ASK THE EXPERTS
by Bill and Jenn Gehr
After owning and operating Bill’s RV Service in Ventura, Calif. for 34 years, Bill Gehr and his wife, Jenn, are now living the dream of the full-time RV lifestyle. Bill is an RV technician and has starred in the DVD series, The ABCs of RVs, and RV Today on RFDTV. He and Jenn have also written many technical articles for a variety of magazines.
To submit a question to Bill and Jenn, send an e-mail to editor@rvjournal.com.
Question: I have a 1999 Dolphin Motorhome with a front and rear Duotherm air conditioner. The rear AC fan no longer comes on at all and the front AC seems to operate as normal. The digital dual-zone wall thermostat seems to function properly between the two zones. After having my local RV repair shop explore the issue, I have been told that the control board is defective and no longer available. Do I have to buy a new air conditioner or can I have the control board repaired?
––Jim Hancock, Phoenix
Answer: We all know that AC is very important, especially living in Arizona! Your repairman is correct: that particular control board is no longer available. In 1999, Dometic (Duotherm) used a four-button comfort-control wall thermostat that was designed to operate two air conditioners and two forced-air heaters. A few years later, Dometic changed to a five-button thermostat that is more user friendly. Dometic makes a kit that contains one control board and a new five-button thermostat that you can order using your old model and serial numbers. You also need to purchase a second control board since you have to change both boards in order to function with the new five-button thermostat. All the wiring will match up and will not need rewiring.
Question: My Winnebago Adventurer came from the factory with a fiberglass roof. The threads are now exposed and flaking off. Is there anything I can do other than spend $5K to have it replaced?
––Tony Harbor, Oxnard, Calif.
Answer: Winnebago used the fiberglass roof for many years with great success. For various reasons, some of the roofs did deteriorate prematurely. Painting your roof is a less expensive solution that should last about five years. You will have saved money and acquired better form and function. Good preparation will be key to longevity. If the caulking around your vents, moldings, etc., needs replacing, this is an ideal time to scrape it off and replace after the roof is painted. First, sand the fiberglass until it is relativity smooth. After sanding, clean the roof with a degreaser and rinse with water to ensure that there are no contaminates. Using painter’s plastic, mask around the entire coach to prevent the paint from dripping down the sides. Mix sand into the paint for safety and apply two to three coats of a high-quality primer and marine-grade deck paint over the entire roof.
Question: I decided to upgrade my Shurflo Water Pump (Model 2088) to the higher-pressure, higher-volume Shurflo Smart Sensor 5.7. The pump functions normally when running water. Sometimes, it shuts off all the way. Other times, when the faucet is shut off, the pump doesn’t always shut off completely and makes a whining noise.
––Steven Swope, Wimberley, Tex.
Answer: It sounds as though you may have a voltage problem that is common with heavier-duty, variable-pressure water pumps. Manufactures tend to run the proper size wire for the pump that they install; not oversized wire for heavier-volume pumps such as the Smart Sensor 5.7. The problem you are experiencing is that the current smaller gauge and length of the wire result in a voltage drop when adding the heavier draw of the larger pump. Pulling a new, larger-gauge wire through the walls is not very practical. Because the wire runs from the fuse to the switch and from the switch to the pump, the only solution you have is to install a Bosch or an automotive relay switch. Run a heavier gauge wire to the relay and utilize the original switched wire to the pump to activate the relay. A wiring schematic should be available on the Internet.
The complete article can be found in the current issue of RV Journal, available at quality campgrounds, RV dealers, parts, and service suppliers. Subscriptions are also available for this quarterly publication.
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