Why Is My Boiler Making Noise?
Many homeowners rely on boilers to keep their houses warm. However, the sounds that a boiler makes can be alarming, especially when you hear one you’re unfamiliar with. So, why is my boiler making noise?
If your boiler is rumbling, it may mean that the heat exchanger has limescale buildup that you must clean to fix the problem. Drilling and vibration sounds can point to a loose blower or flue blockage, respectively. Hissing and clicking sounds are normal boiler noises you don’t have to worry about.
Call a local plumber right away if you hear new sounds your boiler doesn’t usually make. Otherwise, you don’t typically need to worry if your boiler is noisy when it first turns on. Follow along as we explore why your boiler is making noise and highlight solutions.
9 Common Boiler Noises And What They Mean
1. Hissing
Hissing sounds coming from your boiler may sound bizarre, but there is nothing to worry about. Some people refer to it as a “whirring” sound, but a hissing sound doesn’t indicate a problem. Hissing or whirring sounds typically appear when a boiler first turns on.
Don’t rush to conclusions and assume that something is wrong with your boiler. However, it’s worth calling a plumber if the hissing sound never ends. For example, that may indicate excessive limescale near the heat exchanger.
In that case, they will use a special solution, such as a descaler to clean the heat exchanger. You can do that without professional help as well. However, it’s worth calling a plumber if you aren’t familiar with your boiler’s components.
2. Grinding
Grinding is among the most concerning boiler sounds you can hear. This typically indicates serious problems, such as a loose or worn bearing within the pump motor. Your boiler may seize up or overheat if the pump motor bearings become loose.
In that case, your boiler may unexpectedly stop working. It’s important to call a plumber right away if you notice grinding sounds coming from your boiler. That way, you can rule out serious problems or address them as needed.
After all, loose bearings can cause irreversible damage that can shave years off the lifespan of your boiler. The best-case scenario is that the grinding sound is due to trapped air within your boiler.
3. Humming
Humming is a common boiler sound that distresses some homeowners. However, it doesn’t necessarily indicate that something is wrong with your boiler. In some cases, a humming noise indicates that water is moving around too quickly for the system.
Humming can also indicate that the pressure within the boiler is too high. It's similar to a tea kettle that fills with steam and pressure and hums loudly before it turns into a shrill whistle. You can typically fix this problem if you adjust the speed of your boiler.
Follow the instructions and set the boiler to the recommended speed. If you lost the instructions and can’t figure out how to adjust the boiler speed, contact a plumber.
4. Banging
Understandably, you may get scared if you hear banging sounds from your boiler. This can happen for several reasons, such as delayed ignition and overheated water. Once water overheats, the steam and bubbles can create pressure, resulting in banging.
This can also happen if the water in your boiler rapidly changes direction. You can fix this problem if you reverse the pump’s direction. However, that is best done by a plumber if you have no experience with boiler maintenance.
Otherwise, the banging sound may occur because the pipes leading to the boiler rub against each other, the wall, or wooden supports. In that case, it helps to place foam around the pipes to minimize the noise.
5. Clicking
The mixture of heat and water present within boilers can cause expansion and pressure. This often leads to a clicking sound that worries some homeowners and renters alike. However, this is a normal sound that you don’t have to worry about.
The pipes and heating elements within your boiler produce a clicking sound when they expand. This happens when a boiler first heats up. Don’t worry about this problem unless the clicking doesn’t seem to stop.
In that case, it’s worth calling a plumber to see if something is wrong with your pipes or heating element. Otherwise, you should be more concerned if you don’t hear your boiler clicking. That may be a sign that your boiler isn’t working, or at least not fast enough.
6. Drilling
Drilling sounds aren’t normal when it comes to boilers. However, they are common, as many people run into problems with their boiler’s blower. A drilling or pinging sound indicates that the air blower is loose, dirty, or even corroded.
The best-case scenario is that you must simply clean the blower. However, you may need to replace the air blower if it’s heavily corroded and damaged. It costs an average of $600 to replace the blower, or as little as $200 depending on the model.
7. Vibration
Vibration is common with boilers, and it isn’t always a problem. In some cases, it simply indicates that your boiler has a few loose screws. This is an easy fix, as you can simply tighten the screws to reduce the vibration and fix the problem.
However, excessive vibration may indicate that your boiler’s flue has a blockage. Boiler flues can get clogged with debris and cause the unit to vibrate as it runs. In that case, you must shut your boiler off, let it cool down, and clean the flue.
8. Whooshing
Does it sound like a gust of wind is trapped inside your boiler? This whooshing sound is common in some boilers, and it requires attention. There’s a good chance that your circulation pump is clogged with debris.
The sound comes from air struggling to pass through the circulation pump. Whether it be debris, dust, dirt, or animal dropping, the problem will continue until you remove the debris. It’s worth calling a professional if you aren’t familiar with your boiler’s parts.
9. Rumbling
Much like hissing, rumbling often occurs when your heat exchanger has lots of debris. While hissing points to mineral buildup near a heat exchanger, rumbling points to debris within it. This typically happens when the heat exchanger becomes full of limescale.
It can also happen because of a faulty gas valve or pressure imbalance within your boiler. You can fix this problem by replacing the gas valve if it’s faulty. Otherwise, you must clean your heat exchanger or adjust the pressure.
Summing It Up
Hissing is one of the most common boiler signs when it first turns on, and it’s nothing to worry about. Grinding is more concerning, as it may mean that your pump motor has loose bearings that you must tighten or replace. Rumbling can indicate excessive limescale in or around your heat exchanger, and you must clean it.
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Nick Durante is a professional writer with a primary focus on home improvement. When he is not writing about home improvement or taking on projects around the house, he likes to read and create art. He is always looking towards the newest trends in home improvement.
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