I had a 310 that had that issue as well. Replaced with a Thetford and no more smell. The seal between the porcelain bowl and the plastic base leaked. Called Dometic and there was no fix. Toilet was less than 3 months old.
Originally Posted by owen5716
I have a 2014 coachmen freelander 28qb. It has a dometic 300 series toilet in it. For months it smelled of strong urine smell. We were constantly cleaning the toilet with no change in the oders. After research online I realized the toilet was defective and would allow urine to collect within the inner casing of the toilet. I took the toilet out and turned it upside down and urine poured out of it from the back area of the toilet. I contacted the manufacturer and they are replacing them with a model 310 series. Amazing.
I had a 310 that had that issue as well. Replaced with a Thedford