The trap arm after the vent can be 1-1/2"
The inspector likes to see a 2" cleanout on the kitchen line.
I guess this is simple compared to a lot of the DIY work here, but I can't find all the answers searching the archive. I want to move a kitchen sink 30" down the wall and run the drain through the cabinets to the new location. I've found a post saying 42" is the limit for an arm, so I'm good there I think, and the pitch is no problem. I have 2 questions: Since the pipe in the wall is 2" should I make the arm run 2" also because I can, or step it down to 1 1/2 at the wall because it makes no difference? The other is that I am under the impression from reading here that the horizontal bend into the wall from the arm needs to be a wide radius bend. Is this true, and should I use a tee-wye there and put a cleanout plug on it? That would make sense, but I have no idea if its required.
If it were me, I wouldn't put in 1 1/2" on that horizontal run, whether you can or not. You can end up with a good bit of flow coming through the kitchen sink (from d/w draining, gunk from disposal, etc). It will be just as easy to keep it 2" until the trap adapter (or at least the long sweep 90 to turn it towards the new sink location, you could use a bushing there)... you have the space. The cost difference is almost nothing for the extra peace of mind it brings.
You def want a 2" cleanout either in the vent or just below the santee the vent drops into (where i prefer it for ease of access).
and yes, if it wasn't clear from my reference to a long sweep 90, you do have to have a long sweep on any horizontal bend in a drain. I wouldn't want the cleanout on that horizontal portion personally, I'd put it below or above the SanTee in the wall. It makes for easier snaking if you don't have to force the snake through the SanTee.
Thanks MT. I guess I'd like to avoid opening the wall, what was there was just the original drain coming a few inches out to the trap adapter. Easy to cut off and put on a fitting, much more involved to open the wall and muck about with the vent and drain line. I don't believe I've ever seen a kitchen drain line with a separate cleanout above or below it! But then I'm not a plumber either.
I think your idea would work... use a combination wye or a wye with a 45 to take the drain over to the sink, then insert a cleanout plug adapter into the top of the Y.
They want to see cleanouts in a lot of places these days. Generally you should put one on kitchen sink, laundry, and any time a horizontal drain turns more than 135 degrees. The bottom of the stack gets one, and if you have long enough horizontal runs I think you need one every 100 feet, but not sure about that one. I live and work in the city where you never see runs like that. Generally, you don't need cleanouts on 2nd floor fixtures, and I'd put one on every fixture in a basement.
I can certainly understand not wanting to snake through a laundry standpipe trap, but most sinks I've ever had were straight shots into the wall. Take off the trap and snake away!
Can I ask another question?: this drain arm seems a little low, the sink tube is quite long. I suspect at one time it had one of those monstrous deep cast iron 2 bowl sinks. Is there any way to raise the line in my arm, or is that the dreaded S trap I've read about? Is there an optimum height for the trap or is it just anywhere below the bowl? I've always preferred the trap high to allow more undersink storage space.
Yeah, getting a larger snake through a P trap is basically impossible. It is nice to avoid things like SanTee's as well, as they turn pretty hard, but you can get through them, its just better if you don't have to, hence having the cleanout even when the trap is easily removable.
Standard through the wall for a kitchen sink is 18" off the floor. The trap height is usually just whatever works to line up with the trap arm, doesn't matter too much. If you put more than 1/4" per foot fall on the trap arm, I believe you will end up creating an S-trap, but I'm not sure. Maybe you can go up to 1/2" before that becomes a problem? I'm not positive, but you can't really move it much until after the vent, that I'm aware of.
I know you don't really want to get into the wall, but I think your best bet would be to cut into the wall a bit to do this. Get your trap arm through the wall up to 18" so your trap in the sink base is higher like you want it, and put a 2" cleanout in the line while you're in there. It really isn't that much work, and if you're having this inspected, it may be required if your inspector wants to see that 2" cleanout. This would also allow you to bring it over to the sink in 2" if you'd like. As Terry said, as long as your trap arm from the point the vent comes off is less than 42", you don't need to go up to 2", but if it was my kitchen and I was running it over there with 2 elbows in it like that, I'd keep it 2" until it turns to pick up the sink, then use a bushing in the end of the 2nd 2" long sweep 90 to bring it down to 1.5" for the trap adapter. I don't think you'd have any problems really with 1.5" through there, but I just wouldn't risk it, when you have potentially 2 sink bowls, a dishwasher, and disposal all going through that 1.5" horizontal line. Even if you don't have all those things now, there's potential that they could be there at some point.
Where I live, they now require 2 separate traps, vents, and drains for a double bowl sink... I wouldn't be too surprised if we eventually see something like that coming into the IPC... they're slowly increasing pipe size requirements over time (tubs/showers/laundry/kitchen sink all have to be 2" now, I think all of these were 1.5" years ago). Better to oversize it while you have the chance, in my opinion.
quote; I don't believe I've ever seen a kitchen drain line with a separate cleanout above or below it! But then I'm not a plumber either
ANd you have NOT seen many sink drains. EVERY sink drain is required to have a cleanout in it, except for a very few cases where the connection to the main line is so short that it is not needed.
Licensed residential and commercial plumber
HJ, You're correct that not being a plumber I've not seen it all. Though I've lived in a fair number of places, they've all been pretty old (how I've become familiar with plumbing!). What does this separate cleanout under a sink look like, does the pipe come through the back of the cabinet and have an escutcheon, or what?
You could put in a wye to bring it forward into the cabinet then install a cleanout fitting there, or just leave access and use a standard cleanout Tee (Tee with a plug in the side). Since yours is going to be in a separate cabinet from the sink (the bowls/disposal/etc won't be in the way), I would probably put the cleanout above the SanTee if you're worried about what it looks like. Mounted up at 22" or so, you'll never see it unless you're laying on the floor looking into the cabinet, and you'll still have reasonable snaking access. I normally don't like it up high like that b/c the sink bowls make it harder to maneuver the snake in the cleanout, but in your case it would be fine. Keep the pipe 2" up past the SanTee to a cleanout, then you can reduce to 1.5" if that's what your vent line is.
[QUOTE=mtcummins;324590]Code says otherwise. While you can work a snake through the trap arm and SanTee, its a pain with a large professional snake. The 2" cleanout after the SanTee is much easier to work with, there shouldn't be any turns that tight beyond that point if the drain lines were installed correctly.
Does it really? Please show me where because both the IPC and the UPC allow a removable trap to be used as clean out access. Nobody puts clean out under lavs here and damn few put them under kitchen sinks either but then we don't generally glue up p traps like most of the rest of the country seems to be fond of doing.
Last edited by Tom Sawyer; 12-17-2011 at 09:30 PM.