View Full Version : Rear Outlet Toilet Installation Question

06-01-2006, 07:17 AM
We are installing a Gerber #21-310 Ultra-Flush, Back Outlet, Floor Mount toilet in what is in effect new construction. I have seen recommendations to use a neoprene gasket rather than a standard wax gasket with this toilet because the wax will sag and leak over time. My question: is the neoprene gasket preferred and if so, what type of flange is required? Gerber's installation instructions only cover the specific location/dimensions of the rough-in, but not flange or gasket type. Also, if a neoprene gasket is required, where can I find one. I have been unable to locate one at the plumbing supply stores or online. Perhaps I am not using the correct term. I would certainly appreciate any help from forum members. Thanks.

06-01-2006, 07:46 PM
A wax ring is not suitable for a rear discharge toilet. The neoprene is a very common plumbing item and is available at any plumbing supply house, but not at HD.

The toilet needs to be installed to a wall carrier, which will cost more than the toilet. Again, available through a commercial supply.

06-02-2006, 06:50 AM
A floor mount back outlet toilet does not need a carrier because nothing is being supported by the wall. You need a flange at the wall positioned at the proper height above the finished floor. There are wax rings with an insert for use with wall hung toilets, or good plumbing supply stores will have the neoprene foam gaskets. A wall hung toilet would work better with the full sized foam ring which covers the entire flange and has two holes for the bolts to pass through.

06-02-2006, 08:19 AM
It is also important to note the recommendation on the toilet's instructions about how far the nipple or flange should stick out the wall. On the American Standard Yorkville they recommend flush to 1/16th exposed. This is _different_ from the spec for wall-hung units.

Question to the experts: How do you clean off old wax from an ABS nipple?

Yes, a plumber had installed the previous toilet with a wax ring (arrrrgh...). Scraped it off as good as possible but still feels "waxy", afraid the neoprene ring glue won't adhere well. Can I use alcohol or some detergent?

Regards, Joerg.

Bob NH
06-02-2006, 08:32 AM
Wax is a petroleum product. Gasoline or similar solvent will work. Check for its effect on the pipe, but it should be ok if you use minimum solvent and don't leave it on long.

Gary Swart
06-02-2006, 09:32 AM
I'd suggest mineral spirits (paint thinner) with a rag to clean wax from the ABS.

06-02-2006, 01:06 PM
Thanks, Bob and Gary.

One more remark for dmont: Before drilling the holes in the floor measure or spot the actual toilet. On mine I had to be 13" off the back wall. The spec sheet said 12-3/4". Had I drilled per spec sheet there would probably have been no way to get the screws into those holes, they would have been 1/4" off.

Regards, Joerg.

06-02-2006, 09:00 PM
Thanks to all for the help! Now, all I need to do is find a neoprene gasket. We are in the "boonies" and nobody around here stocks them (and in many cases, don't even know what they are.) All of the local plumbers I've talked to say they just use wax gaskets on everything. Can anybody suggest a brand name or some other term I should use to try to find one online? So far, searching for "neoprene gasket" hasn't turned up much.

Thanks again.

06-03-2006, 09:28 AM
Sioux Chief #490-10545 through 490-10548 are the full size gaskets. The first one is 3/8" thick and the last is 1". The two intermediate numbers are 9/16" and 3/4" respectively. They also make the smaller pattern #490-10540 through 480-10544 also in various thicknesses. The reason I like the sponge gaskets is that they are a compressible product, so when you tighten the bowl to the flange the gasket is compressed making the bowl and flange a single unit, as opposed to a wax ring that just flattens out more as it is tightened and has no rebound if the bolts loosen. The only time a wax ring allows the flange and bowl to be joined solidly is when it is completely squeezed out of the connection and then you have a leak.

06-03-2006, 12:03 PM
Ok, just got done installing a rear-outlet bowl. This is the gasket I used: Zurn Z-1210-57 (found that number on the Zurn web site). No part number on the package when I bought it but it says Bonded "Neo-Seal" Closet Gasket on the carton. Comes with a glue. Before mounting, I discarded the little plastic spacer ring in the center. It should be loose.

We also live in the boonies and none of the big box stores had anything. Call the large plumbing suppliers. I found one in the quaint little town of Placerville, CA (Ferguson). You should also be able to order it from Terry.

Regards, Joerg.

06-03-2006, 01:26 PM
Question to the pros: On the Zurn Neoprene gasket package it says to wait "several days before running water through the bowl" to let the glue cure.

Well, how many days is "several"?

Regards, Joerg.

06-03-2006, 07:41 PM
I like to wait at least 10 minutes.

As I recall in the bicycle shop, repairing a flat took less time than that, and then it was tested in water.

If the glue for that could hold 70 psi, I figure that it should hold a toilet being flushed.

06-05-2006, 12:26 PM
Thanks, Terry. Then I'll fire her up, see if our new loo leaks. If it can be noticed, that is. I hate those gaskets, the inner diameter is so large that it could slip over the outer diameter of the nipple but you can't see that. For $20+ they could have at least made them grooved.

On bicycle inner tubes it's different. I usually throw them in right away after patching. The air inside presses the patch hard against the tire but there won't be any water. The only time it "re-leaked" was when I didn't inflate enough and headed off for a long ride, or when it was raining hard and I couldn't find an underpass. Done that, learned my lesson. One hastily fixed inner tube even exploded on me, bursting and jamming the front tire and sending me sailing over the handle bar.

Regards, Joerg.

06-06-2006, 07:18 PM
Thanks to forum members, I was able to find a Zurn Neo-Seal gasket for my floor-mounted rear outlet toilet. Unfortunately, in the mean time, the plumber, in an effort to be helpful while installing the new water heater, also went ahead and installed the toilet, with...you guessed it...wax rings. So, now I am rereading the suggestions for cleaning wax residue off the flange and the toilet. Don't know what I'd do without this forum. Thanks again to everybody who took the time to respond.

07-08-2009, 12:40 PM
I know this is kind of an old thread, but I wanted to thank everyone that posted here for helping me hopefully fix the problem our toilets were having. My Fiancée and I closed on a bank owned house, "as is" and unfortunately despite having a home inspection and 2 plumbers check it out, the plumbing issues proved to be bigger than thought. We had figured out before purchase that all the indoor plumbing was above ground, which is pretty unusual here in AZ for a house built after the 40s, so I was unfamiliar with it. Basically what happened is about every pipe outlet in the bathroom walls had been fixed improperly and was slowly leaking underneath the tile floor. We decided to bite the bullet and just update the entire bathrooms, as they were the last rooms in the house to be updated. Obviously, with the above ground plumbing the new toilets had to be rear outlet, which I was totally unfamiliar with and found out the cost a quite a bit extra. My plumber got a pretty good deal on the Crane Economizer, so we went with that.

The toilet in the guest bath was working great, but the one in the master was slowly draining from the bowl and leaking on the floor. My plumber felt it was do to the bowl being unleveled and reset it, but still leak. He said he would try to reset it and if it happened again the bowl must be cracked and he would ship it back to be replaced. We eventually got the guest bath fully functional and with all the other house needs of a new home work on the master was pushed back, so I just cut the water supply and have been waiting to have the plumber back out when we are ready to work on the master.

So come 4th of July we decide to finally have some people over, had a good time but once our guest had left we found water all around the toilet in the guest bath. After checking everything it was obvious the guest toilet was doing the same thing as the master, a result of the extra use on it. We decided to use it sparingly and check into what else may be the problem. I looked up the installation at Crane's site and that is the first time I heard of a "neoprene" seal. I have only set a few toilets in my life and all have been floor outlet with wax rings, which I actually hate wax rings but they work fine for floor outlets. After running searches for neoprene I found this forum with great info! Unfortunately, I was only able to find 1 Zurn Neo-Seal 30 miles away, and no Sioux Chief, but did find some neoprene seal at a plumbing supply store no box or anything for $10.

I set the master toilet last night with the neoprene seal, after cleaning out 2 or 3 wax rings with of crap and after about 10 flushes most loaded no leaking! Hopefully, when I return home today everything will be ok and I'll set the guest toilet!

Sorry, this got so long, but I wanted to say thanks!

Aside from that, the Crane toilets are working well and I love the extra power from the pressure tank.

12-14-2009, 02:44 PM
Exactly like the last poster, I just bought a house and decided to remodel the bathroom. There is a Crane floor mounted wall outlet toilet that we removed and who ever installed the toilet used a wax ring. I know it was leaking because the floor was wet and had a very strong odor. I found a neoprene gasket from a local plumbing supply store that cost only $3.50. I asked if they came in different sizes and he told me no. I also asked if I needed any glue for it and said no...just use a little silicone. I removed all the old wax and installed the new gasket. It appeared to be working fine but after a few days I noticed a cracked tile next to my toilet and that every time I flushed water would come up through the tile crack. Does anyone have any suggestions? I have read so many different posts and articles but am no closer to solving my problem. Most plumbers I spoke to said they use wax rings and hate those kinds of toilets which is one reason I would like to avoid using a plumber in fear that I pay them just to have it continue to leak. Any help would be greatly appreciated!

12-15-2009, 04:24 PM
I would wait as long as it took me to finish installing the toilet and tank, and then turning the water on. Zurn engineers can wait a day, because they do not have people waiting to use it, and do not have to charge another call to come back the next day.

12-17-2009, 05:30 AM
Has anyone looked at this toilet?

It's strong enough to flush into the mascerating unit horizontally that pairs with it, so why wouldn't it work to just run into the drain pipe that runs behind it?

The outlet is also WAY off the floor, so it'd allow a bit more distance to gravity feed to the stack.

Its bowl is the SANI003 and the tank is the SANI007. It's only a 1.6 gal tank, but I'm sure its gravity not pressure assist. But for < $200 it seems like an option I'd like to explore.

I've attached a picture. It says to use a 3/8" slope for the 15" extension which is just beyond the 1/4"/ft typical for horizontal runs.

Thoughts on this?

UPDATE: Called Saniflo... their toilet IS gravity fed (as i suspected). The extension pipe shown in the picture is metric sized. The end in the wall is 99 mm OD ~3.9" Their technical assistance guy said as long as there's a 1/4" slope, you can feed it wherever you want. Am I asking for trouble?

12-29-2009, 03:54 PM
Hi, I hope that somebody can help. I purchased a home 2 years ago. After doing some work on the house we decided to fix up the half bathroom. I tried to do some research on these floor mounted rear outlet toilets but there really isn't much out there.

Ok here is my problem. The existing pipe/coupling in the wall does not come out flush with the sheetrock. Its flush with the stud track on the floor. And the hight of it is 4" from top of floor to CL of pipe. How ever built this place didn't take in consideration that there is typically lauan on top of the subfloor and then some linoleum or VCT tile. How can I extend this pipe up to 1/16 or 1/8 from the face of the sheet rock? And also isn't there supposed to be a flange as well? There wasn't any before. Im installing a Kohler barrington K-3652.

Thank you