Originally Posted by Taroni
Found a solution to the problem: Traded it in for a 2016 Flying Cloud.
Well...that's ONE way to sell a new trailer... sell a defective one and then later take it back in trade for some simple fix...
The backflow preventer is a building code requirement for hooking up to city water to flush the black tank. This is because code-writers believe you are likely to leave your hose hooked up and the valves open and let a germ climb backwards into the city water supply. NOT LIKELY to happen!
Since I only hook up to my own private well...and/or a campground supply...with a dedicated garden hose.... and since I only do so to pressurize the flush system and never leave that hose connected unpressurized....it's NEVER GONNA HAPPEN that a backflow preventer would prevent anything except the flush-system's proper operation.
So... after I found the insect nest in the backflow preventer that blocked the flush system from working... I removed it and replaced it with a "shark-bite" elbow, which was a very simple matter: Cut the PEX tubing, insert the "shark-bite" elbow... and FLUSH anytime/everytime with no problems.