78822.1
Man, oh man, it’s been a bad couple of days for the in-laws…
Those of you who read or responded to the HD reroof thread got a glimpse of one of their problems.
Earlier this week, we got about 2 inches of rain in 30 minutes, and their basement flooded due to a downspout that had come loose from the gutter, allow water to pour down right next to their foundation. So they’ve been dealing with that all week. THEN…
Last night we celebrated the MIL’s birthday. After supper, DW and her sisters were clearing the dishes, and water backed up in the sink that’s connected to the garbage disposal. Assuming the disposal needed to be run, the MIL ran the disposal. A few minutes later, she was in the basement and noticed water all over some books. My BIL and I take a look, and determine that when the disposal is run, water gushes out of the open end of a 1-1/2″ PVC pipe, flooding the under-sink cabinet, and then taking every available route through the 1x subfloor to the basement below.
My BIL and I spent the next three hours disassembling various parts of the plumbing and then snaking everything we could reach. Here’s what we determined (plumbing schematic attached for your reference)
1. When water is run into either sink (S1 or S2), water eventually backs up into both sinks. (within 1 minute of running water at less than full-flow)
2. Traps T1, T2, and T3 are all clear, as are the drain lines from S1 and S2 to the CI drain pipe in the wall.
3. The dishwasher appears to drain into point G. The connection from the dishwasher is with 3/4″(?) rubber hose, going to 1/2″(?) rigid PVC that empties into 1-1/2″ PVC at point G.
4. Point G is also where we get a geyser when we run the garbage disposal.
5. I opened cleanout 1 (C/O 1) in the basement and was able to snake from C/O 1 to C/O 2, so unless the clog is beyond C/O 2, that part of the system shouldn’t be the problem.
6. Our conclusion is that the clog is somewhere in the indicated area. Our diagnosis is that water drains OK until it hits the clog. It then begins backing up in the drain lines until it reaches the sinks. When the disposal is turned on, it attempts to force water down the drain. Since the water can’t be forced past the clog, it’s only available exit is at point G, hence the gusher. Does this make sense? What else could possibly be the problem? I tried to snake this area as best I could, but I’m not sure I did a thorough job…
I’m not a plumber, but I can’t think of any other scenario that could cause this kind of symptom. I advised them not to call a plumber till Monday to avoid getting raped by after-hours Sunday rates, so unless I can get some good direction from BT, they’ll be calling a plumber tomorrow so that they can use their kitchen… Open to any and all ideas.
Keep in mind that the attached image is a schematic. It’s not meant to be to scale, or to show every Y, T, 90, or 45.
Thanks for all your help!!!!!!!
Replies
I think the point G is a vent for the dishwasher. Garbage disposers act like a pump and make a lot of pressure. I would try to rod out the pipes. Mine had a grease and hair buildup where the garbage disposer and shower combine at the stack. I tried to plug the other sink and run the dishwasher, only to fill the shower with nasty water. I finally rodded out the pipes. Then a good dose of lye to help wiith the grease buildup.
Yep, I think you've read it correctly. The disposal acts like a centrifugal pump and pumps water into the clogged pipe, causing an overflow in the garbage disposal standpipe.
The clog is somewhere below/beyond all of the above, below/beyond where the sink traps and standpipe all mate up, but above/ahead of any other connections that are running free.
This would generally be fairly easy to snake out. A small "canister" type "drain auger" is handy to have and would work well in this situation. Usually it's easiest to gain access to the pipe by disassembling one of the traps.
Something like this: http://www.acehardware.com/product/index.jsp?productId=1280064&cp=1254880.1255013.1260768&parentPage=family&page=1&doVSearch=no&pageBucket=0&parentPage=family&searchId=1260768
Note: DO NOT use any sort of acid or lye drain cleaner until the pipe is flowing. It rarely does any good and creates hazards for those attempting to auger out the pipes.
LOL - I know this, but my FIL had to give it a go. After we spent 3+ hours on "physical" cleaning attempts last night, he went out today and bought Drano. Emptied a whole bottle into the drain, which effectively filled all the lines (and didn't help), so the plumber now has that to deal with first thing... I didn't know he was going to do it, or I would have advised against it...
A standard dishwasher connection should be a 1½x1½x1½ Y or t-Y with a ¾" barbed insert adapter glued (or threaded) into secondary arm of the Y. The DW drain hose is supposed to be hose-clamped nice and tight to that barbed insert so it can't leak.
If the hose is simply inserted loose into an open pipe, the way some (laundry) washing machines are installed (also a bad installation, but very common), you should buy the proper fittings and install them.
If there is no vent stack in the system, there might be a spring-type air valve t-Y'ed into the drain line just above the DW's drain Y, but they are not supposed to leak as any pressure from inside the system should force the valve shut.
The fact you get a geyser at that point 'g' when you pressurise the sytem with the GD unit indicates you have a problem with either the air valve or the dw's drain hose connection. That shouldn't happen no matter how blocked the main waste line is.
In any event, your blockage is likely where you think it is, and you'll need to get an auger in there to clean it out.
Dinosaur
How now, Mighty Sauron, that thou art not brought
low by this? For thine evil pales before that which
foolish men call Justice....
"The fact you get a geyser at that point 'g' when you pressurise the sytem with the GD unit indicates you have a problem with either the air valve or the dw's drain hose connection. That shouldn't happen no matter how blocked the main waste line is."Dino,Can you explain this more to me? If the air valve or dw drain hose connection was ok, what would happen when I pressurize the system with the disposal? You are correct that the dw drain hose connection is not "fitted" or sealed. It's just a 1/2" pvc pipe stuck about 2" into the 1-1/2" pvc. Obviously, if this was sealed properly, I couldn't get a geyser at G, but wouldn't it then backfeed into the DW? That wouldn't be good either...Thanks for your help!torn
Yes, sewage would backup into the DW, some fancy ones have a kind of check valve after the ejection jump but it is rare. A GD works as kind of an open pump so it will pressurize the system only so much before it stops working as a pump. In such a case I have seen a GD pump the water out of the sink into the drain line and then when you turn it off the water floods right back into the sink.
If the clog is in cast iron pipe, I have been successful at finding clog locations by tapping lightly on the pipe with a ballpeen. A water filled pipe makes a thump thump sound while an empty pipe makes a heavy ting ting sound. It is kind of like finding a stud by tapping on a wall.good luck
dayPS. Someone is going to warn me that old cast iron pipe can get thin and brittle and one is likely to bust a hole in a pipe with this method which is why I say tap LIGHTLY.
Torn, see my reply to Bill Hartmann below. He and I disagree on this one; here's hoping our discussion will illuminate the issues so you can decide how to handle it from an informed position.Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
On the contrary. The DW connection is suppose to be an Indirect drain (if I remember the term correcly).One way of doing it is to have an air gap.Another is with the gap at the top of a standpipe.Not unlike a washing machine drain.The idea is to prevent waste from backing up into the DW.If you use a fitting to tee it into the sink drain the a common solution was to loop the drain line up to the top of the cabinet so that could not backup in the DW without overflowing the sink.
Bill: you are right about the accepted hook-ups for a dishwasher, "May the force be with you"
On the contrary. The DW connection is suppose to be an Indirect drain (if I remember the term correcly).
I have heard this theory expounded--although I never heard the term 'indirect drain' before--along with the caveat to use an air gap. I disagree, and here's why:
Both DW's and laundry washers are pump emptied, which means they not only pressurise the drain system but they are capable of putting a very high volume of waste into it in a very short period of time. That demand is pushing the drain system to work right up to its design limits in most cases.
Well, design states are fine, but we know nothing in the real world is ever perfect. Remodelers routinely add branches to drain systems not using the correct size or venting; gunk collects on the insides of all pipes; tree roots get into sewer lines; etc. All of a sudden, the design state no longer exists, and the system is incapable of performing up to the design limit.
Now you ask the system to handle a peak demand, and what happens? That 'indirect drain' (if that's what it's called) pisses waste out the top of the unsealed pipe, because the throughput exceeds the momentary absorption capacity of the system.
For laundry washers, the old solution of dumping the drain hose into a slop sink works well...so long as the slop sink has a capacity equal to or greater than the maximum water load the washer will fill to. That way, the slop sink acts as a holding tank, allowing the drain system to absorb the waste water at its own rate. No overflow, no back-up, no problems.
Most people don't want their DW drain dumped into the kitchen sink, though. (Kitchen sinks aren't as deep or large as slop sinks, anyway, so there could be splash-out.) So the connection is made under the sink in the base cabinet, or, in cases where the DW is not near the sink in the kitchen, under the floor, in the basement ceiling or pipe space. For reasons stated above, I think that connection should be sealed.
There is a very simple solution to preventing backup of pressurised waste through sealed drains into either dish- or laundry-washers: Put a check valve in the drain line if the machine does not come equipped with one from the factory. No garbage disposal--or anything else normally found in a residential plumbing system--is going to generate enough pressure to blow past a check valve (the more pressure, the tighter they close); nor is it going to rupture a sealed fitting, even a barbed insert with hose clamps (assuming they are properly installed). So why take the chance of leaving an open point in your drain system?
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
You have three traps under the one sink? If thats true start over. You should only have one, the reason being that draining one could/will cause the others to syphon and allow stink up into the house.
Edited 9/17/2006 7:57 pm ET by MSA1
yep, three traps under the one sink... with any luck this will be appropriately reconfigured by the plumber they call tomorrow...
"You have three traps under the one sink? If thats true start over. You should only have one, the reason being that draining one could/will cause the others to syphon and allow stink up into the house. "You can have more than one trap. The question is how are they connected to the drain/vent line.
As long as they're not gonna syphon each other. So, yes as long as they're properly vented no problem. Alot of times theres not a vent near by so its generally speaking easier/safer to run one trap.
Hi Guy,
I gotta' ask.....was this place inspected before purchase? I'm not trying to make light or anything but you mentioned the roof, now this plumbing thing. These and the fact that you did mentioned the "Raymond" show....and how your FIL used Draino already.
Please keep us posted on further developements.
bum
...a bad day at the beach is better than a good day anywhere else... :)
Have had my drain back up like that - but not with such drama. Just a sink of crud. My drains date from the '60s and doubtless have a buildup of gook - saw this on a demo project we did. Drains were down to .75" with buildup.
FWIW - Had no luck with a 25' snake so, just before calling the plumber, I got out my 100 elect. fish tape, found a pan headed machine screw that would thread into the tip and tried that. Worked just fine. Easier to handle than the snake. Never called plumber.
Now I am thinking of some attachments for the tape that would do drains and knock the crud loose.
The ToolBear
"Never met a man who couldn't teach me something." Anon.
I'm wondering if the house was painted recently and the brushes were cleaned in the kitchen sink and a lot of paint was washed down the drain and has accumulated in the drain lines closeby.^^^^^^
S N A F U (Situation Normal: All Fouled Up)