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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. (liquid propane) 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 utilizes 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 (Direct
Spark Ignition) 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.

DIRECT SPART IGNITION (DSI) SYSTEM COMPONENTS/FUNCTIONS