One of the last things you want to encounter on a cold winter night is strange noises coming from your boiler. Following are three of the most common sounds that boilers make, what they mean, and what you should do about them.
Gurgling sounds coming from your heating system means that there's water trapped inside your pipes. Although this problem does not present an immediate danger to household residents, it should be fixed as soon as possible because air in the pipes will cause your heating system to work harder to produce results -- and this will cause wear and tear on parts and may increase your utility costs. To fix the problem, check the owner's manual of your boiler for an air-release valve. These may also be located on radiators. Opening these valves will allow you to release trapped air from your water pipes.
However, use extreme caution if you decide to go this route. Your furnace should be turned completely off and left that way long enough for the water in the lines or in the radiator to cool down. Otherwise, you run the risk of being burned by escaping steam and even hot water. If your owner's manual doesn't show an air-release valve, call a boiler repair professional for assistance.
Creaking sounds are frequently the result of pipes that have been placed too close to the floorboards in a home. As the hot water moves through the pipes, it causes the metal to expand, and if there is inadequate room beneath the floorboards for the pipes, they'll end up making contact with the floorboards during expansion, causing the creaking. This situation can sometimes be alleviated using insulation to keep the pipes from moving provided there is ample space, but otherwise, the pipes will have to be lowered so that they don't come into contact with the floorboards. Like gurgling sounds, creaking noises caused by expanding pipes doesn't pose an immediate threat to the safety of household occupants, but if allowed to continue, wear and tear on the heating system as well as on the floorboards will definitely become an issue.
Kettling noises are similar to gurgling sounds only louder and with more variation -- they may for instance, include loud rumbling, clanking, and percolating not often associated with simple gurgling. If your boiler is kettling while it's in operation, the culprit may be mineral deposits -- particularly if your boiler hasn't always made this specific noise. As boilers age, mineral deposit buildup may take its toll, particularly if hard water is a part of the picture. The mineral deposits themselves, however, don't actually cause the kettling sounds -- those happen as a result of large air bubbles being formed, otherwise known as boiling, because the lime deposits on the boiler's heat exchange tubes create the need for higher temperatures, resulting in boiling.
Contrary to what its name implies, the boiler is not supposed to boil water. The water running through your system is supposed to be heated by the boiler to just several degrees below the water's boiling point, but the layer of mineral deposits on the exchange tubes causes hot spots to form. The settling noise is caused by the air bubbles collapsing as they come into contact with cooler water elsewhere in the system. Like the other problems mentioned above, this issue doesn't put your family at immediate risk, but it may cause fuel costs to increase because the system is working harder. Also, the mineral deposits won't go away on their own, so it's best to have the affected parts replaced by a professional technician experienced in maintaining and repairing boilers. Please feel free to contact a company like Moorhead Machinery & Boiler Co. at your convenience for more advice on how to keep your furnace boiler working in top condition.