Where is the least worst place to go from 2" to 1.5" for laundry

[Pghsebring]

So this is my dilemma...I've never half-assed anything before in my life, but I cannot take the time to fix this properly, even though I know how to.

I bought a house that has a 1.5" copper standpipe for the washer that is an s-trap and has no vent, no sanitee - oh, and the utliity sink drains into the same line downstream too (into a combo wye on its side of course) which would be wet vented if there was a vent. A total mess that was put in by a plumber - its all soldered copper drainlines. So basically, everything is wrong. Anyways, after the washer stand pipe p trap and the utility sink , the drain line goes around a corner, travels about 5ft, then around another corner, travels about 1ft, through a fernco into a 1.5" PVC pipe, and then it goes into a 4" x 4" x 2" combo wye that some A-hole stuck a 1.5" bushing in. I just can't win here. So, I can fix all that early mess and plumb it correctly in the laundry room. The problem is, I already broke out an 18x18 travertine tile to get to the fernco. To get to the 4" stack to replace the (now) 4x4x1.5 combo wye, I'd have to break out 2 more on the wall, and then, because the combo wye is so low into the ground, I'd have to start digging through 18" travertine tiles on the floor and start breaking up concrete, etc, etc, etc - make a total mess of the one room that is actually finished in this house. There is just no way to cut out the combo wye and put in a new 4x4x2 combo wye without destroying my bathroom. And for once, I just can't do that.

I know I need a 2" stand pipe for the front load washer and its supposed to be a 2" drain the whole way, but it just can't happen this time. So, my question is this: where is the LEAST WORST place to go from 2" to 1.5"? Is it right before the p trap for the washer? Right after the p trap? Just for that last inch when it goes into the 4x4x1.5 combo wye? Somewhere else?

Or did someone invent a drill bit so I can drill my combo wye back to 4 x 4 x 2?

I know, I know, I'm a bad DIYer. I apologize in advance.

 

[Jadnashua]

Old WM standpipes could have been 1.5". The reason they changed it to be 2" is because some of the newer WM pump water out faster than the old ones did. As a result, things can back up. If it's going to happen with your WM, can't tell. I don't think it will really matter...if it's going to happen, it will, regardless of where you have the reduction.

 

[Sponsor]

 

[Cacher_Chick]

Most new washers use a lot less water, and if the line is kept clear, a 1.5 will probably work fine.

 

[wallbobby]

Although I just replaced it with a 2 inch cause I moved the pipe, my standpipe was 1.5 inch steel and clearly had been working just fine since 1952 through many generations of washers. I wouldn't worry about it too much.

 

[Reach4]

There is a plumbing rule that drain lines can go to a bigger size but not a smaller size as the water flows. So in practice, would it be better to go 2 inch for a ways, then to 1.5 and then to 2 again, or to stay 1.5 all of the way?

I don't know which would work better. If you do reduce, you want to have a cleanout to allow that reduction to be easily cleaned. The bigger portion may serve to let the flow straighten out and become less turbulent before getting squeezed down.

Which one might stand inspection better based on a portion being 1.5 inch already and is not practical to increase in size? I suspect the 1.5 standpipe might come out as the better choice. I am just speculating.

 

[Jadziedzic]

Or did someone invent a drill bit so I can drill my combo wye back to 4 x 4 x 2?

Perhaps a 2" Ram bit would work to drill out the bushing in the 2" section of the wye.

 

[Jadnashua]

While many modern WM may use less water, especially on front loaders, they spin VERY fast, and can output the water that is there faster. Any restriction in the pipe can become an issue. Admittedly, the hose outlet is smaller than the 1.5 or even 2" piping, but one is working on gravity, and the other is being pumped. The drainage line will not flow as fast as the pumped one unless it ends up being larger in diameter. Whether you'll have a problem is dependent on the length of the piping, the number and type of fittings and changes in direction. Just the p-trap will add some resistance in the line and slow things down. The codes are written for many of the 'what-ifs' that can occur, and try to prevent problems from any proper use. Lots of times, you may never see one of those 'what-if' situations, and may never have an issue. Then, you update to a new WM, and most of the water ends up on the floor!

If you're lucky, there is a bushing reducing the wye outlet size, but it could be a 1.5" arm, and then, the RamBit won't work.

 

[Pghsebring]

Perhaps a 2" Ram bit would work to drill out the bushing in the 2" section of the wye.

I took a look at those, but determined that the 2" wouldn't fit in there because its made for a 2" pipe which has a different ID than the OD of the 1.5" pipe (which is what I would have drilled into the bushing.) IE, I don't think it would fit in the hole. So, then I was looking at using a guide off of a 1.5" or maybe a 2" sched 80 etc, etc, etc. And nothing was guaranteed to work.

But looking at videos of the socket savers led me to videos of using a heat gun and wouldn't you know it, it actually works. First I got out the 1.5" pipe, then I got out the 1.5" bushing. Then I took a section of 2" pipe and shoved it in there to make sure the socket was still round and not deformed from the heat. Now I pray that there are no leaks when I put in the 2" drain. I think there is still plenty of interference for the 2" pipe so I'll make sure to seat it really deep.

 

[Jadnashua]

A plastic fitting is intentionally an interference dry fit...when you add the cement, it literally melts the plastic, and you can then insert the pipe and bottom it out into the fitting. Because it starts out tapered slightly, and the cement liquefies things and is slippery until the solvent evaporates and things harden again, it can tend to push the pipe out of the socket, which is why you must hold things in place for awhile; otherwise, it can create problems! It's worse on bigger pipe, or if you use excess cement, since then, there's more solvent that has to evaporate.

 

[Plumber69]

Most new washers use a lot less water, and if the line is kept clear, a 1.5 will probably work fine.

Less water faster discharge.... hence the 2 inch

 

[Cacher_Chick]

Less water faster discharge.... hence the 2 inch

Code in Canada is still 1.5", no?