50-Amp Service
I’m curious. Since all electrical appliances in a motorhome are 120 volts (or 12 volts DC), why is a 240-volt source provided? Is there a rectifier or some such device in the motorhome that converts the 240-volt input to 120 volts?
Donald Jacobs, F424301
Woodbine, Maryland
The RV industry uses two basic types of AC service, depending upon the amperage requirement of the RV. A good rule of thumb is that a motorhome with one air conditioner usually will have 30-amp service. This is just one line of 120 volts capped at 30 amps for that line. A motorhome with two (or more) air conditioners usually will have two lines of 120 volts capped at 50 amps per line. Anytime you have two lines of 120 volts (on opposite phase), this is a 240-volt service (at 50 amps, in this instance). The breaker box distributes one leg of 120 volts and another leg of 120 volts, but neither leg can exceed 50 amps total without tripping a breaker. If a motorhome happens to have an appliance such as a high-capacity clothes dryer or a Gaggenau cooktop, then taking both legs of the service can power up a 240-volt requirement.
Inverter Info
I am considering replacing my two 12-volt house batteries, which are rated at 255 amp-hours, with four six-volt golf cart batteries rated at 300 amp-hours each. My coach has a 2,000-watt Xantrex inverter; does a large increase in amp-hours require more inverter capacity? In making a battery swap, are there safety precautions I should take to prevent damaging the electronics in the inverter or power switch?
Jim Williams, F210847
Helena, Montana
The 2,000-watt rating relates to the inverter output and is not affected by the current rating of the battery bank, which is still just 600. I would caution that there should not be any loads on the system when installing the batteries, as this may cause arcing at the connections. The coach may have a system disconnect switch that could be turned off. I always make the negative connection the final one. Personal safety is a must, which means wearing gloves, a face shield, and safety glasses. Explosions have been known to happen.
A Boost For Air-Conditioning
I have a 2005 Mandalay Presidio on a Workhorse chassis and would like to improve the dashboard air-conditioning. It’s not as cold as normal. I purchased EZ Chill R134a refrigerant with a gauge, and the only pressure point I see is near the glass window. It seems easy to do, but I would like to run it by you before adding.
Jerry Burke, F361186
Sioux Falls, South Dakota
While I, too, enjoy working on my own motorhome and Jeeps, when it comes to a task that could be dangerous, I turn to experts. I don’t fill my own propane tanks; I don’t work on 120-volt-AC problems; and I don’t refill my own air-conditioning system. If you do not protect yourself from the R134a refrigerant, it could severely “burn” your skin. It’s not that expensive to have a shop replace the refrigerant. The shop’s techs also will verify that the system is not leaking and is in good condition. If you do insist on doing the job yourself, make sure you follow to the letter all the safety precautions on the R134a package, and wear eye protection.
Longing For Warmth
We have a 2013 Winnebago Journey with two Suburban heaters. We were in cold weather for three nights in a row, and on each night the outdoor temperature dropped below 30 degrees Fahrenheit. On both heaters, the air handler would work but the igniter would not. Needless to say, it was cold! Above 30 degrees, they both work as they are supposed to. Have you ever heard of this happening before?
John and Susan Wiener, F432760
Sarasota, Florida
Three possibilities have occurred to me. First, the propane tank’s safety valve may be faulty or may be working as it should. With two heaters going at those temperatures, the safety valve may have “thought” a leak existed in the propane system and thus shut off the fuel flow. Have the tank’s valve checked; it may be too sensitive or it may be faulty.
Second, many years ago my furnace exhibited the same symptoms you have described. At the time, no one had any idea what was causing them, because everything checked out when the system was examined. Each time I had the propane tanks refilled, the problem disappeared for a while and then would begin again. In the spring I discovered that the propane tank’s regulator was defective. As long as the tank was more than half full, it worked fine; at less than half full, the pressure was insufficient to feed the furnace when it was quite cold. I replaced the regulator and never experienced the problem again.
Finally, some propane tank manufacturers pressure-test their tanks by filling them with water and then pressurizing them with air. That way, if the tank ruptures, it does not become a missile. This is done without the service valve. Then the tank is passed to the next station in an inverted position while the water drains out. In some instances, not all the water is expelled. Since you have a newer coach and any water would not have had time to normally dissipate, this may be a possibility.
A rule of thumb for neutralizing moisture in an American Society of Mechanical Engineers (ASME) propane tank calls for adding 1 pint of genuine absolute anhydrous methanol for each 100 gallons of water capacity of the tank.