Sequence Of Operation Flow Chart - A.O. Smith BTI 120 Installation & Operation Manual

SEQUENCE OF OPERATION FLOW CHART

Description of this flow chart can be found in the "SEQUENCE OF OPERATION" section found on page 23.
Switch power on
to unit.
Thermostat calls
for heat.
Ignition Control
Board performs
diagnostic check on
components
Ignition Control
Board sends power
to Exhaust Inducer
Exhaust Inducer
engages Prover
Switch
Ignition Control
Board provides
power to Silicon
Nitride Ignitor
Silicon Nitride
Ignitor
warms up for
20 seconds
Ignition
Control Board
opens Gas
Valve.
Ignition Control
Board shuts off
Silicon Nitride
Ignitor after
3 seconds
Ignition Control
Board waits 3 more
seconds to
monitor Flame
Sensor.
Did Main
Burner Light?
YES
Ignition Control
Board monitors
units until T'Stat
is satisfied.
30
Ignition Control
Board shuts off Gas
NO
Valve and allows the
Exhaust Inducer to
purge appliance for
20 seconds.