Normally, a hot water boiler heating system operates so quietly, you may not even notice that it’s running. However, occasional issues can crop up, creating unusual noises in your system. Here are some common causes of a noisy boiler, along with advice on how to restore peace and quiet.
When the water in your boiler heats up, naturally-occurring minerals precipitate out and settle at the bottom of the tank. If the buildup restricts normal flow inside the heat exchanger, water trapped inside overheats and begins to rapidly boil and bubble.
As these bubbles move upward and dissipate in the cooler water near the top of the tank, they make a loud rumbling or percolating sound known as “kettling.” To quiet things down, add a descaling product to dissolve the mineral buildup, and then drain and refill the tank.
A faulty boiler thermostat that allows water to overheat and boil can also cause disturbing kettling noises. In some cases, the thermostat may simply be set too high and lowering the temperature will solve the problem. If your system’s heat output decreases after doing so, have your heating professional check whether your thermostat is defective and needs replacement.
Air Inside the System
If air gets into your system, pressure differences in the tank can cause knocking and banging sounds in the radiators and pipes. Air can infiltrate the boiler system through faulty valves, the expansion tank or leaks in the pipes and connections. You can put a stop to the noise temporarily by using the bleed valves on your radiators and boiler. To avoid a recurrence, have your HVAC contractor locate the source of the air leak and correct it.
Low Water Pressure
When the water level or pressure is too low, your boiler can overheat, resulting in rumbling kettling noises. A knowledgeable HVAC specialist can diagnose whether faulty valves, frozen pipes or incorrect flow-rate settings are responsible for the system’s pressure and water flow issues.
If you have a noisy boiler in your Greater Cleveland area home and need expert advice, contact Stack Heating & Cooling today.
Our goal is to help educate our customers in Cleveland, Ohio about energy and home comfort issues (specific to HVAC systems). For more information about boilers and other HVAC topics, download our free Home Comfort Resource guide.
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