Build your own Water Heater / Furnace Unit?
I know there are newer campers that have combined water heater / furnace units but they are pricey and not necessarily an easy drop in unit. It got me to thinking that it would be an interesting exper...
Forum Discussion
JD5150 wrote:
I have worked around air to water heat exchangers most of my life. Hot air from engine exhaust blowing on a stainless or copper coil to heat water at 600 psi around 2 gallons or more a minute.
The idea you have most likely will not work. Someone mentioned that a 12 gallon RV water heater is around 12,000 btu. So lets say a 6 gallon one is 6,000 btu. By the time you use air flow/fan to blow the heat you will be down to 3,000 btu or less. The fan will cool the air some so there will be some loss of heat there from fan picking up cooler air and blowing through the radiator coil.
I just started looking at the Truma Combi eco plus. I'm still studying it to see how much juice it will take to run in electric and gas mode. I want to run it off solar and a 200 amp hour lithium battery pack plus gas if needed. It will do both at the same time
The lower BTU output actually works to my advantage in this scenario. An Atwood 8 Gallon water heater is 8,800 BTUs, an Atwood Furnace is 35,000 BTUs. I don't need 35,000 BTUs constantly, there is a cycle time involved or I will be cooked out of the camper. Having a constant 8,800 BTUs burning with a lower fan speed and lower overall heat level but over a longer running time can have the equivalent effect as a blast furnace running for shorter periods of time.
