Patent ID: 6390027
Filing Date: 2002-05-21
Classification: F22B,G01F,G05D

Abstract:
A cycle control system for use with a boiler having a fluid therein, the boiler including an associated burner and a demand control circuit for turning on and off the burner responsive to demand, the cycle control system comprising:a timing circuit for producing a burner control signal having alternating on and off states, the timing circuit including: an on-period timer having an on-period for controlling the on state of the burner control signal, the timing circuit switching the burner control signal to the off state at the end of the on-period; an off-period timer having an off-period for controlling the off state of the burner control signal, the off-period being of sufficient duration to allow foam and surging fluid in the boiler to settle to allow accurate determination of fluid level in the boiler, the timing circuit switching the burner control signal to the on state at the end of the off-period; and a burner monitor circuit having an input for monitoring when the burner is on and off, the timing circuit resetting the on-period timer whenever the burner monitor circuit indicates the demand control circuit has turned off the burner for a length of time sufficient to allow foam and surging fluid in the boiler to settle; and a relay responsive to the burner control signal and connected to enable and disable the burner, the relay permitting the demand control circuit to turn on and turn off the burner when the burner control signal is in the on state and the relay disabling power to the burner when the burner control signal is in the off state.