Goodman Furnace Won’t Stay Lit? | Quick Fix Guide

Your heater starts, flames appear, then the fire dies and the blower coasts to a stop. That stop-start loop wastes gas and leaves rooms cold. The good news: this symptom usually traces back to a handful of predictable parts and setup issues. Below is a clear, homeowner-safe path to find the most common triggers and fix what you reasonably can before booking a service visit.

What This Symptom Tells You

Gas furnaces follow a sequence: call for heat → inducer starts → pressure switch proves venting → igniter glows or sparks → gas valve opens → burners light → control board looks for flame signal → blower ramps. When flames drop out a few seconds after light-off, the control board is usually losing one of two confirmations: a steady flame signal or safe operating temps and airflow. Short cycling with flames that won’t hold often points to a dirty flame sensor, weak airflow that trips the high-limit switch, or a vent/pressure switch problem.

Fast Cause-And-Effect Guide

Start here. Work down the list in order. Each line shows the likely cause, the symptom you’ll notice, and quick checks a homeowner can do safely.

Goodman Burner Keeps Shutting Off — Common Causes

1) Flame Sensor Isn’t Proving Flame

A thin metal rod sits in the fire. When flame wraps that rod, microamps flow to the control board. Oxide on the rod acts like a jacket and blocks that signal. Light polishing brings the signal back.

What To Do

• Kill power at the switch or breaker. Let the unit sit for a minute.
• Remove the sensor (usually one screw and a single wire). Don’t bend the rod.
• Polish the rod with a clean Scotch-Brite pad or extra-fine steel wool. No liquids.
• Reinstall snugly; confirm the tip sits in the burner flame path.

If flames still drop out, the rod may be cracked, misaligned, or the board input is weak. At that point, a replacement sensor or board testing is a shop job.

2) Airflow Is Restricted And Trips The High-Limit

Heat builds up behind the heat exchanger when the blower can’t move air. The high-limit opens and cuts gas. After the heat falls, the switch closes and the board tries again. That loop repeats until the real airflow block is fixed.

What To Do

• Install a fresh filter sized for the cabinet. Avoid overly restrictive media if your ductwork is tight.
• Open supply and return grilles. Pull furniture and rugs back a few inches.
• Peek at the blower wheel and indoor coil face. Dust mats act like felt blankets. If you see a fuzzy layer, schedule a clean.

3) Pressure Switch Or Venting Fault

The inducer must pull a set pressure before gas is allowed. A loose or cracked tube, a blocked intake or exhaust, or water in the pressure tubing can drop that signal and end the burn.

What To Do

• Inspect PVC terminations outdoors. Clear snow, leaves, nests, and lint.
• Confirm rubber tubes are tight, not brittle, and free of water slugs.
• Check that the condensate trap is clean and reassembled with the same routing.

4) Igniter Is Weak

A healthy hot-surface igniter glows bright and sets gas off quickly. A tired one glows dull or cracks, causing random light-off and early flame loss.

What To Do

• Look through the sight glass during start. If glow looks faint, plan a swap.
• Never touch the ceramic element. Skin oils can shorten its life.

5) Condensate Backup On High-Efficiency Models

Condensing units route water through a trap and hoses. A blockage can hold water in the collector box, upset the pressure reading, and end the burn.

What To Do

• Pull the trap, rinse, and reassemble in the same orientation.
• Confirm hoses slope to the drain with no kinks.

6) Gas Supply Or Valve Issue

Low inlet pressure or a closed manual valve can give a weak flame that drops out. This needs proper test gear to confirm with the burners on.

What To Do

• Make sure the manual shutoff is fully open and the meter or tank has fuel.
• If other gas appliances stumble, call the utility or your fuel provider.

7) Rollout Or Flame Disturbance

If flame lifts off the burner or rolls out, safety switches open and the board locks the system. Causes include a blocked heat exchanger or venting fault. Leave that to a licensed tech.

How To Troubleshoot Safely, Step By Step

1. Shut power off at the switch or breaker. Give the board a minute to fully de-energize.
2. Swap the filter first. Choose a fresh, correct size. Keep spares on hand for the season.
3. Open registers and clear returns. Aim for strong airflow across the coil and heat exchanger.
4. Watch a start cycle through the sight glass with panels on. Note the exact moment flames quit: right after light-off, mid-burn, or at blower ramp.
5. Clean the flame sensor if flames die a few seconds after light-off.
6. Check vent and intake outdoors. Clear debris. On condensing units, clean the trap.
7. Check the thermostat. Fresh batteries, steady setpoint, fan set to “Auto.”
8. Read the control board LEDs. Note the blink pattern. You can match patterns to meanings using the official Goodman diagnostic codes.
9. Reset once by restoring power and calling for heat again. If the same code returns, stop and schedule service.

Safety First With Combustion

Any gas appliance can produce carbon monoxide if it burns poorly or vents badly. Keep working CO alarms near sleeping areas and on each level. See the U.S. safety guidance here: CO safety guidance. If a detector sounds, go outside and call for help. Do not relight anything until the source is cleared.

Board Codes: What That Blink Usually Means

The board tells a story with flashes. This table gives plain-English cues a homeowner can use alongside the legend on the furnace door sticker.

Deeper Fixes A Pro Handles

Some problems need meters, static pressure readings, combustion checks, or factory setup steps. A tech will:

• Measure flame sensor microamps and compare to spec.
• Check pressure switch setpoints with a manometer and confirm vent sizing and lengths.
• Verify gas inlet and manifold pressure with burners firing.
• Inspect heat exchanger surfaces and burner alignment.
• Confirm blower speed tap and temperature rise fall inside the nameplate range.

Prevent The Next Shutdown

• Filter cadence: monthly checks, change as soon as light can’t pass through.
• Annual tune: cleaning, readings, and a quick combustion review catch small issues early.
• Keep vents clear: after storms and yard work, walk to the terminations and clear obstructions.
• Condensate care: rinse the trap at the start of heating season on high-efficiency models.
• Room airflow: leave supply and return grilles free by a few inches; avoid thick furniture right against returns.

When To Stop And Call A Pro

Stop DIY steps and book service if any of these show up: repeated flame loss after cleaning the sensor, rollout switch trips, burning smells, loud rumble or whistling at the burners, or a CO alarm event. Those conditions need expert testing and parts.

Final Checks Before You Wrap Up

Run a full cycle from cold start to steady heat. Watch flames for a steady blue base with small yellow tips. Listen for smooth inducer and blower sound. Check supply registers for warm, even airflow. If all stays steady, you’ve likely cleared the trigger. If the code returns, you’ve narrowed the hunt and your service visit will be quicker and cheaper.

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