For heating boilers, summer means shutdown. But 'shutting down' doesn't mean 'walking away'. Improper lay-up is the #1 cause of boiler corrosion.
Why Corrosion Happens
When a boiler cools down, the steam condenses, creating a vacuum that pulls in air. Oxygen in the damp environment attacks the metal, causing 'pitting' which can perforate tubes in a single season.
Method 1: Dry Lay-up (Recommended for >3 months)
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Drain & Dry: Drain the boiler while still warm compared to the boiler room. Open all handholes and manholes. Use fans to blow hot air through the shell until Bone Dry.
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Desiccant: Place trays of quicklime (2 lbs per 1000 gallons volume) or silica gel inside the shell.
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Seal: Close all openings tightly. Check monthly; if lime turns to powder, replace it.
Method 2: Wet Lay-up (Short Standby)
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Fill: Fill the boiler completely to the vent valve with treated water.
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Chemicals: Add excess oxygen scavenger (sulfite) and caustic soda to maintain pH > 11.
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Monitor: Check chemical concentrations weekly. Circulate water periodically if a pump is available.
This summer, take care of your boiler, so it takes care of you next winter.