RV Doctor Column RV Doctor #305 Dear RV Doctor, my Atwood Water Heater recently became difficult to light when attempting to use it in the gas mode. When finally lit, the flame was a very soft, yellow flame instead of the blue, intense flame that one is used to seeing. The soft, yellow flame also produced a great deal of soot that blackened the access door slightly. (Naturally, I turned the gas off before any damage was done.) I'm wondering if I simply need to clean the controller, and how one goes about doing that. Maybe I have another problem I need to look for. Thanks for your help. I was glad to find your site as a resource. David Baughman, (Colorado Springs, CO) David, though simple in design, LP water heaters do have an element of sophistication about them. As with any LP burning appliance, cleanliness is of utmost importance. Specifically, the orifice opening must be free of dirt, dust, lint, spider nests, etc. The large opening of the main burner orifice rarely becomes completely blocked, but it could become distorted by improper attempts to keep it clean. Inspect the main orifice carefully under a magnifier and be sure the opening has not been damaged by someone inserting something in the opening. I've mentioned this several times, but never stick a probe or a needle or any object into the orifice opening. Clean orifices only by soaking them in acetone or a like liquid, (be sure to use the proper precautions), and let them simply air dry. Shared by all four LP appliances, the pressure of the delivery fuel is another important consideration. It must be maintained at 11.5 inches of water column and checked often. I've long encouraged and taught RVers in my seminars to carry manometers and to check their own LP pressure, but if you feel uncomfortable doing so, let the professional technicians do it at least twice a year. Another "sticky wicket" concerning the RV water heater is the alignment of the components. The curved "U" tube must be fully encasing the orifice fitting at the leading end of the tube. Position the tube so that the center of the orifice is at the exact center of the tube. Additionally, visualize a straight line exiting out of the orifice entering the "U" tube. The "U" tube must remain on the same plane as that straight line exiting the orifice. This is crucial and often overlooked even by the pros. Keep in mind the control valve is threaded into the inner tank and the orientation of that valve will vary slightly on each water heater. Consequently, the "U" tube must be manipulated into a straight orientation in line with the orifice fitting in order to maintain the correct alignment. Just remember the orifice must be centered and the "U" tube must be aligned with that centeredness in every direction. Also, adjust the air mixture shutter to where you can hear the roar of the main flame to a maximum of about five feet away with the access door closed. The fire must remain blue in color and no sooting should be evident. Which brings us to your symptoms...... as far as the initial lighting of the burner; ensure the probes are cleaned and free of soot and carbon buildup. The gap between the ground probe and the ignitor probe should be half as much as the gap between the ground probe and the flame sense probe. Only manipulate the ground probe to achieve these differences. The soft yellow, lazy, sooty flame screams, LP pressure, "U" tube alignment, air shutter adjustment and orifice opening. Follow the above procedures and your water heater should be back to normal. Dear Gary, I have a 2002 Winnebago. I have tried to find out whether running the generator charges my starting ignition battery as well as the coach batteries. Nobody seems to be able to answer this with any convincing certainty. What is the case here? Pete Martin, (Harpers Ferry, WV) Pete, running the generator will not charge the engine start battery.....typically. The alternator is the only device that charges that particular battery in your case. And rarely does the generator itself charge any battery. What usually occurs is that the generator energizes the 120-volt AC to 12-volt DC power converter and the converter charges the auxiliary battery bank. The degree of sophistication of the converter/charger determines how effective it will be as a battery charger. Most are, quite honestly, not very effective at fully charging the batteries without the danger of overcharging. And it may take some time for attain a "full" charge. Some highly sophisticated chargers are equipped with a secondary charging circuit that can be wired to the engine start battery. So, though it is possible to charge the automotive start battery via the converter, only the top-end RVs are equipped with the computer controlled chargers with that capability. However, they are available in the aftermarket and can be adapted to any RV system. Though not inexpensive, they are, however, the state of the art and you are virtually guaranteed complete battery charging without the fear of overcharging. It is one of my recommended upgrades. Dear RV Doctor, I've got a Sportsmobile Class B with no stove built in. I'd like to keep it simple and use a Coleman two-burner propane camp stove, usually outside on a table, but maybe on a counter near the side door in inclement weather. I'm thinking of a 20-pound propane tank stored inside, also right by the door, with a hose assembly long enough to reach either location. Would this arrangement be safe and is there anything I need to be aware of as far as storing the gas bottle and using the stove in the RV? There is a carbon monoxide detector in the unit. Peter Korb, (Folly Beach, SC) Peter, under no circumstances would I recommend using a Coleman camp stove inside an RV. Though the typical RV range is the only LP burning appliance that does not require venting through to the exterior, it is however, secured to the cabinetry quite solidly. The Coleman two-burner could easily be knocked off the counter or otherwise dislodged while operating. Additionally, LP cylinders must be located and secured in a separate vented compartment, sealed completely from the interior of the RV. Special fittings are required for the LP hose to pass through the walls of the container. To do this in the correct manner, I would recommend a small, horizontal ASME container bolted to the frame and plumbed according to the codes and standards of today. A properly routed LP line can then terminate at a fixed two-burner stove that is secured to an inside cabinet. That section of the cabinet can be modified in such a way using quick release fittings that would make it portable and able to be moved outdoors. A separate LP line can then be attached to the horizontal LP container to operate the stove while outside on a table.
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