Thanks OTRA15
I’ve tried all the above and still with only pushing the flush button it still fills the toilet bowl to the top. It’s worryingly close to over flowing everytime. The other night someone flushed when the tank was full and it over flowed running under the back bunk bed and dripping out the back of the trailer
. I checked and don’t have the pamphlet for the toilet (Dometic).
You hear the bowl draining when it filled itself to the top. It drains slowly down to where it should be the level it’s at.
I don’t know what else to try.