Most homeowners around Macon wait until the first real cold snap before they think about the furnace, and that’s exactly when our phones melt down. So here is the short answer up front: you should call furnace repair the moment you notice repeated clicking without ignition, a burning or rotten-egg smell, a breaker that keeps tripping, or a system that starts and stops every few minutes.
Those four things account for most of the genuinely dangerous calls we run in Middle Georgia. Everything else in this guide is detail, but if one of those is happening in your house right now, stop reading and pick up the phone.
And a neglected furnace doesn’t just quit. That’s the part people miss. Long before you feel a chill, a struggling furnace can start putting combustion byproducts where they don’t belong, or quietly dragging down the air your family breathes while it limps along.
Whether you’ve got older ductwork in a Baldwin County farmhouse or a high-efficiency system in a new Covington subdivision, the common furnace issues that lead to breakdowns show up early. You just have to know what you’re listening for.
One more thing before the list. Ignition trouble and short cycling matter more than everything else in this article combined, so we’ve spent more words on those two. If you only read two sections, read those.
Ignition Failures: When to Call Furnace Repair
Repeated clicking with no whoosh of flame behind it is the single most common reason to call furnace repair, and it’s also the one people ignore the longest. The furnace tries to light, fails, tries again, and eventually locks itself out.
You bump the thermostat, it catches once, and you tell yourself it’s fine. It is not fine. Ignition lockout is the furnace protecting your house from unburned gas, and every failed attempt is the system telling you something upstream is wrong.
Nine times out of ten, what we find is a dirty flame sensor. A flame sensor is a thin metal rod that proves to the control board that flame actually exists; coat it with enough residue and the board never gets that proof, so it cuts the gas within seconds.
The fix is often fifteen minutes of careful cleaning (assuming decent access, which in some Macon crawlspaces is a generous assumption). On older equipment the same job might be a tired pilot assembly instead, and on newer stuff it’s frequently a hot surface igniter, which is brittle enough that looking at it wrong can crack it. Different parts, same symptom: click, no flame, lockout.
The Startup Pop That Was Never the House Settling
A homeowner over near Milledgeville had a burner that made an occasional pop on startup. He figured it was the house settling.
What was actually happening was delayed ignition: gas pooling in the burner compartment a beat too long, then lighting all at once. Every one of those pops was a small explosion inside a sheet-metal box in his hallway closet. By the time we opened it up, the burners were sooted over and the heat exchanger had absorbed years of abuse it was never designed for.
Delayed ignition almost always traces back to dirty or misaligned burners, and the dirt almost always traces back to skipped maintenance. A thorough winter HVAC maintenance checklist catches these problems before they compound.
Moisture down here is legitimately hard on equipment and can meaningfully shorten system lifespan compared to drier climates. Then the maintenance gets skipped three winters running, and everybody acts surprised when it quits. It’s the most avoidable failure in this whole trade, and it frustrates me every time.
Should You Clean the Flame Sensor Yourself?
Cleaning a flame sensor is one of those jobs the internet will tell you to do yourself, and I go back and forth on it. Honestly. Some techs I respect say a careful homeowner with fine steel wool does no harm, and they may be right.
We’ve also seen sensors snapped off at the mount, gaskets never reseated, and one door safety switch taped down so the unit would run with the panel off. Maybe I’m too conservative here; my own guys tease me about it. I’ll also admit the manufacturers haven’t made this easier, because some newer cabinets nearly require you to remove the sensor blind. My rule stands anyway: if you’ve never had the burner compartment open before, the first time should not be a cold Friday night with the family waiting on heat.
Cracked Heat Exchangers and Why We Shut Furnaces Off
The bigger issue hiding behind ignition trouble is the one nobody wants to hear. Sometimes the pops and lockouts trace back to a cracked heat exchanger, and that’s a different ballgame entirely, because a cracked exchanger can pass carbon monoxide into your supply air. According to the CDC, carbon monoxide is an odorless, colorless gas that’s responsible for hundreds of accidental poisoning deaths in the U.S. Every year. When we condemn an exchanger, the furnace stays off until it’s repaired or replaced, and I don’t apologize for that.
I know it sounds like the AC guy telling you to spend money. But we watch “temporary fixes” turn into carbon monoxide calls and the occasional house fire every single year, and I’d rather have the awkward conversation in your driveway than read about your house in the paper.
A tech who condemns an exchanger should show you the crack, on camera or with a mirror, not just point at an invoice. If someone condemns yours and won’t show you evidence, get a second opinion. If they do show you, believe them and leave the furnace off.
Gas Leaks: Leave First, Call From the Yard
If you smell rotten eggs near the furnace, leave the house and call the gas utility from outside. Not us first. The utility.
Don’t flip switches on your way out, don’t open windows to “air it out and see,” and don’t go hunting for the source with your phone flashlight. Gas leaks are the one furnace problem where reading a blog post is the wrong move, including this one. Once the utility clears the house, then you call us to find and fix whatever failed.
Breaker Trips and the Blower Motor Death Spiral
Electrical faults are sneaky because they masquerade as an annoyance. One breaker trip is usually not an emergency; it might have caught a voltage sag or a hard start. But a furnace that trips the breaker twice is telling you something, and what it’s usually telling you is that the blower motor windings are failing and pulling more current than they should. Resetting the breaker over and over to see if it holds just cooks the motor and stresses the wiring a little more each time.
Stop. Kill the power and get someone out there. A control board fried by a dying blower turns a manageable repair into a much longer visit, and possibly two. The last board we replaced on a call like that ran the homeowner a typical figure some on top of the motor.
And don’t jump control wires with paperclips or foil. It bypasses the exact safeties that keep a gas appliance from becoming a news story. These kinds of shortcuts are among the most serious HVAC fire hazards we encounter. We opened up a unit on the west side of Covington last winter where somebody’s handy fix had jumpered a limit switch. The blower compartment was scorched. The homeowner had no idea.
The Filter Failure That Starts Everything Else
The ugly part is how often that electrical failure started as a ten-minute filter change nobody did. A filter packed solid with red clay dust and pet hair makes the blower work harder, run hotter, and die younger.
People will spend an hour on YouTube hunting a diagnostic video but won’t walk to the hall closet for the filter. It’s genuinely funny and a little depressing at the same time.
A starved filter also drives the overheating behind short cycling, which I’ll get to below, so this one cheap habit sits underneath half the failures in this article. If dust and allergens are a constant battle in your house, that’s its own conversation, and our indoor air quality options cover more ground than a better filter alone.
Short Cycling Means You Call Furnace Repair
A furnace that starts, runs a few minutes, and shuts back down is overheating, oversized, or starving for airflow, and all three deserve a professional visit. Short cycling is the failure people tolerate longest because the house stays warm-ish.
But every short cycle is a full ignition sequence, a full inrush of current on the blower, and a full thermal stress cycle on the heat exchanger. Furnaces are built to run. They’re not built to sprint and stop dozens of times a day.
The filter thing matters here, again, because restricted airflow is the same problem at a different point in the sequence: the exchanger overheats, the high limit switch opens, the burners shut down, the house cools slightly, and the whole cycle repeats. Each trip of that limit switch is the furnace saving itself. Limit switches are rated for a finite number of operations, and a short-cycling furnace can burn through that lifetime in a couple of seasons.
The Oversized Furnace Nobody Could Fix With Parts
Not every short cycler is broken. We ran a call in Gray on a furnace that had been through two other companies, a new limit switch, a new board, and it still shut down after a few minutes every cycle. Nothing was failing.
The unit was an oversized furnace stuffed into a smallish ranch, sized by rule of thumb instead of a load calculation, and it satisfied the thermostat so fast it never completed a proper run. You can’t repair your way out of that. You can slow the fan, adjust the temperature rise, sometimes stage the burners down, but the honest fix waits for replacement day, when somebody finally sizes the thing correctly. I bring this up because a good diagnosis sometimes ends with “the equipment is wrong,” and a homeowner who’s paid for three parts deserves to hear it.
High-Efficiency Furnaces and the Condensate Problem
Condensing furnaces, the high-efficiency units going into most new Covington subdivisions, add a failure mode older equipment never had: water. These furnaces wring so much heat out of the exhaust that the flue gases condense into acidic liquid, which drains through a trap and out a small PVC line.
When that trap clogs with sludge or algae, water backs up into the collector box, the pressure switch can’t close or closes intermittently, and the board refuses to light the burners. The symptom looks exactly like an ignition failure: click, no flame, lockout, sometimes a pressure switch fault code blinking on the board.
The diagnostic order matters. Check the switch hoses for water first, then pull and flush the trap, then verify the inducer is pulling proper draft before you ever condemn the pressure switch itself. We replace far fewer pressure switches than we clean traps.
Vent terminations cause the same trouble from the other end; intake and exhaust pipes exit through an exterior wall, and we’ve found them blocked by wasp nests, leaves, and in one case a bird that got most of the way in. Vent slope matters too. Horizontal runs need to pitch back toward the furnace so condensate drains to the trap instead of pooling at a low spot in the pipe, and a sagging strap in a crawlspace is enough to create one.
Weak Airflow, Old Ductwork, and the Thermostat to Rule Out First
If the air at your registers feels like a light breeze instead of a push, check the filter first. If the filter is clean and the flow is still weak, you may be looking at a failing blower, crushed flex duct, or duct leakage bleeding your heat into the attic.
Older ductwork in Baldwin County farmhouses is notorious for it. We open up runs that have been quietly heating a crawlspace since the Carter administration.
Before you assume the worst, rule out the thermostat. A dying thermostat or a loose wire at the wall can typically fake almost every symptom in this article, and it’s a minor service call to sort out.
Crawlspace and attic installations complicate all of this; some of the crawlspaces around here are tight enough that a diagnostic feels like surgery in a closet, and attic units behind finished ceiling hatches are worse. We’ve pulled more dead rodents out of blower wheels in the last month than I care to count. Chewed low-voltage wiring right behind them, usually.
When the Repair Money Should Buy a Replacement Instead
Middle Georgia throws a meaningful stretch of serious summer heat at your equipment every year, so a system down here works both ends of the calendar hard, and the humidity compounds it. The furnaces we swap out are typically well into their teens in age, and the ones that made it past twenty almost always belonged to maintenance customers.
If your furnace is old enough to vote and needs its second major repair in two winters, it’s worth working through the repair vs. replace decision carefully before you commit to another service call.
Our techs are EPA and NATE certified, and we’re certified Carrier experts, so our heating repair team can walk you through both paths without pretending the answer is always “buy new.” It usually isn’t.
I’m not going to cover heat pumps in this article, by the way. They fail differently, the diagnostics are different, and cramming them in here would shortchange both topics.
CO Detectors: What Most People Get Wrong
A CO detector that chirps for anything other than a low battery is a call-now situation, but most of the detector problems I see happen before any alarm sounds. Detectors expire. The sensor inside degrades whether or not it ever alarms, and most units are done around the seven-year mark; people treat them like smoke detectors from 2009 and assume they’re standing guard.
The CPSC recommends seasonal furnace inspections specifically to reduce the risk of CO poisoning, and proper detector placement is part of that picture. Check the date on the back of yours.
Placement is the other miss. You want one near the sleeping areas, where it can wake you, not mounted six inches from the furnace where nuisance readings teach you to ignore it. And if you have a gas furnace and no CO detector at all, fix that before you fix anything else in this article.
It costs less than our diagnostic fee and it’s the only warning sign on this list that works while you’re asleep. Our full guide to carbon monoxide detector checks before winter covers the details worth knowing.
Noises That Don’t Need a Service Call
Not everything deserves a truck in your driveway, and I’d rather tell you that than collect the fee. A single metallic bang from the ductwork when the blower starts is usually oil canning, sheet metal flexing under pressure change, annoying but harmless. A few minutes of dusty burning smell on the first fire of the season is normal; that’s summer’s dust cooking off the exchanger, though if the heat smells funny beyond that first startup, it’s worth a closer look.
A furnace that runs longer cycles on the coldest morning of the year is doing its job, not failing. We took a call last February from a customer convinced her furnace was dying because it “never shut off.” It was a genuinely frigid morning and the system was simply keeping up. Save your worry, and your money, for the signs that repeat.
The Quick Reference List, and What To Do Next
“The cheapest furnace repair I ever sell is the one where somebody called at the first weird noise instead of the fifth.”
What prevents most of these calls is boring: an annual heating check before the season starts. Customers on our maintenance plan see far fewer breakdowns, mostly because we catch the dirty flame sensor and the tired igniter in October instead of January. The short version of everything above:
Clicking without ignition, especially if the process takes several tries or locks the system out entirely. Any burning smell that lasts beyond the first dusty startup of the season. A breaker that trips more than once. One trip might be a fluke; two is a pattern. Booming or popping at startup, because delayed ignition beats up the heat exchanger every single time it happens. A CO detector alarm, plus a rotten-egg smell, which means you leave the house first. Short cycling, even if the house still feels warm.
If your furnace is doing something on that list, or something weird that isn’t, don’t try to diagnose the schematics yourself. That’s what we’re for. Air Conditioning Specialist Inc.
Runs heating calls out of Milledgeville and Covington, with same-day appointments most days and a prompt response target on true emergencies. I’d especially like to hear from you if you’ve got an attic unit tucked behind one of those finished ceiling hatches nobody can reach. Tell us what it’s doing, or not doing, and we’ll get the diagnostic visit on the books.
By the Air Conditioning Specialist Inc. Team
Frequently Asked Questions
What are the signs that a furnace needs professional repair rather than a filter change?
Four symptoms indicate a furnace needs a professional repair, not a DIY fix: repeated clicking without ignition, a burning or rotten-egg smell, a circuit breaker that keeps tripping, and short cycling where the system starts and stops every few minutes. A dirty filter causes weak airflow and higher energy bills, but those four symptoms point to mechanical, electrical, or combustion failures that carry safety risks and require a licensed technician to diagnose safely.
How do I know if my furnace has a cracked heat exchanger?
A cracked heat exchanger rarely produces a visible sign a homeowner can spot, which is what makes it dangerous. Common indicators include a furnace that short cycles, soot buildup around the burner compartment, or a carbon monoxide detector alarm. Because a cracked exchanger can allow carbon monoxide, an odorless and colorless gas, to enter the home’s supply air, any furnace suspected of having exchanger damage should be shut down and inspected by a technician before it is operated again.
What causes a furnace to make a loud pop or bang when it starts up?
A loud pop at furnace startup is usually caused by delayed ignition, a condition where gas accumulates in the burner compartment before it ignites, producing a small pressure burst inside the unit. Dirty or misaligned burners are the most common culprit, and the dirt typically builds up when annual maintenance is skipped. Delayed ignition is not a quirk of an aging house and it is not safe to ignore, because repeated occurrences stress the heat exchanger and can accelerate serious damage over time.
How often should a furnace be serviced to avoid breakdowns in a humid climate like Macon, GA?
A furnace in a humid climate like Macon, Georgia should be professionally serviced once a year, ideally before the heating season begins in fall. High ambient moisture levels can accelerate corrosion on burners, flame sensors, and heat exchangers compared to drier climates, meaning skipped maintenance cycles compound faster into component failures. Annual service typically includes cleaning the flame sensor, inspecting the heat exchanger, verifying ignition performance, and checking the burner assembly for soot or misalignment.