3 Characteristics Of A Short Cycling Furnace

Posted on: 8 February 2022

Short cycling is a problem that can occur with any type of HVAC equipment. A short cycling furnace can be incredibly frustrating during the cold winter months when it can leave your home feeling chilly and uncomfortable. Unfortunately, short cycling can also have even more severe consequences, including increased wear on furnace components and premature failures.

In general, short cycling refers to any situation where the furnace shuts off too quickly. However, recognizing when your furnace is behaving this way can be challenging. If you think your heating equipment may be suffering from this problem, look for these three identifying characteristics.

1. Furnace Fully Ignites

One critical characteristic of short cycling HVAC equipment is that the system turns on before quickly shutting down. Modern furnaces go through a relatively long start-up sequence that involves conducting several safety checks, engaging a draft inducer motor, and finally igniting the burners and turning on the house blower.

If you think your furnace may be short cycling, check that it turns on and produces heat, even if it only does so for a short time. To confirm this, feel for heat coming from your vents. You can also stand near your furnace and listen for the sound of the draft inducer motor coming on and the burners engaging. If the furnace isn't turning on at all, you're dealing with a problem other than short cycling.

2. Thermostat Cannot Reach Setpoint

When operating normally, your furnace should turn on and run until your thermostat temperature reaches its setpoint. The time required to meet the setpoint can vary based on outside temperature, furnace capacity, and numerous other factors. Although this time can vary, you should generally expect your furnace to turn on and off a few times per hour.

If your furnace shuts down before it reaches the target temperature on your thermostat, that's a good indication you've got a short cycling issue.

3. Furnace Quickly Restarts

Your furnace should generally remain off for a while after running, kicking back on only as the temperature in your house begins to fall below your thermostat setpoint. If the furnace turns off and then quickly turns back on, that's another good indication that you're dealing with a short cycling issue. Note that some safety switches may prevent a short cycling furnace from turning back on immediately.

If you think your furnace is short cycling, you should contact an HVAC technician as soon as you can. Short cycling can damage your furnace equipment, and it may also be a symptom of a cracked heat exchanger, which is a potentially hazardous problem. A technician can help you rule out the more severe possibilities and get your furnace running normally again.

Contact a furnace repair service for more information. 


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After we purchased our very first home, I realized that I was really struggling with paying for the heating and cooling costs. We were spending much, much more money every month than we thought we were going to, and it was really difficult to figure out what we should do. We thought long and hard about how to minimize our expenses, but we didn't really get anywhere until we talked with an HVAC contractor. He mentioned specific, actionable ways to lower our bill, such as programming our thermostat and using more of our ceiling fans. This blog is all about lowering your bill.

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