Takagi t-k3 won't work

Discussion in 'Tankless Water Heater Forum' started by Donontime, Nov 4, 2011.

  1. Donontime

    Donontime New Member

    Nov 4, 2011
    New Hampshire
    Lost power for a week and once the power came back I discovered my tankless heater doesn't come on at all when the hot water faucet is open. It doesn't seem to get electricity and I checked the recepticle it uses to make sure it had juice. I read something about a flow sensor possibly causing this problem. Any suggestions on how to troubleshoot the problem?

    HANK WHITE New Member

    Mar 10, 2010
    redding calif
    Takagi tk3


    I had the same Takagi problem and with this forums' help, I fixed it quickly.
    Takagi has a fuse wire wrapped around the back and sides of the heat exhanger
    and it is called the HEAT ECHANGER OVERHEAT FUSE. It is connected with blue
    wires and a cheap white plastic connector to the HIGH-LIMIT SWITCH in the
    extreme upper left of my TK3 unit. Mine had BURN MARKS ON THE CONNECTOR
    and when I "cheated" it out with a paperclip, I got hot water.
    So, why did it happen? My unit lives outdoors on the porch, and our summers
    are hot, about 105 or so on the porch. This may have caused a false overheat
    signal, but the connector was burned brown where the wires went into it.

    I will repair the bad plug, and maybe open the air vent above this area to drop
    the internal heat in the housing. I will let you know if it helps. Tiny automotive
    probes and tools from the tool truck help with the repairs.

    Redding, Calif.
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  4. Dana

    Dana In the trades

    Jan 14, 2009
    I've read several 3rd-party assessments that the Takagi telephone technical support is both competent and patient about helping people diagnose problems with their equipment. It's surely worth a shot:

    (888) 882-5244

    It's also worth having downloaded (maybe even printed) and read the manual before calling.
  5. joegreen

    joegreen New Member

    Sep 15, 2012
    Irvine, CA
    I just had the same problem... Yesterday the Takagi K3 worked , this morning it didn't . Power was good, Gas was good. The Red Led in the MCU was blinking 3x. According to the Takagi Manual that could mean one of 6 things.
    1.Ignition Failure
    2.Flame Blows Out
    3.Abnormal Gas Solenoid Valve
    4.Abnormal Gas Main Valve
    5.False Flame Detection
    6.Abnormal Burning

    To make this long story short: Since the Alarm (blinking LED 3x) would come on ~15 Seconds after turning on the power switch even with no demand for the Flame to be on. I thought that the Gas Valves would be most suspect. After checking for open coils with an OHM meter and finding them all ok (~44 ohms on the big one to ~1.2k ohm on the small ones) I still had the problem... As I pondered, I wiggled the Proportional Gas Valve wire (#714 on pg 35 of the manual) and the LED flashing went from 3 to 1... I turned the unit off and on ... No flashing LED... and everything worked.
    Last edited: Sep 15, 2012
  6. joegreen

    joegreen New Member

    Sep 15, 2012
    Irvine, CA
    Almost 11 Months later the same thing happened again.... No Hot Water.. Same Symptoms as above...

    Wiggling wire #714 did not help..
    I called Takagi and they had me RESET the K3 by holding the 2 buttons on the left (there are 4 black push buttons near the bottom of the K3) until the blinking light went SOLID... Then turn the K3 off...

    When I turned it back on , all was OK.
  7. Dana

    Dana In the trades

    Jan 14, 2009
    Does that mean the control hardware is running a MicroSoft operating system? :)

    When in doubt, do a hard re-boot!

    It would be curious to know how it's getting into this locked-out logic state, but it may not be all that relevant, if it's a 1/10,000 event.
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