I've purchased a 2015 montana 350qbq. We are living in it full time while we build our house. I noticed the rear valves for the grey/black water are not labeled. Anyone know which is which? It my first time dumping the rear tank and only need to drain the grey water
From your floor plan, you probably have a grey and a black control valve in the convenience center. Those are for the black (toilet), and grey, (shower and bath sink). The rear valve should be for the galley (kitchen grey tank). So, to drain the bath grey, pull the valve labelled grey in the convenience center.
Bob & Becky
2012 Chevy 2500HD D/A CC 4WD
Stated problem was no labels. To eliminate any guessing (if the dealer cannot answer your question) take a hose, fill your black tank thru the toilet. Pull a valve and if the toilet does not dump, that valve is your gray. FYI, our 3915 has two grays, two blacks, the left hand pulls are the black tanks.
Mike and Lorraine
2002 3655 FL, 2005 3650RK
2010 3665RE, 2015 3910FB
F350 crew cab dually 6.7