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Sten
Re: Dripping sound in ducts

The popping sound could also be caused by an unbalanced system or not enough return or supply, Check to see if the main trunk has cross bracing (diagonal bends from corner to corner). If it does not have the cross bracing then more than likely it's popping. Good Luck!!:)

johnL
Re: Dripping sound in ducts
Sten wrote:

The popping sound could also be caused by an unbalanced system or not enough return or supply, Check to see if the main trunk has cross bracing (diagonal bends from corner to corner). If it does not have the cross bracing then more than likely it's popping. Good Luck!!:)

I can't really picture this. Can you describe it another way?
Thanks

gmyu
Re: Dripping sound in ducts

I have the same problem. I just changed my water heater (the old one had an internal leak), and I start to hear this drip sound in the exhaust vent (went into the attic, put my ear on the exhaust vent, and clearly hear the drip in the vent pipe like every 1~2 second couple of minutes after the burner is on).

Not sure it is a condensation issue or expansion/contraction issue, but I heard the suggestion of better insulation of the venting pipe. Mine is exposed in the attic. Anybody had the experience on the improvement after adding the insulation ? If so, what kind of insulation should I do ?

canuk
Re: Dripping sound in ducts

Let's put it this way --- you've been out driving your vehicle.

When you park and shut off the engine --- you get out of the vehicle there are tinking , clicking , tapping and other similar sounds.

These are from the metal components like the engine and exhaust that have been heated --- it's a metallic sound from expansion and contraction.

gmyu
Re: Dripping sound in ducts
gmyu wrote:

Not sure it is a condensation issue or expansion/contraction issue, but I heard the suggestion of better insulation of the venting pipe. Mine is exposed in the attic. Anybody had the experience on the improvement after adding the insulation ? If so, what kind of insulation should I do ?

Follow-up on this : found out today that insulation should NOT be used around the venting pipe. In fact, min of 1" clearance to
combustibles is required.

Daniel Adams
Re: Dripping sound in ducts

I am having the same issue in my master bedroom. It is only one vent which is strange. It is very on and off and is not around water pipes. I recently got my vents cleaned when I moved in which I would've thought taken care of things.

I am thinking it may be flexing because my water pipes flex and sound like dripping. It is so weird though because it is so similar to a dripping sound and it is very steady. I would think flexing would be more inconsistent.

Should I call the vent cleaner back? I want to cut up the floor because I wake up early and hear it and cant fall back to sleep

dj1
Re: Dripping sound in ducts

The sound of metal expanding and contracting is not the same as water dripping.
To me the difference is: metal sound is inconsistent while water drip is somewhat consistent.
Metal sound is nothing to worry about, and dripping sound is a cause for action, like insulate, replace ducts or look for signs of mold.

robert jonhson
Re: Dripping sound in ducts

Hello,

I have the same annoying dripping sound from the duct in my master bedroom. Has anyone been able to solve this as yet?

Thanks

Oldfoggy
Re: Dripping sound in ducts

Natural gas contain a lot of hydrogen and when it burn turns into water. If it condenses in the exhaust vent you will hear it dripping and it could eventrually cause a puddle. Google condensing furnacs. A drain line might solve a leak caused by condensation that has collected in the bottom of the exhaust stack and is now dripping into the fire box or onto the floor. Changing the exhaust flue may solve the problem, but safely venting the exhaust is the most important issue. Oldfoggy.

danwhite77
Re: Dripping sound in ducts

Old thread, but I want to spread the word about my solution to this problem.

I had a sound in my hvac duct that I swore was water dripping. It sounded exactly like water. But it wasn't a drip at all. Instead it was, as many others suggested, thermal expansion. But it was a specific form of thermal expansion. Specifically, my water drip sound (I swore it was water!) came from the point where an elbow HVAC joint joined with my long, straight HVAC duct. I put a large worm gear clamp around the point where the long, straight duct hit the point where it joined the other duct and tightened it down hard. That worked like a charm, the sound immediately went away. You can test it before you use (or buy) the worm gear clamp by grabbing the duct with your hands and squeezing while it's making the sound. If it stops, buy the band and tighten it right where the two ducts join. Mine hasn't come back after a month or two of putting the clamp on. Just google "worm gear clamp" and you'll see what I mean. Just get a big enough one for your duct. Good luck!

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