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Any Takagi Experts Out There?

paul_somlo Member Posts: 9
edited November 2020 in Domestic Hot Water
I've got a 14 year old TK-Jr that's not initiating, no blower, nothing. I've replaced the flow sensor, had the flow control valve apart, appears to be functioning correctly. I troubleshot voltages at the flow sensor connector, all good. Takagi tech support says new controller board at $229.00.

Some more info: When I reassembled the flow control valve, it was in the fully closed position. Running water without the unit powered, there was obvious flow restriction. When I powered up the unit, I could hear the motor inside the flow control valve turning, so as to open the valve, apparently. With the unit powered and water running, it initiated and fired (no flow restriction). I had hot water, although it seemed as though the flow was modulating slightly, and I could hear something modulating while standing in front of the unit. I ran hot water for a minute or so, shut the tap, tried it again, wouldn't initiate anymore.

If I unplug the flow control valve at the controller board and run water, the unit initiates, but the burner never fires. It'll initiate, shut down, wait 8 seconds or so, initiate again, shut down, continuously until I turn off the tap. Another data point - with the flow control valve plugged in, unit sitting idle, I can hear a ticking noise about every 2 seconds that I've confirmed electrically, is the valve being pulsed by the controller board.

The easy answer is controller board, but I'd hate to spend $229 and find out it was something else - any ideas?



  • Larry Weingarten
    Larry Weingarten Member Posts: 3,137
    Hi, Takagi has troubleshooting flow charts. Have you had a chance to find the one for your unit? This might be for your heater. https://www.manualslib.com/manual/629890/Takagi-T-Kjr.html?page=17#manual

    Yours, Larry
  • paul_somlo
    paul_somlo Member Posts: 9
    Yes, thank you Larry - I've seen that. I don't have any error codes and I think that's one of the reasons that Takagi is pointing at the controller board.
  • mikeapolis
    mikeapolis Member Posts: 46
    What's the full model #? Thanks
  • paul_somlo
    paul_somlo Member Posts: 9

    What's the full model #? Thanks

    Other than "T-KJr.", I don't see any model #, not on the cover, not on the literature.
  • Snowmelt
    Snowmelt Member Posts: 1,399
    When you do all that what is the temp of the water comming out. What is the remote reading. I went to a job. And the thermistor was all scaled up. It was ready 140 so even if 70 degree water was going through it the computer was reading 140 and nothing go on...
  • paul_somlo
    paul_somlo Member Posts: 9
    Well, I can't really tell, because I can't get it to initiate any more. The one time it did, just after I reinstalled the flow control valve, the burner was firing and the water was hot, although I didn't measure it. If you're referring to a remote control, I don't have one. It looks like the thermistor is easy enough to access though - suppose I could pull it and have a look. Wish I knew the expected voltage - it would be easy enough to read it at the connector. Would the thermistor keep it from even turning on the blower?
  • paul_somlo
    paul_somlo Member Posts: 9
    edited November 2020
    I think I'm ready to concede defeat on this - I'm fairly certain that it's the board. Rather than spend $229 to fix, I think I'll just get a new Takagi, the smallest condensing one they make. After a rebate from the gas company and a tax credit, it'll cost me about $274 to replace the whole thing. I got 14 years out of the T-KJr, I was hoping for at least 20, lacking a tank to rust out. Ironic that my 50/60 year old gas furnace keeps chugging along - I guess it's hard to beat old tech (or the lack thereof) when it comes to reliability. The funny part, is that I'll end up replacing my non-condensing Takagi with a condensing one; but not because I need the efficiency - I use about $1 worth of gas to heat water each month. But because the condensing one has the rebates and tax credits attached, while the non-condensing one doesn't, which makes the condenser the less expensive choice.