Installing new dishwasher and double sink....

[Shane]

Ok, I'm a plumbing novice about to try hooking up a new dishwasher, double sink, and new faucet. a plumber has already run the two water pipes (plus valves) and drain pipe into the sink cabinet and made things generally ready. it falls to me now to buy the right stuff--pipes, connectors, hoses, clamps, baskets, and etc--to make the final finished connections to sink and dishwasher (no disposal).

Question #1: is there anyone out there who can walk me through this and give me an idea of what it all ought to look like at the end?

Question #2: in the sink cabinet, the copper water pipes now extend up above the water valves for something having to do with "air", or so the plumber told me before he left. When I went to the plumbing parts store, though, i found an additional part called a "dishwasher air gap" basically a short length of tube that runs above the sink and allows the dishwasher drain hose to breath or vent or something. do i need this, too? and if so, where in the big picture does it go?

not sure if this is possible, but if anyone wants to sketch me a picture and fax it, that might be better then a thousand words.

help?

[Plumber2000]

Air Gap is not really needed, just hang the drain hose from your dishwasher higher then the bottom of the sink line.

[lefty]

Shane,

We can start walking you through it. P2K has already posted the pics re: the DW drain.

I would start with the water supply lines to the faucet. Since the shut off valves are in place, you need supply lines that match the threads on the valves. (The bottom of the faucet is 12" IPS). Did the plumber leave the compression nuts and ferruls on the shut off valves? If so, take on with you so you can match the threads.

The sink baskets are easy -- pretty much one size fits all. Place a bead of plumber's putty under the lip of the basket before you install it and remove the excess that squeezes out.

Below the baskets will be tail pieces, one with a DW drain inlet. Then a cross-over tube into a tee, with the bottom of the tee going into a p-trap.

Do all of the drains in PVC or ABS. All of the joints are slip joints, and it's very easy to work with. Cut parts with a hack saw to the size needed.

[Mike Swearingen]

Shane!
Shane!
Come back Shane!
Oh...lost it for a minute.
Can't go wrong with Ron and Mike's directions.
Good Luck!

[Shane]

Thanks everyone. A few follow-up questions....

Lefty: I'm not quite up to speed yet on your abbreviations. PVC, ok, i got that one. But what about IPS and ABS? Also, the drain stub--if that's the right word--that the plumber ran to the sink cabinet is pvc. does that mean that everything else i run in there (save the water lines and dw drain hose, of course) ought to be in pvc, too? Also (sorry), you're going to have to help me with compression valves and ferruls. Unless those are what a layman might call hose clamps....

Plumber2000: thanks for the pictures. figure one, i believe, looks the closest to what i've got. is there anything I need to know about how high or low my p-trap ought to go? the pics all show the drain going out the bottom of the cabinet. mine goes out the back, about 1/3 of the way up. does that change anything? last: when you say "bottom of sink line" does that mean bottom of p-trap or what?

[Mike Swearingen]

Go with PVC white plastic for your drain assembly. (ABS is black plastic.) PVC drain assemblies can be hand-tightened (plastic washer flat side goes toward slip nut).
You will need a 1.25" sink drain assembly to 1.5" drain pipe adapter, and a PVC drain assembly to match up with your sink tailpiece and drain pipe.
See Figures 1A, 2 & 3 for proper trap height.
A compression nut is what copper tubing goes through to attach to something. The ferrule is the brass ring that seals under the nut on the pipe by compression.
Bottom of the sink line means the bottom of the sink.
What is on the end of the two supply lines from the faucet?
Straight copper tubing or threaded fittings?

[brickeyee]

If you have two sinks do yourself a favor and put a trap on each one of them. If you do not suds and such will appear in the other sink when you drain the water. It is sort of annoying. Get a do it yourself plumbing book and it will have the basic info you need. PVC pipe cuts with a sharp hand saw. A miter box (even one of the little plastic ones) will help with keeping the cuts square. Use primer on the pipe joints on both pieces. Spread the PVC cement liberally on the female (socket) side on the joint. Push the joint together firmly with a slight twisting motion. The pipe will go on further than when you dry fit it without glue. It would probably be worth the cost of a few fittings to practice a few times. Think how much $$ you are saving and waste a few. Flexable hoses with a stainless steel braid covering are the easiest way to hook up the faucet. They are pretty much standard on each end and you buy them a few inches longer than you need. The hardest part is often reaching up behind the sink to tighten nuts and hoses. A basin wrench will solve that problem. It has a cross bar handle and a spring loaded head that flips from side to side to tighten and loosen. It allows you to reach up in the narrow space and tighten faucet connections.

[Mike Swearingen]

I completely agree with brickeye's advice, except the need for two traps.
One wil do fine.
Mike

[lefty]

I have to disagree with Mike (Old Guy) on one point -- Don't use 1-1/4" drain pipe under the kitchen sink -- use 1-1/2"! (1-1/4" is fine under a lavy.)

Not sure where Brickeyee is talking about using glue and solvent on PVC under the sink -- You want all the joints there to be slip joints! Don't glue ANYTHING together in the drain line.

PVC is the white plastic pipe.

ABS is the black plastic pipe

IPS is Iron Pipe Size -- 1/2" IPS is the thread size at the bottom of the faucet that your supply lines will connect to.

[Mike Swearingen]

WHAT was I thinking? LOL

[brickeyee]

I just hate the suds backing up from one sink to the other. Down the drain should stay down the drain.

[lefty]

One trap or two??

If soap suds are a pet peeve, like they seem to be with brickeyee, then go with 2 traps. That will end that problem. Otherwise, one trap will do just fine. Of course, if you use half as much soap, things come just as clean, but you only have half the suds to deal with!! And in the DW, using half the amount of soap will keep the drain lines clearer. (I put several hundred dollars a year in the bank cleaning soap buildup out of DW drain lines!!!)

(Mike, when you posted about using 1-1/4" drain lines under the sink, it WAS only 6:30 AM. At that point, you were probably still working on the first pot of coffee, and, if you're like me, NUTHING' works right before the 3rd pot!!)

[Plumber2000]

Not to be picky here but UPC Code says you can not double trap under a sink. A dumb code but it's there.

Either tie the drain hose into the side of the disposal, or use a dishwasher tail-piece that has a baffle in it.

[Mike Swearingen]

lefty,
Me+Computer+6:30 a.m.(even with coffee)=MonkeyMatingFootball.
No Think. My brain cell isn't what it used to be to begin with. LOL

[brickeyee]

A double trap is two traps in sequence, not two seperate traps for two sinks.

[Plumber2000]

Double trap, traps in sequence, does not matter how you see it, code does not allow but one trap per fixture.

[brickeyee]

Passes in all three jurisdictions I work in for both residential and commercial. Just finished a six basin sink in a commercial kitchen. Passed with 6 traps. This thing was so big multiple vents where required.

[Plumber2000]

We don't know whare Shane lives, so we can sit here all day and talk code and both be wrong on how his sink set up should be.

[brickeyee]

BOCA 1990 (still in use here)
P-1001.1 Seperate traps for each fixture: Each plumbing fixture shall be seperately trapped by a water-seal trap, except as otherwise permitted in this code, placed as close as possible tothe fixture outlet. The vertical distance from the fixture outlet to the trap weir shall not exceed 24 inches (610 mm). A fixture shall not be double trapped. A clothes washer or laundry tub shall not discharge to a trap serving a kitchen sink.
Exceptions:
1. This section shall not apply to fixtures with integral traps.
2. A combination plumbing fixture is permitted to be installed on one trap, provided one compartment is not more than 6 inches (152 mm) deeper than the other and the waste outlets are not more than 30 inches (762 mm) apart.
3. One trap is permitted to be installed for a set of not more than three single-compartment sinks, laundry trays or lavatories adjacent to each other in the same room and with the trap centrally located where three such fixtures are installed.

It is thus an EXCEPTION that allows a single trap on a multi basin sink, not the general rule that would otherwise require multiple traps.
While i am well aware of other codes, including state and local, it is unlikely they are significantly different on such a basic rule.

[Plumber2000]

UPC Chapter 10

1001.1 Traps Required

Each plumbing fixture, excepting those having integral traps, shall be separately trapped by an approved type waterseal trap. Not more than one (1) trap shall be permitted on a trap arm.

And since where talking a single fixture which will have one trap arm here, and not a battery of fixtures this code will apply if he falls under UPC Code.

Like I say we can talk code all day.

Read your code, it says A fixture shall not be double trapped

A trap to each side of a two compartment sink is considered double trapped.

[brickeyee]

A trap to each side of a two component sink is NOT double trapped. Double trapping refers to two traps in SERIES. The lack of a vent between the traps can result in siphoning. Read exceptions 2 and 3. They allow a single trap under limited circumstances. If the sinks had a depth of greater than 6 inches or more than a 30 inch spacing TWO traps are REQUIRED under exception 2.

[Plumber2000]

Call it what you want to call it, I interpet as double trapping, you interpet the code as you feel.

Like I said we can talk code all day, everyone will interpet the code different.

Not more than one (1) trap shall be permitted on a trap arm.

Read that passage, this tells be only one trap on a trap arm.

There CAN NOT be more then one trap under that kitchen sink. You CAN NOT have separate traps for each side of that sink.

I failed an inspection once for separate traps under the kitchen sink.

[brickeyee]

You have to use two trap arms back to the vented drain line. That is what "one trap on a trap arm means". Multiple traps on a single arm not sized as a drain line would tend to suction each other.
Do much commercial work?

[Plumber2000]

I know "what it means" do this for a living, you don't have to explain it to me.

Someone said to use two traps, one for each side of the sink, I was informing them, that, it's not code to do that.

Thats all.

You Said

If you have two sinks do yourself a favor and put a trap on each one of them.

This has nothing to do with commercial work, why would he want to run two trap arms to the vent in order to use two traps?

Thats alot of work to hook up a two compartment sink

A bit of overkill don't you think?

All I'm telling here is you can not use two traps on one trap arm, i.e. one trap for each side of the sink. With one trap arm to the vent.

Are you saying your allowed to do this where your at?

Just telling you what the UPC Code has to say about traps.

[brickeyee]

You are the one trying to use a single trap arm.
under your line of reasoning, two basins side by side must be trapped seperately, but multiple basins in a single assembly are prohibited from being trapped seperately?
I would invite you to look at some of the triple bowl sinks. Two large basins on each side and a central basin designed for a garbage disposal. If this unit had a single trap the real possibility exists that garbage disposal waste could be carried back up into the other sinks. Since the vented line is directly in the wall about 16 inches or so from the sink, developing multiple trap arms is hardly a tough chore. One of the basins will probably have a garbage disposal in a two basin installation. That is not the type of thing I would like to see being carried back up into a sink with suds.
I do this type of work for a living also. I cannot imagine telling someone in a $75,000 kitchen remodel that they must live with suds and wast being carried back up from a single trap under a multi basin sink installation.

[Plumber2000]

It still stands in UPC no more then one trap on a trap arm, you can't change the code it's there.

If your putting two traps on one trap arm then your violating the code.

The one with the questions is talking about a kitchen sink and not lav sinks.

I never seen a problem with suds from the kitchen sink line, unless one fails to use a baffled tee, of there drain line needs a good cleaning.

[lefty]

Shane,

Put one trap under the sink.

Under the basket closest to the DW, install a tail piece with an inlet for the DW drain, then use a cross over tube to go over to the other basket. Under that basket you will need a tail piece, a tee, (which the cross over arm will connect to) and that tee will dump into the p-trap.

Ron,

You're right, you can't dbl trap a fixture. That's cut and dry. But SOME jurisdictions (although certainly not ALL) WILL allow you to install a seperate trap under each bowl of a kitchen sink. I guess it's just their interpretation of the UPC. Guess they are treating each bowl as a seperate fixture, much like 2 lavy's that dump into a dbl sanitary tee. Nothing I would waste my time doing, but there IS one jurisdiction around here that I know of that would allow me to do it!

[Plumber2000]

Lefty,

Everyplace will interpet the code differently, the point is, we have no idea where Shane even lives heck he might be living in Iceland, and who knows what the code is there.

I had enough code talk, see you in the next debate.

[lefty]

Ron,

YUP!!

See you there my friend. (and with any luck, it WON'T be as long winded as this one got over something SO SIMPLE!!)

[brickeyee]

You can keep installing new fixtures using any old method you desire. I have been running a circuit vent below the (typical) window and puting a seperate arm and trap on each bowl of these newer sinks. The house I own was built in 1950 by a plumber and has the same type installation. (It had a two bowl cast iron with drainboards on each side. 6 feet, 400 pounds or so.)
I have had two calls in the past 9 months for the 'suds in the sink' (and some other crud) after running a garbage disposal, so I am not the only one who finds this anoying. The original installers will not be back to those customers after a finished install needed rework to satisfy the customer.

[Plumber2000]

Again, if you stack two tee's in the wall to run two trap arms, you will be creating a wet vent, the only way code will allow this is, you must increase the pipe size by one size, so that means, since code requires the drain for a kitchen sink to be 2" from where the vent ties in, then that would make you have to install a 2-1/2" pipe between the two tees stack on top of each other, and since you won't find 2-1/2" pipe anymore, you would have to make that 3"

Why go through that much work when all you have to do is use one trap under the sink.

brickeyee, you work to hard, but it's your time, use it as you feel fit.

[brickeyee]

I work hard and have more customers than I can handle for high end work. They want it to work. And I do get paid for it.
I just checked with the lady that does my purchasing and ordering and she has about 4 places to get 2.5 inch pipe and fittings.

[Plumber2000]

Well there you go, you can now install your two traps arms and meet code requirments.

Me I'll stay with the better way of doing it, one trap for one trap arm.

[Plumber2000]

Oh and brickeyee,

Now that you found this 2-1/2" drain pipe and your all set to wet vent the kitchen sink line and only have one trap arm for it to comply to code.

Now you will have to run the entire kitchen sink line at 2-1/2" all the way to the mainline, cause you know you can never decrease from the lager drain line to a smaller line

But there is another way you can accomplish this and have two trap arms, you can always have a 2nd branch line with two tees in the wall, of course you will now need to tie the two vents together, which that should not be a problem.

Man, this makes me sweat just thinking about the extra work needed to comply with the code.

[brickeyee]

I was going to say you do not have to go up a size if you install a branch vent and a horizontal drain. Each trap empties into a vertical with a sanitary tee between the branch vent and the drain. If you add an extra vertical at the end of the branches you get a circuit vent that will never cause a problem. Hook the vent to the sink stack 6 inches above flood, hook the sink stack to a main stack in tha attic. The only extra work is a few feet of pipe behind the sink. If the work is completed before cabinets go in, it is hardly a significant chore. Often I can measure and prescut all the pieces before even going to do the install.
All 2 inch. All vented. Quick as can be.

[Plumber2000]

brickeyee.

Is This what you was thinking on how you would set it up like in order to have two trap arms and not having to wet vent?

This is how I was thinking to get two trap arms, even thou I never install two traps under a kitchen sink but this way would seem alot easier.

[brickeyee]

The second one is how I do it, except an extra circuit vent is sometimes used. It helps if both sinks are full of water and drained at the same time. If the kitchen is gutted it takes only a little time to plumb it up.
Some of the jobs I have gotten have been royal pains. People in multi-million $ houses do not want to hear the plumbing. I have had to put sound absorber around plastic pipes (foam on each side of a lead sheet), replaced water lines with type L (PEX for the next one like this) to avoid sharp bends (guy could not stand the slight whistle I could barely hear). I am waiting for one to complain about the faucet making noise when the water hits the sink, LOL.
As long as they are willing to pay, I will make it silent. I even have a call from a guy who wants cast iron stacks in his new house. Where is that lead ladle and the caulking tools?

[DUNBAR PLUMBER]

I would of went with the second diagram. I wouldn't want to trap it twice though but I got in trouble for trapping a commercial three compartment sink.


I wanted the customer to have the luxury of being able to dump the sinks individually without having all three slowly dropping at same time when they was full.

So I trapped each one individually and vented individually and the inspector said that it was not necessary and was a waste of pipe.


It was changed but majority was left and was trapped once and the others were capped off.


This was about 14 years ago when I was really green to the trade and now all I do is service plumbing.


My question to plumber 2000 is the diagrams you made up for the piping, is that a software program made for plumbing piping and can it combine different sizes to make like a isometric drawing of piping or normal plumbing system?


I have been looking for software regarding making DWV drawings and have had no luck finding any.

[Plumber2000]

These are individual picture of each fitting, I make them inside of MS Picture it, I just piece them together and save them as one image for posting on my web site.

No special software, however I to would love to find software that can accomplish what takes much of my time making up these diagrams.

[DUNBAR PLUMBER]

When I find some software regarding this, I will let you know where to obtain it.


Someone needs to make it if not. It would sell in a hurry if put out there for people to see.