HVAC help Ducts popping during and slightly after furnace start up

[Meast21]

Not growing currently, but...

Had my furnace for 6 years now and I don't think its ever done this before (basement had fans running before when I was growing weed, so fans were loud), it started maybe 2 weeks ago. Random parts of my ducting in my basement are making a slight popping sound. Its different ducts at random times, sometimes 3 seconds apart, then 10 secs, then 1 minute etc etc. I can hear it threw my bedroom vent sometimes randomly and its annoying bc I am sound sensitive from tinnitus. Any suggestions? I don't care about the noise as long as something isn't wrong. Its been cold here too. Would insulating the duct that runs to the basement prevent me from hearing the slight pops? ....
On other websites people are saying it could be the tin expanding during heat up although its doing it for a few mins after furnace turns off. If it only does this in the winter when the furnace is on does that tell you it is the expanding tin?

Would turning the blower motor down help? Seems like its at a high level bc air pours out of it, also maybe bc I have short duct runs bc house is small. Would turning the blower motor down make less heat come out which would raise my gas bill?

 

[tyler.durden]

Same thing is happening for me because I had all my ducts professionally cleaned. They were dead silent before the cleaning, because the inside of the ducting had a 2 inch coating of dust and debris inside them. The cleaning company stated that is completely normal, and from what I've read, it is common after cleaning. Not sure what would stop this banging, insulating them would probably help, but that sounds like $. If you find a cheap solution, let us know. I'm used to it now, but it still sounds like ghosts are slapping the some of the duct work downstairs whenever the heat turns on, then off again.

 

[Meast21]

Same thing is happening for me because I had all my ducts professionally cleaned. They were dead silent before the cleaning, because the inside of the ducting had a 2 inch coating of dust and debris inside them. The cleaning company stated that is completely normal, and from what I've read, it is common after cleaning. Not sure what would stop this banging, insulating them would probably help, but that sounds like $. If you find a cheap solution, let us know. I'm used to it now, but it still sounds like ghosts are slapping the some of the duct work downstairs whenever the heat turns on, then off again.

Mine is like random popcorn popping and its doing it all over the house randomly. Sometimes 10 secs apart, sometimes 5 mins... I had my ducts cleaned 2 years ago, but the popping didn't happen last year... I wonder if turning down the blower motor speed would solve anything??? We need HVAC guys on this thread...

 

[Meast21]

Same thing is happening for me because I had all my ducts professionally cleaned. They were dead silent before the cleaning, because the inside of the ducting had a 2 inch coating of dust and debris inside them. The cleaning company stated that is completely normal, and from what I've read, it is common after cleaning. Not sure what would stop this banging, insulating them would probably help, but that sounds like $. If you find a cheap solution, let us know. I'm used to it now, but it still sounds like ghosts are slapping the some of the duct work downstairs whenever the heat turns on, then off again.

Does you ever get the noise when the furnace is off?? I do, its like its built up and the first you mins after its off its making the popping noise.... Also check you're air filter, could be clogged up... What size air filter do you use and what is the MERV value? .... Been reading on reddit that all the HVAC guys say a lower MERV value will cause less wear and tear on the HVAC system. My filters are 16x25x1. Since its only 1" thick I should have a MERV filter over 8.

 

[Grandpapy]

Watch for rats, I've seen them bang on heater vent outlets looking for a lose one.

 

[Absorber]

Do you have access to where the duct is popping? you could possibly apply some of this on the area to deaden the sound a little

 

[Meast21]

Do you have access to where the duct is popping? you could possibly apply some of this on the area to deaden the sound a little View attachment 5449795

Thanks its all over the ducting. Random different spots... My hvac guy is coming Tuesday. It only bothers me when I try to get to sleep or back to sleep. Its not loud, way less than a kernal of corn popping.

 

[Meast21]

Watch for rats, I've seen them bang on heater vent outlets looking for a lose one.

It's not banging, its a slight popping sound.

 

[Meast21]

Ok so I'm getting the 13 feet of metal ducting removed and I already bought the flexible insulated ducting myself. How much do you think my hvac guy is charging me to remove the old ducting of 13 feet and putting on the new ducting??

I will keep everyone posted if the popping noise goes away. Its in other ducts too, but the bedroom one where I sleep is bothering me.

 

[raratt]

It's a poltergeist.

 

[natureboygrower]

How much do you think my hvac guy is charging me to remove the old ducting of 13 feet and putting on the new ducting??

Bout a pound

 

[Meast21]

Bout a pound

$140... I'm hoping he can butt the flexible ducting right up against the furnace. This guy is kind of lazy though.

 

[Broncogrow]

$140... I'm hoping he can butt the flexible ducting right up against the furnace. This guy is kind of lazy though.

If it’s a few spots you could identify a self tapping sheet metal screw might work. I’ve also sent a drywall screw through drywall and into duct. One or two screws here and there might take care of it

 

[Meast21]

If it’s a few spots you could identify a self tapping sheet metal screw might work. I’ve also sent a drywall screw through drywall and into duct. One or two screws here and there might take care of it

Yeah I was thinking something like that.. These ducts are circular, which I read its really not suppose to making a popping sound compared to rectangular ducts.... These popping sounds are similar, but different and seem like they are coming from different spots in the 13 foot duct leading to my bedroom... I'm gonna try that bc the duct is coming out and I'm putting the flexible insulated duct in.. Buddy is doing it for $100. I could probably do it myself, but its a 2 person job almost.

 

[Meast21]

If it’s a few spots you could identify a self tapping sheet metal screw might work. I’ve also sent a drywall screw through drywall and into duct. One or two screws here and there might take care of it

I put 3 screws in and its too early too tell, but it may have helped.... Shoud I put more screws in? Its 8" circular duct that runs 13 feet. Any tricks to where to put a few more screws? @tyler.durden screws may have helped. Will keep everyone posted.

Could screws or more screws ever make it worse?

 

[tyler.durden]

Fuck, no. Put in as many screws as you like. In fact, apply them until you can't see any ducting at all, like the ducts were all made entirely of screws! That would be cool, Steam Punk shit. Post pics when you're done.

 

[Broncogrow]

I put 3 screws in and its too early too tell, but it may have helped.... Shoud I put more screws in? Its 8" circular duct that runs 13 feet. Any tricks to where to put a few more screws? @tyler.durden screws may have helped. Will keep everyone posted.

Could screws or more screws ever make it worse?

If you can see it when it’s making noise push on it hear and there to narrow it down. Could maybe be a support strap. Probably only need a few I guess you could over do it like anything. If you had to take them out use the metal duct tape to patch holes? If you were planning on replacing it you don’t have much to lose. Good luck

 

[Drop That Sound]

Probably just came loose on one joint somewhere, after so many seasons of expanding and contracting during the cold months. Same with getting your ducts cleaned. The guys knock shit loose when they are ramming the huge pipe cleaners down the shafts.

If the duct is exposed (even with insulation covering it), I would try shimming it up by jammin a few 2x4s into one long board up against it, and see if the noises go away. Then make sure its all cinched down, and all the screws are tight before releasing the prop sticks.

 

[kahoona]

if its rectangular ducting make sure it is cross broke. popping and banging is the duct expanding when pressurized or heating up. if its light gauge and its flimsy it will do that too.