Why does my furnace make a loud banging noise?
Delayed ignition causes a small explosion of built-up gas inside the combustion chamber, resulting in a loud bang when the furnace finally fires up. This issue stops the heating system from operating smoothly and requires immediate attention to prevent damage to the equipment during freezing weather.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1Turning off the gas line and power to the furnace
- 2Using a space heater and extra layers to stay warm
- 3Waiting for an emergency technician to come out
- 4Switching off the heating system
- 5Lowering the pump speed setting
- 6Replacing the pump or its bearings
In their words
Unedited, most upvoted first, each linked to the thread it came from.
“Gas line and the power to the furnace have been turned off. 15” of snow expected. Looks like we are face tanking this with a space heater and some layers.”source ↗
“Got this picture before I turned it off. It starts up normally when you turn on the thermostat, but after about an hour it repeats this process over and over again.”source ↗
“it creates a constant hum all day, everyday 24/7. What can I do to make it quieter? It's quite hot and so not sure if I can wrap it in anything. I'm quite noise sensitive and it's vibrating constantly giving noise in my bedroom and living room and I just want some peace and quiet, without having to switch off my heating system (it's an older house 70's).”source ↗
“Can confirm it was on speed 2, dropped to speed 1 and still relatively loud, so assuming the bearings have gone.”source ↗
“Yeah it's still noisy on 1 so I'm assuming it's the bearing, we are having work done on the house soon so will get that replaced as part of it, thank you for all your help!”source ↗