Takagi error 99

[RobCR12]

Hi, I've got a Takagi TK-Jr2 natural gas unit that was installed outdoors 4 years ago. No issues whatsoever until error code 99 ("imperfect combustion") yesterday. I tried the recommendations in the manual except for checking for grease/dirt in the burner and fan motor, which I'd rather not get into unless absolutely necessary as it requires removal of those parts.

Called tech support this morning who basically went over the same recommendations with me. He said the usual culprit with a 99 is excessive dirt/dust/cobwebs etc blocking airflow or exhaust, that it's usually a visible issue. The unit is in somewhat enclosed on the front and sides and is remarkably clean, just a bit of dust on the cover, but the interior and connections are very clean and clear. He also said (and the manual states this as well) that this error code should clear when water flow stops- the idea being that it'll reset and get thrown again once water flow starts back up if whatever prompted the code has not be fixed. But I can't get the error code to clear when shutting off the water flow (and releasing pressure by opening the valve and discharging the water in the line.)

Any suggestions would be appreciated. The tech I spoke with agreed that it's unlikely that it's worth removing the burner and fan motor given the clean condition of the unit, but I can do that if needed.

 

[Fitter30]

4 years doesn't matter if it's installed in or out yearly maintenance needed to be done. Been sucking bugs and dirt . Water side dhw has it ever been cleaned with vinegar? Look at the install book under maintenance for things that the manufacture wants. Check u tube see if theres a vidio. Any brand of combi heaters need yearly maintenance if don't want to replace them every few years.

 

[Sponsor]

 

[RobCR12]

4 years doesn't matter if it's installed in or out yearly maintenance needed to be done. Been sucking bugs and dirt . Water side dhw has it ever been cleaned with vinegar? Look at the install book under maintenance for things that the manufacture wants. Check u tube see if theres a vidio. Any brand of combi heaters need yearly maintenance if don't want to replace them every few years.

Thanks for the feedback and suggestions. I've done annual maintenance per the manual but have never used vinegar, I do it before each winter but will do it all again today.

 

[RobCR12]

Solved: Called tech support again and right off the guy suggests resetting the water heater. Depressing two buttons (INC and DEC) next to the DIP switches and then flipping the power switch (of the heater inside the case) off then back on did the trick. No mention of this in the manual or in two prior calls to the same tech support.