Honeywell programmer control rm7840l1018, lhl-lf&hf proven purge features provides safety, functional capability and features beyond conventional controls functions include automatic burner sequencing, flame supervision, system status indication, system or self-diagnostics and troubleshooting access for external electrical voltage checks application flexibility and communication interface capability five leds provide sequence information five function run/test switch interchangeable plug-in flame amplifiers local or remote annunciation of rm7840 operation and fault information nonvolatile memory retains history files and lockout status after loss of power compatible with existing honeywell flame detectors