Safety first: These guides cover simple homeowner checks only. Stop and call a qualified technician for gas odors, burning smells, repeated breaker trips, refrigerant work, or equipment disassembly.
Confirm the Controls
Set the thermostat to Heat and raise the setpoint a few degrees. Replace weak thermostat batteries if applicable. Make sure the furnace switch—often similar to a light switch—is on and that the electrical panel has no tripped breaker.
Check Airflow
A packed filter can overheat a furnace and trigger a safety limit that shuts the burners off while the blower continues running. Install the correct filter with its airflow arrow pointing toward the furnace. Keep returns and supply registers open and clear.
Know the Safety Warnings
Leave the home and call the gas utility or emergency services if you smell gas. Do not bypass switches, relight unfamiliar equipment, or open sealed combustion compartments. A cracked heat exchanger, venting issue, ignition failure, or gas-control problem needs trained diagnosis.
Why Short Cycling Matters
A furnace that starts and stops every few minutes may have restricted airflow, an overheating condition, a sensor problem, or equipment that is improperly sized. Repeated short cycles waste energy and add wear, so it is worth addressing early in a Wasatch Front winter.
Common Questions
Frequently Asked Questions
Why is cool air coming from vents when heat is on?
The blower may be running between heat cycles, the furnace may have shut burners off on a safety limit, or ignition may have failed.
How often should a furnace filter be changed?
Check it monthly and replace it when dirty; the practical interval varies with filter type, pets, dust, and system use.