Black Tank Flush Leak on 2010 355QBQ Check Valve

[BamaAF]

Check Valve Location - I have two black tanks in a 2010 Sierra 355QBQ - tank 1 rinse caused water to be noticed on floor next to master bedroom steps. After getting home I made calls to FR, and to the service dept where I purchased - niether knew where the valves were - was hoping would be under sink as previously posted, but no luck. After taking out panels in pass through bay, slicing a peep hole in my underbelly, taking my shower faucet handles off I was stumped. I decided to check behind my entertainment center in my living area (knowing the valves have to be installed higher than toilet) - there was a hole in wall about size of fist for wires to come into the back of the entertainment center. I put my hand down inside the hole and felt what seemed like pex and valves (yes two). I hooked up waterhose to flush 1 and let her rip - sure enough water started coming out - not dripping but a forceful stream. With no hole, I took off a cabinet door beneath entertainment center and removed panel holding an electrical plug - I then cut a square hole in paneling and replaced valves and then screwed a piece of paneling that I can get to in the future.

[ependydad]

Thanks for sharing. I’ve looked for my valve on my Sabre and can’t find it. I’ll check in the same ballpark area.

[BamaAF]

After more thought I bypassed the valves - I will just remember to dump/flush at 3/4 instead of full - not sure it would matter, but just in case, I will dump prior to tank reaching the flush jets - and I will use a flow back prevention on outside of trailer when flushing. What I did was got a 90 degree elbow that was a half inch slip on one end and a half inch thread on the other end - a strait converter that was half inch slip on one end and half inch thread on other end ---- then I cut one and a half inches of 2 inch pvc and glued all together -- this gave me the angle/direction I needed to screw the home made bypass pvc into the existing pex (where I removed the port) -- I had to do twice since I have two tanks. If this causes any issues as far as draining or whatever I will put the valves back in-line. This will hopefully prevent future malfunctions and leaks inside my wall.