Bradford White HE-4-50S6FSX - Manual (Page 10)

Page 10
Normal Heating Sequence (cont’d)
7. Steady State Operation: During steady state operation, the gas control monitors:
Temperature Sensor: When the setpoint temperature is satisfied, the gas control is
shutdown, and the blower will postpurge for 15 seconds. The gas control LED
flashes a short flash once every 4 seconds (Idle status code).
Pressure Switch / Blower Temperature Switch: If either switch opens, the pilot and
main valves are shutdown. The blower continues to run for 30 seconds attempting
to close the circuit. The gas control LED flashes 3 times with a 3 second pause.
Flame Sensor: If flame is lost, the pilot and main valves are shutdown. The blower
runs for 15 seconds. The gas control attempts to re-light the pilot 4 times. If
unsuccessful, the blower is shutdown, and the gas control proceeds to a 5 minute
lockout. The gas control re-attempts to light the pilot starting at Normal Heating
Sequence #2.
8. Thermostat Satisfies: Gas control LED flashes once every 4 seconds.
9. Burner Off
10. Blower Postpurge (15 seconds)
Abnormal Operation
1. Flammable Vapor Sensor Fault:
A) If the resistance is greater than 70,000 ohms: The gas control immediately turns
off all outputs. The gas control waits and monitors resistance for 30 seconds. If the
resistance is greater than 65,000 ohms after 30 seconds, the gas control proceeds
to verify resistive delay for 2 minutes and flashes 7 times with a 3 second pause.
This process is repeated 5 times until the control either returns to normal operation
or proceeds to flammable vapor lockout.
B) If the resistance is below 240 ohms: The gas control immediately turns off all
outputs and proceeds to flash 8 times then 1 time with a 3 second pause. The error
self clears if the resistance returns to normal range for at least 15 seconds.
Sequence of Operation
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