San T Flush Question

[markcee]

The instructions included with my RV regarding the San T Flush system seem to be pretty generic in that they mention the ability of their system to flush both the black and gray tank(s). My Keystone manual doesn't provide much more definitive instruction on performing this tank flush process at all.

Question: I have a 2020 Keystone Cougar 29RLKWE. It is equipped with two gray and one black tank. I have a single San T Flush port on the side of the trailer. Does this mean I am flushing the black tank only thru this port, or is this single port plumbed to flush both black and gray?

The Swan Industries website indicates that they make systems capable of both....I just don't know if I have that option. or if there is a visual way to tell. Can I assume since I only have a single port it is black flush only?

I am coming from a Class C where my process was to dump black, dump gray and then close the gray valve, leave the black valve open and connect the hose to whatever the Winnebago nomenclature for San T Flush was, and run water thru it for a few minutes until it ran clear.

I seem to recall that my Winnebago manual was insistent on closing gray prior to running the sanitary flush on the black tank. I don't see any such warning on either the Swan documentation, or in my Keystone manual, but I'm concerned that if I have a black flush system only I may be contaminating the gray tanks by keeping the gate valves open when I flush.

Since my documentation mentions black and gray, I'm not certain if my single port flush connection is clearing out both tanks, in which case I assume I should leave all gate valves open or if I should continue with the process I used on our Class C of closing gray prior to flushing black.

I have tried to contact Swan Industries to help determine what system of theirs I have, but of course I receive their voicemail and get no call back.

Any procedural suggestions will be gratefully received!