Furnace Repair & Heating Service in Louisville, KY
Heating repair for gas furnaces, air handlers, and heat pump backup heat across Louisville and Southern Indiana.
Furnaces tend to fail on the first genuinely cold night of the season, because that is the first time they run for long stretches. A no-heat call is often an ignition problem, a dirty flame sensor, a tripped limit switch caused by poor airflow, a failed inducer or pressure switch, or a control board that has locked the system out after repeated failed attempts.
Heating repair begins with reading the furnace control board, which stores fault codes describing what the equipment saw before it shut down. From there, the sequence of operation is checked step by step: call for heat, inducer start, pressure switch closure, ignition, flame proving, blower start. That sequence tells a technician exactly where the process is breaking down.
What a heating repair visit typically covers
- Control board fault code retrieval and sequence-of-operation testing
- Igniter, flame sensor, and gas valve diagnosis
- Inducer motor, pressure switch, and venting inspection
- Limit switch and airflow troubleshooting, including filter and duct restrictions
- Blower motor, capacitor, and belt or bearing checks
- Heat exchanger inspection for cracks or corrosion
- Thermostat wiring, staging, and control diagnosis
- Combustion safety checks and carbon monoxide screening
Common heating failures
Most furnace problems fall into ignition, airflow, venting, or controls. Repeated lockouts in particular are worth taking seriously, because a furnace that keeps shutting itself down is usually protecting against something real.
- Cracked hot surface igniter, or a flame sensor coated in oxidation
- Pressure switch open because of a blocked flue, vent, or condensate line
- High limit trip caused by a dirty filter, closed vents, or undersized return
- Failed inducer or blower motor, or a bad motor capacitor
- Gas valve, transformer, or control board failure
- Thermostat wiring faults and loose low-voltage connections
- Condensate drain blockage on a high-efficiency furnace
Safety issues that change the recommendation
A furnace burns fuel inside the home, so some findings stop being a comfort question and become a safety one. A cracked heat exchanger, a compromised flue, or elevated carbon monoxide readings all warrant taking the equipment out of service until the problem is corrected, regardless of how well it seems to heat.
If you ever smell gas, do not test switches or thermostats. Leave the building, then call your gas utility or 911 from outside. Working carbon monoxide alarms on every level of the home are worth having whatever the age of the equipment.
Worth checking before you call
Simple things account for a real share of no-heat calls, especially early in the season.
- Thermostat set to heat, above room temperature, with fresh batteries
- Furnace breaker on, and the service switch near the unit turned on
- Filter clean, and supply and return vents open and unblocked
- Furnace door panel fully seated, since most units have a door safety switch
- Gas supply on, and the pilot or ignition sequence audible at a call for heat
- Outdoor flue terminations on high-efficiency furnaces clear of snow, ice, and nests
Signs a furnace needs service
- No heat, or the blower runs while the air stays cool
- The furnace starts, runs briefly, then shuts down and retries
- Repeated lockouts requiring a power cycle to restart
- Booming or rumbling at ignition
- Burner flames that are yellow and lazy rather than steady and blue
- Rattling, grinding, or squealing from the blower compartment
- Uneven heating between rooms or floors
- A carbon monoxide alarm sounding, which calls for immediate attention
Common questions
Why does my furnace start and then shut off?
Short cycling on a call for heat usually means the furnace is not proving flame, or is tripping a safety. A dirty flame sensor, weak igniter, blocked vent, or high limit trip from restricted airflow are the usual suspects, and the stored fault code narrows it quickly.
Why does my furnace smell like it is burning when the heat first comes on?
A brief dusty smell at the start of the season is normally dust burning off the heat exchanger. A smell that persists, or a hot electrical or sulfur smell, is worth having looked at rather than waiting out.
How long do furnaces usually last?
Service life varies with installation quality, airflow, and maintenance, and many furnaces run well into their teens. Age matters most in combination with what actually failed, since a cracked heat exchanger on older equipment is a different conversation than a failed igniter.
Should I keep resetting a furnace that keeps locking out?
Resetting once to confirm the condition is reasonable. Repeated resets are not, because the lockout is the furnace responding to a fault it detected, and forcing it to retry can turn a small repair into a larger one.
Do you work on heat pumps with backup heat?
Yes. Dual-fuel systems pairing a heat pump with a gas furnace, and heat pumps with electric backup heat, both come up regularly in this area.
Rolston Heating & Cooling · Louisville, KY · (502) 909-8923 · Mon–Fri 7:00 AM – 5:00 PM