Gas-fired water heaters have a gas burner located below the tank,
a thermostatic
switch, a gas valve and a pilot light. The thermostat will open the
gas valve when it senses the water temperature at
the bottom of the tank has dropped below the present limit. Gas flows
to the burner and is ignited by the pilot light, heating the tank from
below. In addition, the hot exhaust gases are vented through a hollow core
in the center of the tank to help heat the water. The exhaust is then passed
into the draft hood and to the vent connector where it is discharged to a chimney flue.
Once the water temperature reaches the set limit of 120° F to 140° F, the gas
valve is closed and the burner is turned off.
Note: Fuel-fired systems heat the water by heating the tank. As a
result, the tank experiences more wear and tear
than with an internal electric heat source. In addition, proper venting of the exhaust
is always important to prevent carbon monoxide poisoning. Be sure that
the
vent/exhaust system is properly installed. See gas heating
systems.
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