10 • Condensing Models: On-Demand Water Heater Service Handbook
TR
OUBLE
SHOO
TING
Error Codes
All units have self-diagnostics for safety and convenience when troubleshooting.
If there is a problem with the unit, a numerical error code will display on the TM-RE42 Remote Controller (if installed) or on
the temperature controller of indoor models. Installation-related problems may also produce an error code. If the remote/
temperature controllers are not working, the green LED on the computer board will flash a code pattern. (The green LED is located
just above the DIP switches as shown in Figure 3.)
Table 2: Error and Flash Codes
ERROR CODE
GREEN LED ON
COMPUTER BOARD
SYMPTOM OR ISSUE
TROUBLESHOOTING PROCEDURE
031
One Flash
Incorrect DIP switch setting
Incorrect DIP Switch Settings
, p. 12.
101
Five Flashes
Abnormal Combustion
(lockout is imminent)
Abnormal Combustion
, p. 12.
111 or 121
Three Flashes
Ignition failure / Loss of flame
Ignition Failure / Flame Loss
, p. 12.
311
Two Flashes
Outlet thermistor failure
Outlet Thermistor Failure
, p. 13.
321
Two Flashes
Inlet thermistor failure
Inlet Thermistor Failure
, p. 13.
341
Two Flashes
Exhaust thermistor failure
(indoor models only)
Exhaust Thermistor Failure
, p. 14.
391
Two Flashes
Air-fuel ratio rod failure
Air-Fuel Ratio Rod Failure
, p. 14.
Figure 3. Green LED on Computer Board
Figure 4. TM-RE42 Remote Controller
(Continued on next page.)