By Jack Bradshaw – Reprinted from Summer 2006 – 2007 Motorcader
I hope everybody has been traveling a lot and enjoying their FORETRAVEL motorcoach. As we travel this great country with many of you, attending rallies, a lot of questions come up about what routine maintenance should be done and the type of antifreeze to use in your Aqua/ Hydro-Hot system. I will try to explain the difference between what the older models used and what the newer ones use now.
To keep the Aqua/Hydro-Hot running smoothly, it is ideal to have the Diesel-Burner tuned-up annually. A tune-up consists of a new fuel nozzle and fuel filter, along with a thorough cleaning of the combustion chamber. To ensure maximum diesel-burner performance, always use the recommended fuel filter (i.e. 10 microns) when replacing these parts.
NOTE: Be sure to use care when handling the fuel nozzle. Oils and/or small dust or dirt particles from your hands may plug the nozzle’s small orifice. A partially plugged orifice will restrict fuel flow, which will affect the combustion process of the diesel-burner (i.e. excessive smoking).
Most of you probably have dry camped on many occasions. One important thing to remember is the DC voltage from your batteries. The operating voltage for the Aqua/HydroHot system is between 11.5 and 14.0 volts. If your battery voltage gets below this voltage, the Aqua/Hydro-Hot system’s blower fan will slow down. This slow down causes the air and fuel mixture to be incorrectly atomized and carbon starts to build-up inside the combustion chamber. This build-up will cause the photo eye to malfunction and the combustion chamber will get hot and meltdown causing more build-up of carbon. As you can guess the snowball effect starts to happen and other things start to fail. This is when it starts to get expensive. So be sure to pay particular attention to your battery voltage or remember to manage your system during the time of dry camping.
One important question that is being asked is what type of antifreeze to use? Prior to the 2003-year model the antifreeze used was the same as what was used in your engine, Texaco extended life 50/50. After that, another type was used due to how the system was built. In the older units, the heating coils were wrapped around the outside tank. Now the coils are wrapped inside the tank, submerged in the coolant. Due to the coils being inside the tank and in case of a leak, a non-toxic antifreeze is used. The new Aqua/Hydro-Hot utilizes an FDA approved GRAS Propylene Glycol (P.G.) antifreeze and water solution. The P.G. based heating solution utilizes boiler type antifreeze, which is Generally Recognized as Safe (“GRAS”) by the FDA. A 50/50 heating solution of P.G. antifreeze and water is recommended to provide the best overall domestic hot water and interior heating performance (50% P.G. antifreeze and 50% water). For those who have the Hydro-Hot system, the proper antifreeze to water mixture should be 50% antifreeze and 50% water as well. A high concentration of antifreeze will cause poor domestic hot water performance.
Both of these types of antifreeze are pink in color. To know what type to use, look for the decal on the overflow bottle for the Aqua/Hydro system you have. This decal will say what type of antifreeze to use.
While traveling with all of you I have been asked many questions about the Aqua-Hot system. I’ll try to answer some of them for you.
1. Can I leave my Aqua-Hot system while traveling down the road?
Yes. The system was designed to operate and keep your coach warm while traveling.
2. What does the engine heat switch do?
This switch activates a circulation pump on the Aqua-Hot unit to heat the engine coolant. Circulating the engine’s coolant through the Engine Preheat System will adequately warm the engine for easy start-ups on those cold mornings.
3. What does the diesel switch do?
This switch turns on the diesel burner which is the main heating source for providing heat to the interior, the domestic hot water, and the engine aide system. This system will provide 50,000 BTUs for all your needs continuously. You should allow 10-20 minutes for the Aqua-Hot system to reach operating temperature.
4. What does my 120-volt switch do?
The VAC electric heating element is wired directly into your motorhome’s 120 VAC electrical system and is operational whenever VAC power is available. This switch turns on a 1650 watt 120-volt heating element in the Aqua-Hot tank that will adequately provide all your heating needs ONLY for low heating demand situations, such as when moderate ambient temperatures exist and/or when there is a low demand for domestic hot water. It is thermostatically controlled and you should allow 1-2 hours for the electric system to reach operating temperature. The electric heating element only provides 5600 BTUs, so don’t expect the AC element to heat your coach and provide domestic hot water anywhere close to what the diesel burner will do.
5. How much fuel does the Aqua-Hot unit consume?
Fuel consumption will vary according to thermostat settings, outside temperatures, and hot water usage. The best way to answer this question is to tell you the maximum amount of fuel the unit will consume if operating correctly. If the Aqua-Hot unit burner runs continuously for one hour without shutting off, it will burn four pints of fuel. Remember, this is the maximum amount. The more the burner cycles off, the less fuel it uses.
6. Can I use the 120 volts and diesel burners together?
Yes. As stated in question 3, the 120 VAC heating element will only maintain the heat and will not respond to high demands of heat and hot water as fast as the diesel burner. When both switches are on and the water temperature gets low, the diesel burner will turn on to meet the higher demand for hot water. This is a good way to conserve diesel fuel.
7. How often should you service the system?
It is ideal to have your Aqua-Hot tuned up yearly. A tune-up should consist of a fuel nozzle and fuel filter replacement and thorough cleaning of the combustion chamber, if necessary. This simple tune-up will keep your Aqua-Hot running smoothly throughout the year. It will also allow service personnel to inspect for wear and tear of other components.
I hope this clarifies some of the questions about your Aqua-Hot system.