Softener vs. deaerator? Softener AND deaerator. Technical intervention saves a boiler system.

What this case study covers

A growing food manufacturer moved its firetube steam boilers into a new plant on hard Chicago city water. The installer added a deaerator but no softener. The deaerator scaled over every few days, feedwater oxygen ran near 4 ppm, and no treatment residual held, while the contractor and the water treater blamed each other. An independent audit found the root cause, put it in writing, and the installer corrected it at its own cost.

Inside this case study

• Why a deaerator is not hardness pretreatment, and what heating hard water does inside one
• How a restricted vent turns a deaerator into a feedwater heater
• Why sulfite and phosphate fed ahead of the deaerator never reached their targets
• Skimmer versus bottom blowdown, and where the boiler scale came from
• The three-point feed layout: deaerator storage, feedwater line, steam header
• How the dispute ended: contractor-paid corrections, warranties restored, ~$98K avoided