Are you sure the coach has a bypass system?
Locate the water heater.
Follow the hot and cold water lines connected to the back of the unit. Cold on the bottom, hot on top. If you have the old system with three valves. There will be one valve in the cold water line; one valve in the hot water line; and one valve in a line connecting the cold and hot water lines together. The latter is the bypass line and valve.
To bypass the water heater you would close the cold and hot water line valves and open the bypass valve. Don't forget to drain the water heater.
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