Air Microphor Down the Road Odor

[rrueckwald]

It seems a common problem with the Microphor air toilet is odor in the back of the bus when going down the road, unless you have dumped prior to departure. Theories abound about differential pressure, leaking flaps, venturis, etc., etc.

Having this problem I looked hard when replacing the floor and discovered the problem in at least our bus. On the back of the toilet hopper there are two valves, one the air inlet valve with a poppet, and one pressure/vacuum release valve. (Bingo!) I slipped plastic tubing over both and hose clamped them, and then ran them through a hole in the floor inside the conduit box down to the water/dump bay. Actually I teed them but separate lines work if you have room.

Many trips with half full black tank have proven this was the cause; no more odor when going down the road. It took two years of nasty odor to find this. Hope it helps y'all who have these toilets.

Attached are two pictures, one before, and one after adding the tubing.