American Dryer Corp. MLG-460 - Manual (Page 43)

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2) L.E.D. (light emitting diode) and Neon Displays of the BCM (Burner Controller Module)
a) Operating Interlock - L.E.D. (light emitting diode) is lit when:
ALL safety interlock switches are closed applying a 120 VAC signal to terminal #7 of the burner
controller module (BCM).
b) Operating Interlock - L.E.D. (light emitting diode) is not lit when:
One or more safety interlock switches are open. If any safety interlocks switch is open the burner
ignition sequence will not be attempted.
c) Air Failure - L.E.D. (light emitting diode) is lit if:
• Air switch is not closed within 10 seconds of start-up of blower
• Air switch is open during firing cycle.
d) System Unsafe - L.E.D. (light emitting diode) is lit if:
• A dryer safety device, connected in series with terminal #7, is opened. These safety devices
include the door switches, tilt switches, tumbler (basket) stop motion detector, high temperature
limit switches, airflow switches, and high or low gas pressure switch.
• A loose connection on the flame rod or spark plug.
• ALL purge time dip switches are in the off position.
• Flame is detected out of sequence.
• Inductance (H) is detected on sensor wires.
• Wiring fault on terminal #3, terminal #4, and terminal #5.
• Internal controller failure.
• Air switch closed before start-up.
e) Flame Signal - L.E.D. (light emitting diode) is lit when:
The flame rod is in contact with the pilot flame and the BCM (burner controller module) converts
a microampere (
µ)
current between the flame rod and ground into a 3 volt DC to 11 volt DC signal
that can be measured on the BCM. Insert one (1) probe of a DC volt meter into the flame signal
port and put the other probe to ground. The meter will read out the 3 volt DC to 11 volt DC flame
signal. If the flame signal L.E.D. (light emitting diode) flickers on and off, this is a result of a weak
flame signal which can be caused by an intermittent wiring connection between the flame rod and
the BCM, a faulty ground connection, bad ground of the dryer, weak pilot flame, and dirty or
defective flame rod.
f) Burner Controller Power On Indicator - Neon is lit when;
Burner controller has its supply voltage of 120 VAC.
g) Burner for Air Switch Status Indicator - Neon is lit when;
Air switch is closed after start-up of the blower (fan) and the interlocks are ALL closed.