No water even when pump is working or sounding like it is.

[Wazbro]

Originally Posted by aftermath

I have never heard of "back flushing" the hot water lines back into the HW tank.

I have heard of this, only on trailers without a bypass. Airstream didn't start installing the water heater bypass as standard equipment until about 15-25 or so years ago. Some had the bypass from the factory before that, not all.