come on, hit the green reset button above the 
light, and look for the green light on the circuit 
plate at the top left of the unit.  If this light is not 
lit, there is a problem with the electrical 
connection between the GFCI and the circuit 
plate.  Contact Takagi Industrial Company for 
Instructions. 
 
Error Codes 
 
All Takagi units are self diagnostic for errors.  If 
there is a problem with the installation or the 
unit, it will give a signal, through a pair of 
flashing lights on the circuit plate or error 
display on circuit board LED display to 
communicate the source of the problem.  If the 
unit has a TK-RE10 remote control installed, 
this will give also give a numerical error code. 
Consult the following chart for the meaning of 
an error code: 
 
MOBIUS Water Heater Model T-M1 has a built 
in self-diagnostic computer programmed for 
safety and convenience for trouble shooting 
and maintenance service. 
 
AT the T-M1 Computer Board, a numeric 
display will notify of any error displaying a 
numeric code when the MOBIUS water heater 
has or encounters a problem. This numeric 
code will give symptoms for trouble shooting 
service and maintenance service.   
The T-M1 consists of five major components: 
Temperature control, Gas control, Water 
control, Burner Control, and Main computer 
control. 
 
More detail error code can be found at 
Trouble shooting Diagnose Flow Chart. 
 
 
 
 
 
 
 TK-RE10 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Error N0.  Component 
031,141,711,741, 
751 
Main Computer Control 
701 
Temperature Control  
(Setting Temp. + over 50 
°F) 
111, 121  Burner Flame  
311, 321,331  Temperature control 
391,611,721,991 Burner control 
501 Gas control 
651, 661,541  Water control 
101 Combustible Air 
Error Code as 
Three digit Numeric 
numbers