Originally Posted by Mike9224
You might find this hard to believe, I have owned my 2015 Georgetown 378xl since 2016 and due to a blocked tank problem, I found out after paying 350.00 dollars that my gray and black tanks are plumbed backwards! Gray handled valve plumbed to black tank with small piping and black handled valve plumbed to gray tank with large piping! Where do I go from here? Major plumbing and tank costs!
That is pretty hard to believe. Someone would have to be extremely incompetent to do that. Did the people who diagnosed the problem offer to do the repairs for you and at what cost?
You need to verify this before you take any action. Tank colors don't necessarily indicate their function and handles can be inadvertently reversed.
Buy a clear attachment as advised and find out if the handles are reversed by emptying and filling tanks. https://smile.amazon.com/Camco-39572...s%2C207&sr=8-1
I'm curious how they determined which plumbing is attached to which pipe and if you can determine that yourself by feeling the water running through the pipes.
Many things cause blockages. If your handles were reversed and you kept the grey (actually black) water valve open when camping, that would be one cause. You probably know the other causes - not using enough water, keeping the valve open when camping, not flushing occasionally, not using black water treatment.....
Let us know what you find (You might want a second opinion before you invest in expensive repairs.) But I agree with NXR, if this is the first problem in 4 years, $350 isn't unusual to unblock the tank and lots of people have had blocked tanks.