A few rough-in questions

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wwhitney

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P3113.1 Size of vents. Add sentence to paragraph: At least one (1) vent shall be three (3)
inch unreduced in size extending from the main building drain through the roof.
Ah, they stuck it in the Residential Code, not the Plumbing Code. I always forget to check the plumbing portion of the IRC, rather than the IPC.


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Wayne
 

Paul Blakely

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Sure, but that's a different sort of requirement. That would mean any vent, regardless of its size, should be increased to 3" just before leaving the thermal envelope. Versus a requirement that one vent through the roof be 3" all the way down.

Cheers, Wayne
I can't believe it's been a month since I had to postpone work on the venting to do some HVAC and electrical work. But now moving again on the plumbing.
Two questions:
1. In running the 3" vent to the roof, the hole through the top plates was so snug, we had to hammer it thru the hole we cut out with a 3 1/4" hole saw. Am I asking for trouble with a PVC pipe that snug through the top plates?

2. I've purchased two 36 gal HW tanks, to place one close to either bathroom (because several have told me that circ pumps breakdown too often). Question is, can I mount the expansion tank anywhere between the two HW tanks?
 

Terry

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1) Since it's a vent, and not where warm water passes, you may be alright.

2) The expansion tank is on the cold water supply. Anywhere is fine.
 

wwhitney

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On the expansion tank question, does an expansion tank need to be on the heater side of the cold water supply shutoff? If so, then if you want to have local shutoffs at each water heater, you'd need to have an expansion tank at each heater.

Obviously to cover the case where the cold water supply is shut off but the water heater isn't, the expansion tank should be between the heater and the valve. But I'm not clear on whether it's important or required to handle that case.

Cheers, Wayne
 

Reach4

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I think you turn off the breaker if you turn off the valve to the WH. So if you can handle that, it's not going to be important.

It is usual for people with wells to not have a separate thermal expansion tank, because the pressure tank can absorb thermal expansion if you don't add a check valve in the path.
 

Jeff H Young

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On the expansion tank question, does an expansion tank need to be on the heater side of the cold water supply shutoff? If so, then if you want to have local shutoffs at each water heater, you'd need to have an expansion tank at each heater.

Obviously to cover the case where the cold water supply is shut off but the water heater isn't, the expansion tank should be between the heater and the valve. But I'm not clear on whether it's important or required to handle that case.

Cheers, Wayne
I thought the tank should be between the water heater and a shut off valve but cant find mention in codes or manufacture install requirements . I know I was taught to install them where they will function at all times . I think wording may have changed. also an expansion tank i think helps keep pressure down but the t and p is the real protector
 

Paul Blakely

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I thought the tank should be between the water heater and a shut off valve but cant find mention in codes or manufacture install requirements . I know I was taught to install them where they will function at all times . I think wording may have changed. also an expansion tank i think helps keep pressure down but the t and p is the real protector
Thanks folks, I appreciate the advice. I'll go with one expansion tank on the cold water line between the two tanks. I plan to have quite a few shut offs throughout and will remember to kill the breakers on both tanks whenever I have to switch them out. These days, it looks like lifespan on these models is only 6 years.
 

Paul Blakely

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1) Yes, stacked san-tees is fine. [Or the WC could use a wye, which could end up being half of the LT90 below.] The short section between the tub and the WC is a vertical wet vent, but that's allowed, and at 3" it's plenty big enough.

On (2) and (3) I'll defer to others.

Cheers, Wayne
Well that sketch I had provided earlier did not show what I had proposed to do following the toilet and shower hookup and I appear to have messed up by using a couple of san-tees rather than wyes. Inspector told me today I have two san-tees placed on their side and I should have used wyes.
.
Trying to correct this is a challenging problem, because I can't find a short sweep wye. It looks like I would have to lower the entire 60' lateral drain to replace the san-tees with sanitary wyes at the vent stack and the vanities drain connections, because the shower drain connects to the vent stack and the vent stack is connected to the main lateral drain with a san-tee instead of a wye.

Does anyone see any simpler solution than dropping the entire lateral drain? Thanks for any ideas.

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dwv2.jpg
 

wwhitney

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Yes, a san-tee on its back is never allowed when all 3 connections are for drainage. And you won't find a "short sweep wye," the whole point of the wye (or combo) is to have more sweep, which is required when a drain turns from vertical to horizontal.

On the vanity drain, if it is coming in perpendicular in plan (as seen from above, ignoring elevation), then the substitute geometry is pretty simple: replace the san-tee with a upright wye (only) a bit downstream, and roll the quarter bend 45 degrees towards downstream to line up with the wye inlet.

On the tub/vent/WC nexus, it looks like a one piece combo and a street san-tee for the tub may just fit. That's worth checking first before resorting to changing the geometry. What's the exact height difference between the bottom of the joists (assuming that's a level plane) and the mid-line of the 3" horizontal drain, at the location of the current san-tee on its back? I can look up the fitting dimensions in Charlotte's catalog to see if it will fit.

If not, you definitely have some other geometries available, which might be tricky to fit together but would preclude the need to drop your 3" horizontal drain.

Cheers, Wayne
 

Paul Blakely

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Yes, a san-tee on its back is never allowed when all 3 connections are for drainage. And you won't find a "short sweep wye," the whole point of the wye (or combo) is to have more sweep, which is required 3/4"when a drain turns from vertical to horizontal.

On the vanity drain, if it is coming in perpendicular in plan (as seen from above, ignoring elevation), then the substitute geometry is pretty simple: replace the san-tee with a upright wye (only) a bit downstream, and roll the quarter bend 45 degrees towards downstream to line up with the wye inlet.

On the tub/vent/WC nexus, it looks like a one piece combo and a street san-tee for the tub may just fit. That's worth checking first before resorting to changing the geometry. What's the exact height difference between the bottom of the joists (assuming that's a level plane) and the mid-line of the 3" horizontal drain, at the location of the current san-tee on its back? I can look up the fitting dimensions in Charlotte's catalog to see if it will fit.

If not, you definitely have some other geometries available, which might be tricky to fit together but would preclude the need to drop your 3" horizontal drain.

Cheers, Wayne
Wayne, you are a much appreciated God-send!
I can see that the vanities drain connection can be made just as you suggest. The one I can't get my head around is the tub/vent/WC solution. I had purchased a wye and street san-tee as a possibility, but I couldn't really determine the height without gluing the street into the wye.

The attached photos show that the tub drain is connected right at the bottom of the joists, so I can't see how I would connect it to the combo fitting.

To answer your question, the distance between the bottom of the joists to the mid-line of the 3" horizontal is 12", maybe even 12 1/8". The dry-fitted wye and street san-tee looks to be 9 3/4" ??

I was so pumped that you may have a solution that I took a flashlight over to the crawl space tonight to send you the info and a couple of additional pics? Thanks so much!
 

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wwhitney

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OK, per Charlotte's catalog, an upright 3" PVC combo (the one piece fitting you used at the closet bend) has a height (from mid-line of the barrel to the base of the hub) of 7-9/16". And a 3x3x1-1/2" reducing street san-tee has a height of the side entry (from the end of the spigot) of 3-1/4". So together the mid-line of the 1-1/2" side entry would be 10-13/16" above the mid-line of the 3" horizontal drain. Which puts the top of a 1-1/2" pipe at about 11-13/16" above the 3" horizontal drain.

In other words it should just fit under your joist, including a little extra for the hub thickness. You'll obviously a few Fernco 3005-33 or the like to make up the new connections once you cut out some of the existing PVC. And if some reason there's a snag with the above geometry, there are other options, such as using an upright 3" wye, then the street 3x3x1-1/2" reducing san-tee (so the barrel is at a 45), and then a street 45.

While you are redoing that, it looks you don't have enough room to make that cleanout useable? Not sure what plumbing code you are under, but the IPC requires 18" of clearance in front of the cleanout plug. So rather than use a combo at the WC for the cleanout, I think you'd be better off with a LT90 for the closet bend and a downstream 3"wye for the cleanout, where it will have 18" clearance in front of the plug. With the wye rolled up maybe 30 degrees from horizontal so that the cleanout is above the center line.


Cheers, Wayne
 

Paul Blakely

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OK, per Charlotte's catalog, an upright 3" PVC combo (the one piece fitting you used at the closet bend) has a height (from mid-line of the barrel to the base of the hub) of 7-9/16". And a 3x3x1-1/2" reducing street san-tee has a height of the side entry (from the end of the spigot) of 3-1/4". So together the mid-line of the 1-1/2" side entry would be 10-13/16" above the mid-line of the 3" horizontal drain. Which puts the top of a 1-1/2" pipe at about 11-13/16" above the 3" horizontal drain.

In other words it should just fit under your joist, including a little extra for the hub thickness. You'll obviously a few Fernco 3005-33 or the like to make up the new connections once you cut out some of the existing PVC. And if some reason there's a snag with the above geometry, there are other options, such as using an upright 3" wye, then the street 3x3x1-1/2" reducing san-tee (so the barrel is at a 45), and then a street 45.

While you are redoing that, it looks you don't have enough room to make that cleanout useable? Not sure what plumbing code you are under, but the IPC requires 18" of clearance in front of the cleanout plug. So rather than use a combo at the WC for the cleanout, I think you'd be better off with a LT90 for the closet bend and a downstream 3"wye for the cleanout, where it will have 18" clearance in front of the plug. With the wye rolled up maybe 30 degrees from horizontal so that the cleanout is above the center line.


Cheers, Wayne
You da man, Wayne! I will try this proposal and let you know how it goes.
Appreciate you,
Paul
 

Paul Blakely

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I think I'm ready to start cutting, but I want to make sure I've understood your second option, Wayne.
Again in the attached photo, I would cut out the first san-tee, the one that currently has the bath drain running into it.
that san-tee can be replaced with a 3x3x3 wye that would have only the vent.

But following that vent on the 3" main, I can replace the two 22.5s with a 45 and then insert a 3x3x2 to which I can insert a 3x3x2 san-tee reduced to 1.5 and rotate to accommodate the 1.5 bath drain. And this is the part I'd like to confirm with you. Even though the bath drain would not be connected to directly to the vertical 3" vent stack, it would be close enough to serve as a wet vent for the bath ?

If that is OK, then I can replace the other san-tee for the drains with a 3x3x2 and also insert a cleanout at a more accessible point.

Thanks!

FollowUpDWV.jpg
 

wwhitney

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No, that is not my "second option." And I only mentioned that "second option" in passing to indicate there are alternatives to the "first option" if my calculations on the requisite height were off for some reason.

The "second option" doesn't add an additional connection to the 3" horizontal. Instead, it replaces the san-tee on its back with an upright 3" wye (likely a little farther downstream, which could require reconfiguring your double 22.5). Then directly into the branch inlet of that wye is a 3x3x1-1/2 street san-tee. Its barrel is at a 45 to plumb, and its side entry is at 2% slope. Then directly into the top of that san-tee is a street 45.

So it would be the same fittings as if your 3" combo were made from a wye and a street 45, just swapping the order of the street san-tee and the street 45. That will lower the side inlet on the street san-tee, useful if using a combo would put the san-tee side inlet too high.

Cheers, Wayne
 

Paul Blakely

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No, that is not my "second option." And I only mentioned that "second option" in passing to indicate there are alternatives to the "first option" if my calculations on the requisite height were off for some reason.

The "second option" doesn't add an additional connection to the 3" horizontal. Instead, it replaces the san-tee on its back with an upright 3" wye (likely a little farther downstream, which could require reconfiguring your double 22.5). Then directly into the branch inlet of that wye is a 3x3x1-1/2 street san-tee. Its barrel is at a 45 to plumb, and its side entry is at 2% slope. Then directly into the top of that san-tee is a street 45.

So it would be the same fittings as if your 3" combo were made from a wye and a street 45, just swapping the order of the street san-tee and the street 45. That will lower the side inlet on the street san-tee, useful if using a combo would put the san-tee side inlet too high.

Cheers, Wayne
Well Wayne, I finally get it. I read your posts several times before I realized the source of my confusion. I wasn't picking up that the 3x3x1.5 reducing san-tee was a STREET. I didn't know there was such a thing and in fact, I had to go to a second plumbing supply store to get one.
Thanks for all your advice and patience.
 
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