Primer on Furnace Short-Cycling Causes, Part 1

With the Utah winter in full swing, the last thing any homeowner needs this time of year is an issue with the furnace. One potential such issue is known as short-cycling, but luckily this is a concern that’s often caused by areas you can address in fairly simple ways.

At My Buddy the Plumber, we’re happy to provide a variety of furnace repair and installation services for any home that’s in need of an upgrade or some basic maintenance this winter. In this two-part blog series, we’ll first go over what furnace short-cycling is and how you can spot it, plus then dig into some of the potential culprits and how you can prevent them from taking place in your home.

primer furnace short-cycling causes

Short-Cycling Basics

Furnace short-cycling is a situation where, rather than performing its normal heating duties with standard on and off cycles, the furnace instead turns itself on and off far more frequently. It often stays on for very short periods at a time, even some short enough that no heat at all is created before the unit shuts down again.

Not only does short-cycling limit temperature control and comfort in the home, it also puts major strain on the furnace and related HVAC components. Continuously being forced to turn on and off will wear down several parts, making repairs or costly replacements necessary much faster than they would be otherwise.

Our subsequent sections will dig into some of the reasons why a furnace might begin short-cycling, plus what you can do about it.

Overheating Furnace

In many cases, the furnace begins short-cycling as a way to protect itself from overheating issues that are taking place. When furnaces are overheated, they can lead to cracks in the heat exchanger, spilling out dangerous carbon monoxide into your home.

For this reason, many models will automatically shut down if they become too hot. If this is happening too fast, sometimes due to restricted airflow or blocked vents, short-cycling may take place as the furnace tries to protect itself. In these cases, contact our HVAC pros to get to the bottom of the overheating issue.

Furnace Filter Issues

In other situations, a dirty filter is part of the reason the furnace overheats or short-cycles. Dirty filters make it harder for air to flow at proper rates by preventing air from returning at the right speed, something you often notice when air that’s hotter than usual comes out of your grates – this is another potential cause of overheating, but one that can be easily remedied by changing your filters properly.

Bad Flame Sensor

In other cases, a bad flame sensor or flame rod will cause the furnace flame to shut off almost immediately once it’s been lit. This is usually due to a problem with the sensor itself, which does not pick up the flame and thinks it has to shut off the gas valve. In most cases, simply replacing or cleaning the flame sensor is an easy job our team can perform for you to correct this issue.

For more on furnace short-cycling, or to learn about any of our HVAC or plumbing services, speak to the staff at My Buddy the Plumber today.