Lennox Error Code 5 flashes: Watchguard – ignition retries/recycles exceeded (Furnace)

Updated October 13, 2026 · by Aurora Star Tech Inc.

Lennox error code 5 flashes on a furnace means: Watchguard - ignition retries/recycles exceeded. It is also called Lennox diagnostic code 5 flashes.

High severityFurnaceLennox EL195UHNE

Homeowner? What Lennox code 5 flashes means for you

Call a technician Your furnace is reporting: Watchguard - ignition retries/recycles exceeded. The furnace has locked out or cannot run properly. One reset is fine; if the code comes back, it needs a licensed technician to find the cause.

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) 657-2977 Book a service call

Licensed technicians serving Vaughan, Toronto and the GTA.

What does Lennox error code 5 flashes mean?

The burner failed to light within the maximum retries or recycles. The control locks out and retries after 60 minutes (107163-01: 1 hour lockout).

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

Common causes of Lennox code 5 flashes

Same causes as 3 flashes: no gas, ignitor, flame sensor, air orifice, vent/drain restriction

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 5 flashes

EL195UH040NE36B EL195UH060NE36B EL195UH080NE48C EL195UH100NE60C

Other Lennox Furnace codes

Code	Meaning
--	Double dashes - zone sensor problem
1 flash	Line voltage polarity reversed
2 flashes	Improper earth ground
3 flashes	Burner failed to light or lost flame
4 flashes	Low flame signal
7 flashes	Primary or secondary limit open
8 flashes	Rollout switch open
9 flashes	Pressure switch stays open or drops out on a heat call
10	Unknown device detected
10 flashes	Watchguard - pressure switch opened 5 times in one heat demand
11	Missing device
11 flashes	Pressure switch stuck closed before inducer starts

All Lennox Furnace error codes →

Lennox code 5 flashes: homeowner questions

What does Lennox code 5 flashes mean?

Watchguard - ignition retries/recycles exceeded. The burner failed to light within the maximum retries or recycles. The control locks out and retries after 60 minutes (107163-01: 1 hour lockout).

Is it safe to keep using my furnace with code 5 flashes?

It depends on the cause. The furnace has locked out or cannot run properly. One reset is fine; if the code comes back, it needs a licensed technician to find the cause.

Can I reset Lennox code 5 flashes myself?

You can try one reset (power off for 30 seconds, then on). If Lennox code 5 flashes comes back, the cause is still there and a licensed technician should check it.

Who can fix Lennox code 5 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

Blowing cold air All brands · Furnace
No heat All brands · Furnace
Short cycling All brands · Furnace
Blower motor does not run - Lennox SL280UHV ECM checks Lennox · Furnace
Display shows two horizontal bars (soft disable) - Lennox SL297NV Lennox · Furnace
Furnace will not run (no heat) - Lennox EL195UHNE Lennox · Furnace
Furnace will not run (no heat) - Lennox SL297NV Lennox · Furnace
Furnace will not run - Lennox SL280UHV checklist Lennox · Furnace
Indoor blower does not run - Lennox EL195UHNE Lennox · Furnace
Indoor blower does not run - Lennox ML180UHE Lennox · Furnace
Poor ignition or combustion resonance - Lennox EL195UHNE Lennox · Furnace
Poor ignition or loud combustion resonance - Lennox SL280UHNV Lennox · Furnace
Two horizontal lines on display (soft disable) - Lennox communicating Lennox · Furnace

Source: Lennox EL195UHNE Unit Information Corp 1801-L1 (rev 04/2024), Table 4 (103217-03) / Table 5 (107163-01) diagnostic codes, p.8-10. 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.