Trane TR250, Owner'S Manual, Page: 14 / 16

14
Figure 4: ERROR CODES (continued)
Code Description Information
IO
Igniter open error If the control is not in lockout and senses that the igniter circuit is open when the
blower is running the control will turn off the blower and go into lockout. Auto-
matic restart 2 min after error is corrected.
SF
Thermistor error An excessive temperature difference between the two thermistors (5 °F or more)
or an “out of bounds” condition on both sensors (less than 10°F or greater than
180°F) will result in the error code. Automatic restart is 2 minutes after the error
is corrected.
HS
Water Temperature
Sensing Error A) Inlet water temperature sensor is reporting a temperature in excess of 104°F.
Normal operation resumes 2 minutes after inlet water temperature sensor reports
temperatures of 104°F or less. This error functions in both normal and remote
thermostat modes.
or
B) Inlet water temperature sensor is reporting a temperature change at a rate
faster than 6°F in 60 seconds, indicating a potentially damaging low water fl ow
conditon. Normal operation resumes when temperatures stabilize. If this condi-
tion is detected 3 times in a one hour period, the heater will lock-out until the
electrical power is cycled off and back on.
Sb
Keypad button stuck
closed error If one of the keypad buttons is closed (or pressed) for more than 30 s the error
code will be displayed but the control will continue to function. The error code
will be cleared when the condition is corrected.
IF
Ignition failure error If the control exceeds the maximum number of ignition retries or recycles the
heater will shut down and go into lockout. Automatic reset is 60 minutes.
CE
Communication error If communication between the ignition board and the display board is not estab-
lished within 3 s of power-up an error will be displayed. After communication is
established, if it is lost for 30 s, the error will be displayed. The error code will
be cleared upon a valid data exchange between boards.
LO
Limit string open error If the limit string opens the heater shuts down and goes into lockout. Automatic
restart is 2 minutes after the error condition is corrected and the limit string
closes. See below for more detail.
EE
EEPROM ERROR An error was detected in the ignition control circuit board.