How to Properly Shut Down a Boiler

Boiler Storage Options

Boilers should be properly stored when out of service to prevent corrosion and system degradation. There are two main methods for boiler lay-up:

Dry Lay-Up (For Long-Term Storage)

This method removes moisture from the boiler and prevents tube wear and corrosion.

Dry Lay-Up Procedures

• Drain the boiler completely after it has cooled.
• Flush and inspect to ensure no residual sludge is left inside.
• Use warm, circulated air to thoroughly dry internal surfaces.
• Place quicklime or silica gel trays inside the boiler to absorb residual moisture.
• Seal all openings tightly to prevent air and moisture intrusion.
• Inspect every two months and replace moisture-absorbing materials as needed.

Wet Lay-Up (For Short-Term Storage)

The wet method fills the boiler with treated water, preventing oxygen contact and corrosion.

Wet Lay-Up Procedure

• Before shutting down, add boiler treatment chemicals like:
  • BOILER AID 385: Tannin-based treatment to prevent corrosion.
  • BOILER AID 386: Reducing agent to combat oxygen pitting.
• Fill the boiler completely with treated water to eliminate air pockets.
• Maintain a slight positive pressure (5 psig) of nitrogen to prevent air entry.
• Regularly test water quality and adjust chemicals as needed.

Returning an Idle Boiler to Service

Dry Storage Boilers

• Remove all moisture-absorbing chemicals before restarting.
• Check for any residual debris and clean if necessary.

Wet Storage Boilers

• Partially drain and refill with fresh feedwater to dilute excess treatment chemicals.
• If superheaters were stored wet, drain them before startup to prevent water hammer damage.