Top 10 Boiler Problems and How to Fix Them

10 Most Common Boiler Problems

1. Low pressure: Check the pressure gauge (should be 1–1.5 bar). Repressurise using the filling loop.
2. No hot water: Often a diverter valve fault on combis. Call an engineer.
3. Kettling noise: Limescale build-up. Consider a power flush or descaling.
4. Pilot light keeps going out: Draughts, thermocouple fault, or dirty burner. Call an engineer.
5. Boiler keeps switching off: Low pressure, overheating, or thermostat issue. Check pressure first.
6. Radiators not heating up: Bleed radiators. If that doesn't work, may need a power flush.
7. Leaking boiler: Never ignore a leak. Turn off the water and call an engineer immediately.
8. Frozen condensate pipe: Common in winter. Thaw with warm water and reset.
9. Thermostat not working: Check batteries and settings. May need replacing.
10. Boiler not responding to thermostat: Wiring fault or thermostat compatibility issue. Requires an engineer.