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Each waste tank should have its own drain valve. It’s been a running commentary that the tanks may be mis labeled. The only way to verify what each figure drains into is to empty everything. Then simply start running water until one of the tanks shows 1/3 full. Then shut that fixture off and start the next one.
This is the procedure I used for years doing PDI’d with multiple sinks/bathrooms and Washer/dryers.
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2012 Copper Canyon 273FWRET being towed by a 1994 Ford F350 CC,LB,Dually diesel.
Airlift 5000 bags, Prodigy brake control, 5 gauges on the pillar.Used to tow a '97 Jayco 323RKS.
Now an RVIA registered tech. Retired from Law enforcement in 2008 after 25+ yrs.
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