Why Are Your Radiators So Noisy?

Boiler heating has its ups and its downs. It certainly delivers comfortable, even warmth in an energy-efficient manner, but sometimes, the radiators can get a bit noisy. Don't just ignore your noisy radiators. When functioning properly, a boiler heating system should be essentially silent, so any noises coming from your radiators are a sign that something is wrong. Thankfully, the fix is usually simple and easy to tackle yourself. Here's a look at some common causes of noisy radiators and how to address them.

Air in the radiator.

If you have a water boiler system (in which the water itself, rather than steam, circulates through the radiators) any banging and clanging noises you're hearing may be caused by air that's trapped in the radiators. When there's air in the radiator, water can't fill it completely, so portions of the radiator end up being different temperatures. The metal of these various parts of the radiator expands and contracts at different rates, and this causes the banging noises.

All you need to do to remove air from the radiators is bleed them. Locate the bleed valve. It usually looks like a little slot that a key fits into. If you have a radiator key, then you're ready to go. Otherwise, take a picture of the bleed valve and take it with you to the hardware store to find a key of that shape. (There are only a few standard radiator-key shapes, so finding the right one won't be hard). Insert the key into the valve, and give it a turn. Air should come hissing out. When the air stops flowing and a gurgle of water comes out, turn the key back to close the valve again. Your radiator should not operate quietly.

A Loose Pressure-Release Valve

If you have steam radiators, the problem probably traces back to a pressure-release valve that's too loose. This valve is meant to allow a small amount of air to escape from the system, but if the valve is too loose, it can cause hissing and squealing noises. The valve is usually found about halfway up the radiator and looks like a little cylindrical projection from the radiator. The top may twist, either with your fingers or a screwdriver. Turn it to the right or left until the squealing stops.

If your radiators are still making noise after you  consider and address these causes, talk to your HVAC contractor. There's a chance that a leak in your system is contributing to the noises, and this is an issue that needs to be addressed professionally.