Sewer smell when back flushing

[Jamie65]

I have a 2003 Allegro Bus with a Dometic toilet. I am getting an odor from the base area of the toilet, only when back flushing. I have one half bowl of water no bubbles, not coming from the ball seal. Is there a base seal or should the base be sealed to the tile floor with silicone or some other sealant?

Ed

[Skip426]

Should be a base seal . Do you have a model number , maybe we can round you up a manual if you don't have one.

[Jamie65]

The unit model is 2010.

Thanks, Ed

[1mainiac]

There is a flange seal and I would also check your vent on the roof. Are you using a in tank spray system or one of the add on back flush setups? The in tank systems also have a check valve usually under the bathroom sink.

[Jamie65]

I have already run an auger in the vent from the roof. I have identified the flange gasket and the base gasket from Dometic, I will pick them up when I get close to a RV dealer. I looked and found the valve under the bathroom sink, I was wondering where it was.
Thanks, Ed

[Jamie65]

I finally got the necessary part and did the repair, took about 15 minutes. No RV supplies near Yellowstone or Grand Tetons. I passed through Casper, WY. and picked up the repair kit at Stalkup RV supplies, very well stocked, friendly and helpful staff. It is a two part seal kit, one other RV supply store tried to sell me a kit with one gasket, they insisted it only takes one. I called Dometic, they said it is a two part kit. Stalkup had the kit with the Dometic number on it.
The base seal kit Dometic number is 385311462.
Thanks for the tips.
Ed