Modern central heating systems make various sounds during operation. Some are completely normal; others indicate problems that need attention.
Normal sounds
- Gentle gurgling when filling up: Normal — water circulating through the system
- Ticking when pipes heat and cool: Normal — thermal expansion and contraction
- Faint whooshing: Normal — water flowing through pipes
Sounds that need investigation
Kettling (boiling/rumbling from the boiler): Scale or sludge on the heat exchanger causing localised boiling. Needs a power flush and descale. Don't ignore this — it damages the heat exchanger over time.
Banging or clunking: Often water hammer — sudden pressure changes in the pipework. Can indicate a faulty pump, closed zone valves, or incorrect system pressure.
Dripping sounds: Could indicate a small leak. Check around the boiler and all visible pipework.
Whistling from radiators: Air in the system — bleed the affected radiators.
Grinding from the pump: The circulating pump may be failing. This needs attention before the pump fails completely (which will leave you with no heating).
What to do
Don't ignore persistent unusual sounds — what starts as a minor issue usually becomes a more expensive repair if left. Call us for a diagnosis.