[Jay & Bobbie]

As a general rule, tankless water heaters activate on water flow.
I have always suggested to customers, set the temp at, or near, the comfort level for showering. That way you get near full flow (from the hot side) without tempering too much.
I believe tempering can reduce the flow through the water heater and therefore, possibly cause the water heater burner to shut down intermittently.
That has been my experience in the residential style tankless water heaters.
I would assume rv tankless water heaters operate with flow sensors, in the same manner.