Furnaces today are more efficient than they have ever been before, and this is in part due to the absence of a standing pilot. In the past, a pilot light had to remain on throughout the winter so that the burners were always able to heat up. Now, electronic ignition heats up the burners with a spark only when your thermostat signals that heat is needed.
This is how startup is supposed to work with your furnace: The gas valve opens and gas goes to the burners. The ignitor ignites the gas. The heat transfers to the heat exchanger, and air enters the furnace plenum. The air heats up and keeps moving through your ducts and into your home.
When a loud popping or banging noise occurs during this process, there’s something wrong.
Delayed Ignition
Most likely, the loud bang or pop coming from your heating system only at startup is a result of delayed ignition. This means that something is happening that stops the combustion process from occurring quickly enough when the gas valve opens up. The gas builds up in the furnace and once it finally ignites…BANG!
A Miniature Explosion
This is essentially a tiny explosion within your furnace. It may cause little harm right now or do very little to affect your heating system. However, over time, this banging can wear down your system. The most dangerous effect is if your heat exchanger cracks. A cracked heat exchanger could allow carbon monoxide to leak into your home, and carbon monoxide is a dangerous toxic gas.
If you notice this problem, you should call a technician as soon as possible so that you don’t have to worry about the possibility of a CO leak, and so that you don’t quickly wear down your furnace.
Call DB Heating & Cooling, Inc for all of your heating and cooling needs in Mahwah, NJ and the surrounding areas.