An AquaHot is an appliance in the basement of the motorhome that makes coach heat and hot water. There are many different versions and capacities of these. In our coach it is an electric and diesel fired boiler that heats antifreeze just like you have in your car. This hot antifreeze can be circulated through any of the seven heat exchanger/fans in the coach and the basement of the coach in four separately thermostatically controlled zones and another zone that circulates heated antifreeze through the engine to pre-heat it to make it easier to start when it is really cold out. It also heats 16 gallons of water and will supply continuous hot water no matter how much or how fast you use it.
There are lots of hoses coming out of the top pumps and back into the side where the red plugs are. The cover over the left end has been removed. A bunch of wires too.
If you are driving, the engine circulates hot coolant through the AquaHot providing coach heat and hot water. You can run the diesel part of the boiler at any time for more and faster heat. If you are plugged in you can run the electric side of the boiler for hot water and heat. For us that is down to about 40 degrees.
It is a pretty amazing appliance but like anything it needs maintenance. If you use it properly you can go for several years between “annual” service. This usually consists of replacing the diesel fuel filter, the nozzle that sprays the fuel into the burner chamber, cleaning out the burner chamber and the flame sensor and setting the gap on the spark starter. This is something you can do yourself or get someone else to do it. We have done it both ways.
Other than normal service we have had to replace the fuel pump (a factory recall sort of thing) and the ignition coil that makes the spark and a plastic clutch between the motor and the burner blower. Not much considering it is on almost all of the time and is 17 years old.