American Dryer Corp ML-310 Phase 7 service manual With a Flame

3.Troubleshooting and System Detailed Diagnosis For Johnson Direct Spark Ignition (DSI) Module P/N 128935

When the dryer calls for heat, 24 VAC from the step down transformer is applied to the “TH” and “GND” terminals of the DSI module. The DSI module light emitting diode (L.E.D.) indicator will LIGHT “GREEN.” The gas valve will be energized, and the spark burst will be evident (on) for approximately 8-seconds at the tip of the electrode flame-probe assembly. The flame should now be established and confirmed. If a flame is not sensed and confirmed by the ignitor/flame-probe sensor after the approximate 8-second spark burst, the DSI module will wait 30-seconds and start ALL over again.

If a flame has been established and confirmed and then lost, the DSI module L.E.D. indicator will continue to LIGHT “GREEN,” wait 30-seconds and try again. The flame should now be established and confirmed. If a flame is not sensed and confirmed by the ignitor/flame-probe sensor after the initial try, the module will try two (2) more times, then if flame is still not established it will go into LOCKOUT mode (the L.E.D. will

BLINK “GREEN” CONTINUOUSLY). a. System Diagnosis

1) Gas Pressure

A gas pressure test should be taken at the gas valve pressure tap provided on every gas valve to assure that the water column (W.C.) pressure is correct and consistent.

There are two (2) types of devices commonly used to measure water column pressure. They are the spring and mechanical type gauges and the water column test gauge (manometers). The use of the spring and mechanical type gauges is not recommended because they are not always accurate. The preferred type of gauge is the manometer because it is a simple device to use and is highly accurate. A manometer is simply a glass or transparent plastic tube with a scale graduated in inches. When it is filled with water and pressure is applied, the water in the inner tube lowers, showing the exact water column pressure in inches.

WARNING: Test ALL connections for leaks by brushing on a soapy water solution.

WARNING: NEVER TEST FOR LEAKS

WITH A FLAME!!!

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