Does Your Toilet Bowl Lose Water?

[bootsthecat]

I have a Dometic Model 320 elongated bowl with a foot pedal flush. After a period of potty usage the toilet starts to not hold water in the bowl anymore by slowly draining out to the black tank.
HERE IS THE FIX.
After removing the old ball seal and installing a new seal in the potty, close the flush ball and fill the bowl with hot water and let it sit for a while of NON-use SO THE NEW BALL SEAL CAN EXPAND. This will allow the closer flange (flush ball) to properly seat itself against the new expanded ball seal you just installed.
I have done this procedure and it works.
See the attached from Dometic.

[Winddancer]

Originally Posted by bootsthecat

I have a Dometic Model 320 elongated bowl with a foot pedal flush. After a period of potty usage the toilet starts to not hold water in the bowl anymore by slowly draining out to the black tank.
HERE IS THE FIX.
After removing the old ball seal and installing a new seal in the potty, close the flush ball and fill the bowl with hot water and let it sit for a while of NON-use SO THE NEW BALL SEAL CAN EXPAND. This will allow the closer flange (flush ball) to properly seat itself against the new expanded ball seal you just installed.
I have done this procedure and it works.
See the attached from Dometic.

I have also heard of taking a small amount of petroleum jelly, Vaseline or plumbers jelly, and applying it around the ball of gasket area to help seal it. This might be a temp fix to the problem but could help in a pinch.

[bootsthecat]

Originally Posted by Winddancer

I have also heard of taking a small amount of petroleum jelly, Vaseline or plumbers jelly, and applying it around the ball of gasket area to help seal it. This might be a temp fix to the problem but could help in a pinch.

I have also tried those type of fixes in the past, however, the fix didn't last long. I found the best thing was to replace the ball seal and do the Hot Water bath to expand the ball seal.
Some owners do not know they can replace that ball seal themselves. It is very easy once tried. In the past I've wasted $$ at repair shops getting them to do it.

[NMWildcat]

That is certainly a good method for replacing the gasket.
I have always thought about doing that when mine starts leaking out, then I clean it, test it, wash my hands, and go on until the next time. Been doing that for 5 RVs and many years now. One day maybe I'll actually replace one

[dbledan]

Just be sure to put "this side up" label towards you....if not they leak. Ask me how I figured that one out. Hard to read black letters on black in low light.

[RiverRat22]

The toilet in my FR3 also stopped holding water. I purchased Thetford RV toilet seal and as soon as I started using it, the toilet held water. Now I use it all the time, and no problems.

[bootsthecat]

Originally Posted by KsWhoDat

The toilet in my FR3 also stopped holding water. I purchased Thetford RV toilet seal and as soon as I started using it, the toilet held water. Now I use it all the time, and no problems.

Another solution to try. Beats Tech repair costs.

[rk06382]

I applied Plumbers Grease to both sides the gasket of my 320 when it was installed three years ago. I just make sure an inch of water is in the bowl at all times. (RV antifreeze in the winter.)

It is still holding water, but I have more Plumbers Grease if needed.

[jbrosecity]

Although I installed a new Dometic 320 in our Avalanche 5th wheel last August, and it was not used while in storage all winter, we were having trouble with water loss this spring. I removed the original seal which looked fine... I reinserted it and it still leaked so I ordered a new one on amazon
Sealand Toilet Flush Ball Seal #385311658 Compatible with Dometic Toilet
https://www.amazon.com/gp/product/B07HFRTCPP/
it's super easy to replace - here's a video

https://www.youtube.com/watch?v=yuoimjhIBLo

Turns out the Sealand replacement was much more flexible than the original Dometic. I'm not sure if the Dometic seal had stiffened with age sitting in Camping World's warehouse for a long time or if a new one is still much stiffer than the Sealand, but the more flexible seal seems to work great.

Good bulletin from Dometic cited above about using hot water to get the seal to conform better, but probably unnecessary with the flexible Sealand seal

[pengle]

No one has mentioned that cleaning the ball valve is important before you install the new seal. The top of the ball valve (the part you can see) gets minerals attached to it and then it won't seal to the bottom of the seal.

So, remove the old seal, clean the top of the ball valve even where you can't easily see it, then install the new seal (dropping the seal INTO the black tank is not recommended).

[Edmund]

Do you have a dog and leave the top up? I was having the same problem until I caught her one day. Starting putting the top down. Problem solved.

[gdowds]

Get plumbers grease and apply to black gasket to stop water from draining off in between uses. Vasoline works in a pinch

[SquiggyFreud]

Just tried the hot water trick on mine and it did work! Dometic 310.