RV Doctor Column RV Doctor #329 Dear RV Doc, how do you test an RV converter? We are installing a satellite dome system on our motorhome and we are getting "dirty power" which keeps blowing out some of the sensitive electronic components. Thomas Hoffer, (New Stanton, PA) Thomas, when troubleshooting any typical RV power converter, here are five basic preliminary steps to first take into consideration: (1) Verify the proper incoming AC voltage. Be sure the incoming voltage falls between 103 volts AC 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 miswired. (3) Eliminate the battery as the culprit. Because of their 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 traced to loose wires and connections. It is a common occurrence because of the jostling most motorhomes 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. Thirdly, 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 of the converter without the battery in the system The output voltage with the battery connected Should you need to call a service facility or seek advice, 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, albeit, not inexpensively in most cases. All converter manufacturers have a service and repair facility in-house or one that they can recommend to perform internal converter repairs. Contact your converter manufacturer for the details of their service policy. 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. Dear Gary, I have an older American Appliance water heater on my 1985 coach. The burner won't shut off and the pressure/temperature safety valve then does its thing, but it doesn't just "weep," it goes hysterical. Water jets out of the valve as fast as the city water is coming in. I have reviewed all your columns on-line but haven't seen another problem like this. Help! Jim Schrankel, (Olympia, WA) Jim, as long as your incoming water pressure is not abnormally high, it could be something as simple as a faulty P&T relief valve. But if your pilot-type water heater is not properly shutting off the main LP burner when the temperature of the water has reached the limit of the control valve thermostat, then that safety valve is operating properly. If you manually shut down the water heater does the P&T valve finally snap shut at some point? If so, than most likely the integral thermostat itself is faulty as well as possibly the ECO (energy cut-off) device encased inside the very tip of the sensor; that portion immersed in the water. There were two types of ECOs used in those older pilot model RV water heaters; one was a bi-metal thermal switch of sorts (pictured) that should eventually reset itself once the water temperature cools. The other type was electronic by design and will not reset. It's a one-time safety and once it's tripped, there is no way to regain continuity through the device. Chances are the whole control assembly will have to be replaced if the ECO is the culprit. As old as that water heater apparently is, however, I would consider replacing the entire unit and obtaining a new warranty, etc. The newer models are much more efficient and offer the best in the latest technology. You certainly would not want to invest in a costly repair only to have the inner tank rupture in the coming months. I'd vote for a new unit if it is the main control valve at fault. Dear RV Doctor, how do you care for a rubber roof? Chuck Hamilton, (Cocoa, FL) Chuck, my first response would be "with compassion," but after thoughtful repose I offer this: By nature, EPDM rubber requires no protection from UV rays or ozone bombardment, though it is prone to oxidize. Normal oxidation is a condition due to the disintegration of surface binders or elastomers simply by weathering. Other destructive environmental conditions can also add to the degree of chalking. The result is that surface chalking actually removes a portion of the rubber. This is a normal occurrence and you should not be concerned about the direct effect on the rubber itself. Oxidation will, however, usually manifest itself as long, unsightly streaks running down the sides of the RV. The streaks are usually caused by dirt, road grime and air-borne pollutants that settle and adhere to the roof and are washed over the side along with the loosened powdery surface elastomer. The simple solution is to keep the roof clean. The degree of chalking associated with EPDM may vary from coach to coach. And according to the makers, tighter controls during the copolymerizing procedure leads to a slower rate of oxidation though most will surrender up to 10% of the overall thickness during the life of the roof. But that's for the manufacturers to worry about. Cleaning your rubber roof should be a regularly scheduled maintenance task performed often enough to keep the EPDM surface white. Usually four to six times per year will suffice depending on your climate and its propensity to gather and distribute dirt, and how pure the copolymerizing process was performed during manufacture. Dear RV Doc, can ceramic tile be installed in a motorhome? If so, what type of flooring is best to put down? Clark Ward, (Knippa, TX) Clark, yes indeed, ceramic tile can be successfully set onto a motorhome floor. Proper preparation is the key. The surface must be leveled and all seams in the underlayment must be smooth with even transitions between them. Most every home builders supply center, such as Lowe's or Home Depot, will have all the necessary preparation materials you'll need. 5/8 or 3/4-inch plywood works very well as an underlayment. It seems motorhomes built on the larger chassis' fair better with tile since the upper flooring is somewhat stiffer than those of a standard Class A design. There have been some evidence of cracking in the grouted joints with smaller RVs which tend to flex more, but with the proper materials and workmanship, ceramic tiles add much to the individuality of your RV. Marginal weight restrictions may have to be considered on those RVs approaching their limit. You might have to do some math first.
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