How To Fix Takagi Error Code 111: Ignition Failure

Enhancing your home’s comfort begins with ensuring your water heating system operates flawlessly. In this guide, we’ll address ignition failure and explain how to fix Takagi error code 111, so you can restore your hot water supply.

Among the many issues that can affect tankless water heaters, even reliable brands like AO Smith, Takagi, State, and John Wood are not immune to operational hiccups, particularly those leading to a lack of hot water.

A common culprit behind this inconvenience is error code 111—a cryptic message that can leave users cold and frustrated.

This comprehensive guide provides step-by-step troubleshooting tips and solutions to resolve the issue, offering valuable insights for both homeowners and technicians to effectively restore your water heater’s functionality.

Understanding Takagi Error Code 111

Takagi error code 111, accompanied by three flashes, typically indicates an ignition failure. This issue can arise from various factors, including a malfunctioning ignition system, a faulty flame sensor, gas supply issues, improper venting, electrical faults, or even a blown fuse.

Identifying the root cause of this error is critical for resolving it effectively. Error code 111 is more than a simple malfunction indicator—it highlights a range of potential problems impacting the heater’s operation.

The error code is displayed on the control panel or temperature controller. On many Takagi models, the system will attempt to ignite the gas burner three times. If these attempts fail, the unit shuts down to prevent further issues. Essentially, this error signifies that the control system did not detect a flame during the ignition process.

Below, you’ll find a step-by-step guide to fixing the ignition failure, clearing error code 111, and restoring your water heater to full functionality.

How to Fix Takagi Error Code 111: Step-by-Step Guide

Initial Checks

• Reset the unit by turning it off and on.
• Confirm that water is flowing through the system.
• Remove the cover and look through the sight glass to check for a brief blue flame lasting about three seconds.
  • If you see the flame: The issue is likely with the electronics, such as wiring corrosion, dirt, damage, or looseness.
  • If you don’t see the flame: The problem is likely with the combustion system, including ignition, gas supply, or venting.

Ensure Proper Gas Supply and Line Check

• Verify that the gas supply is at the correct pressure and that the gas line is clear of debris and air. Ensure the pressure is above the recommended minimum and below the maximum (14 IWC).
• Listen for a “clunk” sound from the gas control valve when the unit is running. If no sound occurs during ignition, check the voltage on the ignition and gas valve wires. Refer to the manual (opens in pdf) for proper voltage specifications and replacement guidance.

Clean the Flame Rod/Sensor

• Inspect the flame rod through the sight glass for a strong blue spark. A weak or erratic spark suggests an issue.
• Check the ignition wires for damage or looseness.
• If the flame ignites but extinguishes after 1–2 seconds, clean the flame rod with 100-grit sandpaper to remove soot and debris. Be careful not to alter its position.
• If you hear a buzzing sound near the gas burner but see no spark, check for 120V on the ignition wire at the control board. If voltage is present, replace the spark box.

Check for Vent Blockages

• Inspect the venting system for obstructions like dirt, debris, or bird nests. A clear vent path is essential for combustion.
• Check for dirt or lint in the air pipe, which can clog the fan or gas burner holes. Signs of this include dirt collecting on the heater’s internal walls near the vent opening.
• If necessary, remove the gas valve and burner, and clean them with compressed air.

Check the Hi-Limit Switch

The hi-limit switch shuts off the heater if the water temperature exceeds a safe limit (185–194°F).

• First, turn off the power to the water heater.
• Press the white button on the hi-limit switch until you hear a click, indicating a reset.
• Turn the power back on and attempt to ignite the heater.

If the heater lights, investigate what caused the hi-limit switch to trip. Common causes include limescale buildup, which may require descaling.

Inspect the Overheat Cutoff Fuse (OHCF)

• Locate the OHCF (usually white and wrapped around the heat exchanger).
• Disconnect the white clip at the end and use an ohmmeter to check for continuity.
• If there’s no continuity, the OHCF may need replacement. This task typically requires a professional technician.

Preventive Measures and Regular Maintenance

Regular maintenance is essential to reduce the risk of error code 111 and other potential issues with your Takagi tankless water heater.

This includes periodic checks of the gas line, cleaning or replacing the filter, ensuring proper ventilation, and monitoring for any error codes or signs of wear and tear.

By performing these preventive measures, you not only extend the lifespan of your water heater but also ensure it operates safely and efficiently.