Noisy radiators irritate and disrupt sleep. Banging, hissing, gurgling or clicking? Read on… with your radiator making a noise, here’s what you can do.
What we’ll do first here is identify underlying issues that may require attention. Then we’ll help you to understand what different sounds mean, and how you can shut them up!
Radiator making a noise? This article is important to not only for short term fixes, but to avoid more serious heating system issues that could be costly.
Skip to:
- Understanding radiator noise
- Steam radiator: Troubleshooting
- Hot water radiator: Troubleshooting
- Quick fixes and immediate steps
- How to bleed radiators
- Adjusting valves
- Pipe issues
- When to call a professional
Understanding radiator noise
Radiator sounds vary significantly in their characteristics, causes, and urgency levels.
Identify the noise. This will help you troubleshoot and repair.
🔊 Banging or knocking sounds
They are among the most common and alarming radiator noises. These sharp, metallic sounds often occur when the heating system starts up or shuts down, though they can also happen during normal operation. The intensity can range from gentle tapping to loud hammering that echoes throughout the house.
🔊 Gurgling or bubbling noises
This is water moving through the radiator with air pockets creating irregular flow patterns. These sounds might be continuous during operation or occur intermittently as the system cycles on and off. Gurgling often indicates air trapped within the heating system or water flow irregularities.
🔊Hissing sounds
These sounds resemble steam escaping or air being forced through small openings. This noise might be subtle and barely noticeable or loud enough to be heard from other rooms. Hissing typically indicates pressure-related issues or problems with seals and connections.
🔊 Clicking or ticking sounds
Usually rhythmic and occur as the radiator heats up or cools down. These sounds are often related to thermal expansion and contraction of metal components and are nothing to worry about, though they can also indicate loose hardware or mounting issues.
Steam radiator: Troubleshooting
Steam heating systems rely on steam distribution and condensate return. Once you get to grips with that, you can find out why identify noises occur and what you can do about it.
To operate quietly – a steam radiator system needs… proper pitch (the slope back down to the supply valve that sends the condensate back to the boiler), functioning steam traps, and adequate venting to operate quietly.
As you can see, there is a lot that could go wrong. Look out for the following…
👉 Water hammer in steam systems creates violent banging sounds when steam and condensed water collide within pipes or radiators. This phenomenon occurs when condensate cannot drain properly from radiators back to the boiler, creating slugs of water that get pushed by incoming steam pressure. The collision between steam and water creates shock waves that produce loud banging sounds and can damage system components over time.
👉 Proper radiator pitch is essential for quiet steam system operation. Steam radiators must be angled slightly toward the steam supply pipe to allow condensate to drain back toward the boiler. If radiators have settled or been improperly installed, condensate can pool within the radiator, leading to water hammer and associated banging noises.
👉 Steam trap failures cause various noise issues in steam heating systems. These devices are designed to allow condensate to drain while preventing steam from escaping the system. When steam traps fail, they might allow steam to blow through continuously, creating hissing sounds, or they might block condensate drainage, leading to water hammer and banging noises.
👉 Air venting problems in steam systems can cause gurgling, hissing, or banging sounds. Steam radiators require proper air vents that allow air to escape as steam enters the radiator. Clogged, damaged, or improperly sized air vents prevent proper system operation and create various noise issues.
Hot water radiator: Troubleshooting
Hot water or hydronic heating systems have different noise characteristics and causes compared to steam systems.
As the name suggests, these systems circulate heated water through radiators and return cooled water to the boiler for reheating. Noise issues often relate to air in the system, pump problems, or circulation irregularities.
Look out for…
👉 Air trapped in hot water radiators creates gurgling or bubbling sounds as water tries to flow around air pockets. This air can enter the system through various sources, including fresh water additions, loose connections, or automatic air elimination device failures. Removing trapped air typically resolves these noise issues.
👉 Circulation pump problems can cause various noises in hot water heating systems. Worn pump bearings might create grinding or squealing sounds, while cavitation within the pump creates rattling or rumbling noises. Improperly sized or failing circulation pumps can also cause water flow irregularities that manifest as radiator noises.
👉 Thermal expansion and contraction in hot water systems can create clicking, ticking, or creaking sounds as metal components expand and contract with temperature changes. While some thermal noise is normal, excessive sounds might indicate improperly supported pipes, loose mounting hardware, or insufficient expansion accommodation.
Immediate steps to take
When your radiator starts making unusual noises, take the following steps:
1. Assess and identify
Begin with a systematic assessment to identify the problem and determine appropriate next steps. Start by noting when the noises occur, their duration, intensity, and any patterns related to system operation. This information helps narrow down potential causes and guides troubleshooting efforts.
2. Check radiator position
Check the radiator’s physical position and mounting to ensure it’s properly supported and level. Loose mounting brackets, improper pitch, or inadequate support can cause various noise issues. For steam radiators, verify that the unit slopes slightly toward the supply pipe to ensure proper condensate drainage.
3. Examine for signs of leaks and damage
Examine visible connections, valves, and fittings around the radiator for signs of leaks, corrosion, or damage. Loose connections can cause hissing sounds and allow air to enter the system, while corroded components might not function properly and create various noise issues.
4. Listen for source of noise
Listen carefully to identify exactly where sounds are originating. Noises might come from the radiator itself, connecting pipes, valves, or other system components. Accurate noise location helps focus troubleshooting efforts and prevents unnecessary work on unrelated components.
Bleeding air from radiators
Air trapped in radiators is one of the most common causes of noise issues and can usually be resolved through a process called bleeding. This procedure releases trapped air from the highest points in the radiator, allowing water or steam to flow properly and eliminating gurgling or bubbling sounds:
🪛 For hot water radiators, locate the bleed valve, typically found at the top corner of the radiator.
🪛 You’ll need a radiator key, small screwdriver, or appropriate tool to open the valve. Place a container under the valve to catch any water that might escape during the bleeding process.
🪛 Turn the system on and allow it to reach normal operating temperature before beginning the bleeding process.
🪛 Starting with the radiator farthest from the boiler, slowly open the bleed valve until you hear hissing air escaping.
🪛 Keep the valve open until water begins flowing steadily without air bubbles, then close the valve firmly but don’t overtighten.
🪛 Repeat the bleeding process for all radiators in your system, working from the farthest to the closest relative to the boiler.
🪛 After bleeding all radiators, check the system pressure gauge and add water if necessary to maintain proper operating pressure. Some systems have automatic fill valves, while others require manual water addition.
Adjusting valves
If radiator valves aren’t adjusted right, they can cause noise issues and impact heating performance. These valves control water or steam flow into radiators and must be properly set for quiet, effective operation.
Basically, you should understand the proper way to adjust each type of valve, because it can help you to solve noise noise problems:
🚰 Thermostatic radiator valves – should be set to appropriate temperature levels for each room’s heating needs. Valves set too high might cause excessive flow rates that create noise, while valves set too low might not provide adequate heating.
Find the proper balance that provides comfortable temperatures without creating flow-related noise issues.
🚰 Manual radiator valves – should typically be fully open or fully closed, not partially open. Partially open valves can create turbulent flow that generates noise and reduces heating efficiency. If you need to reduce heat output from a radiator, consider adjusting the return valve instead of throttling the supply valve.
🚰 Steam radiator valves – should generally be fully open during heating season. These valves are designed to be either fully open or fully closed, and partial opening can cause various noise and performance issues. If a steam radiator is overheating a room, consider adjusting the air vent rather than closing the supply valve.
Pipe issues
It’s not just the radiator itself that could be to blame.
Inadequate pipe support and improper accommodation for thermal expansion can cause significant noise issues in heating systems.
As pipes heat up and cool down, they expand and contract, and this movement must be properly managed to prevent banging, clicking, and other unwanted sounds:
🗜️ Examine exposed heating pipes for proper support and spacing. Pipes should be supported at regular intervals with appropriate hangers or brackets that allow for thermal movement while preventing excessive vibration or movement. Loose or missing pipe supports can cause banging or rattling sounds as pipes move during system operation.
🗜️ Check for pipes that might be rubbing against joists, walls, or other structural elements. Thermal expansion can cause pipes to rub against these surfaces, creating scratching, scraping, or banging sounds. Installing pipe insulation or padding at contact points can eliminate these noise sources.
🗜️ Ensure that pipes have adequate clearance through walls, floors, and other penetrations. Pipes that are too tightly fitted through these openings can bind during thermal expansion, creating stress and associated noises. Expanding these openings slightly or adding sleeve materials can provide necessary movement accommodation.
When to call a professional
We’ve advised on basic troubleshooting and maintenance to help you root out radiator noise. But certain situations require professional heating system expertise.
Recognize when to seek professional help:
👨🔧 Gas-fired boiler systems present safety considerations that require professional attention. Any work involving gas connections, combustion components, or boiler controls should be performed by licensed heating professionals. Signs of gas leaks, combustion problems, or boiler malfunctions require immediate professional evaluation.
👨🔧 Complex system issues like pump failures, boiler problems, or extensive pipe modifications typically require professional diagnosis and repair. These repairs often involve specialized tools, knowledge, and parts that aren’t readily available to homeowners.
👨🔧 Persistent noise issues that don’t respond to basic troubleshooting might indicate underlying system problems that require professional assessment. Heating professionals have diagnostic equipment and experience to identify complex issues that aren’t apparent through basic inspection.
