オリジナル投稿者： alsuchy ,
There are not one but two “flow check valves” in my ldf6920st. One in the top of u shaped plastic tube with black hose attached. It lets a small amount of air into the pipe and will air break the hose to try to stop siphoning. Another is a one way flapper type in the “drain line “ going to disposal or sink drain. This also will try to prevent back flow. It closes shut from the sink to the pump, it’s open from the pump to the sink. These two checks “should work together to prevent water from going back into the sump. Obviously inadequate and they knew it, since installation instructions say to have airgap or high loop to do the same thing. blowing compressed air from the sink side to the pump WILL damage the flapper and possibly push it into the pump. Just a piece of rubber waiting to plug something up. IMO it would work just fine without it in there. I got into mine because the hose failed and destroyed my oak floor. That hose is junk! Nowhere in the owners manual does it say to replace the hose as part of a maintenance plan. But if you dig around enough you can find where lg does say it to the tech. i hope mine works again and the water goes where it supposed to, the squealing stops, the sump drains, and dishes are clean after I removed three pieces of plastic from various places inside. All of which came from it but I have no idea where. Possibly there from day one out of assembly plant. A check valve on drain pump was broken and jammed the pump. Plastic pieces plugging drain lines. Shaft seal leaking. no food at all plugging up any thing, it was very clean inside. Al in all I highly recommend a Bosh or Kitchen Aid or something other than LG. NEVER AGAIN FOR ME. washing by hand always works and doesn’t need a tech.