Thetford 2018 replaced with Dometic 310

Question

I have had a few issues with our 2018 MW 25b plumbing. First the pump froze on the road and I took it apart but could not get the part unless I ordered it so purchased an AquaPro and installed it at the campsite. The next trip the toilet started overflowing so I assumed it was the valve. Luckily we were parked across from a nice bathroom and could do without water. I bought a new kit to fix it and while I was replacing the pedal the spring popped off. I saw a video of how to replace the spring by holding it against the toilet with a pvc pipe cap but realized the plastic lip that held the spring had broken off. We had our former RV toilet, a Thetford for the 11 years we owned it (and 6 before that) and never an issue. Bah humbug.
So I needed a new toilet and decided on the Dometic 310 china bowl on a plastic base. Camping World had the best price but our local store was sold out. So I ordered online and drove about an hour to another store to pick one up. Could not wait for delivery since the next trip was coming up too soon. The install was easy and almost a direct replacement for the Thetford. The toilet install kit is sold separately but one also comes with the toilet. I kept the old bolts and just used the new ring. I did not have any problem with the new toilet leaking like some review complaints. I did drill a new hole for the water supply since the connection is in a different spot.

I think it takes less space so there is a wider aisle to the sink and shower.

bobndot · Answer

Nice , very easy to keep clean.
I had the same 310 installed on my 2018 from day one. From time to time the ‘O’ seal stops holding water in the bowl.
At 5 years , the water valve was just replaced bc it started a slight leak that seemed to be dripping from the round portion of the pedal.
Replaced the water valve. Very simple to do. Youtube shows a ‘how-to’.

I also bought a spare 4” ball seal for the bowl in case i need to replace it on the road. I bought a small tube of plumbers grease to keep it slightly lubricated so it holds water better . Once each season, I remove the seal to clean and lubricate it. Remove it carefully to not drop it into the tank.

The same seal fits the Dometic 300,310,320.

emd360 · Answer

Thanks. Good to know. I hope the valve lasts longer than five years. We also keep our RV’s for a long time. Although the problem must have been the pedal since that was what was actually worn out and beyond repair. I have a small tub of silicone grease that i’ll use. I have read about folks who had to change the gasket so when the time comes …

bobndot · Answer

The seal and valve are inexpensive.
The valve is plastic with tight tolerances.
There is a plastic plunger with an O ring inside the valve. Minerals from the water can build up or dirt from inside the freshwater tank can cause the plunger to malfunction at any time.
I mention dirt from the water tank bc i did a Netboy mod on my tank to clean the inside. I was very surprised to find so much build up inside the tank which i always kept sanitized over time.
Here is the interesting mod page that can be used on most RVs, not just TC’s.

I did the deck plate freshwater tank mod to gain access to my tank.
Hope you enjoy this mod page.

http://ourelkhorn.itgo.com/netboy/index.html

emd360 · Answer

I looked at the mods. Some I have done. Can’t put the opening on top of our water tank because it is under the refrigerator. I can see how the tank could get crud in it though. I should probably order the parts. We took our first trip with the new toilet and we like it.

bobndot · Answer

It’s a great toilet for people on the GO !   :)

Forum Discussion

Thetford 2018 replaced with Dometic 310

About Motorhome Group

Related Content

Replace Thetford Aqua Magic Style II with Dometic 320?

Thetford toilet sewer smell

DOMETIC A/C REPLACEMENT SHROUDS

dometic fridge heat element replacement

Thetford Toilet Misbehaving