Grey Tank Drain
OK, folks....when we are parked for any length of time I leave the gray tank valve open and the black tank valve closed until it needs to be dumped, just like a lot of people do. Close the gray to fill when it's getting close to time to dump black so as to have a flush for the hose.
Since about last February every so often the gray tank will fill even though the valve is wide open. It let's us know when the shower starts filling! Yuck! (can't rely on sensors) I was thinking the tank may have some sort of construction debris in it that causes a blockage but also have noticed a "burp" just before it begins to drain. When the gray has stopped up I usually need to dump the black, then refill the black with fresh water, close the exterior valve I installed on the sewer outlet, open the gray valve then open the black valve to "backflush" the gray and then the gray will break loose and drain. But before I open the exterior valve I hear that "burp". It also seems to happen when we have used the washer/dryer for a couple of loads. But not always.
Could it be that the gray tank in not vented properly? Or a vacuum breaker isn't working. How the heck to you test that???
2011 Georgetown 378TS in FireMist
2013 Jeep Wrangler Toad
Kirby the Old Dog, passed but still in our hearts
Max E. Dog, the new pup
Eureka the Old Cat, still hangin' on