I get asked often what do I consider to be the my best “RV hack” that I have done to the coach. That would have to be the “Auto On” of the Aqua-Hot burner, but only when taking a shower, using a flow switch!
The idea here is we know we will need more hot water than the electric heating element can provide for showers, especially in the colder months, so this will be sure the burner is ON for us when taking a shower. If the burner is OFF, the diesel burner will not fire and we will run out of hot water quickly as electric element can’t cut it with the delta swing. (The temperature differential between the ground water in the amount of heat you need.)
So I accomplished this by using a flow switch. A flow switch is a device that detects fluid movement, in this case water, and activate the switch. It then deactivates the switch when the water stops moving. So in this case, the switch is being used to activate the diesel burner option of the Aqua-Hot as if the Burner Switch was turned ON.
You see, even in cooler weather, like it has been here in Texas, if the burner is on, we will hear it fire up now and again even though you would think the electric would be able to keep up with the needs. However as soon as you use any hot water at the sink for a short period of time, it will fire the burner when it really does not need to thus wasting fuel throughout the day.
This is not hard, but does require you to CUT the water line. As such, leeks can happen. You also need to be sure to adjust the switch so it turns on even with a slow flow as the hot water in the shower is usually not used at a high flow rate. Don’t attempt unless you understand what is involved and how it works! Most flow sensors can be adjusted for flow speed by sliding the magnetic switch forward or back on the housing.
Hope this makes sense as why we love this hack I came up with. The below video talks about how I did it.
Here is a list of different Flow Switches that may fit your need if you should choose to do this: Amazon Flow Switch Search