Installing a Kitchen Sink Drain

installing kitchen sink drainToday I am going to show you what’s involved in hooking up a kitchen sink drain. So, we are going to be using AVS fittings and you can see a bit of an assortment here of the different ones that you may need. Most importantly we are going to need a P-trap.

Ok so this particular item, what it does is it creates a water trap down here so your sewer gases cannot come back through the wall and back out through your sink into your house so very important to be on all your sink drains and that sort of thing, tub drains.

Ok so we have got the P-trap, in this particular case, we are going to also have a dishwasher in this kitchen so we need a fitting where the dishwasher drain line can drain into the drain and an important thing about this is it needs to be in front of or ahead of the P-trap. So this would be the end where the sink drain is in and then it drains down through here and out into the sewers so it’s important that it’s on this end. If you put it on this end ahead… before the P-trap has a chance to stop the gases, you can get sewer gas coming into the house through the dishwasher so it has to be on this end, on the sink end of the P-trap.

So that’s those two pieces now on top of that… actually why don’t I just show you. We have got the particular one just taken off of the sink that we are going to show you this on so I have got the P-trap right here and the only thing that’s missing is this little elbow cause it’s glued on. So we have got the P-trap, we have a little pipe here, this is an inch and a half AVS pipe then here we have got that dish water fitting…. Dish washer fitting, we have got another stub of AVS in there then we have got this fitting up top so that looks like this and what that is is the drain stub on the bottom of your sink, it fits down there and that makes that connection.

So your drain on your sink could be copper, could be plastic, doesn’t really matter as long as this fits this fitting, this fitting basically, how it works is this… if this is your sink stub, threaded on part goes on then you have got a washer fitting like this that’s tapered, you want the taper down, it would slide up on that pipe and then what happens is when you lower this down onto that tapered fitting and thread it onto here, it just tightens everything together and makes a seal around here, that wedge just fits right inside this tapered edge of the pipe as well.

So that’s how that works. So that’s another item that you might need. This is just an inch and a half coupler so depending on your situation, you could need one or two of those, you might need a ninety degree elbow. It’s just going to depend on where your drain line is coming in to the cabinetry and where the actual drain sink is. So you are going to need a variety of few different pieces as well as one or two feet of inch and a half pipe to cut into lengths. The AVS pipe that we used in here for stubs, that is simple… you can just cut it with a hacksaw, you can cut it on your electric wire box, that sort of thing.

So it cuts pretty easily. Just try to make as square and straight cuts as you can. All these pieces are glued together with some AVS solvent cement, it’s usually yellow, I think there is a while clear color out there so it’s just some glue. Now we do have another video on working with AVS pipes so to see the actual cutting and gluing and fitting everything together, just reference back to that video. This one here is just solely about the parts you are going to need for the sink drain.

kitchen sink drainOk so we have got the parts, we have actually… this has all been made up and ready to fit onto the sink so we are going to change the angle of the camera so that you see underneath that when I actually install this underneath then you can see what it actually looks like.

Ok so we have moved down below where you can see the kitchen below the kitchen sink here, we have taken the doors off the cabinet for clarity. So you can see here, our piece of drain is going to thread on to there and this is the tail piece, in this case, it’s plastic and this will slip on over there. So what we did is we took off these two pieces off the top here and I will just insert them onto the tail piece so there is our black threaded piece, here is our wedge shaped gasket right there. So when you are doing this you will dry fit all your pieces as you go to make sure it works.

We have already done that and glued everything up so I know it’s going to fit on there so we just need to slide everything up until everything makes good contact. This nut comes around, threads on to the elbow of the P-trap, just tighten that up, this one like I said before, this little wedge gasket slides down in there through this nut, tighten it up. It’s not usually necessary that you need to use a wrench, get it nice and snug with your hands. So you can see now, this is the drain in the sink, water is going to flow down here through the P-trap, up again slightly, back here into the horizontal pipe and down into the drain, this pipe up here is the vent system that vents out to the roof to get air behind water.

As I mentioned before, some water will always stay trapped in the P-trap and it prevents any sewer gas from coming up, once it gets to this point, it can get through the water, if this just came straight across in a ninety degree elbow and up, there is no water to prevent that gas from getting up through the sink drain into your home so really important that you have the P-trap. Your setup can be slightly different, your drain might be coming out of the wall or maybe from another cabinet or something so it’s all going to depend on what your actual setup is as far as what you need for parts and pieces. I recommend you buy a few extra little things, maybe a couple of forty fives, that sort of thing. You can always return them if you don’t use them, it always seems like, when it comes to plumbing, generally, you need to do a little bit more messing around than you thought you were originally going to have to.

Kevin Mills