House Calls with the RV Doctor
By Gary Bunzer
August 2006
Dear RV Doctor:
Q: I have an older (1976) RV I am trying to fix up. I would like to know whether it is advisable to use 3/8-inch copper tubing for my stove/oven instead of 1/2-inch. It would only be about 3 feet long coming from the elbow that has a 1/2-inch line going to the LP container about 10 feet away. Lastly, should I use all flared fittings instead of compression fittings on propane lines regardless of size? Any help is appreciated.
Carl Davis
Fort Worth, Texas
RV Doctor: Carl, many motorhomes today come equipped with 1/2-inch copper tubing for the branch runs of the LP distribution system, though you’ll still see some units outfitted with the smaller 3/8-inch copper lines. LP-gas piping systems are sized by the Btu demand load of that particular RV. Of course, you’ll also find black iron piping used for the main manifold, with the copper branches going to each appliance. Unless your range is a “high demand” appliance, you should be okay with a short run of 3/8-inch tubing. But use only SAE pipe fittings and flare fittings, and use no sealant of any type on flare fittings. Compression fittings are not allowed in the LP delivery system, even though you may find some utilized inside LP appliances.
Electrical Enigma Exposed
Dear RV Doctor:
I’m redoing some electrical items in my “˜94 motorhome. I checked for continuity between the neutral and ground in the alternating current system (power off and unplugged) and got nothing. Should my coach’s frame and 120-volt-AC system’s ground and neutral be tied together? Would the generator and inverter be safe in this configuration as well?
Dave Ferrin
Overland Park, Kansas
RV Doctor: Dave, a very good observation on your part. Indeed, the motorhome AC electrical system is not like that in a conventional home. In the motorhome, the neutral conductors are not grounded; the neutral and ground must be kept separate. In the panelboard distribution box, the neutral buss bar is isolated and separate from the ground buss.
The reason for keeping the ground wires separated from the neutral wires is to prevent the “skin” and chassis of the coach from becoming “hot” if the power supply cord (or campground pedestal) has reversed polarity. Only the ground circuit is connected to the frame of the motorhome. If, for example, you did measure continuity or resistance between the neutral and ground prongs on the shoreline cord, you’d need to dig further to find that interconnectivity. The rules are identical for the generator and the inverter.
Another thing altogether is electrical “bonding.” Bonding is not the same as “grounding,” however. Bonding is required for those metal components that are not part of the electrical system but could become energized, such as the chassis; a metal roof; aluminum siding; the metal casings of the inverter, convertor, and furnace; metallic water piping; and LP-gas tubing.
One For The Road
Dear RV Doctor:
I read something that indicated that the black and gray systems should not be interconnected; that is, they must each have a dedicated method of storing the waste in holding tanks and each must have its own waste termination or dump valve. Why must they? No explanation for this was provided in the article. Is this one more “Old Paradigm” that should not be propagated? I’m planning to have a single tank, called the septic tank, with one dumping valve. Why would this not work?
Randy Davidson
Magnolia, Texas
RV Doctor: Randy, a single holding tank will indeed work, per se, but you may soon find that it will need evacuating quite often, depending on the tank size. RVers tend to use more gray water than that which is flushed down the toilet. In modern coaches, the two waste systems are kept separate in order to comply with the RV Codes and Standards as applied to manufactured RVs. Individual builders, as well as private RV owners, however, can do anything they desire. In years past it was quite common to find a toilet tank only, with the gray water bypassing any container on the RV altogether. But this proved quite inconvenient. For longer excursions, a separate black and gray system is considered optimum.
Where’s The Junk?
Dear RV Doctor:
Somewhere in the USA there has to be a junkyard for motorhomes where a person could buy used parts. Stuff like a leveling unit, electric steps, antennas, etc. I know a local junkyard has one motorhome that is 30 years old. Ever heard of any?
Gary Prosser
Salida, Colorado
RV Doctor: Gary, in many cases, even after a catastrophic fire that reduces a motorhome down to the frame rails, that chassis is eventually rebuilt by someone. Still, RV junkyards do exist. Many dealers and aftermarket service centers, likewise, will salvage usable components and simply offer them for parts. This is especially true for those hard-to-find orphan parts. There is a risk and certainly no warranty when purchasing used RV components, but when strapped for funds, it does prove to be an option.
I’ve compiled a list of facilities from various sources, including the Internet, but I must caution you, I have not verified each location. Here’s what I found:
Arizona RV Salvage “” 2737 W. Lincoln, Phoenix, AZ 85009; (602) 272-0301
Bontrager’s Surplus Inc. “” 18719 E. U.S. 12, White Pigeon, MI 49099; (269) 483-7017
Brandon Auto Salvage “” 3159 State Route 60, Valrico, FL 33594; (800) 282-7462
Cherokee RV Salvage “” 7102 Raleigh St. #8, Westminster, CO 80030; (303) 295-3433
Colaw RV Salvage “” 10389 Cimmaron Road, Carthage, MO 64836; (417) 548-2125
Cooper RV Salvage “” 1300 Thornton St., Elkhart, IN 46514 (219) 293-3027
Economy RV Parts “” 1678 W. Superstition, Apache Junction, AZ 85220; (800) 224-2601
Elkhart Surplus Salvage “” 28301 U.S. 33 W., Elkhart, IN 46516; (574) 295-8903
Gundie’s Inc. “” 1283 Mount Baker Highway, Bellingham, WA 98226; (360) 733-5036
Icke’s RV Surplus “” 701 W. Huntington St., Montpelier, IN 47359; (317) 728-5668
Mather Auto Wrecking “” 4095 Happy Lane, Sacramento, CA 95827; (800) 822-6110
Midwest Salvage “” 1700 N. State Road 5, Shipshewana, IN 46565; (574) 825-9822
National Recovery Service Inc. “” P.O. Box 310, Liberty, NC 27298; (800) 903-7285
RV Recyclers “” 3391 Fitzgerald #B, Rancho Cordova, CA 95742; (916) 635-9303
RV Surplus & Salvage Inc. “” 1400 W. Bristol St., Elkhart, IN 46514; 574-264-5575
Shaw & Co. “” 6374 State Road 303, Albuquerque, NM 87105; (505) 877-8949
Singleton RV Salvage & Sales “” 383 Nelson Road, Rochester, WA 98579; (360) 273-9566
Vanderhaag’s Inc. “” 3809 Fourth Ave. W., Spencer, IA 51301; (800) 831-5164; (712) 262-7000
Walt’s RV Surplus “” 16616 Valley Blvd., Fontana, CA 92335; (909) 823-0563
Weller Auto “” 2525 Chicago Drive S.W., Grand Rapids, MI 49509; (616) 538-5000
Winnebago Surplus “” P.O. Box 152, Forest City, IA 50436-0152; (515) 582-6935
I’m sure there are many more, but this should give you a start. Use caution and remember it’s not wise to reuse any plumbing or LP-gas fittings.