During unsafe firing conditions in a large automatic auxiliary boiler, various control actuators are interlocked with the burner circuit to prevent start-up, in addition to safety shutdown. These controls are referred to as __________.

Correct Answer: Option A — limit controls

Limit controls are critical safety interlocks, such as low-water cutoffs, high-pressure limiters, and draft switches. They verify safe operating parameters before allowing burner start-up and immediately initiate safety shutdowns if unsafe operational conditions develop during automatic boiler operation.