BoilerTroubleshooting2026-02-26
Combi Gives Short Bursts of Hot Water
Bursts of hot then cold water point to scale, a flow sensor or low flow.
If your combi delivers hot water in bursts, flow and scale are the usual culprits.
Common causes
Scale in the heat exchanger, a faulty flow sensor, or low water flow from clogged aerators cause the boiler to cut in and out.
What to do
Clean aerators and the inlet filter; if it persists, descaling or a flow-sensor repair is needed.
Key takeaways
- Clean taps and inlet filter
- Scale causes hot/cold bursts
- A flow sensor may be faulty
- Descaling often helps
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