You might want to open the taps in your unit while draining the fresh water tank. This allows the lines to breathe and removes a possible vacuum situation.
The only vent for the FW tank is the FW tank vent. The taps are isolated from the FW tank. The limiting factor draining the FW tank is the drain line size. Without accessing the tank and replacing the drain tube not much you can do.
Wouldn't the check valve in the pump prevent this?
You can also open the fresh water fill cap to help it drain faster.
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Mike and Yvonne
and Sophie, the little white dog
2017 Columbus 320RSC
2021 Chevy Silverado 3500HD DRW 4X4 Duramax “It's not how old you are, it's how you are old.” ― Jules Renard "It's not the years...it's the mileage." - Indiana Jones
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