When your home's gas furnace is running, you may be used to certain sounds, such as the popping of the air ducts due to temperature changes or maybe even the occasional soft bang as the furnace settles. However, if you start hearing loud banging noises almost every time the unit kicks on, these are not normal and require the services of a repair technician. If this is happening to your furnace, there are a couple of possible reasons for the banging.
1. Pilot Light's Gas Delivery System Is Malfunctioning
One possible reason why your gas furnace is starting to make banging noises could be that the pilot light's fuel delivery system is malfunctioning. This is especially true if you only hear the bang when the unit first starts up.
The tube leading to the pilot light holds the natural gas under pressure. Whenever the signal is sent for the furnace to kick on, a valve opens to allow enough gas to feed the light so that the burner will ignite.
If something goes wrong with this system, the gas will not be delivered properly to the pilot light. If the pilot light's burner becomes clogged, the tube's valve is faulty, or the pressure of the increases within the tube, the system will have to force the gas through to the pilot light. This most often creates a banging sound.
2. Furnace Has a Faulty Ignition Switch
Another possible problem causing the banging noises coming from your furnace could be a faulty ignition switch. This switch is what sends the signal to the furnace to release the gas through the delivery system. A bad switch could be a standalone problem or coexist with a malfunctioning gas delivery system.
When the ignition switch is to blame, it may be sending the wrong signals to the delivery system. If it signals to turn off the gas flow too early, for example, the sudden stoppage of the gas and increased pressure within the system could cause the banging sounds.
While hearing one or two bangs coming from your furnace may not be a cause for alarm, constant banging noises are always an indication that your furnace needs professional attention. Contact an HVAC contractor who provides furnace repair services to have them inspect the unit to find the actual source of the noises so that they may take the appropriate action to fix the issue they find.Share