Gas Furnace Repair in Phenix City, AL

How a gas furnace lights, and where the sequence breaks

Every heating cycle on a modern gas furnace follows the same checklist. The control board won't move to the next step until the last one checks out. That's useful for diagnosis: where the furnace stops tells us which part to look at first.

Most furnaces also blink a fault code on a small light inside the lower panel. Note the pattern before you call. It often narrows the problem down before we even arrive.

• The thermostat calls for heat and the control board wakes up
• The inducer motor starts and pulls air through the heat exchanger and vent
• The pressure switch confirms the vent is drawing properly
• The hot surface igniter glows, or on some models a spark lights a small pilot
• The gas valve opens and the burners light
• The flame sensor proves there's a flame within a few seconds
• After a short warm-up delay, the blower sends heat to the house

Ignition trouble: igniters, flame sensors and pilots

The hot surface igniter is a thin ceramic element that glows bright orange. It's brittle, it wears with every cycle, and it eventually cracks. When it does, the inducer runs, nothing lights, and the furnace tries a few times before locking out. A replacement is a common and straightforward repair, but the igniter has to match the furnace and be handled carefully during install.

The flame sensor is the most common reason a furnace lights and then shuts off a few seconds later. It's a small metal rod sitting in the flame. Over time it picks up a coating that weakens the tiny signal it sends to the board. The board can't confirm a flame, so it closes the gas valve as a precaution. We clean or replace the sensor and check the signal with a meter, so we know the fix will hold.

Older furnaces may still use a standing pilot with a thermocouple, or an intermittent pilot that sparks on each call. A pilot that won't stay lit usually points to a worn thermocouple, a dirty pilot orifice or a weak gas valve. If your furnace is old enough to have a standing pilot, we'll also talk with you about its age and condition while we're there.

Draft trouble: inducer motors, pressure switches and venting

Before any gas flows, the furnace has to prove that combustion gases have a clear path outside. The inducer motor creates that draft, and the pressure switch confirms it. If either one fails, or the vent is blocked, the furnace won't light. That rule protects your family.

A noisy or slow inducer often has worn bearings. A pressure switch fault is often not the switch at all. It can be a cracked rubber hose, water trapped in the tubing, a blocked vent, or a condensate drain that's backing up. High-efficiency furnaces vent through plastic pipe and drain water from the combustion process, and the same slime that clogs AC drain lines in our humid climate can build up in a furnace's condensate trap.

We trace the real cause instead of just swapping the switch. Bypassing a pressure switch to get heat back is never an acceptable fix, and we won't do it.

Gas valves, burners and gas pressure

The gas valve opens only when the control board tells it to. A failing valve may not open at all, may open late, or may deliver the wrong pressure to the burners. We test it with a manometer rather than guessing, because low gas pressure can cause weak flames and poor heat, while high pressure can overheat parts of the furnace.

Burners collect dust, rust flakes and the occasional spider web during the long off-season. Dirty burners can light unevenly, delay ignition or burn with a lazy yellow flame instead of a crisp blue one. A delayed ignition that ends in a small boom, or a tripped flame rollout switch, means flame is going where it shouldn't. Shut the furnace off and call us. Don't keep resetting it.

Heat exchangers and carbon monoxide: the part you can't see

The heat exchanger is the metal chamber that keeps combustion gases separate from the air you breathe. Years of heating and cooling can crack it. A crack can let carbon monoxide into the airflow, and you can't see, smell or taste it. Signs can include soot around the burners, a flame that dances when the blower starts, or headaches and nausea in the household that ease when you leave the house.

The U.S. Consumer Product Safety Commission recommends CO alarms on every level of the home and outside sleeping areas. If yours goes off, get everyone outside and call 911 or your gas utility from there. Our guide to gas furnace safety and carbon monoxide covers the warning signs in more detail.

If you smell gas, the rotten-egg odor added to natural gas, don't flip switches, don't try to find the leak and don't run the furnace. Leave the home and call the gas utility or 911 from outside. Once the utility says it's safe, call us to find and fix the cause.

What a gas furnace repair visit looks like

We start with a few questions on the phone: what the furnace is doing, any fault code you've seen, and whether anyone smells gas or has a CO alarm sounding. That tells us which parts to bring.

On site, safety comes before the repair. Then we run the furnace through its sequence, find where it stops, and test the part instead of guessing. You get the findings and a written, upfront price before any work begins.

• Watch the full ignition sequence and read the fault code
• Check for gas leaks at the valve and connections
• Inspect the heat exchanger, burners and flame pattern
• Measure gas pressure and the flame sensor signal
• Check the inducer, pressure switch, vent pipe and condensate drain
• Test for carbon monoxide near the furnace and at the registers
• Run several full heat cycles after the repair to confirm it holds

Repair or replace your gas furnace?

Most gas furnace calls end in a repair. Igniters, flame sensors, pressure switches and inducer motors are wear parts, and replacing one can give a healthy furnace years more service.

The answer changes when the heat exchanger is cracked, when a furnace is well along in years and needing parts every season, or when your home has never heated evenly. A cracked heat exchanger usually tips the decision, because the repair is labor-heavy and the rest of the furnace is often just as old. If you're weighing a new system, our heating replacement page and our guide to furnace replacement cost factors walk through the options, including whether a heat pump makes more sense for your home. We'll give you the honest numbers either way.

What affects the cost of a gas furnace repair

We don't quote prices over the phone without seeing the system, because the same symptom can have a cheap cause or an expensive one. What we will do is explain the price in writing before we start, so there are no surprises.

• Which part failed, and whether it's a common or brand-specific part
• Whether the problem is a single part or several worn components
• The furnace's age and how easy it is to get parts for it
• Access to the furnace: closet, crawl space or attic
• Venting or condensate drain problems that need correcting
• Whether the visit falls on a weekday or a weekend call

Annual combustion safety checks for Chattahoochee Valley homes

Winters here are mild, with a few hard freezes and cold snaps. That means a gas furnace can sit idle from spring through fall in very humid air. Rust forms on burners, insects nest in the burner area, and drains dry out or clog. Small problems then show up all at once on the first cold morning.

A yearly gas furnace tune-up before the heating season catches most of this. It covers the same safety checks as a repair visit, including the heat exchanger inspection, gas pressure, flame sensor, venting and a CO test, plus cleaning that keeps ignition reliable. If your furnace is already acting up, our guide on why a furnace blows cold air lists the simple things to check first.

Weekday hours are Monday through Friday, 8:00am to 6:00pm. For weekend service, call +1 (327) 210-5999.