Takagi T-K2 Error Code 11

Discussion in 'Tankless Water Heater Forum' started by halogen25, May 30, 2009.

  1. halogen25

    halogen25 New Member

    Messages:
    10
    Hi All,

    I have had my Takagi T-K2 for 3 years and love it. But lately there has been a problem with it failing, giving error code 11. The machine fires about 10% of the time, but after it fires once, it fires fine for most of the day. But at night and in the morning, it always fails.

    I have talked to Takagi support twice and had my gas company come out to check the pressure gas pressure (which was fine - 9 inch WC).

    Here is what I know. When hot water is turned on: the fan turns on OK; the igniter sparks OK (best to check this in the dark); and it sounds like the gas switch turns on OK (ie, it "clunks").

    Despite all of this, the flame does not light!! The machine repeats three rounds of igniter sparking, then gives up and reports error 11. If you try this 5-10 times, eventually it will light, work just fine, and continue working for the rest of the day.

    When thinking about the issue, the obvious things can be ruled out. The gas pressure is fine; the gas line is sufficiently large (3/4" from the meter 10' away); the burners look perfectly clean, with no visible dust or grime when looking through the opened ignition plate hole. I also have been vigilent about descaling the heat exchanger and cleaning the water filter once a year.

    I will continue to discuss this with Takagi customer service, but any constructive input from this group would be helpful.

    Mike
  2. Dana

    Dana In the trades

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    So... did they/you figure it out?

    Being an owner of a KD20, I'd like to know what it was! (The KD20 is basically a sealed-combustion version of the TK2)
  3. SewerRatz

    SewerRatz Illinois Licensed Plumber

    Messages:
    1,705
    Location:
    Chicago, IL
    Mike It can be a couple of things, but what it sounds like is that it is not getting enough air to ignite the burner. If a lot of dust has gotten into the unit and burned it can clog up the fins in the heat exchanger and not allow the fan to pull enough fresh air through the unit. Best to call someone that services these units. First thing they will check is there is no obstruction in the flue pipe. If that is clear then check the gas pressure at the unit, and at the burner manifold. If that checks out then the have to remove the burner assembly and clean the unit of soot build up on the heat exchanger.


    With a sealed combustion version it is not as much as an issue, since you are bringing in fresh air from the outdoors.. It still can happen just not very likely. Only thing I can recommend is when you have an error code that has to do with ignition failer, call a plumber that has been certified by the manufacture to service the unit.
  4. Dana

    Dana In the trades

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    I've read (I think it was on THIS site) that there were "issues" with some of the T-K1 & T-K2 flame sensors being flaky (IIRC they're apparently degraded by hair-spray propellants or some other volatiles found in hair salons!?!) and there's a resistor-hack around it (not for the electronically un-gifted), but IIRC that was error-code 12(?). According to the manual, code 11 is a generic ignition-failure flag, and the causes could be quite a range.
  5. SewerRatz

    SewerRatz Illinois Licensed Plumber

    Messages:
    1,705
    Location:
    Chicago, IL
    All tankless units can have the flame sensors go bad due to stuff like hair sprays, grease and any other contaminates that build up on it. The fix is to remove the sensor and do not touch the probe with your hands, clean it off with the soft green Brillo pads. They say do not use sand paper or emery cloth, just the green Brillo pad.

    I would never do a resistor -hack or any kind of modification to any water heaters safety devices. If I was concerned with hair sprays of such things I would install the direct Vent units. Takagi even makes a Direct Vent conversion kit for most of their units. This way we know we are getting fresh air for the combustion air.
  6. halogen25

    halogen25 New Member

    Messages:
    10
    Still not resolved....

    Hi All,

    Thanks for the suggestions. The problem still isn't fixed.

    Discussions with technical support (they are very helpful and patient) have led me to believe that it is one of two problems:
    1) dirty/clogged heat exchanger. The unit is outside, and dust can cause problems. Tech support emailed step-by-step instructions for removal and cleaning of the heat exchanger.
    2) malfunctioning residential gas meter. While the gas company came out and verified gas pressure at 10 inches of water, I neglected to ask them to check working pressure. There is the possibility that the gas valve at the meter does not open up fully when first switched on, leading to insufficient pressure at the unit. This would prohibit proper ignition.

    I am waiting for the right time to remove and clean the burner, as I suspect it will take me several hours. In the mean time, I'm turning the hot water off and on about 20 times every morning, waiting for the damn thing to fire up. Happily the remote control unit has a burn sensor light, but what a drag!

    Stay tuned...

    Mike
  7. SewerRatz

    SewerRatz Illinois Licensed Plumber

    Messages:
    1,705
    Location:
    Chicago, IL
    Yep just like I said sooted up heat exchanger, or not enough gas. The gas should be checked at the unit itself. Where the gas line hooks up there is a port to hook up the meter to. Isn't your water heater under warranty? If it was a Noritz unit they would send out a service technician to trouble shoot it for you, and make the needed repairs.
  8. Scott D. Plumber

    Scott D. Plumber In the Trades

    Messages:
    67
    thoughts on this one

    Code 11 is Failure to Ignite on almost everyones brand. Weird things happen sometimes but recheck the gas pressure. Not while it's sitting still but While its trying to light off! (Called "Dynamic" Pressure) you should have less thana 1" pressure drop.

    Also, you might have to clean out the burner. If there has beena build up of stuff for whatever reason where the gas is supposed to be ignighted, you might not be getting gas to the proper location to light. This can be caused by improper instalation, venting, or other things that result in condensate getting into the unit and messing stuff up.

    Try that.
  9. halogen25

    halogen25 New Member

    Messages:
    10
    The saga continues

    So I finally got around to cleaning the heat exchanger this weekend, a process that took me about 2 hours. (I highly recommend the use of a digital camera to help you remember which screws go where!) The unit had some dust in it, but nothing terrible.

    The results: same problem. The next morning, I had to turn the thing on and off about 15 times in order to get it to fire. It was fine for the rest of the day.

    But there is more. I then carefully monitored the remote control unit while a family member showered and found that the temperature control is not functioning properly. The upper temperature was set for 110F, and the outgoing water temp gradually increased from 110 to 135 over the course of about 5 minutes, with the burner finally shutting off at the upper temp. I do not know if this problem is brand new (as a result of my cleaning) or had been ongoing but I just didn't recognize it.

    Another call to the friendly Takagi support, and again the regulator at the gas meter is blamed -- another call to the gas company. The gas man comes out and checks both the standing and operational gas pressure. 8.4 and 8.4 inches, respectively. Not the gas regulator.

    So what options are left for me? The unit is no longer under warranty (with the exception of the heat exchanger), and all the usual suspects have been ruled out.

    At least the cold showers match our current heat wave. :eek:

    -M
  10. SewerRatz

    SewerRatz Illinois Licensed Plumber

    Messages:
    1,705
    Location:
    Chicago, IL
    Best to call someone that is certified to service the unit. They need to check manifold pressure, check the flame sensor. With the temperature fluctuating like that it could be the gas control valve not regulating the needed flow of gas per the water flow. Also could be a faulty water flow sensor.
  11. Cass

    Cass Plumber

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    5,980
    Location:
    Ohio
    Did you clean the flame / heat sensor ??? When cleaning them on power vents I use a 400 grit or higher wet or dry sand paper and the sensor has to be cleaned all the way back and all sides... is it a spark type or glow ignition ???
  12. Cass

    Cass Plumber

    Messages:
    5,980
    Location:
    Ohio
    Sounds like dirty sensors or bad connections...

    I was dealing with one the day the Twin Towers fell that had a similar problem. I ended up replacing it with a tank...
  13. wbull55

    wbull55 New Member

    Messages:
    2
    Location:
    DC Metro area
    I have a 4-year old T-K2 that is starting to have the same issue as the first post. My assumption is dirt since I haven't cleaned the unit since it was installed. (What can I say? If it ain't broke don't fix it. Plus I have a whole house water filter.) I'll post what I find out.
  14. seabiskit

    seabiskit New Member

    Messages:
    1
    Location:
    portland, oregon
    takagi tkd20 fails to light or quits intermittently

    We have a TKD20 exhibiting similar problems. Sometimes it starts up but quits 10 seconds to 10 minutes later. Then it flashes either an 11 or 12. With Takagi phone assistance, I have cleaned the flame sensor, done the big burner cleaning project (it was clean to begin with!), replaced the flame sensor/ignitor panel. Problem continues. Quite often it will not light at all. The ignitor glows blue for a few seconds, there's a click, but no gas comes on. It does this three times, then gives error code.

    Gas company came out and checked pressure (6.5). There is no drop in pressure when the Takagi lights. There was no change in pressure when the Takagi shuts itself down.

    This has been going on for months now, and we are so tired of taking turbo showers - afraid that we won't get the shampoo rinsed out in time!

    Would love to hear a solution. I'm calling Takagi again tomorrow. If we find a solution, I'll be sure to post it here.

    Tim
  15. SewerRatz

    SewerRatz Illinois Licensed Plumber

    Messages:
    1,705
    Location:
    Chicago, IL
    See troubles like this are real hard to troubleshoot over the internet. There can be so many different things causing the issue, same goes for trying to troubleshoot it over the phone. All they, and we can do is go through each and every troubleshooting step, and many times the person we are telling to do the troubleshooting steps (a) do not understand whats being told to them, and or (b) do not have the right tools. This is why on units like these it is best to call someone that has been trained to troubleshoot the unit they know the steps, the have the tools, and they have the knowledge to understand the troubleshooting process.
  16. wbull55

    wbull55 New Member

    Messages:
    2
    Location:
    DC Metro area
    It took me awhile to fix. I started with cleaning the fire box. Then the symptoms were as if the flame sensor was not working. It would spark and light off but after a few seconds it would it would shut-down amd recycle. So I replaced the flame sensor and ignightor since I noticed the gasket was torn and missing 1/2 inch of material. Same problem but when it did light and I gave the unit a high demand it would blow itself out. So the tech on the phone told me it was probably a gas supply problem. They were right. I replaced the gas supply line since it was undersized and got new high flow ball valves and replaced the pressure regulator. It's working fine now.
    Last edited: Aug 17, 2009
  17. Scott D. Plumber

    Scott D. Plumber In the Trades

    Messages:
    67
    Wish I would have thought of that.

    :):d:d:d:d
  18. Gregerathome

    Gregerathome New Member

    Messages:
    1
    Location:
    Seattle
    RESPONSE TO: "It took me awhile to fix. I started with cleaning the fire box. Then the symptoms were as if the flame sensor was not working. It would spark and light off but after a few seconds it would it would shut-down amd recycle. So I replaced the flame sensor and ignightor since I noticed the gasket was torn and missing 1/2 inch of material. Same problem but when it did light and I gave the unit a high demand it would blow itself out. So the tech on the phone told me it was probably a gas supply problem. They were right. I replaced the gas supply line since it was undersized and got new high flow ball valves and replaced the pressure regulator. It's working fine now."​

    I have read through this entire post and everything mentioned previously exactly mirrors my experience with a KD-20. My installer and I have done all of the recommended fixes mentioned here, usually with only temporary success.

    We have proper sized gas lines and when we checked pressure we got readings of close to 7" WC and and just over a 1/2" drop when the KD-20 kicked on. Thinking that the regulator at the gas meter was flakey, we had it checked but it received a passing grade by the Gas Co.

    Which is the more likely scenario: 1) I have a failing gas control valve in the KD-20, or 2) I have a failed regulator at the gas meter and the Gas Co. guy was ducking a repair?

    Overall, I like the way my HW system works (when it works!) but after only 4.5 years of service, I'm considering switching back to a gas tank heater.
  19. Roof Pro

    Roof Pro New Member

    Messages:
    1
    Location:
    Macon, Tennessee
    Fix for Code 11

    I have a Takagi t-m1 and had all of the same issues posted in this thread. I have power, flow, ignition great gas pressure. Long story short there are 2 fuse wires that wrap the the burner can at the top of the unit this is the part where the high limit switch is located. check the continuity of the white fuse wires. On ours the upper or longer wire checked to have none confirmed by making jumper wire to by-pass and unit works perfect. Cold showers are very motivational.
  20. atpl53

    atpl53 New Member

    Messages:
    1
    Location:
    Toronto, ON
    As a certified Takagi installer and service tech, that is the issue in over 90% of our service calls. It took many frustrating and angry hours on the phone with Takagi to find a solution.
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