Lennox E270: soft lockout after ignition retries, no flame sensed

Furnace control display or LED

E270

“Soft lockout - Exceeded maximum number of retries. No flame current sensed.”

Printed on 19 model series · 19 documents

SL280*V, SL280*NV, SL297*NV, SLP98*V, SLP99*V, EL296*V, EL296*E, EL297*V, EL297*E, EL280*E, EL195*NE, EL196*E, EL180*NE, ML180*, ML193*E, ML196*E, ML296*V, ML297*V, G71MPP · 508559-01 p. 30; 508561-01 p. 37; 508585-02 p. 50; 506610-01 p. 63; 508589-02 p. 46; 1126-L5 p. 17; 1246-L10 p. 14; 508583-01 p. 53; 508577-02 p. 45; 1901-L1 p. 15; 508575-02 p. 47; 508573-01 p. 46; 508545-01 p. 29; 508547-01 p. 49; 508565-01 p. 43; 508569-01 p. 46; 508521-01 p. 44; 508907-01 p. 48; 506509-01 p. 66

Technician

What it means

E270 means the control used up its ignition retries without sensing flame current and went into a soft lockout. The compact ML180UHVK table spells it out as a flame failure on ignition, with ignition retries above the maximum and the last failed retry due to flame failure 508547-01, p. 27. The action in most tables is: check for proper gas flow, make sure the ignitor is lighting the burner, and check the flame sensor current; the code clears when a heat call finishes successfully 508585-02, p. 50. The SLP99DFVK table gives the same three checks in one line 508589-02, p. 46.

The SL297UHNVK instructions also describe an internal Watchguard control, separately from the code table: an automatic reset for an ignition control lockout caused by ignition failure, which acts after one hour of continuous thermostat demand for heat 508585-02, p. 64. They do not say which codes it resets, and the E270 row does not mention it. More on lockouts: clearing a code and lockouts.

Lennox’s thermostat alert 270 is “GF Flame Failed To Ignite”, priority Service Urgent. The alert guide describes the furnace as being in Watchguard mode, with the igniter unable to turn on the flame, as a five strike condition during a single demand; the alert clears automatically on successful ignition 100017, p. 22. Lennox’s documents do not say that alert 270 and display code E270 report the same event.

Check these first

Lennox’s owner’s manuals have no code table and give no steps for E270. What they give is a general list for a unit that will not operate, to work through before calling a Lennox service technician. In the SLP99DFVK manual the order is:

Check that the electrical disconnect switches are ON 508590-01, p. 5.
Check the room thermostat for proper setting 508590-01, p. 5.
Replace any blown fuses or reset circuit breakers 508590-01, p. 5.
Check that the gas valve is ON 508590-01, p. 5. Its switch is behind the outer access panel; the manual’s gas valve steps set the thermostat to the lowest setting and turn off all electrical power to the unit before that panel comes off, and the switch is moved by hand only, never with tools 508590-01, p. 4.
Check that the air filter is not plugged, which would limit air flow 508590-01, p. 5. The SLP99DFVK manual says its filters are installed external to the unit, should be inspected monthly, and that a filter must be in place when the unit is operating 508590-01, p. 4. Before any service or maintenance, it says to turn the electrical power to the unit OFF at the disconnect switch 508590-01, p. 2.
Check that gas is turned on at the meter 508590-01, p. 5.
Check that the manual main shut-off valve is open 508590-01, p. 5.

Then record the model and serial number from the nameplate and call 508590-01, p. 5. The list is not tied to any code. More on it, and on how other Lennox manuals word it: owner checks before a service call.

The manual says the furnace has an ignition device that lights the burners automatically, and not to try to light the burners by hand 508590-01, p. 4. If you smell gas, follow the steps at the top of this page.

When to call a licensed technician

Gas flow to the burners, whether the ignitor is lighting the burner, and the flame sensor current 508585-02, p. 50.
The gas valve switch will not move by hand. Do not try to repair it; call a licensed professional service technician 508590-01, p. 4.
Any work inside the furnace. The owner’s manual leaves maintenance to a licensed professional service technician 508590-01, p. 5.
The furnace still will not run after the checklist 508590-01, p. 5.
E270 keeps coming back after it clears. The owner’s manuals give no step for that; these pages send it to the technician.

Notes for different models

Series or document	Code	Wording	Source
E-code tables of most series, including the SL280, SL297, EL296, EL297, ML296, ML297 and the K editions of the EL180, EL195, EL196, ML180, ML193 and ML196	E270	“Soft lockout - Exceeded maximum number of retries. No flame current sensed.”	508585-02, p. 50; 1126-L5, p. 17; 508569-01, p. 46; 508521-01, p. 44
SLP98V, SLP99V, G71MPP	E270	Same wording. Action: “Check for gas flow, ignitor lighting burner, flame sensor current.”	508589-02, p. 46; 506610-01, p. 63; 506509-01, p. 66
ML180UHVK, compact table	E270	“SOFT LOCKOUT-FLAME FAILURE ON IGNITION, IGNITION RETRY>MAX, LAST FAILED RETRY DUE TO FLAME FAILURE”, in the group “SOFT LOCKOUT FAULTS (60 MINUTES)”	508547-01, p. 27
Lennox thermostat alert table	270	“GF Flame Failed To Ignite”, Service Urgent	100017, p. 22

Furnaces with a red LED report burners that do not light as a flash count. The documents do not translate flash counts into E-codes. On the 13-flash board 103217-03, 3 flashes is “Burner failed to light, or lost flame during heat demand” and 5 flashes is “Watchguard - burner failed to light, exceeded maximum number of retries or recycles.” 507966-04, p. 40. In the 9-flash tables, 7 flashes is “Lockout, burners fail to light.” 507121-01, p. 39; 507869-04, p. 46.