The short answer
E270 on a Lennox furnace in Northern Virginia means the furnace tried to light several times, never saw a flame, and gave up for an hour. Lennox calls it a soft lockout: “exceeded maximum number of retries, no flame current sensed.” The usual reasons are a cracked igniter, no gas getting to the burners, or a flame sensor that can’t see the flame. It tries again on its own after an hour. If it locks out again, call.
If you smell gas, skip all of it. Leave the house and call the gas company and 911 from outside. If a carbon monoxide alarm is going off, get everyone out first (what to do when the CO alarm sounds).
E270, E207 and E290: the ignition codes
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| Code | What Lennox says | What it usually is |
|---|---|---|
| E270 | Soft lockout, exceeded maximum retries, no flame current sensed | No flame, or a flame the sensor can’t see |
| E207 | Hot surface ignitor sensed open | The igniter is broken, usually cracked |
| E290 | Ignitor circuit fault, failed ignitor or triggering circuitry | The igniter, or the board that powers it. One-hour soft lockout |
| E271 | Soft lockout, last retry failed because the pressure switch opened | Venting, not ignition (pressure switch codes) |
On a Merit furnace, a burner that won’t light blinks 7 flashes on an ML180UH, ML195UH or ML296UHV. On an ML180UHE it’s 3 flashes for a burner that failed to light or lost its flame, and 5 flashes once it locks out for an hour.
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What it looks and sounds like
The thermostat calls for heat. The small inducer fan starts, you hear a click, and the igniter should glow orange through the burner window. Then one of three things happens. The igniter never glows, which points at the igniter (E207 or E290). It glows, the gas clicks on, and nothing lights, which points at the gas. Or the burners light for a few seconds and go out, which is almost always the flame sensor. After a few tries it quits, and that’s E270. Lennox uses two kinds of lockout. A soft lockout waits an hour, then tries again on its own if the thermostat still wants heat. A hard lockout stays off until someone turns the power off and back on.
What to check before you call
Is the gas on? If the stove lights and the water heater makes hot water, gas is coming into the house. The valve on the pipe into the furnace should have its handle in line with the pipe. If it’s sideways, someone shut it.
Was there work on the gas lately? A new meter or a service restart can leave the furnace short on gas for a few tries.
Photo the code, then reset once. Turn the furnace switch off, count to ten, and turn it back on. Take a photo of the code before you reset anything. A reset can clear what’s showing, and that number saves the tech time and you money.
Don’t touch the igniter. Older ones crack if you bump them, and the oil from a finger can shorten the life of a new one. Don’t keep resetting it over and over either; it won’t light on the tenth try if it didn’t on the third.
What it usually turns out to be
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| The cause | How a tech confirms it | Our price |
|---|---|---|
| Cracked or worn-out igniter | Measures its resistance. Open or out of range, it’s replaced. | $240 to $410 |
| Dirty flame sensor | Burners light and drop out in seconds. Microamps read low. | $95 to $180 |
| Flame sensor or igniter replaced together | Both worn on an older furnace. | $240 to $410 |
| Control board not powering the igniter | Voltage at the igniter plug during a try. | $550 to $1,180 |
| Gas valve or gas pressure | Pressure measured at the valve. | Priced in writing |
Most no-light calls are the igniter or the flame sensor, and both are usually on the van. Flame sensor problems goes deeper on the second one. The diagnostic is a flat $99.
Our heating check is $67 per system, through December 31: furnace, heat pump or boiler. On a furnace, for $229 (regularly $467) we also pull the blower wheel and clean it blade by blade. A yearly check is when a weak igniter gets caught before the first cold night. If your furnace won’t turn on at all and there’s no code, start with furnace won’t turn on.
Every Lennox code in one place: Lennox error codes.
Call or book a Lennox repair
Call (703) 997-9757. We answer day or night. Or book online and pick a time. The diagnostic is a flat $99, and you see the repair price in writing before we touch anything. Furnace running fine and you want to keep it that way? Book the $67 heating check from goswiftpro.com/cookiesoffer (book by November 30) and a box of warm cookies comes with the visit. Rated 5.0 stars across 1,138 reviews on Google, Angi, Yelp, the BBB and Facebook, Virginia Class A license 2705192276. More on Lennox repair in Northern Virginia.
Questions people ask
What does E270 mean on a Lennox furnace?
The furnace tried to light the maximum number of times, never sensed a flame, and went into a one-hour soft lockout. A cracked igniter, no gas, or a dirty flame sensor are the usual causes.
How do I reset a Lennox E270 soft lockout?
It resets itself after an hour if the thermostat is still calling for heat. You can also turn the furnace switch off, count to ten, and turn it back on. If it locks out again, the cause is still there.
What’s the difference between E207 and E290 on a Lennox?
E207 means the control sensed the igniter open, so the igniter itself is broken. E290 is an igniter circuit fault, which can be the igniter or the board circuit that powers it.
What does 7 flashes mean on a Lennox Merit furnace?
It depends on the model. On an ML180UH, ML195UH or ML296UHV it’s a lockout because the burners failed to light. On an ML180UHE, 7 flashes means a limit switch is open. Check the model on the sticker inside the door.
