Daikin RDT-135c Installation And Maintenance Manual page 63

Sequences of Operation: Heating
and keeps the supply fan running until the furnace cools down
(this might happen during night setback operation).
If the furnace overheats, the FLC high limit control (line 603)
cycles the burner, preventing the furnace temperature from
exceeding the limit control's setpoint. When the furnace cycles
off, low fire start relay R23 de-energizes. The normally closed
R23 contacts (line 633) cause VM1 to drive to its minimum
position, overriding MicroTech II control of VM1 via MCB-BO10
and MCB-BO9. Because relay R23 de-energizes whenever GV2
de-energizes, the burner always starts at low fire.
Safety Lockout
If the pilot flame does not ignite or the flame safeguard fails to
detect its flame within 10 seconds, the flame safeguard control
enters the "safety lockout" state. FSG terminals 4, 8,9 and 10
de-energize and the burner shuts down. FSG terminal 3
energizes relay R24 (line 610). The R24 contacts (line 225)
signal the controller that the problem exists by energizing the
input to MCB-BI5. If a safety lockout occurs, manually reset
the flame safeguard control.
IM 738-2
61