Questions about Proheat and pumps/zones

[gumpy]

Is anyone using a extra pump and the engine to provide heat while cruising down the road?  I would use a flat plate exchanger to get heat to/from the engine.  Would I need an 8 GPM pump like the Proheat already has?

I have a separate pump on my engine preheat line. It's only used when I'm actually heating the engine. When the engine is running, the engine pump pushes water through this pump and heats the Aquahot reservoir so I have hot domestic water when I stop for the day.

The heat exchanger will not provide enough heat for use in heating the bus while going down the road. You'll have to run the proheat unit.