David the Aqua Hot system has nothing to do with floor heat. That is an electric grid installed under the tile by Fleetwood. It is all electric and you must be on 50A service to properly utilize it. The two switches you mention in the baths are for the heater registers in those areas. 

Louis,  go to the Members area,  In the education tab, you will find the Aqua-Hot presentation with phone numbers and helpful info.   Between the two, you should be able to get the right answer for you.

Hi David,

According to the Aqua Hot 400 series manual, the Aqua Hot Diesel is the primary source of heat, with the Aqua Hot Electric being secondary.  (Fleetwood Manual says Aqua Hot Diesel burns about 1/3 gallon of diesel fuel per hour.)  There are numerous uses of Aqua Hot heat, including: hot water, front and rear heaters, sub-floor heaters to prevent water lines from freezing, and your front and rear floor heaters.  Depending upon the outside temperatures, the number of uses you have selected, and the thermostat temperatures you've set ALL determine the hot water "draw" needed.  The more "draw" being used (meaning the more things turned on), the more power needed by the Aqua Hot -- both Aqua Hot Diesel and Aqua Hot Electric.  The Aqua Hot Manual also states you will need the Diesel below 50 degrees.  

To save diesel fuel, from experience I've found that for my wife and I, above 50 degrees, we can get by solely with Aqua Hot Electric as long as we manage how many uses we have going at any one time. For example, we turn off other uses to fully heat up the water for showers.Upon hitting the low 40's you will need to turn on the Aqua Hot Diesel to heat up the shower water and for floor heat if the Aqua Hot heaters are turned on.  Below 40 degrees, you will definitely need the Aqua Hot Diesel, and of course, it becomes very important as you get close to the the freezing temperatures.

Hope that helps?