RV Water Heating Systems
The hot water system doubles the plumbing
in an RV. Beyond the pump and the city water valve, are the
hot water tank and a complete separate plumbing system to
each sink and shower installation.
The water heater consists of an
insulated storage tank of six to ten gallon capacity, and a
propane gas burner that is used to heat the water. The
storage tank is made of aluminum or glass-lined steel,
depending on the model. The steel tanks use an anode rod to
help prevent corrosion of the tank material. The corrosive
elements in the water attack and "eat up"the anode rod
rather than the material of the tank. These anode rods
should be inspected and replaced annually, if required.
Aluminum tanks do not require an anode rod.
Additional options include electrical
heating elements and motor assisted hot water systems in
some motor homes.
The cold water in the water heater
expands as it is heated thus increasing the water pressure.
This additional pressure may cause the temperature/pressure
relief valve to "weep" and cause other leak problems. The
RV water system is designed for water pressures of about 45
PSI. If the city water connection is hooked up to a water
source, a water pressure regulator should be used to
control the higher pressure. This pressure, along with the
added pressure from the heated water may cause leaks to
develop.
The water heater is designed to trap a
pocket of air above the water level in the tank. This air
pocket compresses as the water is heated. The air pocket
can eventually be absorbed by the motion of the vehicle and
should be restored from time to time.
To restore the air pocket, turn off the
water pump or city water supply and open a hot water tap to
reduce the water pressure to zero. Remove or open the water
heater drain plug or valve. Allow the water heater to drain
and flush it by running water through it for several
minuets. Insert the plug or close the drain valve and
re-fill the water heater tank until the water appears at
the opened hot water faucet.
Another solution would be to add an
accumulator to the system. An accumulator is basically a
sealed tank in the water system that has an air pocket to
absorb extra pressure.
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