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120 AC/12 DC/LP-gas - The power sources on which RV refrigerators operate; 120 AC is 120-volt alternating
current (same as in houses); 12 DC is 12-volt direct current (same as in motor vehicles); LP-gas. Some RV
refrigerators can operate on two of the three sources, others on all three.
ANODE ROD - an anode rod, when used in a water heater, attracts corrosion
causing products in the water. These products attack the anode rod instead of the metal tank itself. The anode rod
should be inspected yearly and changed when it is reduced to about 1/4 of its original size. The rods are used in
steel water heater tanks - an aluminum tank has an inner layer of anode metal to accomplish the same thing. Anode
rods should not be installed in an aluminum tank!
AXLE RATIO - The ratio between the pinion and ring gears in the differential that multiply the torque
provided by the engine. It is the number of drive line revolutions required to turn the axle one time. As an
example, with a 4.10:1 axle the drive line turns 4.1 times for each full axle revolution. The higher the number,
the more torque and thus more towing power. However, the higher the number also means less speed.
BLACK WATER - disposal water from the toilet system, held in a holding tank until you dump it, in large
tanks or dumping station available at most campgrounds.
Brake Actuator - a device mounted under the dash of a towing vehicle to control the braking system of the
trailer. Most Brake Actuators a based on a time delay, the more time the tow vehicle brakes are applied the
"harder" the trailer brakes are applied.
Brake Controller - a device mounted under the dash of a towing vehicle to control the braking system of
the trailer. The Brake Controller senses the amount of braking force of the tow vehicle and applied a proportional
force to the trailer braking system.
BTU - British Thermal Unit - A measurement of heat that is the quantity required to raise the temperature
of one pound of water 1 degree F. RV air-conditioners and furnaces are BTU-rated.
Camber - Wheel alignment - Camber is the number of degrees each wheel is off of vertical. Looking from
the front, tops of wheels farther apart than bottoms means "positive camber". As the load pushes the front end
down, or the springs get weak, camber would go from positive to none to negative (bottoms of wheels farther apart
Castor - Wheel alignment - The steering wheels' desire to return to center after you turn a corner.
CONDENSATION - condensation is a result of warn moisture laden air contacting the cold window glass.
Keeping a roof vent open helps to reduce the humidity levels. Those added roof vent covers help to prevent cold air
from dropping down through the vent while still allowing moist air to escape. Using the roof vent fan when
showering or the stove vent fan when cooking also helps prevent excess moisture buildup.
CONVERTER - A converter is device that converts 120 volt A/C (alternating current) to 12 volt DC (direct
current). The RV devices mostly run on 12 volt DC power that is supplied by the battery, which allows the RV to
function independently. When "shore power" (an electrical supply) is available, the converter changes the voltage
from 120 to 12 volt to supply the appliances and to recharge the battery.
DINETTE - booth-like dining area. Table usually drops to convert unit into a bed at night.
DSI IGNITION - direct spark ignition - this term refers to the method of igniting the main burner on a
propane fired appliance. The burner is lit with an electric spark and the flame is monitored by an electronic
circuit board. This ignition system is used in refrigerators, furnaces and water heaters. There is now a version of
stove tops that light the burners with a DSI ignition.
DUCTED AC is air conditioning supplied through a ducting system in the ceiling. This supplies cooling air
at various vents located throughout the RV.
DUCTED HEAT is warm air from the furnace supplied to various locations in the RV through a ducting system
located in the floor. (similar to house heating systems)
DUAL ELECTRICAL SYSTEM - RV equipped with lights, appliances which operate on 12-volt battery power when
self-contained, and with a converter, on 110 AC current when in campgrounds or with an onboard generator.
DUALLY - A pickup truck, or light-duty tow vehicle, with four tires on one rear axle.
Equalizer Hitch - Also called a weight distributing
hitch - a devise used on a travel trailer hitch to distribute the tongue weight to all four wheels of the tow
GENERATOR - An engine powered device fuelled by gasoline or diesel fuel, and sometimes propane, for
generating 120-volt AC power.
GREY WATER - disposal water from sinks, shower. In some units, this is held in a tank separate from black
water; is also dumped in tanks at campgrounds.
GROSS AXLE WEIGHT RATING (GAWR) - The manufacturers maximum load weight, in pounds, that can be placed on
the axle. If an axle has a 3500-lb. GAWR and the RV has two axles (tandem axles), then the RV would have a Gross
Vehicle Weight Rating (GVWR) of 7000 lbs.
GROSS COMBINED WEIGHT RATING (GCWR) - The manufacturers maximum load weight, in pounds, allowed for the
trailer and tow vehicle. This rating includes the weight of the trailer and tow vehicle plus fuel, water, propane,
supplies and passengers.
GROSS VEHICLE WEIGHT RATING (GVWR) - The manufacturers maximum load weight, in pounds, allowed for the
vehicle. This rating includes the weight of the vehicle plus fuel, water, propane, supplies and passengers.
Gross Trailer Weight (GTW) - Gross trailer weight is the weight of the trailer fully loaded in its actual
towing condition. GTW is measured by placing the fully loaded trailer on a vehicle scale. The entire weight of the
trailer should be supported on the scale.
HEAT EXCHANGER - A heat exchanger is a device that transfers heat from one source to another. For
example, there is a heat exchanger in your furnace - the propane flame and combustion products are contained inside
the heat exchanger that is sealed from the inside area. Inside air is blown over the surface of the exchanger,
where it is warmed and the blown through the ducting system for room heating. The combustion gases are vented to
the outside air.
HEAT STRIP - A heat strip is an electric heating element located in the air conditioning system with the
warm air distributed by the air conditioner fan and ducting system. They are typically 1500 watt elements (about
the same wattage as an electric hair dryer) and have limited function. Basically they "take the chill off"
HITCH WEIGHT - The amount of a trailer's weight that rests on the tow vehicle's hitch. For travel
trailers this weight should be 10% to 15% of the total weight of the trailer. For fifth wheels this weight should
be 15% to 20% of the total weight of the trailer.
HOLDING TANKS - There are three different holding tanks on most RVs;
fresh water tank, gray water tank and black water tank. The fresh water tank holds fresh water that can be stored
for later use. The gray water tank holds the waste water from the sinks and showers. The black water tank holds the
waste from the toilet.
HOOKUPS - The ability of connecting to a campground's facilities. The major types of hookups are
electrical, water and sewer. If all three of these hookups are available, it is termed full hookup. Hookups may
also include telephone and cable TV in some campgrounds.
INVERTER - An inverter is a device that changes 12 volt battery power to 120 volt AC power. It is used
when "boondocking" (camping without hookups) to power certain 120 VAC only devices like a microwave oven. The
amount of available power depends on the storage capacity of the batteries and the wattage rating of the
LAMINATE - A sandwich of structural frame members, wall paneling, insulation and exterior covering,
adhesive-bonded under pressure and/or heat to form the RV's walls, floor and/or roof.
LIVABILITY PACKAGES - items to equip a motorhome for daily living, which may be rented at nominal cost
from rental firm, rather than brought from home. Include bed linens, pillows and blankets, bath towels, pots and
pans, kitchen utensils, cutlery.
LP GAS - Liquefied Petroleum Gas. LP gas is used to fuel appliances in the
RV, such as the stove, oven, water heater and refrigerator. Propane tanks are usually rated as pounds or
NET CARRYING CAPACITY (NCC) or Payload Capacity - Sometimes called the payload capacity, this is the
maximum weight of fuel, water, propane, supplies and passengers that can be added to an RV without exceeding the
Gross Vehicle Weight Rating (GVWR).
PILOT - a pilot is a small standby flame that is used to light the main burner of a propane fired
appliance when the thermostat calls for heat. Pilots can be used in furnaces, water heaters, refrigerators, ovens
and stove tops.
PROPANE - LPG, or liquefied petroleum gas, used in RVs for heating, cooking
and refrigeration. Also called bottle gas, for manner in which it is sold and stored.
RIG - what many RVers call their units.
ROOF AIR CONDITIONING - air conditioning unit mounted on roof of RV, to cool the RV when it is parked.
When moving, most RVs are cooled by separate air conditioning units which are components of the engine, or they may
be cooled by a roof top if a proper size generator is installed.
RV - short for Recreation Vehicle, a generic term for all pleasure vehicles which contain living
accommodations. Multiple units are RVs and persons using them are RVers.
SELF CONTAINED - RV which needs no external electrical, drain or water hookup. Thus, it can park
overnight anywhere. Of course, self-contained units can also hook up to facilities when at campgrounds.
THERMOCOUPLE - a thermocouple is a device that monitors the pilot flame of a pilot model propane
appliance. If the pilot flame is extinguished the thermocouple causes the gas valve to shut off the flow of gas to
both the pilot flame and the main burner.
TOAD - A "toad" is an RV'ers term referring to a vehicle that is towed behind a
motor home. Some vehicles can be towed without any modifications - others cannot be towed at all, or at least
without extensive alterations.
Toe - Wheel alignment - Toe is the measure of whether the front of the wheels (looking down from the top)
are closer (toe-in) or farther (toe-out) than the back of the wheels.
TONGUE WEIGHT - Tongue weight (TW) is the downward force exerted on the hitch ball by the trailer
coupler. In most cases, it is about 10 to 15 percent of GTW. TW of up to 300 lbs. can be measured on a household
scale by resting the trailer coupler on the scale and placing the scale on a box so that the coupler is at its
normal towing height. The trailer must be fully loaded and level.
For heavier tongue weights, place a household scale and a brick that's as thick as the scale three feet apart. Set
a length of pipe on each and rest a beam across the pipes. Re-zero the scale to correct for the weight of the beam
and pipe. Securely block the trailer wheels. Rest the trailer jack on the beam, one (1) foot from the pipe on the
brick and two (2) feet from the pipe on the scale.
To obtain the TW, multiply the scale reading by three (3). For greater tongue weights, place the scale and brick
four (4) feet apart, rest the jack on the beam three (3) feet from the scale and multiply the scale reading by four
UNDERBELLY - The RV's underfloor surface, which is protected by a weatherproofed material.
UNLOADED VEHICLE WEIGHT (UVW) or Dry Weight - Sometimes called the Dry Weight, it is the weight of the RV
without adding fuel, water, propane, supplies and passengers. The manufacturers uvw will not include any
Waste water tanks - The gray water tank holds the waste water from the
sinks and showers. The black water tank holds the waste from the toilet.
Weight Distributing Hitch - also called an equalizer hitch - a device used on a travel trailer hitch to distribute the tongue weight to all four wheels of the tow vehicle. See more at etrailer.com
WET WEIGHT - The weight of the vehicle with the fuel, freshwater and propane tanks full.
WHEELBASE - Distance between center lines of the primary axles of a vehicle. If a motorhome includes a
tag axle, the distance is measured from the front axle to the center point between the drive and tag axles.