The air filter is a relatively small part of the overall structure of a furnace. It is basically just a woven mesh, stretched over a frame and installed in the air return duct. Despite its small and simple construction, however, the air filter plays a very important role. Let’s take a look at how the air filter works, and why neglecting yours could lead to problems with your furnace.
The Role of the Air Filter
There is a lot of dust and other debris that is frequently circulated through the ductwork of a home. If that debris is allowed to infiltrate the furnace, it can cause all sorts of havoc with the system. The air filter is there to prevent that from happening. As the air from the ducts flows into the furnace, any airborne debris is captured in the fibers of the filter. The air itself passes through the filter and into the furnace, now free of harmful debris.
There is one problem with these air filters, however: they have no way to rid themselves of the particles they capture. This means that if they are not cleaned or replaced every few months, they can become so clogged that they restrict the flow of air into the furnace. That’s where things start becoming problematic.
There’s one very big problem resulting from clogged air filters that you should be aware of: short-cycling. This is when your furnace keeps turning itself on and off over and over again throughout the day. When the air filter restricts airflow into the furnace, heat becomes trapped inside the unit. When that happens, the internal temperature of the furnace rises to dangerous levels. This activates the limit switch, a safety device that monitors the temperature of the furnace. The limit switch shuts down the system to prevent it from damaging itself by overheating.
Unfortunately, this doesn’t solve the original problem. When the furnace cools off enough to start again, the clogged air filter causes it to overheat again and the short-cycling repeats indefinitely. This puts the entire system under a lot more strain than it is designed to handle, increasing the likelihood of a breakdown. If allowed to continue for a long enough period of time, short-cycling may damage the furnace beyond repair.
If you notice your furnace short-cycling, call ACI Northwest immediately. We provide furnace repair services throughout Sandpoint.