Help with sink drain in RV

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isonychia

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Hi guys,

I need some help figuring out how to fix the drain in the sink area of my rv.

I recently installed an electric point of use water heater in the trailer. It is hooked up in series with my existing gas/electric trailer heater.

I installed it under the trailer vanity in the bathroom.

The problem is the p-trap for the sink doesn't clear the heater. So the existing p-trap is now elevated about 2-3". The tail piece

If I try and insert the tail piece into the trap it's not lined up plumb anymore. So I need to reset the angle of the trap/drain line. Can anyone suggest a way to do this. A plumber friend suggested possibly two 22 1/2 degree elbows and some other steps. I don't really want to bother him with this so I figured I would come here for advice. Trying to do something like this over the phone is difficult. I'm not that great at knowing all the fittings, sizes, names etc. So when he references possible options my eyes glaze over in confusion...:confused:

Here is a pic. I labeled the parts with numbers so it's easier to reference as I assume I will have to make the modification to one or more of those areas..

Note: I don't know the diameter of the tail piece from the sink. I'm not sure if they are standard.
I assume I do not have the distance between the bottom of the sink and the trap to use a flexible tailpiece to fix this problem. Plus the drain is under tension so it's probably a bad idea to force it in this elevated position. My guess is I have about 1-2" between the top of trap and bottom of sink drain in this elevated position.

Thanks
r5fb5Vp4HtP3C1xxhfZyqLrcL_mLKwQOw2VpdIWcv35rEbLe58UeAbK_gilztwK-1lPGXhkgzaftN-uogKSn8AgMMp7hd7O8iaYIrCOsmgCPUgYGHQhZZiBtnp6CIAd_ZbN8gFA5qQ=w1590-h1192-no
 

WorthFlorida

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Does the vanity cabinet have a 4" toe kick? From the picture it doesn't look like it. That is the floor of the cabinet is 4" above the floor of the RV? If yes, cut out a section of the cabinet floor to drop the heater to the RV floor. If you can do that put some padding unter the heater to absorb bumps when you travel down the road.

Is there room to place the heater closer to the cabinet door to get is away from the wall?

Another possibility is the sink itself. Generally the sink drain are in the center of the bowl or at the back part of the bowl. The back drain location may give you the room.

Since this is a trailer/RV, I would move the trap to location 3 and get one of these to extend from the sink tailpiece to the trap. However, you need to be careful not to create an S-Trap. The slope of the drain pipe would need to be at the same level as before the heater was added.
https://www.homedepot.com/p/Everbil...ste-Arm-Budget-Gauge-Chrome-C2137-2/205154060


The conduit clamp for the NM cable is a no no. The edges are too sharp and can gradually cut into the insulation casing a short, but worse, arcing and causing a fire.
 

isonychia

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Thanks Worthflorida.

The conduit clamp on the left is a 1-hole NM clamp, not a conduit clamp. I added that myself

The black plastic one on the right was existing on the trailer.

There is no cabinet in the photo. The heater is sitting on the floor of the trailer. The vanity cabinet simply slides over everything. It is currently removed.

My plumber suggested 2 options just going by the photo I texted him.
22 1/2 or 45 degree elbows or a combination to raise the trap.
I think he suggested placing them in location 3 but I am not sure.

Or placing the trap against the back wall (there is space behind the heater) by removing #2 and then adding some type of extension to complete the connection to the trap. (maybe the piece you linked to??)

Again, this was all over the phone and I was somewhat confused, hence why I came here.

My initial thought was to add two 22 1/2 elbows in location #3 someplace to gain my rise on the trap, then drop the short tailpiece into the trap as it normally existed. Or, as my plumber suggested, cut the threads on the trap, then use a fernco fitting to connect the tailpiece. Again, I'm not really sure. I wasn't sure what he was fully describing.

Any other suggestions?

I thought there would be some definitive way to do this.

Thanks,
iso
 

isonychia

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Is this the premise on the 90 degree extension from the tail piece?

(link from a post on this site)

nRsh4fn.jpg
 

Reach4

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That new picture would have been to illustrate what not to do with a trap. That picture is OK up to the trap.

Normal kitchen sink tailpieces are 1.5 in OD, which is 1.5 inch nominal for a tailpiece.

Your photo sorta looks ok if the black pipe going up to the right of #3 is a vent.

I would suggest putting a trap adapter at about #1 or #2 or #3 and using slip pieces for the trap etc. The slip stuff (usually white if plastic) is a whole lot easier to align and to clean if needed. The slip will let you avoid flex tailpieces and other bad stuff. The slip means that you don't have to get things aligned just right as you do with glue.

When you need to swap out or work on the water heater, the slip stuff would be easy to temporarily remove to access the WH area.


With 1.5, there is a max of 42 inches from the trap to the vent. And that depends on the slope being 1/4 inch per foot.

I presume that your black pipe is 1.5 nominal pipe and that is much bigger than 1.5 slip.
 

isonychia

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That new picture would have been to illustrate what not to do with a trap. That picture is OK up to the trap.

Normal kitchen sink tailpieces are 1.5 in OD, which is 1.5 inch nominal for a tailpiece.

Your photo sorta looks ok if the black pipe going up to the right of #3 is a vent.

I would suggest putting a trap adapter at about #1 or #2 or #3 and using slip pieces for the trap etc. The slip stuff (usually white if plastic) is a whole lot easier to align and to clean if needed. The slip will let you avoid flex tailpieces and other bad stuff. The slip means that you don't have to get things aligned just right as you do with glue.

When you need to swap out or work on the water heater, the slip stuff would be easy to temporarily remove to access the WH area.


With 1.5, there is a max of 42 inches from the trap to the vent. And that depends on the slope being 1/4 inch per foot.

I presume that your black pipe is 1.5 nominal pipe and that is much bigger than 1.5 slip.

Reach, thank you for the info.

Maybe I am not explaining my problem correctly.

The trap is currently sitting on top of the heater in the picture. It is being pushed up from it's original position by about 2-3" because the heater is too tall.

I need to raise the trap/drain line about 2-3" to clear the heater. Does that make sense?

So somehow, with elbows or change the location of the trap, I need to clear the heater and set the drain in a way so it clears the heater and is still positioned appropriately to function.

I'm trying to figure out how to do that.

As an example: Cutting pipe 3 lets say in the middle, then placing TWO 22 1/2 degree elbows there to raise the trap and sections 1 and 2. by about 2-3" to clear the heater. Then simply using the existing tailpiece to connect the trap to the sink.

I'm not sure if that will work.

And yes, the pipe on the right side of the picture is the vent.
I did not modify any of the existing drain.
iso
 

Reach4

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You must not go down at more than 1/4 inch per foot between the trap and the vent. Consider a sanitary tee up higher, and go horizontal below with a long sweep. See white and green. Ignore orange.

img_3.jpg


Alternatively, do the steps I think you are describing, but add an AAV (top orange in picture) after the trap and before the first step down. Orange describes this alternative. Existing vent can stay, but it will not be considered to be the vent for the trap.

Rather than elbows and sweeps for the dip down, I think two 45s would probably be better.

You could also have a santee with the AAV above that. That might be simpler still. The trap adapter would go into the side port of the santee.
 
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isonychia

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I am considering doing the ORANGE bend out of 22's to raise the pipe.

Question: Why are you suggesting the AAV or the sanitary tee?

Is it because by raising the trap with the 22's I will be too high above that wye fitting for the vent thus negating the vents functionality?

I just went to HD and got as many parts as possible as I expect to have to try a bunch of options.

Seems this is more complicated now...as expected. I hate plumbing...LOL

How about removing section #2, and placing the trap against the wall and then somehow connecting the sink drain to the trap at the back wall?

Thus negating the need to modify the vent or add an AAV?

Thoughts?

iso
 

isonychia

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Cut the existing 22 out and add a coupler.

Now the trap is against the wall and at the height/angle it was originally at before.

So one of these that Worthflorida suggested from the tailpiece.
https://www.homedepot.com/p/Everbil...ste-Arm-Budget-Gauge-Chrome-C2137-2/205154060

The waste arm into a 90 degree elbow that connects to the trap.

Does that sound doable?

If so, my tailpiece is 1 1/4". I looked it up. It's this.
https://www.etrailer.com/Accessories-and-Parts/LaSalle-Bristol/34465PPR1303.html

I would need to figure out the parts needed to do this. I don't think I can use the waste arm as it's 1 1/2.

Do they make a 90 degree slip joint that would somehow thread onto the existing trap?
 
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Reach4

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Question: Why are you suggesting the AAV or the sanitary tee?

Is it because by raising the trap with the 22's I will be too high above that wye fitting for the vent thus negating the vents functionality?
The order needs to be trap, vent , first turn turn down. The santee would have the vent via AAV on top, and the first turn-down on the bottom. However I would modify that to be trap, trap adapter, vent , first turn turn down (45 or 22.5), turn back horizontal .

So order becomes trap, santee (which has AAV on top, and drain down on the bottom). Or as I would prefer, trap, trap adapter in side port of santee (AAV above, and output down on the bottom port). Another good alternative is trap, trap adapter on pipe, pipe into side port of santee (AAV above, and output down on the bottom port). With the santee, you need either a long sweep or two 45s to go back to horizontal.

22.5s and 45s are good.

There needs to be at least 3 inches (two pipe diameters) between the santee trap output going horizontal and the vent/santee. That is not hard to achieve. It would be almost hard to not achieve that.

I would discard the existing trap. A slip joint trap gives you a lot of freedom. A glued trap cannot be angled to easily meet up with the tailpiece. I am not a plumber. I doubt could I glue up a trap and have it end up just where it needs to be on the first or second try. A slip trap swivels to where you need it to go.
 
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WorthFlorida

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This how I would do it. Getting to the wall would be at an angle and then probably a 45 degree at the wall before the new trap. I now have an MAC and paint programs are not as easy as microsoft Paint.
RVSink.jpg RVSink2.jpg
 

Reach4

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Let this represent a top view. Let the black line represent part of your black pipe. White is the WH.
  1. What length are the yellow and pink arrows?
  2. Where are the tailpiece locations?
img_3.png
 

isonychia

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Thank you both.

Reach4, I don't have those dimensions. I am not at my trailer. I will be there this weekend.

Worth, I created a diagram of what I think I should do after all the suggestions on this thread. (place existing drain/trap against back wall)

What I don't know is how to connect the slip joint waste arm to the EXISTING ABS trap. (see note in diagram)
The existing trap has threads on the end.

• How would I connect a 45 or 90 slip joint to that?

• Should it be a 90 degree slip joint elbow?

• If so how would I connect the other end to the existing trap? I havent seen a 90 slip joint elbow that has threads on the other end to connect to that existing trap. Or even one with a glue fitting on the other end.

• If the overall suggestions is to remove the existing trap and replace it with something else, what exactly should I replace it with?

• This? https://www.homedepot.com/p/Everbilt-1-1-2-in-Plastic-P-Trap-C9704B/205153793

• How would I connect the new trap to the existing ABS?
A fernco 1 1/2" coupling?

• When I remove the existing 22 1/2 ABS elbow to place the drain against the wall, should I use a fernco coupler there or just go buy ABS glue and an ABS coupler?

Here is the diagram I made.

oEKpQyny8_82nUIvOCao3xM0avKCIbRJlnZwFOdmYz04SOBLdaGpuzdjKTapTN2sb5TDK7Ug8qfsQ_JOIDFEXnq1x_KWC1XXL_wY3I3ZM5-Un46B3Grw8eshzxEZjFCjSHUqw08OppuTTKZvpquaf7r5tDcQAOgTGCNRuAlK2P7F8QF4hUu9_03DmR7NPop-HP8cDN6H0EwBFev9jlpz03QC_xACgl1Qwm1RCTcJuzDnC2QsBUWcF09L2OZfWfhh-joOQWgmmzDuArS83QIT7HHW3CJBCg_r-RKInGQ4SGVVxrORglkVcQABPQEtQKOmJgqwvg7mk4xhXn3YHu4J0iKGRek9gPA9akXnynFR9O6Lb0iswit0vKpxuurymQeYENbJsoIHkO7mhTybH3JhTT8Vy846BHKZBQrOxzvO6xQnn7vOVLAvDOB3IKT69Ife58OQjEyJGde3xvhJhcwRpqqH_wQjXKwv1Yzs77j34jq1fSJxXgiDeQEysdIJ89TnBX7CuofSyeMl3s2WArfi6Vy5NArTpgrh3t7XUtRb8i1p-NMQ4_HHpmddsSPd0wIpma6QNVEA1jm6aHFfmJsSjI5hPcFfhMoUpPVaxRwnC2olXGq3AYSR63i8sHdRt5QI_MP41UVB2G2kpKVOnroVBSJWHMe_R8s=w1896-h961-no
 

Reach4

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I think a disposal kit would have what you need plus a lot of stuff you don't need.
white-everbilt-drain-repair-installation-kits-c9104-76_145.jpg


Based on your photo, it looks like your tailpiece is long. I think you would want to cut that shorter.

HD sells a tool that is nice for cutting the 1.5 inch slip plastic. If your tailpiece is metal, you would probably use a hacksaw. You can also use a hacksaw on plastic. A bit of raggedness or non-squareness gets hidden.

This is a slip-joint elbow and slip joint connector:
white-everbilt-drains-drain-parts-c9675-64_145.jpg
white-everbilt-drains-drain-parts-c9793d-64_145.jpg

Maybe for that transition you are asking about, you could put cut a short section of 1.5 od pipe and use that like a nipple between the elbow and the trap. You might have that left over after cutting down your waste arm. I did not find a "street" version of the elbow except as part of the disposal kit.
 
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isonychia

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How about my question concerning the joining of the new trap to the existing ABS?

Or how to connect the 2 straight pieces of ABS after I remove the existing 22?

Thanks
 

Reach4

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How about my question concerning the joining of the new trap to the existing ABS?
I am thinking a 1-1/2 in. ABS DWV Hub x SJ (slip joint) Trap Adapter to the right of #1 and left of the existing 22.5. You will cut the pipe carefully, dress the end, and glue the trap adapter onto the cut end. Your slope needs to be 1/4 inch per foot after the trap until the vent. I think you should support the existing black pipe to make the slope on that and the 22.5 to be exactly correct.
plastic-nibco-abs-fittings-c58017hd112-1f_145.jpg
plastic-nibco-abs-fittings-c58017hd112-c3_145.jpg


Or how to connect the 2 straight pieces of ABS after I remove the existing 22?
We don't know dimensions, but I am thinking that the 22. 5 could maybe stay. If that is not the case, then what is the case?

In the guess-sketch, the orange represents the tailpiece. The gold is the trap arm. The trap is in red. Note that we can swing the trap whichever way, so I swung it to have its input part parallel to the WH. The black+white meeting is the trap adapter.
img_3a.png


Note that a lot of the trap is cut off. So the leftover piece can be cut to connect the elbow to the trap. To raise the waste arm, if there is excessive length, shorten the tailpiece on the drain.

If the yellow-arrow dimension is too small for what I drew, you could glue on another ABS 22.5 to jog the path to make the output of the trap arm parallel to the wall.

Alternatively, maybe there is enough flex in the ABS to put the trap adapter to the right of the existing 22.5. That puts the output side of the trap next to the wall. It all depends on what you find when you get back to the site.
 
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isonychia

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Reach, thank you for all the info.

The only reason I may need to omit the 22 and place the trap/drain parallel to the wall is I may not have room for the trap between the heater and the wall. It may have to be flat against the wall. I will know when I go up this weekend.

This piece was the missing part I wasn't sure about, thank you.
1-1/2 in. ABS DWV Hub x SJ Trap Adapter

If I can reach, I can omit the 22 and place the hub and trap adapter on the end of pipe 3.

I will get an ABS coupler in case I need to extend 3 with the remaining part of 2. Since I need to glue the trap adapter, I may as well use a glue fitting for the coupler instead of the fernco.
 
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