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    ChrisV07's Avatar
    ChrisV07 Posts: 5, Reputation: 1
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    #1

    Aug 31, 2007, 11:19 PM
    Washing machine discharge, standpipe
    Last week our washing machine drain overflowed. The plumber tried to snake it out, but the problem only became worse (i.e. no flow at all any more). He opened up the drywall and discovered a very corroded cast iron pipe going horizontally from the standpipe via a trap to a T at a vertical pipe (upwards a vent, down into the concrete slab). The plumber blamed the clog on the fact that the horizontal pipe had essentially no slope to it, and said the only solution was to replace standpipe, trap, and horizontal pipe with new plastic pipes. An expensive job, but we seemed to have no choice. As part of the job he installed an "eliminator outlet box" on top of the standpipe, in which the washing machine discharge hose is supposed to go (and which also has valves to connect the water hoses to). Tests with water from a faucet flowing through a hose into the drain worked fine. But as soon as we actually ran the washer, the drain immediately backed up and overflowed. Clearly it cannot handle the large volume of water that is being discharged. I did some research on this site and see two possible problems: (1) a partial blockage farther down the drain pipe (i.e. where it disappears into the concrete slab; (2) the height of the standpipe. For some reason the new setup has the standpipe at a height of only 29", much lower than it was before. The washing machine manual specificies 39".
    We will obviously complain to the plumber, but I'd like to be more informed before making my complaint. In particular, is the height of the standpipe really a crucial issue? Would there be a way to test whether it really causes the problem? All I can think of is raising the end of the discharge hose by 10" and running the water through a hose into the standpipe; is that a good test?
    Finally, regarding the possibility of a partial blockage in the pipe underneath the floor: I assume it can be snaked out, but I have this fear that snaking could turn the partial blockage into a complete blockage, as it seemed to do with the above-ground pipe. And that would mean jackhammering the floor to replace it. Am I wrong to worry?
    speedball1's Avatar
    speedball1 Posts: 29,301, Reputation: 1939
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    #2

    Sep 1, 2007, 10:33 AM
    I think your plumber's blowing smoke. Even if the pipe that leads from the trap to the sanitary tee on the vent stack had no fall at all the head pressure plus the force of the pump would push it through. In my opinion you paid for unnecessary work.
    How large did he make the new trap and stand pipe? 1 /12" or 2"? (The answer should be 2 inches).
    He made the standpipe woefully short. It should be at least 36" long and terminate two inches over the flood rim of the washer.

    "Finally, regarding the possibility of a partial blockage in the pipe underneath the floor: I assume it can be snaked out, but I have this fear that snaking could turn the partial blockage into a complete blockage, as it seemed to do with the above-ground pipe. And that would mean jackhammering the floor to replace it. Am I wrong to worry?"


    Any time you have to question your plumbers work is a good time to start worrying. Unless he went up on the roof and dropped a snake down the washer vent pipe he hasn't snaked diddly-squat. If he attempted to snake from the stand pipe he had just as good a chance of going up the stack and out the roof as he had in going down into the washers drain. My advice? Extend the stand pipe to at least 36" and snake the washer drain from the roof vent. After that if there's still a overflow problem I recommend adding a compression fitting, (see imsge) on the stand pipe and making this a closed
    System. I have this on my own standpipe and have never got a complaint back from any of the people that I advised using it. Good luck and let me know what happens. Tom
    ChrisV07's Avatar
    ChrisV07 Posts: 5, Reputation: 1
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    #3

    Sep 1, 2007, 07:26 PM
    Dear Tom,

    Thanks for your expert advice and fast response! You're great!

    Yes, the trap and standpipe are 2". Today we ran some more loads of laundry, turning off the washer every time the drain started overflowing. In the process of doing so, we must have dislodged whatever was causing the partial blockage, because after a while things started flowing a lot better; and right now it drains perfectly without overflowing at all.

    However, I am still very unhappy about the standpipe being only 29" high. Your advice as well as other references we have consulted indicates it should be 2" above the rim of the washer (our washing machine instruction manual specifies 39" height). I'm afraid that any slight blockage in the future might cause the overflow problem again, and I think a higher standpipe would offer some protection against this (right?).

    What I am wondering about now is how to convince the plumber to re-do this (at no extra charge). We were thinking that we would be able to point to a violation of the plumbing code; but unfortunately, neither the "Uniform Plumbing Code" nor the California code seem to specify a height; they only mention the standpipe should be no less than 18" (and no more than 30") above the trap. Re-doing this is not a small job because of the way the plumber combined the standpipe and the water pipes into one "eliminator outlet box". What's our best argument for convincing him to re-do this, and do it right?

    Chris
    iamgrowler's Avatar
    iamgrowler Posts: 1,421, Reputation: 110
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    #4

    Sep 1, 2007, 08:13 PM
    Quote Originally Posted by ChrisV07
    What I am wondering about now is how to convince the plumber to re-do this (at no extra charge). We were thinking that we would be able to point to a violation of the plumbing code; but unfortunately, neither the "Uniform Plumbing Code" nor the California code seem to specify a height; they only mention the standpipe should be no less than 18" (and no more than 30") above the trap. Re-doing this is not a small job because of the way the plumber combined the standpipe and the water pipes into one "eliminator outlet box". What's our best argument for convincing him to re-do this, and do it right?
    No less than 18 inches and no more than 30 inches above the trap seems pretty darn specific to me, Chris.

    Tom and I have gone round and round about the issue of minimum and maximum standpipe heights for clotheswashers -- And as someone who has been installing 18" standpipes for over twenty years without any issues, I can say that if plumbed properly, there is no reason whatsoever a 18" standpipe cannot keep up with newer high capacity clotheswashers.

    As for convincing the Plumber to re-do his work (for free and) in violation of local plumbing code, I hope he sticks to his guns and refuses to make the change.

    Frankly, if you want to go after anybody, go after the appliance manufacturer who sold you a product they knew full well didn't meet the code requirements of the region they were marketing in.
    speedball1's Avatar
    speedball1 Posts: 29,301, Reputation: 1939
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    #5

    Sep 2, 2007, 07:49 AM
    Common sense will dictate that the larger the standpipe the less chance of a over flow. In my area local codes mandate a 36" stand pipe that terminates 2inches over the flood rim of the washer. The manufacture recomends a 39" stand pipe. That should tell you that if the manufacture recommends a 39" stand pipe and our local code mandate a 36" standpipe that 18" is woefully undersized. Sorry Growler! I have the utmost respect for your plumbing knowledge but it amazes me that simple physics,( larger is better for containing liquids) seems to allude you. A newer Maytag washer pump would blow a 18" standpipe away. Regards and peace, Tom
    iamgrowler's Avatar
    iamgrowler Posts: 1,421, Reputation: 110
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    #6

    Sep 2, 2007, 01:00 PM
    Quote Originally Posted by speedball1
    Common sense will dictate that the larger the standpipe the less chance of a over flow.
    As I keep saying -- If it's plumbed correctly (Trap, trap arm, drain and vent sized, graded and run properly) then it isn't going to overflow.

    Period.

    In my area local codes mandate a 36" stand pipe that terminates 2inches over the flood rim of the washer.
    And in my area, as well as the OP's, no less than 18" and no more than 30" above it's trap.

    The manufacture recommends a 39" stand pipe.
    The manufacturer is neither the code writing authority or the code adoptee.

    Plumbing code is very specific as to who has the final word in a tug of war between the manufacturer and the local authority.

    If the manufacturer is selling appliances that do not meet the prevailing code in the areas they are marketing in, then they have left themselves wide open to a class action lawsuit.

    That should tell you that if the manufacture recommends a 39" stand pipe and our local code mandate a 36" standpipe that 18" is woefully undersized.
    No, it tells me no such thing, Tom.

    I receive cut-sheets on every appliance I provide plumbing for, including high capacity Maytags, and I have yet to have one overflow an 18" standpipe.

    Sorry Growler! I have the utmost respect for your plumbing knowledge but it amazes me that simple physics,( larger is better for containing liquids) seems to allude you. A newer Maytag washer pump would blow a 18" standpipe away.
    Well, I hate to say it, but my respect for you goes right down the toilet when I see you telling people to ignore the codes that prevail in their area, Tom.

    Look, you know I teach code compliance classes, so me being a stickler for code compliance should be a no-brainer.

    As for the physics lesson -- Think about how commercial dishwashers with indirect drains are plumbed.

    The full sump of the dishwasher, which is comparable to the full drum of a clotheswasher, pumps at the same velocity into a 8x8 floor sink with a 2" trap and virtually no standpipe;

    The surface area of the floor sink is slightly less than the surface area in an 18" standpipe, and yet the floor sink can keep up with the discharge without any problems whatsoever.

    How's that for physics?
    ChrisV07's Avatar
    ChrisV07 Posts: 5, Reputation: 1
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    #7

    Sep 2, 2007, 01:43 PM
    I see no conflict between the code and the specs of the washing machine. Code says: standpipe should be between 18" and 30" above its trap. Code also says: trap should be between 6" and 18" above the floor. Combining these numbers I can see the final standpipe height being between 24" and 48" above the floor. Requiring 39" (which it needs to be to be 2" above the flood rim of the washing machine) is perfectly consistent with code.

    By the way, code also says that "...receptors of indirect waste pipes shall be approved for the use proposed and shall be of such shape and capacity as to prevent splashing or flooding". The 29" standpipe does not meet the requirement of "preventing splashing or flooding". So it does not comply with code, in my opinion.
    iamgrowler's Avatar
    iamgrowler Posts: 1,421, Reputation: 110
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    #8

    Sep 2, 2007, 03:49 PM
    Quote Originally Posted by ChrisV07
    I see no conflict between the code and the specs of the washing machine.
    I do, let me explain...

    Code says: standpipe should be between 18" and 30" above its trap.
    A more or less accurate iteration of section 804.1 of the UPC.

    Code also says: trap should be between 6" and 18" above the floor.
    Right, they're talking about the very bottom of a 2" trap -- The 6" limitation is a throwback to the days when cast iron durham fittings were still commonly used, acids in soil would eat away at the galvanized nipples used to connect the cast iron durham p-trap to the sanitary tee or wye.

    The 18" limitation is because anything over 18" would bring the drain hose of the appliance well over the flood rim of the appliance using just the bare minimum requirements of the code.

    Combining these numbers I can see the final standpipe height being between 24" and 48" above the floor.
    Right -- But that isn't What Tom or the manufacturer is recommending.

    Tom and the manufacturer are saying that the 'developed length' of the STANDPIPE should be in excess of 30".

    Which is most definitely not in compliance with the UPC.

    Requiring 39" (which it needs to be to be 2" above the flood rim of the washing machine) is perfectly consistent with code.
    Well, this is a red herring at best -- No where in the UPC does it state that a clotheswasher standpipe must be 2" above the flood rim.

    Don't try to kid a kidder -- I teach this stuff fer crine out loud.

    By the way, code also says that "...receptors of indirect waste pipes shall be approved for the use proposed and shall be of such shape and capacity as to prevent splashing or flooding". The 29" standpipe does not meet the requirement of "preventing splashing or flooding". So it does not comply with code, in my opinion.
    Right -- but if you knew code as do -- You would also know that the paragraph that precedes the above is superseded by the paragraph that follows.

    Y'know, I'm not trying to be a butt here, but as mentioned earlier, I teach classes in code compliance -- And as an instructor, I cannot condone violating the very codes and practices I do my best to drill into the heads of my students.

    Also -- As mentioned time and time again, if plumbed properly, there is no reason whatsoever why an 18" standpipe cannot keep up with the discharge of a high capacity clotheswasher.
    ChrisV07's Avatar
    ChrisV07 Posts: 5, Reputation: 1
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    #9

    Sep 2, 2007, 05:19 PM
    Right -- But that isn't What Tom or the manufacturer is recommending.

    Tom and the manufacturer are saying that the 'developed length' of the STANDPIPE should be in excess of 30".
    The washer manual says: "Top of standpipe must be at least 39" above floor." I called that the "height". Sorry if that was unclear.

    Discussions about code aside: personally, I think a plumber should follow the installation instructions for the washer. If it says it MUST be 39", and if it previously was plumbed that way and was working fine for many years, I am baffled as to why a plumber would choose to make it 10" lower.
    iamgrowler's Avatar
    iamgrowler Posts: 1,421, Reputation: 110
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    #10

    Sep 3, 2007, 03:48 PM
    Quote Originally Posted by ChrisV07
    The washer manual says: "Top of standpipe must be at least 39" above floor." I called that the "height". Sorry if that was unclear.

    Discussions about code aside: personally, I think a plumber should follow the installation instructions for the washer. If it says it MUST be 39", and if it previously was plumbed that way and was working fine for many years, I am baffled as to why a plumber would choose to make it 10" lower.
    I e-mailed this thread to a friend who services appliances for Sears.

    His first question had to do with the detergent you might be using.

    He wanted to know if you are using a 'High Efficiency' detergent -- I'd never heard of such a thing, so I did a bit of research.

    Apparently "HE" detergent is a lower sudsing detergent and is recommended for newer clothes washers that use less water, but discharge the contents of the drum at a much higher rate than older clothes washers.

    Non-HE detergents create a situation in the drainage system where the suds push up into the vent and block it, much like vapor lock will cause a carburetted car to stall.

    His second question had to do with how the drain hose is connected to the standpipe.

    39" from the floor to the top of the standpipe is recommended because this is the height at which the drain hose when inserted into the standpipe is under nominal extension and is least likely to be pushed out of the standpipe by the velocity of the discharge pump.

    If the drain hose can be easily pulled up and out of the standpipe, then he recommends zip-tying it to the water hose closest to the drain inlet in the in-wall box.

    Short of that, he, like Tom, is a strong proponent of raising the height of the standpipe.
    iamgrowler's Avatar
    iamgrowler Posts: 1,421, Reputation: 110
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    #11

    Sep 3, 2007, 03:58 PM
    Quote Originally Posted by AandZ4ever
    Get a new one?
    A new what?
    speedball1's Avatar
    speedball1 Posts: 29,301, Reputation: 1939
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    #12

    Sep 3, 2007, 05:50 PM
    Quote Originally Posted by iamgrowler


    Well, I hate to say it, but my respect for you goes right down the toilet when I see you telling people to ignore the codes that prevail in their area, Tom.

    Look, you know I teach code compliance classes, so me being a stickler for code compliance should be a no-brainer.

    As for the physics lesson -- Think about how commercial dishwashers with indirect drains are plumbed.

    The full sump of the dishwasher, which is comparable to the full drum of a clotheswasher, pumps at the same velocity into a 8x8 floor sink with a 2" trap and virtually no standpipe;

    The surface area of the floor sink is slightly less than the surface area in an 18" standpipe, and yet the floor sink can keep up with the discharge without any problems whatsoever.

    How's that for physics?
    Wow! Lost respect for me? Now that cuts! Now for that physics lesson you so kindly laid out. Comparing the discharge force and volume of a washer to a dishwasher is like comparing apples to oranges.

    You say, " The full sump of the dishwasher, which is comparable to the full drum of a clotheswasher, pumps at the same velocity into a 8x8 floor sink with a 2" trap and virtually no standpipe".
    The sump of a dishwasher is comparable to the tub of a washing machine??
    You don't get into many dishwashers do you? The sump of a diswasher is designed to hold that part of the discharge after the pump shuts off and the discharge drains back into the dishwasher from the hose and no more Now the tub will hold more but still not as much as a washer.

    Now let's take a hard look at the volume each one puts out.
    A dishwasher discharges through a 3/4" hose that's choked down to 1/4 or 5/16 ths. Of a iunch as it passes through those air gaps you love so well. Also the amount of water in a dishwasher is no where as large as in a washer.

    A washer discharges much more water through a 1" hose with no air gap restriction with enough force behind it to send a 1" column of water up to a 8 foot head.

    So much for comparing dishwashers to washing machines. Let's move on!

    You may know and teach code but we're not out on a job that will be inspected. Ya got to be more flexible, Sport! We aren't out here to force anybody to plumb by code. We can suggest it. We can advise that it's the best way to go. If a 80 year old house has 1920's plumbing that's still working and has a blockage do I even suggest repiping his drainage to do away with "S" traps and run vents to bring his place up to code? Hell no I don't! If it ain't broke don't fix it! These are do it yourselfers we're dealing with. They don't give a rats about the finer points of plumbing code. They just want what they install to end up working. So if they fudge a bit on the length of a drain arm from trap to vent I let them. I don't shove code down their throats unless they're way out of line. In other words, loosen up!
    And lastly, when you convince me that a 18" piece of 2" pipe will hold as much volume as a piece of 2" pipe 36 inches long and will be less liable to back up and run over, I'll buy into your argument and I don't give a hoot what your code calls for. 18 inches is just too damm short for a standpipe.
    iamgrowler's Avatar
    iamgrowler Posts: 1,421, Reputation: 110
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    #13

    Sep 3, 2007, 09:43 PM
    Quote Originally Posted by speedball1
    The sump of a dishwasher is comparable to the tub of a washing machine??
    You don't get into many dishwashers do you? The sump of a diswasher is designed to hold that part of the discharge after the pump shuts off and the discharge drains back into the dishwasher from the hose and no more Now the tub will hold more but still not as much as a washer.

    Now let's take a hard look at the volume each one puts out.
    A dishwasher discharges through a 3/4" hose that's choked down to 1/4 or 5/16 ths. of a iunch as it passes through those air gaps you love so well. Also the ammount of water in a dishwasher is no where as large as in a washer..
    Reread what I did say, not what you'd like to think I said, Tom.

    I distinctly mentioned a "COMMERCIAL DISHWASHER" -- Most of which hold in excess of 17 gallons of water, which also happens to be the normal amount of water discharged by a high capacity front loader clothes washer.
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    iamgrowler Posts: 1,421, Reputation: 110
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    #14

    Sep 3, 2007, 09:54 PM
    Quote Originally Posted by speedball1

    You may know and teach code but we're not out on a job that will be inspected.
    Ummm...

    I teach compliance classes in the evening twice a week -- And somehow I still manage to be "out on a job that will be inspected" in excess of 40 hours a week.

    Ya got to be more flexible, Sport! We aren't out here to force anybody to plumb by code. We can suggest it. We can advise that it's the best way to go. If a 80 year old house has 1920's plumbing that's still working and has a blockage do I even suggest repiping his drainage to do away with "S" traps and run vents to bring his place up to code? Hell no I don't! If it ain't broke don't fix it! These are do it yourselfers we're dealing with.
    Give me a break, the above in no way applies to this thread and you know it.

    They don't give a rats about the finer points of plumbing code. They just want what they install to end up working.
    The OP in this thread cared enough about Plumbing Code to research it to determine if the Plumber he hired had done the job properly.
    rogerie's Avatar
    rogerie Posts: 1, Reputation: 1
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    #15

    Sep 13, 2013, 12:17 AM
    If the stand pipe is 2in and at least 18in long and at 30in above floor it will work

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