
38
OPERA
TION
Figure 17. Burner System with Auto Ignition & Temperature Control
Burners with Automatic Ignition and
Temperature Limiting Control
Equipment Description
The temperature limiting control box contains the
temperature limiting control components as well as the
automatic ignition circuitry.
The automatic ignition circuit consists of two 12V
coils, two spark plugs, a pair of thermocouples, (one at
each burner), and a momentary pushbutton switch. The
12V coils send high voltage to the spark plugs that
causes sparks to arc intermittently at each pilot burner
whenever there is fuel pressure in the line from the main
supply tank. The thermocouples provide a signal that
indicates when there is a flame at the pilot burners. The
momentary pushbutton switch on the control box is used
to fire the main burners once the pilot burners have ig-
nited and the thermocouples have been heated suffi-
ciently.
The temperature limiting control circuit consists of
a temperature probe in the distributor tank that senses
the asphalt temperature, a thermostatic switch in the
control box and a temperature adjustment dial on the
face of the control box. When the temperature of the
asphalt in the distributor is heated to the temperature
selected with the temperature adjustment dial, the ther-
mostatic switch shuts down the burners.
Burner Operation with Auto Ignition &
Temp Control
Open the dampers on the exhaust stacks
Circulate the asphalt in the tank before lighting the
burners. If the asphalt is too cold to pump, start circu-
lating the material in the tank as soon as possible after
lighting the burner.
Ensure that all burner valves are closed.
With this type of control, the inside or lower burner
may be operated without opening the positive shut off
valve to the outside burner. If both burners are to be
used, the positive shutoff valve should be opened.
Open the main fuel valve at the supply tank. The
spark plugs will begin to arc and will ignite the pilot
burners.
Set the thermostat to the desired temperature.
Allow the pilot burners to heat the thermocouple
probes for at least 2 minutes. When the pilot burners
have heated the thermocouples sufficiently the sparker
will stop. Press the cycle button to fire the main burn-
ers. The bleeder valves may then be opened.
On new or rebuilt units, monitor the product ther-
mometer to make certain that the burners shut down
when the desired temperature is reached. (as set on the
temperature adjustment dial. If the burners do not shut
down at the correct temperature, refer to “Calibrating
the Thermostat”.