Sequence Of Operation - Brant Radiant Heaters DET3 Series Manual

DET3 Series
This heater must be installed and serviced by trained gas installation and service
personnel only.
Do not bypass any safety features or the heater's built in safety mechanisms will be
compromised.

Sequence of Operation

Two voltages (120VAC supply and 24VAC control) must be supplied to the DET3 Series burner control box
for proper operation.
Starting Circuit: Upon a call for heat, the low fire relay is energized by 24VAC from the thermostat. The
relay is closed sending 120VAC to the blower beginning the sequence of operation.
Air pressure generated by the blower causes the normally open pressure switch to close, sending
power to the ignition module. After a seven-second pre-purge, the spark electrode, transformer and
gas valve are simultaneously energized. The trial for ignition is 15 seconds.
Single Stage Running Circuit: After ignition, the electrode monitors burner flame. If sense of flame is
lost, the control immediately disrupts power to the gas valve and then re-cycle the unit (identical to
the starting sequence). If flame sense is not established within 15 seconds, the heater will attempt
two (2) additional ignition sequences before proceeding to lockout mode. The control can be reset
by briefly interrupting the power source.
Two Stage Running Circuit: High fire operation is actuated by the thermostat sending a 24VAC signal to
the high fire relay. The energized coil of the relay is closed, allowing 24VAC to continue onto the
high fire of the gas valve.
WARNING
!
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4.0 Operation • Sequence of Operation