Banging, whistling or a kettle-like rumble means the heat exchanger is overheating locally — usually limescale or sludge. Left alone it shortens the boiler's life; caught early it is a flush, not a replacement.
Noisy or kettling boiler — Edinburgh repair?
Kettling is caused by scale or magnetite sludge restricting flow through the heat exchanger, so water boils locally and knocks. On Edinburgh's soft mains supply it is more often sludge from old steel radiators than limescale. The fix is a chemical or power flush plus an inhibitor and a magnetic filter, not a new boiler.
Key points
Magnetite sludge from ageing steel radiators restricting the exchanger
Limescale on harder supplies at the Midlothian and East Lothian fringe
Pump running too slowly or set to the wrong speed
Air trapped in the system after works or a top-up
Most likely causes
Magnetite sludge from ageing steel radiators restricting the exchanger
Limescale on harder supplies at the Midlothian and East Lothian fringe
Pump running too slowly or set to the wrong speed
Air trapped in the system after works or a top-up
Failing pump bearing — a distinct constant whine rather than a rumble
Check these before you call
Bleed the radiators and re-check the pressure
Note whether the noise happens on heating, hot water or both
Look at the radiator water when bleeding — black water means sludge
How the visit works
Fixed £95 diagnostic, booked to a two-hour window
Fault traced to the component — no speculative part-swapping
Written quote before any repair begins
Common Worcester, Vaillant, Ideal, Baxi and Glow-worm parts on the van
Rarely. It means the water side is dirty or restricted. A flush, an inhibitor dose and a magnetic filter resolve most cases and cost a fraction of a replacement.
Chemical flush or power flush?
A chemical flush suits a system that is mildly dirty and still circulating well. A power flush is for heavy sludge, cold-at-the-bottom radiators or repeated pump failures. We tell you which on the diagnostic rather than defaulting to the expensive one.
How much does a boiler repair cost in Edinburgh?
Heatscape charges a fixed £95 diagnostic across every EH postcode, deducted in full from any repair carried out on the same visit. Out of hours (after 6pm and weekends) is £140. Most common repairs land between £120 and £420 all-in including parts and labour. If a repair would cost more than about £600 on a boiler over 10 years old, we quote a like-for-like replacement at £2,295 instead.
Are boiler repairs guaranteed?
Every repair carries a 12-month workmanship guarantee, and manufacturer part warranties are passed through in full. If the same fault returns inside 12 months there is no second diagnostic fee.