Takagi Tankless Water Heaters Problems and Solutions

takagi-troubleshootingTakagi is a credible tankless water heater known for its diverse models. This brand has been consistently supplying developed versions of every last one by solving the common problems people are facing at the time. This has spread a lot of love to customers who also share about how great Takagi tankless water heaters are.  However, even the best of the best masterpieces are flawed. In spite of this brand being up to date and solving most water heating challenges in both residential and commercial setups, it has its own share of problems.

So, we decided to state the common Takagi tankless water heaters problems and replace them with the correct Takagi tankless water heater troubleshooting for more clarity of what you own or willing to own. Let’s get to it already!

Solution To Takagi Tankless Water Heaters Problems Manually

Problem: Insufficient Hotness Of Water

Possible causes and Solutions

-Unit may be hard water scaled. Contact a Takagi service agent for help.

-Unit may not be receiving enough gas due to improper sizing, it may be closed or the gas pressure could be too low. Open the gas supply valve if closed, check and correct the sizing, check if gas regulator is malfunctioning.

-Check for a 101-error code, this error reduces the amount of gas put to work. Check if there is damage in venting system and rectify it, the intake and the exhaust terminal could be too close that the latter could contaminate the former.

-Check for any debris in the venting or cabinets. It impedes air flow which in turn affects temperature. Follow the cleaning guide and check again.

Problem: The Hotter Is Too Hot

Possible causes and solutions

-Check the gas supply for any malfunctions just like in problem 1.

-Check it the venting is done according to manufacturer specifications and it should also not exceed 50ft.

-Look for any hard water scaling or debris at the inlet and clean.

-Contact technical department if floor censor is compromised.

Check if there are any problems with the temperature and water flow settings. If they are ok, your plumbing is the problem.

Problem: Unit Is Failing To Ignite When There Is Water Going Through

Possible causes and solutions

-Check if gas supply is open and devoid of air.

-Check if inlet is clean and do the necessary if it’s not.

-Check for both reverse ad cross circulation.

Problem: Unusual Sounds Coming From Unit

Possible causes and solutions

-Check for any debris and clean up. If there isn’t any, contact the technical department for a thorough look.

Problem: Unit Isn’T Turning On While Everything Seems Ok

Possible causes and solutions

-If the fan never starts too, check for a fouled flow sensor.

-Clean the filter.

-If with new unit, check if the plumbing was done correctly. Shut off the cold-water feed and open the hot water tap which should stop. If not, the plumber did a cold cross water connection. Also, open the pressure relief valve and if the water doesn’t stop flowing, the plumbing was done backwards.

Troubleshooting error codes

Problem: Dipswitch Incorrect Settings

Error 031

Solution: Follow the manual to correctly set DIP settings.

Problem: Ignition Fail

Error code 101

Solution: Clean the vent or increase the distance between inlet and exhaust terminal because it could be causing contamination. Solve the error code 991 which is abnormal combustion.

Error code 111

Solution: Ensure the computer board is uncompromised, flame rod is clean and the heat exchanger has no leakage. The Hi Limit switch should be working properly.

Problem: Flame Loss

Error code 121

Solution: The solution for error code 111.


Problem: Inlet Thermistor

Error code 321

Solution: Verify correct working of inlet thermistor and if damaged, replace it with another.

Error code 331

Solution: Verify correct working of outlet thermistor and if damaged. Replace with another.

Problem: Outlet Thermistor

Error code 311

Solution: Ensure the heat exchanger thermistor, outlet thermistor and wire connections are working perfectly.

Problem: Failure Of Air-Fuel Ratio Rod

Error code 391

Solution: Mend any loose or broken wire connections

Problem: Flow sensor

Error code 441

Solution: Verify that the flow sensor wires are damage free and well connected

Problem: Gas Solenoid Valve Malfunction.

Error code 510

Error code 551

Solution: Ensure wires and the computer board are not damaged.

Problem: Fan Motor Problem.

Error code 611

Solution: Check any loose wire connections and damages of computer board.

Problem: Faulty Flow Adjustment Valve.

Error code 651

Solution: Fix any damaged wires and purge any mineral buildup

Problem: Bypass Valve Issues

Error code 661

Solution: Fix damaged wire connections and lime build up

Problem: Computer Board Error.

Error code 701

Solution: Check and fix wire connections.

Problem: Gas Solenoid Valve Circuit Failure.

Error code 711

Solution: Same with error codes 111 and 121.

Problem: False flame detection.

Error code 721

Solution: Check if the combustion chamber properly sealed

Bottom Line

As it is recommended by the manufacturer, you should let a licensed installer to do the Takagi unit set-up. In case you encounter these problems, you can contact them for clarity or servicing of a damaged part. These malfunctions are however normal because it’s a machine and lots of factors are involved. You can worry about any malfunctions but do not include non-professionals to check or fix a shortcoming. This is because they might mislead you or cause more damage. It is advised to call your licensed installer or the manufacturing company for more support.