Thetford "Aqua Magic Style Plus" - won't do water only-fixed

Have you tried lifting the pedal?
That's how some of them work.

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ScottG wrote:
Have you tried lifting the pedal?
That's how some of them work.

Nope, this one works by depressing half-way for water to fill bowl.
Have owned the rig for 7 years now and it just started acting up last year, thought the rod was binding on the back of the toilet so shaved away a bit of the area with a utility knife to give a little more clearance and that helped. Not this year though, acting up first time using it. Greasing up the slot does not help.

Just went thru this on my Aqua Magic Style Plus,, You must take the toilet out so you can get to the back of it , I tried to lub it while still in the RV and could not make it work, after I removed the toilet I was able to lub the plastic part and the wire , Make sure you get a new rubber seal to put in the hole before to put the toilet back in the RV. Hope this works for you

I had the same issue last year. The rod wasn't sliding as designed, causing the flush valve to open as soon as the pedal was depressed at all. I pulled the toilet and replaced the water control valve that was catching the rod. Simply lubricating it may have solved the problem but since I had the part, I changed it and cleaned and lubricated the old one for a spare. While I had it out, I replaced the flush ball seal at the same time.

While the part description didn't say so, it was packaged with a new floor seal, so you may not need to order that separately. Got the part on Amazon for about $20.

Not as bad of a job as I had imagined.

OP update - fixed my problem. I think the underlying problem was caused by a failing ball valve seal. The water only vs flush issue started last season and thought I had it fixed with a little lube and some relief on the back of the toilet so the rod did not bind up.

De-winterized a week or so ago and this year the toilet would not hold water along with the issue of flushing immediately upon depressing the flush pedal. Talked to Thetford and ordered both a new ball seal and a new water control valve. Replaced both parts tonight and toilet is working like new.

I think the real issue was the ball seal. While playing with the unit to see what the problem might be, I could put just a bit of pressure on the arm that does the water flow and the operation was normal (rod slides down a slot in this lever to add water and when rod reaches the end of the slot, opens the ball valve to flush). I think the new ball valve seal added enough pressure on the ball valve that the rod slid down the slot and worked as designed. Similar to what I did with my finger on the lever arm, the extra sealing tension of the seal to the ball valve allowed the rod to go down the slot, add water as designed, and then open the ball valve when the rod reached the end of the slot. And now it holds water just fine.

So, my suggestion, if your foot flush valve is getting finicky about just adding water, first I would change the ball valve seal and lube the rod while you have it all apart. The extra tension of the new seal on the ball valve may be just enough to cause the "add water" function to return to normal.