ADC AD-410 service manual Repairable

e. The Tumbler Hi-Limit Switch is a thermostat type switch located above the Lint Basket. Its function is to discontinue heat (flame) in the event of an over temperature situation (above 225º F).

MAN3484

225º F Thermostat

f. The gas valve used in the dryer is of the redundant type which means that the gas valve is actually two (2) gas valves in one; one in series with the other. This is a safety feature which provides protection against gas flow in the event that one of the valves does not seat properly. The valve also regulates the incoming gas pressure.

NOTE: THE DSI GAS VALVES ARE NOT FIELD

REPAIRABLE.

Redundant Gas Valve

g.Normal Operation of the Direct Spark Ignition (DSI) System (refer to the illustration on page 29).

1)The DSI (Direct Spark Ignition) System consists of a microprocessor-based control module, along with an Ignitor and Flame-Probe Assembly. This control utilizes a high voltage synchronous spark ignitor and a rectified flame sensor probe signal to locally control ALL basic functions in the gas burner.

On a call for heat by the dryers' controls, 24 VAC is applied to the DSI (Direct Spark Ignition) module at which time the DSI modules' L.E.D. (light emitting diode) indicator will light "RED" indicating that power has been established to the DSI module. Almost immediately (up to approximately 1.5-seconds [prepurge]) the indicator will light" GREEN," the gas valve opens and the spark burst will be evident (on) for approximately 8-seconds. The burner flame should now be established/confirmed.

If at this time the flame has not been established and confirmed, the DSI (Direct Spark Ignition) module will "LOCK-OUT" and the DSI modules' L.E.D. (light emitting diode) indicator will light "RED" and stay on continuously. To reset or cancel the "LOCK-OUT" condition, open and close the main door then restart the dryer.

Once the burner flame is established and confirmed, the DSI (Direct Spark Ignition) module indicator will light "GREEN," and the burner system will continue through a normal heating cycle, where the DSI (Direct Spark Ignition) system will cycle on and off as required by the dryers controls.

During the normal heating cycle, should a "FLAME-OUT" occur (i.e., severe air turbulence forces the flame away from the ignitor and flame-probe assembly), the DSI (Direct Spark Ignition) module shut the gas valve off and immediately try to reestablish the burner flame. The DSI module will attempt to light the burner ONLY ONCE. If flame is not established, the DSI module will "LOCK- OUT." To reset or cancel the "LOCK-OUT" condition, open and close the main door then restart the dryer.

2 9