A modern furnace runs a strict startup sequence, and knowing where the sequence breaks is most of the diagnosis. The thermostat calls, the inducer motor spins up to prove draft through a pressure switch, the hot surface igniter glows, the gas valve opens, the burners light, the flame sensor confirms fire, and only then does the blower deliver heat to the house. In Florence, SC, the failures cluster at predictable points: an oxide-coated flame sensor, a hot surface igniter cracked from years of thermal cycling, a pressure switch that will not close because the inducer is weak or the condensate trap on a high-efficiency model has clogged, or a control board with a burned relay. Each one stops the sequence cold, and each one mimics the others from the hallway.
Florence HVAC repairs furnaces by testing the sequence, not guessing at it. Our experienced technicians verify each stage with a meter rather than a hunch: igniter resistance, flame signal in microamps, pressure switch operation against actual inducer draft, gas valve voltage, and blower and capacitor health. Every visit includes the safety fundamentals on a fuel-burning appliance: heat exchanger inspection, leak-testing of gas connections, and flue draft verification, because the difference between a furnace problem and a furnace hazard is not visible from the thermostat. We measure temperature rise against the data plate before we leave so the fire and the airflow are matched the way the manufacturer intended.
Conventional or condensing, gas, propane, or electric, we work on them all, across every major brand, including the traps, drains, and dual pressure switches that come with high-efficiency models. The parts most likely to fail are stocked on every truck: igniters, flame sensors, pressure switches, capacitors, inducer assemblies, and blower motors. That is why most repairs are finished in a single trip. If your furnace is down anywhere in Florence, call (843) 268-6987 and we will get the burners lit today.
Cooling trouble instead? See AC Repair in Florence.
How Much Does Furnace Repair Cost in Florence?
For most Florence homes, a furnace repair runs $150 to $600. Ignition and sensor problems are usually the least expensive, while blower motors, control boards, and heat exchangers cost more. You'll get a written, upfront price from Florence HVAC after we diagnose the problem.
| Repair | Typical cost | What it usually means |
|---|---|---|
| Flame sensor cleaning or replacementBurners light but cut out almost immediately | $80–$250 | Burners light but cut out almost immediately |
| Hot surface igniter replacementNo ignition; one of the most common winter failures | $150–$400 | No ignition; one of the most common winter failures |
| Draft inducer motorLoud humming or grinding at startup, then lockout | $400–$1,000 | Loud humming or grinding at startup, then lockout |
| Blower motorBurners run but little or no air comes out of the vents | $400–$1,500 | Burners run but little or no air comes out of the vents |
| Control boardErratic behavior, error codes, or no response at all | $300–$700 | Erratic behavior, error codes, or no response at all |
| Gas valve replacementIgniter glows but gas never flows to the burners | $250–$700 | Valve fails to open, so the furnace never lights |
Ranges are typical for these repairs; you get an exact quote before any work starts.
What Affects the Price
- Furnace age and type, because 90%+ efficiency models have more specialized parts
- Whether a cracked heat exchanger is found, which usually means replacement rather than repair
- Timing, such as a no-heat call on a cold night versus a scheduled repair
- Access to the furnace in attics, closets, or crawlspaces
For older furnaces facing a big repair, we'll show you what replacement would cost too, so you can compare. Call (843) 268-6987 for a quote.
Warning Signs for Furnace Repair
Catching these issues early helps you avoid costly problems and protect your property. Watch for these telltale signs that professional help is needed:
- Clicking and a glowing igniter with no burner flame
- Yellow, wavering burner flames where they should be sharp blue
- Repeated shutdowns just seconds after the burners light
- Squealing or grinding from the blower compartment
- Booming or banging at light-off from delayed ignition
- Air moving through the vents that never gets warm
- A furnace that shuts off every few minutes before the house warms up
- Rust streaks, soot, or water around the cabinet or flue
Don't Wait for a Total Failure
Left unchecked, even a small fault or temperature swing often signals a system working its way toward a breakdown. If you notice any of these signs, contact Florence HVAC at (843) 268-6987 for a prompt inspection.
Frequently Asked Questions About Furnace Repair
Why Professional Furnace Repair Matters
Gas, open flame, high voltage, and a flue share one cabinet in a furnace, and the most dangerous failure is the one you cannot see: a damaged heat exchanger that lets combustion gases into the air the blower circulates. Every morning that delayed ignition keeps booming at startup, that exchanger takes more stress. The diagnostic side has its own pitfalls. When a furnace trips its high limit, the switch itself may be bad, or the furnace may be protecting itself from a clogged filter or a failing blower. Swapping the switch in that second case removes a safety device and leaves the actual problem in place.
At Florence HVAC, no symptom gets treated in isolation. A meter tells us the flame signal, so we never condemn a good sensor while the real culprit, a cracked igniter or a weak gas valve, stays in place. We confirm draft at both the pressure switch and the flue, measure temperature rise against the data plate to flag airflow problems early, and test the gas side with a leak detector, not a guess. When we are done, the furnace has proven itself safe and correct through a full cycle, and if it is nearing the end of its useful life, we tell you honestly.
What to Expect From Our Furnace Repair
Every visit follows a step-by-step method refined over years of hands-on experience. Here's how we handle furnace repair from start to finish:
Sequence Diagnosis
Instead of guessing, we follow the startup sequence step by step, with readings on the inducer, pressure switch, igniter, flame sensor, and gas valve, until the broken link is clear.
Safety Verification
Every repair includes a safety check: heat exchanger inspection, instrument leak testing on the gas side, and flue draft verification, because a furnace that runs is not the same as a furnace that runs safely.
Expert Repair
Igniters, flame sensors, pressure switches, capacitors, and motors ride on the truck, so most furnaces are lit and heating again before we pack up.
Full Verification
We run complete cycles, measure temperature rise against the data plate, confirm clean ignition without booming, and verify every limit and safety control before we leave.
Want a Professional Opinion?
Our experienced technicians can assess your situation and recommend the best solution.
Get Help: (843) 268-6987Maintenance Tips for Furnace Repair
A few simple habits now, like regular filter changes and seasonal tune-ups, can add years to your system's life. Start with these practical measures our team relies on:
- If you have a high-efficiency furnace, check that the condensate drain is flowing freely
- Notice how the furnace sounds at startup, because a quiet light-off is healthy and a boom is not
- Book a fall tune-up so weak igniters and fouled sensors are caught before the first freeze
- Make sure the furnace has clear combustion air; a packed utility room starves the burners
- Put a carbon monoxide detector on every level and test them monthly
- Change the filter monthly during heating season; it is the cheapest furnace part you will ever buy
- Keep storage, lint, and especially chlorine-based products away from the furnace closet
Comparing DIY and Professional Furnace Repair
A homeowner can swap a filter with ease, but diagnosing capacitors, refrigerant charge, control boards, and error codes calls for the equipment and know-how only a pro brings. Consider the following comparison:
| Factor | DIY Attempt | Professional Service |
|---|---|---|
| Heat Exchanger | No way to see a crack from outside | Checked every time we open the unit |
| Ignition Faults | Parts swapped against a code list | Each ignition component tested |
| Gas Connections | A loose union goes unnoticed | Instrument leak test on each visit |
| Limit Trips | A safety device jumpered out | The airflow fault behind the trip found |
| Blower Setup | Fan speed never checked | Rise measured and blower adjusted |
| Final Check | One good start and done | Full cycles proven clean and safe |
Talk to a Furnace Repair Expert
Don't let a failing system get worse. Call Florence HVAC now for prompt, professional service.
Call (843) 268-6987 NowAreas We Serve for Furnace Repair
Our technicians handle furnace repair throughout Florence and the surrounding communities, with the same upfront pricing everywhere we work.