Commercial toilet in residence.

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Dollar_Bill

Dollar_Bill

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Building an extra room. Wife wanted a commercial, wall hung toilet. Said she is tired of celaning behind toilets that bolt to the floor. I miss, sometimes. :eek:

So I got her a nice commercial toilet. Problem is, it won't flush. We have a 3/4" line coming into the home and can't seem to get enough pressure/volume to flush.

I would pull it and replace with a tank type, but this was expensive toilet and I am not really sure I could find a tank type that would wall hang. Have poured a slab floor, and while I could saw through the slab and tie into the sewage line . . . . I don't want to.

I have replaced the valve with the highest flow I could find, don't tell the Water Police, no good. I am getting about 70 psi where the service line comes in, but a long way to the toilet.

I have heard that I might be able to put in an expansion tank in the attic and run a line to the toilet, but the tanks for water heaters are too small. I have considered a pressure tank like goes with a well pump, but they are expensive and the bladders won't handle very high pressure.

Sure would appreciate some ideas.

Bill
Atlanta
 
you need a 1" line minimum for a flush valve on a W.c.
thats the problem .

most houses do not have water lines big enough all the way to the bathroom which is a big reason you dont put a commercial toilet in a residential setting.

the 3/4 valve you have is intended for a urinal.
 
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LiQuId said:
you need a 1" line minimum for a flush valve on a W.c.
thats the problem .

most houses do not have water lines big enough all the way to the bathroom which is a big reason you dont put a commercial toilet in a residential setting.

the 3/4 valve you have is intended for a urinal.
Click to expand...


Thanks. I understand that now, Can I put the one inch line up to a 1.6 gallon (or larger) expansion tank in the attic above and have the necessary volume to flush? I realize that another response suggests I use a rear discharge toilet. This is a good idea, but if any way possible, I would like to keep the wall hung commercial toilet I have now. It looks great! Just need to make it work.
 
What size is the supply line into your house? if its the usual 3/4 then you may have issues.

what is your intended perpose for this expansion tank ? you realize they are not water storage vessels but are used to combat expansion/contraction of water in a system ?
 
I would say that if you use a large enough expansion/bladder tank, it should work. I don't know that a small expansion tank will do the trick, though. If I were to try this, I would use a small bladder tank meant for a well.
 
phishfood said:
I would say that if you use a large enough expansion/bladder tank, it should work. I don't know that a small expansion tank will do the trick, though. If I were to try this, I would use a small bladder tank meant for a well.
Click to expand...

Thanks, Phishfood, I have this tank
http://www.flotecpump.com/ResidentialProduct_fl_hw_tk_FP7110.aspx

While the gallonage is more than I need (19gals) to flush the toilet, it is the smallest tank I could find that has a 1" NPT.

It would seem I can connect this in my system with my 3/4" supply and a 1" discharge to the toilet. My incoming pressure, through the aforementioned 3/4" supply is at about 75psi. I can adjust this pressure as needed. The tank has a pressure limit of 100psi and is pre-charged at 40psi.

Since this tank has only one inlet/outlet it would seem that I can bring the 3/4" line into a 1" "T", with a 1" pipe to the tank and the remaining opening of the "T" feeding down to the toilet through a 1" pipe.

I have a backflow preventer on my incoming supply line, would I need another backflow preventer at the tank?

Your kind suggestions are appreciated.
 
Actually, if I were attempting this, I would in fact run a 1" line from the bladder tank to the flush valve. Those water closet flush valves demand a lot of water in a very short time span, and I would bet that a 3/4" line wouldn't deliver enough.

I can't think of a reason that you would need a backflow preventor on the tank.
 
I am gonna go with the bladder tank. Will let you know how it turns out.

Bill
 
phishfood said:
Actually, if I were attempting this, I would in fact run a 1" line from the bladder tank to the flush valve. Those water closet flush valves demand a lot of water in a very short time span, and I would bet that a 3/4" line wouldn't deliver enough.

I can't think of a reason that you would need a backflow preventor on the tank.
Click to expand...

You would be correct, our code here says that the minimum soze for a flush valve W.C. is 1".

...

I wouldnt think you would need a check valve to the toilet, but I;ve not installed a commercial toilet withing a residence and have never had need for a bladder tank, I will let others chime in on this one as I've always had a sufficiantlly sized line to work with. As far as the pressure goes, this shouldnt be the cause of the problem, and you definatelly dont want pressures to exceed 80 psi ... 75 is even up there.
 
I mentioned 75 psi because that is available where the supply comes in. I will reduce that pressure to a more appropriate amount. I have more than enough pressure, just need to up the volume.
 
My thoughts...1. Installing a backflow preventer before the pressure tank on the branch and increasing the pipe diameter to 1" would be an attempt to duplicate the effect of a dedicated 1" service line to supply the flush valve. The branch would maintain the pressure in the line separately from the rest of the water system and hopefully provide much needed volume through the 1" piping. The down side to this is that a higher pressure in the 1" piping, due to the pressure tank, may cause to back flow preventer to close prematurely and not allow enough water in from the existing 3/4" line even when the toilet is flushed, because of the quick action of the flush valve. The pressure tank would need to be adjusted to match or be slightly lower than the incoming 3/4" pressure at the point of connection.
2. Though, without a check valve, a pressure tank may provide enough pressure throughout the entire water dist. to give the 1" just the kick it needs to create the same effect as a 1" service...both pressure and volume.
Curious to see how this all turns out, Dollar. Let us know.
 
Your problem is Volume, not pressure, the pressure remains the same in a flushometer on both sides of the diaphragm, its the relief port that restores the equal pressure and seals the valve. You need Volume, what is happening with the 3/4 Urinal flushometer is that you are not getting enough volume to induce a syphon, flushometers are designed to operate on less water than conventional toilets but do require the line to be properly sized for their application, Im not saying "it cant be done" but I wouldnt do it.

If I were to ( hypothetically ) do this, I would be looking at a scenario of "how can I get enough water to this", and that again takes me back to volume.

holding vessel, perhaps a expansion tank with a bladder...
 
phishfood said:
Actually, if I were attempting this, I would in fact run a 1" line from the bladder tank to the flush valve. Those water closet flush valves demand a lot of water in a very short time span, and I would bet that a 3/4" line wouldn't deliver enough.

I can't think of a reason that you would need a backflow preventor on the tank.
Click to expand...

Got the bladder tank installed and it works great! Wife is happy. Simple installation. To recap.

A commercial toilet needs a 1" supply line at about 70psi to operate the flush mechanism. I have a 3/4" water supply line coming in to our home at 70psi.

Toilet would not flush. Not enough water to initiate the siphon to get the toilet to work.

The pressure/bladder tank with a 1" inlet/outlet valve. I placed this in the attic above the toilet. I use CPVC for cold and hot to simplify, so I had to transition to the 1" PVC. I brought a 3/4" line into a "T", this allows the water to flow into the tank, the toilet valve temporarily blocking the flow to the toilet.

http://www.hardwareworld.com/Vertical-Pressure-Tank-42-Gallon-Equivalent-pEC0QRQ.aspx

The water flowing into the tank caused the air-filled bladder to compress until the pressure on the water was at about 70psi, I guess. That is the pressure where the supply enters our home. The tank system is rated at 100psi.

When I flushed the toilet, a stream of water came down the 1" pipe at 70psi (or so) and the toilet flushed very well. The pressures equalize so there is no back-flow. I do have an anti-back-flow valve where my supply line comes into the home.

There was a small leak, but I fixed it.

IMG_0957 (Medium).JPG
 
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