Rheem Gas Heavy Duty Water Heater Models 265 Litre and 275 Litre - Manual (Page 8)

8
HOW YOUR WATER HEATER WORKS
Water is stored in a vitreous enamel lined steel cylinder and heated by a gas
burner located under the cylinder. The heat produced by the burner is
transferred to the water through the base of the cylinder and through the wall of
a flue pipe which passes through the centre of the cylinder. A flue baffle in this
flue ensures the efficiency of the water heater is correct. The gas supply to the
burner is controlled by the thermostat so the water is heated to a constant
temperature. Automatic safety controls are fitted to the water heater to provide
safe and efficient operation.
MAINS PRESSURE
The water heater is designed to operate at mains
pressure by connecting directly to the mains water
supply. If the mains supply pressure in your area
exceeds that
shown on page 18, a pressure limiting
valve must be fitted. The supply pressure should be
greater than 350
kPa for true mains pressure
operation to be achieved.
ELECTRONIC THERMOSTAT
The thermostat automatically operates the gas
control by switching its power on and off, so a
constant temperature is maintained. The thermostat
is mounted externally on the water heater and the
protective over temperature cut out is mounted inside
the lower front cover of the water heater.
There is no need to switch the water heater off when
it is not in use. The thermostat is fully automatic and
only allows the gas control to open when the burner
requires gas for heating. The thermostat may flash
“AH” (alarm high) and the current water temperature,
or “AL” (alarm low) and the current water
temperature. This is not a cause for concern unless
the temperature displayed is more than 10ºC above
the set temperature. Refer to
“Diagnostic Features of
Electronic Thermostat” on page 12. To adjust the
thermostat settings refer to “Temperature Control” on
page 43.
HOT SURFACE IGNITION
The water heater incorporates an automatic burner ignition system. A hot
surface igniter (HSI) probe automatically heats up when the thermostat
registers heating of the water is required. When the HSI probe is fully
energised, the gas valve opens allowing gas to the burner which in turn is
ignited by the HSI probe.