Sequence Of Operation - Re-Verber-Ray LD Series Installation Manual

4.0 Operation •

Sequence of 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.
Sequence of Operation
Standby: The MICRO 60U-24 CONTROL continually checks for internal faults, circuit integrity and relay
contact positioning.
Starting Circuit: Upon a call for heat, the control verifies that the burner and exhaust pressure switches
are in their proper positions. The control energizes the fan. Once operational static pressure is
achieved, the burner pressure switch will close initiating the ignition sequence. The hot surface
igniter is powered and the gas valve opens after 45 seconds. If the flame is not sensed, the heater
will attempt to re-ignite for a total of 3 trials for ignition before proceeding to soft lockout.
Low Fire 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. If flame sense is not established within 8.5 seconds, the heater will attempt
two additional ignition sequences before proceeding to soft lockout. The control can be reset by
briefly interrupting the power source.
High Fire Running Circuit: The second stage on the gas valve is powered directly from the second
stage of the thermostat. In order for high fire to engage, low fire must be energized as well. The
thermostat determines which stage to maintain for the desired comfort level.
Shut Down: When the thermostat is satisfied, the fan will enter a two (2) minute post-purge cycle.
• Thermostat
WARNING
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LD Series