A boiler concentrates everything that is wrong with untreated water. It boils water constantly, so the impurities left behind build up fast, forming scale that wastes fuel and corrosion that eats the boiler from the inside. Treating the water is basic boiler protection.

Here are the fundamentals for facilities managers and building services engineers in Ireland.

Why Boiler Water Needs Treating

A boiler is an evaporator: it turns water to steam or heats it hard, and whatever was dissolved in the water stays behind and concentrates. Hardness (calcium and magnesium) precipitates onto the hot surfaces as scale, which is a good insulator, so even a thin layer forces the boiler to burn more fuel to transfer heat, and in bad cases causes local overheating and damage. At the same time, dissolved oxygen and aggressive water chemistry corrode the boiler metal. Untreated, a boiler both wastes energy and destroys itself.

What Boiler Water Treatment Controls

Boiler water treatment addresses several linked factors, each doing a specific job in protecting the boiler:

• 1 Feedwater quality: treating the make-up water, for example softening, to reduce the hardness entering the boiler
• 2 Scale control: dosing to prevent hardness forming hard scale on heat transfer surfaces
• 3 Corrosion and oxygen control: dosing to protect the metal and deal with dissolved oxygen
• 4 Boiler water chemistry: keeping the boiler water within the correct parameters
• 5 Blowdown: removing a portion of boiler water to control the build-up of dissolved solids

Testing Keeps It Right

Dosing without testing is guessing. The boiler water and feedwater are tested regularly to confirm the treatment is holding the chemistry within range (hardness, dissolved solids, inhibitor and oxygen-related parameters), so the dose can be adjusted before scale or corrosion takes hold. Regular testing and records are how you know the boiler is protected, and they are part of running the plant responsibly.

The payoff

Proper boiler water treatment keeps heat transfer surfaces clean, so the boiler runs at its rated efficiency and burns less fuel; protects the metal, so the boiler lasts; and avoids the overheating and failures that scale and corrosion cause. It is one of the highest-return maintenance tasks on a boiler. Halpin & Hayward provides boiler and closed system water treatment, dosing and testing across Ireland see closed system treatment for heating and chilled water circuits, which share the same principles.

• Water hygiene is a duty
  This is general guidance for Irish premises. Managing water hygiene and legionella risk is a legal duty for those in control of premises, based on a written risk assessment. Confirm your obligations against current guidance (including the HPSC national guidelines and HSG274) and treat this as background, not a substitute for a site-specific assessment.

Frequently Asked Questions

Why does boiler water need to be treated?

Because a boiler continually evaporates water and concentrates the impurities left behind. Hardness forms scale that insulates the heat surfaces, wastes fuel and can cause overheating, while oxygen and aggressive chemistry corrode the metal. Treatment controls both, protecting efficiency and the boiler itself.

What does boiler water treatment involve?

Treating the feedwater to reduce hardness, dosing to control scale, corrosion and oxygen, keeping the boiler water chemistry within range, and blowing down to control dissolved solids, all confirmed by regular testing of the boiler and feedwater so the dose stays correct.

What is blowdown in a boiler?

Blowdown is removing a portion of the boiler water to control the concentration of dissolved solids that build up as the boiler evaporates water. Along with dosing and feedwater treatment, it keeps the boiler water chemistry within the correct range to prevent scale and corrosion.