Haunted radiators

November 19, 2006 3:55 PM

Weird noise filter: the heater in my new apartment makes this metallic noise every so often. What is it, and can I make it stop?

My apartment has these radiators (one or two in each room) that look like electric baseboard heaters, but they use hot water. The one along the wall in the living room makes this odd noise every 2 to 3 minutes. The radiator works fine otherwise and appears to be identical to the other, silent, radiators in the apartment. The sound is similar to a metal folding chair being scooted across a hard floor, and its quite startling, especially when I'm trying to sleep in the middle of the night.
Its not a major problem, but I'd like to hear if anyone else has had the same experience, and what your solution(s) were.
More info: the building is medium sized, about 40 years old, and uses a central boiler for heat. It hasn't been remodeled as far as I know, but its in decent condition. I've heard the same noise in the basement garage as well (something with the pipes?) but I'm still at a loss.

posted by azuresunday to Home & Garden (4 answers total)

It depends on the kind of radiator. As far as I know there are at least two kinds. One has a single pipe, and operates by steam (vapor) coming up the pipe, condensing into liquid, and then draining back out the pipe. The other has two pipes, and hot water simply circulates in one and out the other. In this type, air bubbles can get trapped in the system and make noise, which is what it sounds like you have. The trapped air could be do to a number of reasons, and could make all sorts of strange ghostly noises. It really is just a matter of getting on your landlord's case about it, as there is nothing you as occupant can really do.
posted by Rhomboid at 4:12 PM on November 19, 2006

Rhomboid mostly covered it. However, a bit more on the steam-style radiators: they will only have a pipe at one end, not both, and if they're not at a slight decline back toward the pipe, the condensate can't go back down the pipe as well, and funny noises occur. (if you have steam) try shimming up the end away from the inlet pipe, maybe 1/4 inch.
posted by notsnot at 4:49 PM on November 19, 2006

Also, metal expands when warmed, so it can creak when heat is applied and it rubs against other metals/surfaces.
posted by Loto at 5:25 PM on November 19, 2006

Probably your radiator needs bleeding. If this is the case, it should really be an easy fix. No matter what the cause, it sounds like it's been a while since the system was inspected - probably high time.
posted by plinth at 6:27 PM on November 19, 2006