The usual suspects
Scale on the heat exchanger
Mineral deposits insulate the metal; water trapped behind them flash-boils and bangs. The defining cause.
Restricted flow
A tired pump or clogged strainer slows the water so it overheats in the exchanger.
A faulty aquastat
A control letting the boiler overshoot temperature produces the same theatrics.
Trapped air
Adds pops and gurgles on top — and often accompanies the real problem.
Descale it before it retires early.
Kettling shortens exchanger life every week it runs. The flush-and-treat fix is routine for us, priced upfront.
Book My Same-Day Visit60 seconds online · or call (206) 486-6373
Worth trying first (5 minutes, free)
- 1
Note when it rumbles: at firing, steadily, or after zone changes.
- 2
Check the pressure and temperature gauges — snap a photo for the visit.
- 3
Don’t max the thermostat to compensate — it makes kettling worse.
Still not working? Then it’s a technician job — and the sooner it’s booked, the sooner the house is comfortable again. Book the visit →
Stop and book a pro if…
- Banging that’s getting louder week over week.
- Lockouts or leaks joining the noise.
- Temperature gauge running hotter than its usual mark.
- The boiler is 15+ years old and kettling hard — get the honest assessment.
Why homeowners hand it to us
- You approve the price first. Upfront quote before a single screw turns.
- Same-day service. Book in a minute, hear from a tech within 1 business hour.
- 500+ jobs done by 4.9★ rated, professional technicians.
- Fixed right, guaranteed. If it’s not right, we make it right.
Quick answers
Is kettling dangerous?
Modern boilers have safety cutouts, so explosion fears are movie stuff — the real cost is efficiency and exchanger life draining away. It’s a book-soon, not a panic.
Can it be fixed or is the boiler done?
A power flush and inhibitor treatment cures most kettling outright. A badly scaled older exchanger changes the math — we’ll show you honestly which side yours is on.
Will it come back?
Not soon, if the system is dosed with inhibitor after the flush — that’s standard in our fix, and it protects the pump and radiators too.
Done guessing?
A quieter, cheaper-to-run boiler is one visit away. Book it.
Book My Same-Day Visit60 seconds online · or call (206) 486-6373
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