Basically it doesn't make any difference to the instant water heater whether your on city water or the internal pump. The prime consideration is setting the temp control right. While it seems logical to think of setting at a medium to high level so you have hot water that doesn't apply here. Took me long enough and plenty of advice from this forum to grasp the notion that the instant water heater heats the water to a certain level, period! In other words the temp control is not affecting the temp of the hot water, it tells the water heater the temp of the water entering the heater. Cold incoming water means set the knob in the middle, icy incoming means set the knob at the high end. Realistically, most people are going to have cool incoming water and should set that knob at the low end. If the shower is too cold, turn the knob up, but just a little. The system is touchy and it is a trick to master it. All these problems would have been avoided if the owners manual for the water heater, the coach itself and the dealer reps doing the initial walk thru explained the system fully. There is no excuse for the superficial coverage in the manuals. Frankly I don't the the dealer's people understood the system any better than the customers. I don't blame the dealers for that.
2014 Greyhawk 31FS/2013 Chevy Captiva Sport