How to Silence a Noisy Radiator

Are your radiators clanking and keeping you up? That cacophony is what's known as "water hammer."

In short, there is water trapped in the radiator. Steam is trying to get in, and when it can't easily get past the water little pockets of pressure explode and make your wonderful sounds.

What Causes Water Hammer?

There are a number of specific things that could cause water hammer, but the general symptom is always the same.

Steam radiators are usually designed with one opening. This single pipe allows steam to come in and circulate through the radiator. As the steam gives off its heat, it will condense into water.

If the system is working properly, that condensate will drain out of the radiator through the same pipe and return to the boiler. Water hammer happens when the system is not working properly, and the water can't drain out of the pipe.

The steam can't get in without going through the water, and doing so creates a heckuva lot of noise. Not to mention, it reduces the efficiency and effectiveness of your heating system.

Maybe you should do something about it.

Ok. What Do I Do About It?

As we previously established, the radiators are designed to allow water to drain out of them through the intake valve. How does that work? Gravity.

If the radiator is set up properly, it should tilt at a slight grade towards the intake valve. This will allow gravity to force the condensate into the intake valve and out of the radiator. No moving parts necessary - just the work of mother nature.

Unfortunately, radiators have a nasty habit of ruining that perfect grade. Over time the floor can warp or the radiator can dig grooves into the floor. This can eventually result in the radiator being graded away from the intake valve. When that happens, water can't naturally drain - and you end up with water hammer.

The simplest solution for this problem is to shim the radiator until it is graded properly. Any thin piece of wood or plastic will do. My radiators sit on a wood plank, so I placed a couple of paint sticks underneath the far end to tilt the radiator back towards the intake valve.

When you think you've got it right, check the grade with a level. Sometimes your eyes can deceive you.

If you graded the radiator properly, it should start to drain and the water hammer should disappear or be significantly reduced.

Arg! It's Still Loud!

If you still have a problem, then you may be suffering from something else. While that's a topic for another day, here are a few suggestions for what you might consider.

Your steam pipes are uninsulated, causing the steam to cool prematurely. Solution? Insulate the steam pipes.

There is a build-up of sediment in your radiator and/or boiler. Solution? Drain the sediment out of the boiler, and disconnect and flush out the radiator.

Your radiator's steam vent is malfunctioning. Solution? Replace the steam vent.

Be patient, and once you diagnose the right problem you'll be able to enjoy some peace and quiet!