Hi, Pollyanna ~
I posted the comment below in a thread started by a prospective 2013 Raven3300CK, 5th Wheel (SunnyBrook/Winnebago) owner who wanted input on any issues we have had. We have owned our rig almost a year now. This was our experience with holding tanks. Just a little more information for you to ponder…...
THE KITCHEN GRAY TANK (#1) OVERFLOWED. (The sensor for this tank is temperamental). Anyway, we were under the impression that if the tank was full, the back up would occur up through the sink. Not what happened.
After doing dishes one evening we heard water running under the 5th wheel, gushing actually. Jim ran out and pulled the holding-tank lever so the remainder of the water drained into the sewer.
When we took it in for the repair, we got this comment from the service dept:
"Connected hose to fill gray tank to find leak. Noticed a leak from behind water valve. Removed panel in pass-through storage compartment to access back of valve and found a loose inlet hose and clamp. Tightened and tested for fresh leak. All OK. Then pulled belly pan down in a couple spots and leak is on top of the tank. Searched more and found leak from pipe coming down from kitchen sink. Removed circuit breaker box and furnace cover and found the y-pipe for sink and vent just above tank is cracked. Removed section of belly pan to lower gray tank. Disconnected pipes and lowered tank. Cut off bad sections of pipe and installed new pipe and fittings."
2015 Forester MBS 24 R Motorhome