Showerpan DWV- can you reduce a 2" to 1 1/2"?

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  #1  
Old 07-23-03, 04:29 AM
InspectorJ
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Arrow Showerpan DWV- can you reduce a 2" to 1 1/2"?

- can you go from 2"drain line to 1 1/2? Or would this just be a straight blunder in itself? Ragnr?? Help out bud!! :}

Hey guys! I bearly was able to fit a 36” shower pan into the space available. I wanted to update the draining under the pan, which was 1 ˝ inch pvc. The shower pan came with a sticker that called for 2” line. I went ahead and setup a “shallow trap” made from different elbows, to tried and make a p-trap that was not so deep, because of the same bathroom’s toilet line, which is 4” diameter, runs directly below. The older 1 ˝ inch drain that was there had NO type of “trapping” of gases, and was dug out and replaced with the trap I made. Please let me know if I can connect this setup about halfway to the old 1 ˝ drain. I don’t want to dig the whole thing up right now, because it connects to older iron dwv pipes underground, and looks toooooo hectic.
Do you think the draining of water would be slower because going from a bigger to smaller drain size, right in the middle of its run?
 
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Old 07-23-03, 08:27 AM
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Shower drains by code must be 2". but if you want to make it a 1-1/2" trap, reduce it to 1-1/2" before the trap, just below the pan or at the pan drain.
 
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Old 07-23-03, 07:20 PM
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The pipe you had was probably originally intended for a TUB which only has a 1.5" drain, but it is not suitable for a shower... You should not reduce it as it will cause very poor drainage in some cases... As P2K says though, if you HAVE to do it, do it before the trap, but unfortunately, I don't think that solves your problem of room...
 
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Old 07-24-03, 04:46 PM
Kray
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I'm afraid I have more questions, not answers. I have a similar situation. I have replaced shower pan in my 40 year old home and had to move the drain about 8" to accomodate the new pan.
The drain pipe is 1 1/2" copper. The new shower pan came with a 2" drain, so I cut drain line just below the existing 1 1/2"
p-trap, discarded the old p-trap and installed a new 2" ABS p-trap assembly. I used a rubber reducing coupling to connect the new 2" p-trap to the 1 1/2" drain line. I couldn't see any alternative other than replacing the entire drain line which seemed like overkill since it is in good shape and has been perfectly adequate for 40 years. Shower walls are not finished so drain has not been tested by actual use but when I simply pour water down the drain it seems to drain smoothly and quickly. Am I OK with this set-up or have I done something terribly wrong? I suppose I now violate code if it is 2", since the need to move the old drain 8 inches would cause the loss of grandfathering of the 1 1/2" drain. Correct? Should I worry about that? Thanks.
 
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Old 07-24-03, 07:51 PM
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Putting the new fixture in with a 2" drain would be enough to make you change the drain size by code, but if you are not having it inspected, don't worry about it... It will probably work, but it will stop up due to hair faster, but won't be a major problem... For the record though, it is actually WORSE to reduce a drain, than to have one that is just smaller to begin with... In other words, you had a better situation when you had a 1.5" fixture drain hooked to a 1.5" drain than you do now with a 2" drain being reduced to 1.5"... It is considered an
obstruction in the drain... It can cause slow flow and can cause buildup more quickly...

But I think you should just try it out and if it works, forget about it until next time...
 
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Old 07-25-03, 06:59 PM
InspectorJ
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yeh I messed up then

To the one trying the same maneuver as I did, dont do it. Reduce as soon as possibble and make a darn trap if room is needed. I think Ill replace 1 1/2 " pipe asap. When I tested the current setup, it was damn slow.. Oh well time to lift up the damn pan again, and hammer the mortar mold I laid for this setup, ahhhhhhhh. Or should I contin ue where I left off, replace the old 1 1/2" line that I had left? My only worry is that the fitting used is cast iron I believe, I dont think lowes carries the one I would need. **** I dont know. excuse my french. Hey ragnar, still coming to vegas, august is very near, and I could use some help. I am broke though, would your advise and assistance cost anything?? later
 
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Old 07-25-03, 07:14 PM
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If you simply cannot install a 2" drain, use a 2" abs or PVC shower drain, tighten drain on the pan, now take a 2 x 1-1/2 ABS or PVC bushing and glue it into the shower drain, pick up your trap next, then tie it to the existing drainage.
 
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Old 07-26-03, 11:11 PM
InspectorJ
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dwv vets, can I get an ok for this idea??

I just wanted to show you guys visually what I meant by the homemade trap. It shoud be cool and effective right? please check me if not.

http://hometown.aol.com/seraloo/myhomepage/index.html

p.s. backer board or green board for the walls? tile most likely, unless someone can direct me where to buy those plastic wall sheets and pieces for those cheaper shower stalls. Only ones I have seen around home D are included only in a kit. Im talking about those sheets that sit in those rail type of corner holder ****s??.. I am sooo broke, Hey, would a mortar coat over that backer board, cement type, work for walls?? Real smooth though??
 
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Old 07-26-03, 11:16 PM
InspectorJ
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one more thing

about cracks in these shower pans. well there one crack, hairline, but it has not hit the floor part of the pan, its just on the wall. its growing though. any improvising ideas that are effective but low cost?? thanks guys, and ragnar esp.
p.s. the drain cover with holes that goes over the open drain hole on the pan, I think that cover allows the water to drain alot smoother for some reason. and also, the drain connecting device is a wedge type, no caulk or anything to attach and connect, just slip pan over 2" pipe drain, and slide in the rubber sleeve/wedge piece.
thanks again DIY!!!!!!!!!!!!!!!!!!!!!!!
 
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