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4.0
Operation
•
Lighting and Shutdown • Sequence of Operation
4.0
Operation
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.
Burner Lighting Instructions
Purge main gas supply line.
1
Rotate heater's manual ball valve to the "ON" position.
2
Close electrical circuit (turn on thermostat).
3
If the burner fails to light, turn "OFF" gas and wait five minutes before repeating the above procedure.
4
Burner Shutdown Instructions
Open electrical circuit (turn off thermostat).
1
Rotate heater's manual ball valve to the "OFF" position.
2
Sequence of Operation
Starting Circuit: Upon a call for heat, power is supplied to the relays at the burner box(es) and vacuum
pump. The vacuum pump is energized creating negative air pressure. This allows the differential
pressure switch in the burner box(es) to close which completes a low voltage circuit from the
secondary side of the transformer to the ignition module. After the ignitor has been powered for
seven seconds, the gas valve opens initiating the ignition trial. If flame is not sensed after 15
seconds, the heater will attempt to re-ignite for a total of three trials for ignition before entering
lockout mode.
Single Stage Running Circuit: After ignition, the flame rod monitors burner flame. If sense of flame is
lost, the control closes the gas valve within one second and a new trial sequence (identical to the
starting sequence) is initiated. The control can be reset by briefly interrupting the power source.
Two Stage Running Circuit (when applicable): The second stage on the gas valve is powered directly
from the second stage of the thermostat. In order for two stage to flow to a higher output, single
stage must be energized as well. The thermostat determines which stage to maintain for the desired
temperature.
WARNING
!
42
HLV
Series
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