The 24 VAC DS845 Direct Ignition Control is applicable to commercial cooking equipment, gas fired heating and water heating systems of many types. The system acts on a demand for heat by a switch or thermostat to open the gas valve. At the same time the DS845 ignition control supplies a spark to the electrode which ignites the gas. After the gas is lit, an electronic circuit proves the presence of flame using flame rectification. When the thermostat is satisfied, the gas valve will be closed to shut off main burner gas.
Robertshaw - Direct Spark Ignition Control - 780-502
installed 12-7 20 ignited flame gas fireplace and is working so far thanks stay safe richard