ADC AD-200 - Manual (Page 19)

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SECTION V
COMPONENT DESCRIPTION/REPLACEMENT
A. HEAT SECTION
The dryer uses three (3) types of heat sources: natural gas, liquid propane (L.P.) gas, and steam. Natural gas and
L.P. gas are not directly replaceable. The gas valves need to be modified to use other than the type of heat
specified on the nameplate.
1. Gas dryers utilize a Direct Spark Ignition (DSI) module to monitor that a flame is established. If for some
reason the flame signal is lost, the DSI module will shut off the gas valve and not retry ignition (no try to
restart the flame). A spark of approximately 14,000 volts is used to establish a flame. The DSI module will
turn the gas valve on and ignitor/flame-probe will spark for 8-seconds attempting a flame. Each time the
dryer calls for heat the microprocessor controller (computer) will send a 24 VAC signal through the exhaust
hi-limit, sail switch, and oven hi-limit. At that point, the DSI module will try for ignition.
DSI SYSTEM COMPONENTS/FUNCTIONS
Johnson (DSI) Control Module P/N 128935
ADC (DSI) Control Module P/N 128973