Believe it or not, a furnace that's too big for your home can lead to short cycling as it heats the space too quickly. Short cycling is more than just an annoyance; it can signal potential safety hazards like carbon monoxide leaks or fire risks.
When a furnace is short cycling, it's working hard to produce heat but isn't making any, causing strain on your furnace. If left unchecked, this could cause major issues for your furnace resulting in hefty repairs.
Warning Signs of a Furnace CO Leak
If you're unsure of how to identify a carbon monoxide leak, there are several signs to keep an eye out for. These warning signs include: Heavy condensation on the windows (found in the room with your furnace) Yellow or brown soot-like stains found around your furnace.
Something as simple as a dirty air filter can cause your furnace to short cycle. Contaminated air filters block airflow, and eventually, cause a backup. This means that warm air will remain in the furnace instead of distributed to the different areas of your home.
Your furnace is an essential part of your home and regular maintenance is needed to avoid the serious harm it may cause you in your home. A dangerous issue that may arise if the furnace is not functioning properly is the emission of carbon monoxide into your home which may threaten your health.
Small carbon monoxide leaks can fill every room in your house with poisonous gas within eight hours. Severe leaks can cause this problem in just five minutes. The EPA states that exposure to concentrations of nine ppm or more for eight hours is enough to produce harmful health effects for at-risk individuals.
To conduct the test, technicians use special CO detectors to measure the carbon monoxide levels in the air that surrounds the furnace. The detector is usually placed near the furnace of an air intake vent. The technicians turn on the furnace and allow it to run while watching the detector.
Common causes of furnace short cycling include restricted airflow, a malfunctioning flame sensor, or a poorly placed thermostat.
A clogged furnace air filter will negatively affect the airflow throughout your house and HVAC system. The lack of fresh air in your furnace will cause the heat exchanger to become too warm and deactivate. Dirty filters indirectly cause short cycling issues and will make it hard to keep your home warm.
Carbon monoxide is invisible, odorless and tasteless. Inspection helps protect yourself and your family. Install a carbon monoxide detector in your house, and plan to check its battery every time you check your smoke detector batteries.
Maintain appliances and equipment in good order. Have a certified heating and ventilation technician check your furnace for proper ventilation and exhaust. Install carbon monoxide monitors and regularly test the air in areas where carbon monoxide is generated. Check monitors monthly for proper function.
Your boiler won't be able to produce carbon monoxide when it's switched off because it isn't burning any fuel. However, if you think you may have a carbon monoxide leak, you should switch off your gas supply at the mains.
The simple solution: Turn your furnace off and check the filter. If it's dirty or it's been 3 months or more since you changed it, put a new, high-quality filter in place.
What Causes Short Cycling? Furnaces have built-in safety systems that prevent dangerous situations like fires, carbon monoxide leaks, or gas leaks. The most likely cause of short cycling is the fan limiter, which prevents fires and furnace damage by shutting the system down if the heat exchanger becomes too hot.
If your furnace keeps turning off, check for issues such as: Dirty Air Filters. A clogged filter restricts airflow, causing the furnace to overheat. Replace air filters every 60 to 90 days to prevent this problem.
Furnaces typically run for about 10 to 15 minutes in moderate weather. Extreme cold can result in longer cycle times.
Thermostat Troubles Can Cause Short Cycling
Your furnace or central air conditioner spends a good amount of energy simply turning on and off, which is why you want yours to run for at least 15 minutes at a time before shutting off.
The Dangers of Short-Cycling
Customers often ask, “Is furnace short-cycling dangerous?” While short-cycling isn't inherently dangerous, it can reduce energy efficiency, cause safety problems, and increase wear and tear on your home's HVAC system.
Ask twenty professional HVAC contractors the question, “How Much Does A New Furnace Cost?” and you'll probably get the same answer... “It depends.” On average, the cost of a new furnace can range from $2,000 - $14,2001. However, factors like furnace efficiency, type, size, and much more can impact this range.
Signs of a Furnace Carbon Monoxide Leak
These signs may include frequent pilot light blow-outs, soot accumulation in the fireplaces, smears of yellow/brown stains near appliances, duller than normal flames from their fires as well as noticeable smells like stale air and burning.
Since carbon monoxide is odorless and colorless, a detector is the only reliable way to identify its presence. However, signs like soot buildup near appliances, pilot lights frequently going out, stale air, or excessive condensation on windows could indicate a potential issue.
Your furnace needs to be on to burn fuel that releases CO. However, carbon monoxide can travel throughout your home via your HVAC system, so it can still create a dangerous situation even when your furnace is off.