Originally Posted by JFM-jr
If the tanks are visible the black tank will have the larger diameter main drain coming off the tank itself.
Yea, I found that out just the other day working on the camper. The 3 inch dump valve is on the black tank only. Looks like a 1 1/2 inch or 2 inch valve on the gray tank.
They both dump into the same dump mast; but are not plumbed for the gray to go into the black tank.
Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW