No, you don't bypass the hydronic unit. As you found out it's too expensive to replace the exchanger if a little water in it doesn't get blown out. I was doing the blow out thing for 25 years on different RVs, but on the hydronic one I just made sure the unit never got cold enough to freeze, usually by leaving it running at 40-45 degrees during cold snaps, or using an electric heater.
But the risk of unit failure, or power outage, causing temps to decline without my knowledge was too high, so last winter I used antifreeze instead. With the pump kit already factory installed, it was easier than I expected, and took two or three jugs. Your coach is longer than mine, so hose runs may require more pink stuff than mine did; you might pick up 4 gallons, but others with your model coach may provide a different recommendation.
I don't think I pumped to the washer, as the mfr's manual indicated just putting cups of antifreeze in the drum and cycling once is all that's needed as I recall - check your Splendide manual. They must deem draining the washer ports at the coach's plumbing manifold adequate.
Make sure antifreeze makes it all the way through the ice maker lines. Ours made it through several freezing weather episodes with just a blow out and a draining by disconnecting in and out tubes at the solenoid, and the solenoid has heat tape so it can't crack. But the tubes are clumsy and tricky to annually deal with, so cycling the ice maker while pumping antifreeze is a better idea. Then flush it thoroughly next spring so cubes are fresh.
But you allude to a Hurricane unit, which others here are more familiar with than I (we have a HydroHot), and you talk about a hot water tank. I'll leave it to someone else on that one - if your Hurricane only heats the coach, I'm not sure why there'd be water in it to worry about; nevertheless, you say your exchanger needed replacing. ?
Joel
