Must Tanks Be Empty to Replace a 2011 Roadtrek 210 Versatile Macerator?

[teslasmuse]

My rv mechanic is worried he will get covered in urine and grey water when he removes the bad pump, but won't the gate valves stop that? I took it to a portable toilet place and they want 30 bucks to empty the 10 gallon black water through the toilet hole but their hose is 2 inches so he was going to try to brainstorm figuring out a smaller hose to get into the grey water through one of the sinks or the shower, but are we over thinking this? He also accidentally broke off this other gate valve handle claiming it's seized, but I'm not sure what the lower handle opens.

 

[TX-Trek]

IMO overthinking the tank drainage.
I just changed out the macerator on our 210P. Theoretically the gray/black water valves "should" stop any flow but in my case they didn't. Next maintenance will include valve replacement.

You have 2 gate valve handles, one for sinks (gray), one for toilet (black). They both open the valves at the Valterra union that outlets to the macerator.

Suggest replacing the rubber 1.5" cooling that attaches the macerator to the union at the same time. Usually comes with new SS clamps and it's not expensive.

I carefully used a heat gun on the macerator outlet 1" hose to remove it, not a big deal. But stay clear and have a basin, "stuff" will come out. Not the end of the world. I did flush out tanks as much as possible before removing the macerator, but the valves weren't sealing 100%, thus the catch basin. Plus protective eyewear, gloves and a garden hose handy.

Side note, I have a 1" elbow with a clear section that I connect to the end of the macerator hose to so I can monitor black and gray water flow. Better for the pump to not run it dry.

I also added a fresh ground point for the new pump as well as a connector for the power feed. Be sure any connectors are rated for 25 amps. Avoids cutting wires next time (if there is a next time ).

 

[teslasmuse]

I think my valves probably don't close and seal properly, either, so I was thinking about getting an aquarium transfer pump to empty the tanks since there aren't any solids and try to get them as empty as possible, the aquarium hose should be small enough to snake down one of the sinks or shower, will report back in a few days

 

[teslasmuse]

Including the water system schematic here for posterity