4.0
Operation
•
Sequence of Operation
•
Thermostat
38
LS
Series
WARNING
!
!
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
Starting Circuit:
Upon a call for heat, the fan is energized. Once operational static pressure is achieved,
the burner pressure switch will close initiating the ignition sequence. After a 5-second delay, the glo-
bar is energized for 45 seconds and the control allows the gas valve to open.
The trial for ignition is 8 seconds. If flame sense is not established within 8.5 seconds, the heater will
attempt two (2) additional ignition sequences before proceeding to soft lockout. Soft lockout
automatically retries after one (1) hour or the control can be reset by briefly interrupting the power
source.
Running Circuit:
After ignition, the flame rod monitors burner flame. If sense of flame is lost, the control
immediately acts to reignite the gas-air mixture (identical to the starting sequence). If flame sense is
not established within 8.5 seconds, the heater will attempt two (2) additional ignition sequences
before proceeding to soft lockout. The control can be reset by briefly interrupting the power source.
Thermostat
NOTE:
Different thermostats operate according to their particular features. Refer to thermostat
specifications for details.