Latest Discussions : HVAC


04:59AM | 10/27/03
Member Since: 10/26/03
3 lifetime posts
Right before the heat kicks on each time, there is a loud bang that comes from the furnace. I am hoping someone may have an idea about why this is happening and how to stop it. It's loud enough to wake our lighter sleepers up. And there is a new baby coming in a couple of months and you all know we don't want anything avoidable to wake them when they are sleeping. *smile*



09:00AM | 10/27/03
Member Since: 10/26/03
3 lifetime posts
There is a blower on the furnace, so I guess it's forced air. It does sound like someone bangs once on the ductwork when it happens. I hope I can find it too. It's really beginnning to drive us crazy. Thanks for responding!



02:21PM | 10/27/03
If it is possible, try to physically locate which section of duct is 'breathing'. If you can, you can use some small, light guage 1 x 1 angle iron and cut it the full width of the duct. Pilot drill several holes in the cut angle. Use hex head self drilling screws to secure it to the duct where it is breathing. Good luck.


05:03PM | 10/28/03
Member Since: 09/10/03
67 lifetime posts
this could be just a pre ignition combustion when the air adjustment is not correct. this is pretty common on L P or propane gases. you can look at the flame when furnace is burning, if lazy yellow flame, the unit is dirty or the air adjustment is incorrectly set. also, there is a possiblity of a hairline crack in the combustion chamaber. i would suggest a tech look at this, as could be a very dangerous situation.


03:58PM | 10/30/03
Member Since: 10/26/03
3 lifetime posts
Well, from what I can tell, the bang is about 10 feet or so away from where the furnace is. So that rules out the ignitor, right? I am hoping to spend time tomorrow cleaning the basement and hopefully I'll be down there when the bang happens. The weather was too warm today for the furnace to kick on. I may have to wait a couple of days, but will get back to you all with any other info I gather. Thanks for your help so far, everyone!



11:55AM | 11/28/03
Member Since: 11/27/03
6 lifetime posts
If there a bang when the furnace turns on it is one of two things. 1. The duct work is undersized and when the blower starts it crates too much static, expands the duct work and creates a bang. 2. The burners are dirty. When the furnace calls for heat, the ignitor is enegized, which in turn tells the gas valve to open and send gas to the burners, the ignitor then light the burners. If the burners are dirty they will delay the burners from being ignited causing the bang. If left unattended, the buildup of gas from not being ignited could cause a problem.


03:10PM | 01/31/10
Member Since: 01/30/10
1 lifetime posts
I awoke to my furnace making repeated loud banging noises prior to lighting the burners. I checked to see if gas was leaking from anything inside. It turned out everything was okay in regards to gas leaks.

In my furnace there are 5 burners. The last burner, I noticed was turned 45 degrees and not aligned with the others. when the furnace burners were tring to light the gap between the last was causing the popping sound. I used metal wire and held the last burner correctly in place using the second to last burner. From that moment on, the furnace did not bang or pop any longer. Check this out, if you are experiencing this problem.


11:28PM | 01/05/13
I believe the guy that said one of two things cause the loud bang when the heater starts.If it is a duct the bang will come from a location other than the heater.If the bang comes from the heater location it is dirty burners.


12:44AM | 01/28/13
I have dual blowers on my gas fired shop heater. I would blow one leg fuse of the power. The belt would squeek on initial start up. I changed the belt and it and the squek is gone. The belt has proper tension on it/. But it is loud or bangs when the fan motor starts. If I take the belt off, the motor is whisper quiet. Could I have bad bearings on the blowers? When I spin them by hand, they spin freely. I am going to drop back and


05:25AM | 02/02/13
I just had a tech clean the air tubes going across the gas burners but loud boom stopped and has now returned.Lasted about a week..also the tech showed me a rather large hole in the firewall of the gas furnace.I have an American Standard GPH Hydronic Gas Furnace GPH 100.Any Ideas why the problem keeps happening?Oh,and I also noticed a crack and a small hole just above the exhaust pipe going into the chimney,could this be part of the cause? Anybody know? Thanks!


08:39PM | 02/08/13
if this bang noise is air intake, that is one thing, but thebank is a crack in the wall, wouldn't your carbon detector being going off!? both could be bad! just wondering, I have a 25yr old gas furnace in a mobile home


10:54PM | 02/08/13
sorry for the type~o

if this bang noise is air intake, that is one thing, but the bang is a crack in the wall, wouldn't your carbon detector being going off!? both could be bad! just wondering, I have a 25yr old gas furnace in a mobile home


02:30AM | 03/24/13
Mine does it to and scares the s!;t out of me it is freaky it makess me think someone is in my house it makes the floors creak like someone is walking around in my house I hate it and I have had two gas leaks before I hope there is no gas leak.


10:07PM | 01/21/15
this happens randomly with our furnace ... it is in the crawl space and we have had it checkout out and nothing looks wrong, there is no evidence of any small explosions. when it happens, we know the furnace is going to kick on about a minute later ... I do have to admit every time it happens I think .. is THIS the time we are going to be blown to high heaven ????


08:28PM | 08/08/15
Try cleaning or replacing air filters

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