RV Doctor Column RV Doctor #303 Dear RV Doctor, how do you test a RV power converter? We are installing a satellite dome, and we are getting "dirty power" which is blowing some of the components out. Any advice? Thomas Hoffer, (New Stanton, PA) Thomas, when troubleshooting any power converter, there are five basic preliminary steps: (1) Verify the proper incoming AC voltage - Be sure the incoming voltage falls between 103 and 130 volts AC. High and low voltage can have a damaging effect, not only on the converter, but other AC components as well. (2) Verify the correct polarity - Reversed polarity or an open hot or neutral wire somewhere in the 120-volt supply system can indeed be harmful to the converter. Always check the polarity and test the GFCI each time you enter a new campground. If it is not correct move to a new site or simply do not plug in the shoreline. Likewise, check the polarity of the DC conductors from the battery. Some components may be damaged if the battery is mis-wired. (3) Eliminate the battery as the culprit - Because of the close association, many times the converter is blamed for battery or other DC system-caused problems. (4) Make sure all electrical connections are clean, dry and tight - Many electrical problems are associated with loose wires and connections. It is a common occurrence because of the jostling most RVs endure during their lifetimes. (5) Analyze the symptoms closely and carefully - Take notes as you go through the process of checking. Follow a systematic approach by first considering the DC system in general. Next, look at the problem area in specifics. Then, consider the components in the sequence. And finally, accurately measure and record the following voltages: * The incoming AC line voltage * The battery voltage in an open circuit test * The output voltage with the converter without the battery in the system * The output voltage with the battery connected Should you need to call a service facility, having the above voltage information handy will provide a starting point to begin troubleshooting. Due to the level of sophistication in today's power converters, if a problem proves to be interior to the converter, it is recommended that the converter be shipped off for repair. Some well-trained RV service facilities may offer internal converter repairs as a service, but most are probably not fully equipped to handle all possible scenarios. Many components are not field repairable, yet they can be repaired or replaced relatively inexpensively. (Some do have module boards that are easily replaced if necessary.) For aftermarket repairs, I recommend Master Techs. If your converter has out-lived its manufacturer (it does happen), contact Master Tech at 800-848-0558. This company is positioned to troubleshoot and repair virtually any RV converter. Further, the National Electrical Code for RVs mandates that power converters be UL listed for use in a recreation vehicle. It is not permissible to permanently install a battery charger instead of a converter, for instance. Thermal overload (high temperature cut-off) protection is required on all power converters, not so for simple battery chargers. All that said, it may be necessary for the health of some sensitive equipment to install a quality electrical filter to remove damaging spikes or surges in the DC output. Also, consider most RV converters are simply not the cleanest DC power supplies. Perhaps a cleaner 12-volt power supply is better suited for your dome. Dear Gary, I have an early 90's Atwood/Wedgewood range/oven that will not fire up. It appears to have no gas going to it since I have turned the burners and oven on and never smell gas. There is no air blowing through the line because the match never blows out either. I looked for a hidden gas valve, but none was found. Is this a regulator problem or is something plugged up? I just bought this RV and maybe it NEVER worked? Julie Brown, (Boise, ID) Julie, indeed something is amiss and I kinda hate to ask this....but are you sure there is fuel in the container? Also, are you aware if the RV is equipped with an LP leak detector that employs an automatic shut-off solenoid valve? The solenoid valve will be positioned at or near the service valve at the LP container. If you have fuel and you see no shut off valve near the container or under the stove top, then the LP line must be kinked or disconnected somewhere further back in the delivery system; if indeed LP is flowing at all. Try this; be sure the LP container valve is open and light another appliance such as the refrigerator. If you cannot light any appliance, then I would suspect either the container valve is stuck closed or the main LP regulator positioned at the container is faulty. But if the refrigerator ignites and remains lit for say, thirty minutes, one can safely assume that LP is at least getting into the system. Distinguish the flame at the refrigerator before proceeding to the next step. Next, at the stove, saturate the flare nut fitting where the gas line attaches to the manifold with a soapy solution, (be sure to avoid soaps or detergents that contain ammonia products). Then, using two wrenches, slightly loosen the flare nut. If no bubbles materialize as this fitting is loosened, there is no fuel getting to the range. Your only recourse is to follow the copper tubing from the stove down to where it "tees" into the black iron piping. It's not improbable that that section of tubing is kinked somewhere or that it has been disconnected altogether. Be sure to inspect every turn and twist as the tubing is routed behind cabinets and through the flooring. There is the remote possibility of a blockage in the black iron piping, but I would suspect that, at the very worst, you may have to run a new length of tubing from the black iron connection up to the stove top. If all tubing and piping is in good shape, the blockage may be in the stove top manifold itself and further troubleshooting there is in order. Dear RV Doc, I own a 1986 Itasca Sunflyer on a P-30 chassis. I have been having fuel delivery problems while using the main tank. When on the aux tank the rig runs just fine, however, after switching to the main tank I experience symptoms very much like vapor lock. It will cruise fine, but when I slow down and then accelerate, it hesitates and misses. The fuel filters have been changed and so has the fuel tank selector valve. I suspect that it may have an internal electric fuel pump in the main tank that has failed, but I don't know how to test for that. Could I install an inline fuel pump on the main tank line or would I be better off installing one after the fuel selector valve, if I should install one at all? Steve Walton, (Holiday, FL) Steve, check the vapor return line from the canister to the tank. If blocked or kinked, it may act like a fuel starvation issue. Also check all the hoses for cracks. A coach that old should have had new hoses installed at some point, but you never know; you may be sucking air instead of gasoline. Also, it could be the in-tank pump, however, it is necessary to drop the tank to replace or repair that one. Adding another "pusher" pump as close to the main tank as possible may help, but I would want to eliminate everything else first.
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