A condition control system in the form of a fuel burner control means is disclosed. A group of relays and their associated contacts are used to control the burner means. The status of the relays and their contacts are continuously checked by a control logic means by having the voltage on key relay output contacts fed into the control logic means through isolated signal transmission means. All of the relays are capable of being deenergized in the event of the need for safety shut down as determined by the control logic means.