Abstract: A fuel burner sequencing means is disclosed which utilizes a bistable or alternate action switching means for safety checking. The bistable switching means is specifically disclosed as a bistable relay that operates at the start of the cycle, and at the end of the cycle to check the operability of the safety checking means. This same bistable relay means is used as a lockout means in the event of the failure of flame when a flame should exist in the burner, or when a flame is indicated and none should be present.

Abstract: A fuel burner sequencing device is disclosed which utulizes cam operated switches in conjunction with relays to program the initiation and safe operation of a fuel burner. The sequencing device or means provides for a normal start up and ignition of a fuel burner, and then provides for a postpurge pilot operation for a normal shutdown of the burner. The postpurge pilot operation activates the pilot burner during the time the main burner is on thereby lighting the pilot burner before the main burner is turned off. The pilot burner is retained in a burning state for a short period after the main burner has been turned off to burn off any residual fuel before the sequencing device or means completes its sequence and is ready for the initiation of a new operating cycle.