Do new Dometic 310 toilets still have the internal leak problem?

[Wellibe]

I'm potentially in the market for a new porcelain bowl toilet. Not crazy about the Thetford Aqua-Magic II that came in the rig, which is worn out and disgusting.

In general the Dometic 310 seems like a better design, but I'm wondering if they ever fixed the infamous internal leak issue. A quick google search didn't turn up anything definitive. Seems there have been a lot of warranty replacements, but I can't tell if they've actually changed the design to eliminate the problem.

I had Dometic 300 series plastic toilets in my previous two rigs and never had any symptoms of that issue, but I'm still a little leery given all the people who have had the problem.

[NXR]

The 310 has never had the problem of the 300 where dirty water was trapped in the base.

We have a 310 that's six years old with almost three years of actual use.

The 310 does require about another inch from the rear wall than the 300 does so measure carefully.

Ray

[Sam 3]

Get an ADA height toilet. The extra height makes a big difference in comfort. Go with a porcelin toilet. The RV came with a plastic toilet that made you feel like you were dropping down to sit. Put ADA height toilets in our home(2).

[Wellibe]

Originally Posted by NXR

The 310 has never had the problem of the 300 where dirty water was trapped in the base.

We have a 310 that's six years old with almost three years of actual use.

The 310 does require about another inch from the rear wall than the 300 does so measure carefully.

Ray

Apparently some folks have had the issue with the 310:

https://www.irv2.com/forums/f103/dom...ng-610539.html

https://www.irv2.com/forums/f54/repl...et-595860.html

https://www.irv2.com/forums/f54/dome...ak-322315.html

https://www.irv2.com/forums/f87/leak...et-542834.html

[Wellibe]

Originally Posted by Sam 3

Get an ADA height toilet. The extra height makes a big difference in comfort. Go with a porcelin toilet. The RV came with a plastic toilet that made you feel like you were dropping down to sit. Put ADA height toilets in our home(2).

We aren't big fans of high toilets. Without getting too graphic, let's just say things go more easily and completely when your hips are below knee level. Of course if you have trouble getting up from a low toilet, you could use a stool under your feet to accomplish the same thing.

[Wellibe]

Well, I just measured from the wall to the center of the flange, and I've only got 9 3/4 inches. The 310 requires a minimum of 10 inches. So looks like I'm going to have to stick with a Thetford, which requires 9 1/2 inches.

[NXR]

Originally Posted by Wellibe

Apparently some folks have had the issue with the 310:

https://www.irv2.com/forums/f103/dom...ng-610539.html

https://www.irv2.com/forums/f54/repl...et-595860.html

https://www.irv2.com/forums/f54/dome...ak-322315.html

https://www.irv2.com/forums/f87/leak...et-542834.html

That's a different problem. The 300 has a kind of cavity in the base and black water was collecting and sitting there, smelling the place up.

[Wellibe]

Originally Posted by Wellibe

Well, I just measured from the wall to the center of the flange, and I've only got 9 3/4 inches. The 310 requires a minimum of 10 inches. So looks like I'm going to have to stick with a Thetford, which requires 9 1/2 inches.

Can anyone tell me how important it is to have the full 10 inches of clearance for a Dometic 310? Is being 1/4 inch short going to cause it not to work?

The more I learn about Thetford toilets, the less enthusiastic I am about buying one. But I definitely don't want to have to move the flange.

[NXR]

Originally Posted by Wellibe

Can anyone tell me how important it is to have the full 10 inches of clearance for a Dometic 310? Is being 1/4 inch short going to cause it not to work?

The more I learn about Thetford toilets, the less enthusiastic I am about buying one. But I definitely don't want to have to move the flange.

It'll probably work but the hole in the bottom of the toilet almost certainly won't line up with the hole in the floor. So most of the stuff will go down but not all of it.

Maybe an offset flange could work? See: https://www.forestriverforums.com/th...flange.235609/

Not all Thetfords are created equal. We have a Tecma macerating toilet and it's great.

Ray

[Sunnyfalls]

Originally Posted by Wellibe

Can anyone tell me how important it is to have the full 10 inches of clearance for a Dometic 310? Is being 1/4 inch short going to cause it not to work?

The more I learn about Thetford toilets, the less enthusiastic I am about buying one. But I definitely don't want to have to move the flange.

According to this, you might be fine:

https://www.forestriverforums.com/th...ic-310.323640/

The vacuum breaker is what will be closet to back wall.

We replaced our Casita trailer OEM low quality, tacky-looking, tacky-sounding, bacteria breeding, plastic Thetford toilet with a high quality ceramic Dometic 311 Low Profile Round Toilet and we added a 120VAC, residential, high quality Brondell Swash 1400 Round Toilet Bidet Seat which has a heated seat, blue night light and provides function rich control of endless toilet bidet seat warm water.

Gayle & Bob
"Los Gatos Casita"

[Wellibe]

Originally Posted by Sunnyfalls

According to this, you might be fine:

https://www.forestriverforums.com/th...ic-310.323640/

The vacuum breaker is what will be closet to back wall.

We replaced our Casita trailer OEM low quality, tacky-looking, tacky-sounding, bacteria breeding, plastic Thetford toilet with a high quality ceramic Dometic 311 Low Profile Round Toilet and we added a 120VAC, residential, high quality Brondell Swash 1400 Round Toilet Bidet Seat which has a heated seat, blue night light and provides function rich control of endless toilet bidet seat warm water.

Gayle & Bob
"Los Gatos Casita"

Thanks for pointing me toward that thread. Seems like there might be some hope of it working out.

[Sunnyfalls]

Yeah, that thread also mentions perhaps mounting it at an angle to increase the clearance if that's an option given the location. We have been very happy with our 311 and we tossed the brand new Thetford that was in our new Casita trailer to get it. The 320/321 would likely be another good option too. Good luck!

Gayle & Bob
"Los Gatos Casita"

[Wellibe]

One other wrinkle with the 310 is that the water valve connection is in a different location than the valve connection on the Thetford. The Thetford connects in the center near the top of the base, whereas the Dometic 310 has the water valve connection down lower and off center toward the foot pedal.

The water line coming up from the floor probably doesn't have enough give to connect as-is, so I would have to add something to reach over and down to the correct location. I assume I can take off the fitting and use a plastic pex fitting to splice on a short section of flexible hose. Could that threaded fitting then be connected to the end of the flexible hose? I can't really see how it is attached to the existing clear pex tubing. Or maybe there is some other readily available threaded fitting that could be connected using a hose clamp?

[Sunnyfalls]

Originally Posted by Wellibe

One other wrinkle with the 310 is that the water valve connection is in a different location than the valve connection on the Thetford. The Thetford connects in the center near the top of the base, whereas the Dometic 310 has the water valve connection down lower and off center toward the foot pedal.

The water line coming up from the floor probably doesn't have enough give to connect as-is, so I would have to add something to reach over and down to the correct location. I assume I can take off the fitting and use a plastic pex fitting to splice on a short section of flexible hose. Could that threaded fitting then be connected to the end of the flexible hose? I can't really see how it is attached to the existing clear pex tubing. Or maybe there is some other readily available threaded fitting that could be connected using a hose clamp?

Right, take off the existing toilet connection adapter, use a Sharkbite or equivalent fitting to extend the PEX, maybe add a shutoff valve (useful for maintenance and if toilet should ever develop a leak when dry camping), and then a new toilet connection adapter. You may want to use some PEX elbow fittings to get the new toilet connection adapter exactly where it needs to be without having to excessively bend the PEX into position and stress the connection point. Attached photos of what we did. We also put another shutoff valve and water filter on the toilet heated bidet seat water supply line to enable isolating it from toilet water supply line for the same reasons.

Gayle & Bob
"Los Gatos Casita"