Abstract: A boiler sequencer system having a microprocessor based controller which allows the firing rate for multiple boilers to be increased or decreased with a proportional output integrated with the process variable rate of recovery that is desired, preventing unnecessary rapid advancements to high fire even when a boiler is started with a high off-set of the process variable from its set point. The controller automatically overrides this proportionate control when the process variable rises above a predetermined maximum or falls below a predetermined minimum.

Abstract: A microprocessor-based sequencer for a multiple boiler heating system which allows the plural boilers to operate in a base load mode whereby one or more boilers can be made to operate at their optimum operating points and as the heating demand changes, a swing boiler accommodates the change, leaving the other(s) at their Preferred Load value until the swing boiler can no longer satisfy the demand change. At this point, the sequencer adjusts the base load level away from the preferred load set-point.