KC, anticipating possible winter forays to the coast I’ve often left the rig unwinterized, and just went out and set the living room thermostat at 40, and turned on the HydroHot when daytime temps stayed below 32. As others note, mild nighttime dips are normally acceptable as long as they linger above freezing during the day. It’s when you’re below freezing round the clock that jeopardy emerges, because then cold has time to penetrate the coach interior and bays.
The waste tank bay has its own 40 degree thermostat that automatically turns its ceiling mounted heat exchanger on if 12v is not off at the battery mains and the HydroHot is on. Heat in there reaches the water pump and the adjoining bay. The HydroHot is likely in the water tank bay like ours, and via radiant heat will protect any water in that tank. Of course, the HydroHot having at least electric on necessarily protects itself, which is your primary goal. The fridge’s icemaker solenoid should have heat tape around it that also comes on at around 40 as long as the coach’s batteries are switched on.
Joel
