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Lennox Error Code 13 flashes: Low line voltage (Furnace)

Updated · by Aurora Star Tech Inc.

Lennox error code 13 flashes on a furnace means: Low line voltage. It is also called Lennox diagnostic code 13 flashes.

Medium severityFurnaceLennox EL195UHNE

Homeowner? What Lennox code 13 flashes means for you

Check, then call Your furnace is reporting: Low line voltage. This is often caused by something simple. Try the safe checks below; if the code returns, book a service call before it turns into a no-heat or no-hot-water emergency.

Safe things you can check yourself

  • Check the thermostat: right mode (Heat or Cool), set a few degrees past room temperature, and fresh batteries if it uses them.
  • Make sure the unit has power: its on/off switch (often looks like a light switch near the unit) is ON and the breaker in the electrical panel is not tripped.
  • Make sure the furnace front door or panel is closed properly; many furnaces will not run with the door switch open.
  • Look at the air filter. If it is grey and clogged, replace it; a blocked filter causes many shutdowns.
  • Outside, make sure the intake and exhaust pipes or vent cap are not blocked by snow, ice, leaves or a nest.
  • Check that the gas valve next to the furnace is open (handle in line with the pipe). Do not force it.
  • Try one reset: turn the power off for 30 seconds, then back on. If the code comes back, stop resetting and call a technician.

Call (647) 657-2977Book a service call

Licensed technicians serving Vaughan, Toronto and the GTA.

What does Lennox error code 13 flashes mean?

Line voltage is too low. Below 70 V the control will not answer a heat call until voltage is above 75 V; cooling continues.

Applies to: EL195UHNE furnaces with ignition control 103217-03 or 107163-01 (red LED)

Common causes of Lennox code 13 flashes

  • Low utility voltage
  • Loose connections or undersized wiring
  • Generator/inverter supply
Safety: Gas, electrical and refrigerant work must be done by a licensed technician. Turn off power and gas before servicing, never bypass a safety control, and always follow the manufacturer's manual for your exact model.

Lennox models that use code 13 flashes

EL195UH040NE36BEL195UH060NE36BEL195UH080NE48CEL195UH100NE60C

Other Lennox Furnace codes

CodeMeaning
10 flashesWatchguard - pressure switch opened 5 times in one heat demand
11Missing device
11 flashesPressure switch stuck closed before inducer starts
12Indoor unit not detected
12 flashesFlame sensed with gas valve off
13Duplicate comfort sensor ID
14Too many devices of the same type
15Parameter mismatch detected
20Protocol upgrade required
21Incompatible equipment detected
29Over temperature protection (indoor above 90 F)
30Low temperature protection (below 40 F)

All Lennox Furnace error codes →

Lennox code 13 flashes: homeowner questions

What does Lennox code 13 flashes mean?

Low line voltage. Line voltage is too low. Below 70 V the control will not answer a heat call until voltage is above 75 V; cooling continues.

Is it safe to keep using my furnace with code 13 flashes?

It depends on the cause. This is often caused by something simple. Try the safe checks below; if the code returns, book a service call before it turns into a no-heat or no-hot-water emergency.

Can I reset Lennox code 13 flashes myself?

You can try one reset (power off for 30 seconds, then on). If Lennox code 13 flashes comes back, the cause is still there and a licensed technician should check it.

Who can fix Lennox code 13 flashes near me?

Aurora Star Tech Inc. repairs Lennox furnaces in Vaughan, Toronto and across the GTA. Call (647) 657-2977 or book a service call online.

Homeowner help: Furnace Not Turning On: What to Check · Furnace Blinking Light: What the Flash Codes Mean

Troubleshooting guides

Source: Lennox EL195UHNE Unit Information Corp 1801-L1 (rev 04/2024), Table 4 (103217-03) / Table 5 (107163-01) diagnostic codes, p.8-10; flowchart p.51-52. Written in our own words as a summary; always check the original manual.

General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.

Emergency Furnace Repair

647-657-2977