Lennox EL296UHV Error Code E 110: Low Line Voltage
What Does Code E 110 Mean?
Code E110 on the Lennox EL296UHV means the SureLight integrated control sensed that the 120V line voltage feeding the furnace dropped below the acceptable range printed on the unit nameplate. The control monitors incoming power because the variable-speed ECM blower and the two-stage heating logic depend on a stable supply to run correctly; when voltage sags too far, the control flags E110 rather than risk unreliable operation.
The most common source is the utility side — a brownout or a temporary voltage drop, which often shows up during storms, high neighborhood demand, or when large loads elsewhere in the area switch on. A second common source is inside the home: an undersized circuit, a long undersized wire run, or a loose or corroded connection that causes the voltage to sag under the furnace's load.
This is a self-recovering alarm. The system resumes normal operation about five seconds after the voltage returns to the proper range, so a single, isolated E110 during a brief dip is usually nothing to worry about. It is worth acting on when it repeats. Related supply-voltage codes on this board are E113 (voltage too high) and, on the control side, E115 and E116 for the 24V transformer power — E110 refers specifically to the incoming AC mains, not the low-voltage control circuit.
What You'll Notice
- The furnace shuts down or restarts during storms or brownouts, then recovers by itself
- House lights dim or flicker at the same moment the furnace acts up
- "E 110" flashes on the seven-segment LED and then clears a few seconds later
- The blower slows or the furnace hesitates when large appliances start up
- Heating drops out during periods of high electrical demand
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| Utility voltage drop or brownout | Most common | ✗ Call a pro → |
How This Is Diagnosed
A technician measures the actual incoming voltage at the furnace line terminals, ideally while the furnace and blower are running under load, and compares it against the nameplate range. A reading that sags only under load points toward a wiring or connection problem, while a reading that is low even at idle points upstream.
From there they inspect the dedicated circuit — breaker, wire gauge for the run length, and the tightness of connections at the furnace and panel. If the home wiring is adequate and connections are sound but the voltage is still low, the cause is on the utility side, and the homeowner is directed to the power company or an electrician for a service-level check.
When to Call a Professional
This code involves components that are not homeowner-serviceable, so have a licensed HVAC technician diagnose and repair it. Keep in mind:
- E110 appears frequently rather than during a single obvious brownout
- House lights dim noticeably whenever the furnace or blower starts
- The furnace shares a circuit or shows signs of an undersized or overloaded feed
- E110 appears together with E113, E115, or E116
Frequently Asked Questions
Do I need to do anything when I see E110?
If it appeared once during a storm or a brief power dip and the furnace recovered on its own, no action is needed. If it keeps returning, have the incoming voltage and circuit checked.
Is low voltage bad for my furnace?
The control flags E110 specifically to avoid running the blower motor and electronics on unstable power, which is why it pauses until voltage recovers. Repeated low-voltage events are worth correcting to protect the equipment.
Is this the furnace's fault or the power company's?
It can be either — an undersized or loose home circuit, or a utility brownout. A technician measures the voltage under load to tell which side the drop is coming from.
✓ Verified against manufacturer service manual — March 2026