Our 43' rig has the 375D, essentially the same unit except for the fuel. We had problems right out of the box that the dealer was not successful in repairing. Eventually an Aqua Hot rep got his hands on it and it has worked since. The electric element is more than needed this time of year, just to maintain hot water for showers and other needs. We used the diesel heater over a 4 day dry camping trip a couple weeks ago and it seemed to cycle very infrequently while keeping us supplied with all the hot water we needed. It's our first rig with hydronic heating and we really like the 'furnace' function too (once it was working). Much quieter than any of the LP furnaces we ever had. There too, if the temps are only in the 50s, the electric element may be enough for both heat and hot water. The only thing the 375 does not have that I'd like is the engine loop. The 475 model will use engine heat to get the boiler up to initial temp, or in reverse, to pre-heat a cold engine.
Something I'd be interested in, if contemplating an LP unit, is how much LP is it likely to use under the conditions I'd typically be using it? I always considered having to find an LP outlet that I could get the motor home into a big PITA. For us its now one stop for fuel and all systems are go.
Jay & Peggy Monroe with Dolly
Can't take it with you - don't plan on leaving any behind
2016 Newmar London Aire 4553, Spartan chassis
Wrangler Unlimited toad