Fired Heaters

Mr. Norm Lieberman. At the seminar you taught us last year, you talked about adjusting excess O₂. My boss says 3%-4% should always be our target. Is this right?

---James, Ohio

Jim – I remember that you asked this same silly question at the seminar. Excess O₂ must be adjusted without reference to an arbitrary target. Adjust your excess O₂ (assuming you’re on TRC) to minimize fuel gas consumption to reach the desired heater outlet temperature. This is best done on the stack damper unless your draft in the fire box is less than 0.05”-0.10” H₂O. If less than this range, pinch on your air registers.

---Norm