pipe banging on cool down

Brad White

Can you isolate the noise to a particular spot? My thinking here is that you may have a coupling or fitting boss catching on a joist or structure during warm-up, then upon contraction it releases suddenly.

If it is pervasive or less defined, I would suspect sudden condensation (collapse of steam into condensate), the vacuum from which can cause some banging or noise. Uninsulated pipes can be prone to this, or if vents are not opening and thus do not relieve the vacuum.

Just two thoughts from here, others will have more I am sure.

dano

pipe banging on cool down

Hi,

last year I added onto my existing steam system, which was blissfully quiet. I tapped into the 2" main with two tees to bring steam to two rooms in a new addition. It took a while to get the system working well again, (as I am a novice homeowner) but now everything heats evenly (thanks in no small part to dan holohan's "the lost art of steam heating." Thanks Dan!)

However, on cool down, on a branch of the system I did no work on whatsoever, I get some light banging. Just wondering what it might be.

dano

I can isolate it to one, maybe two radiators. Both work off the same portion of the main. I have thought I might have some condensate build-up inside of one of the radiators . . .but wouldn't that make noise on startup?

Brad White

Banging on Start-Up

Condensate sitting in a line would cause banging on start-up, yes. But on cool-down, the motive force is no longer a positive but a negative pressure, the collapse of the steam volume is my thinking.