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3. Troubleshooting/System Detailed Diagnosis
When the dryer calls for heat, 24 VAC from the step down transformer is applied to the “THS” and “GND”
(ground) terminals of the Direct Spark Ignition (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. Flame
should now be
established/
confirmed. If a flame is not sensed/confirmed by the 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/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/confirmed. If a
flame is not sensed/confirmed by the flame sensor probe after the initial try, the module will try two (2)
more times then if it is still not established it will go into LOCKOUT.
NOTE:
To reset the DSI module if it is in the LOCKOUT mode, open and close the main door, then
restart the dryer.
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/mechanical type gauge and the water
column test gauge (manometers). The use of the
spring/mechanical type of gauges is not
recommended because it/they are very easily
damaged and 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 tube rises, showing the exact water
column pressure.
WARNING:
Test
ALL
connections for leaks by brushing on a soapy water solution.
NEVER TEST
FOR LEAKS WITH A FLAME!!!
Summary of Contents for AD-540
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