Power-flush your central heating.

Power flushing forces water and chemicals through your central heating system at high pressure, dislodging sludge, scale, and corrosion debris. It's a non-negotiable step before installing a new boiler and a useful periodic maintenance. This guide covers what it costs in 2026, when it's needed, and what proper power flushing involves.

What Does the Work Involve?

• Connection of power flush machine to system.
• Cleaning chemicals injected to break down sludge.
• High-flow flushing through each radiator, one at a time.
• Reversal of flow to dislodge stubborn deposits.
• Fresh system inhibitor added at end.
• System repressurised.

Typical Costs

How Long Does It Take?

• Average house: 4-6 hours.
• Larger systems: full day.
• Add 1-2 hours for severe sludge.

When Is It Needed?

• Before new boiler install (mandatory for warranty).
• Heating slow to warm up.
• Radiators cold at bottom (sludge collected).
• Boiler kettling.
• Brown water when bled.
• System never flushed (10+ years).

UK Regulations

• Manufacturer warranty typically requires flush.
• No external regulation but industry standard.

Common Problems

• Skipping the flush — new boiler clogs within months.
• Wrong chemical dose — under-effective cleaning.
• Radiator damage from high pressure — old radiators may leak.
• Magnetic filter not installed afterwards — no protection from future build-up.

Frequently Asked Questions