I think you guys saying freezing was the cause are absolutely correct. Here's after pipe was repaired. As u can see the entire pipe was insulated over and is affixed to the concrete wall. Think it would be a good idea to redo the riser to get it off the concrete wall and move it inside the basement? Currently it's about 12" behind the drywalled wall. I took some pics but not sure how to run it if I move it off them concrete anchors because the horizontal portion (part that froze), is almost perfectly above the concrete wall so not sure if I could put bender pipe with a slight angle so that the horizontal pipe can still reside there and I won't need to pop another hole in my house