OM-TDB/6 11
Sequence of Operation
The following “action-reaction” outline is provided to help understand how the kettle
works.
When the operator starts up the kettle by turning the operating thermostat dial from
“OFF” to a desired setting, the thermostat switch closes. This lights up the heating
indicator light and causes the contactors to close, allowing power to flow to the
heating elements. When the temperature of the steam jacket reaches the value
corresponding to the dial setting, the thermostat switch opens. This turns off the
heating indicator light and causes the contactors to open, stopping the power to
the heaters. As soon as the thermostat senses that the kettle is cooling below the
set point, the thermostat switch closes, the heating indicator light comes on, the
contactors close, and the heaters come on again. On-off cycling continues, keeping
the kettle at the set temperature. This is why the heating indicator light cycles on
and off during normal operation. Every time the kettle is tilted, the tilt cut-off switch
interrupts the power supply to the heaters, so that the heating elements will not
operate while not submerged in the jacket water.
If steam pressure greater than 50 PSI (3.45 Bar/345 kPa) is generated in the jacket,
the pressure relief valve will open and relieve the excess pressure.
In the event that the jacket water level gets too low and the heating elements
overheat, the high limit control will open and shut off power to the elements until the
kettle cools. Setting the operating thermostat dial to “OFF” shuts down all control and
heating circuits.
