A.O. Smith XB-1000 Instruction Manual page 65

CODE
124 High fire switch OFF
125 High fire switch stuck ON
126 Low fire switch OFF
127 Low fire switch stuck ON
128 Fan speed failed during prepurge
129 Fan speed failed during preignition
130 Fan speed failed during ignition
131 Fan movement detected during standby
132 Fan speed failed during run
133-135 RESERVED
Start Check Faults
136 Interrupted Airflow Switch failed to close
137 ILK failed to close
138-142 RESERVED
FAULT CODES 149 THROUGH 165 ARE
OEM SPECIFIC FAULT CODES.
143 Internal fault: Flame bias out of range 1
144 Internal fault: Flame bias out of range 2
145 Internal fault: Flame bias out of range 3
146 Internal fault: Flame bias out of range 4
147 Internal fault: Flame bias out of range 5
148 Internal fault: Flame bias out of range 6
149 Flame detected
DESCRIPTION RECOMMENDED TROUBLESHOOTING OF
LOCKOUT CODES
1. Check wiring and correct any potential wiring
errors.
2. Check High Fire Switch to assure proper function
(not welded or jumpered).
3. Manually drive the motor to the High Fire position
and adjust the HF switch while in this position
and verify voltage through the switch to the HFS
input with a voltmeter.
4. If steps 1-3 are correct and the fault persists,
replace the module.
1. Check wiring and correct any potential wiring
errors.
2. Check Low Fire Switch to assure proper function
(not welded or jumpered).
3. Manually drive the motor to the High Fire position
and adjust the LF switch while in this position and
verify voltage through the switch to the LFS input
with a voltmeter.
4. If steps 1-3 are correct and the fault persists,
replace the module.
1. Check wiring and correct any potential wiring
errors.
2. Check VFDs ability to change speeds.
3. Change the VFD
4. If the fault persists, replace the module.
1. Check wiring and correct any possible wiring
errors.
2. Check Interrupted Airflow switch(es) to assure
proper function.
3. Verify voltage through the airflow switch to the
IAS input with a voltmeter.
4. If steps 1-3 are correct and the fault persists,
replace the module.
1. Check wiring and correct any possible shorts.
2. Check Interlock (ILK) switches to assure proper
function.
3. Verify voltage through the interlock string to the
interlock input with a voltmeter.
4. If steps 1-3 are correct and the fault persists,
replace the module.
Contact the service professional.
Contact the service professional.
Contact the service professional.
Contact the service professional.
Contact the service professional.
Contact the service professional.
OEM Specific
1. Holds if flame detected during Safe Start check
up to Flame Establishing period.
65
NOTE
H
H
H
H or L
H or L
H or L
H or L
H
H
H
H
L
L
L
L
L
L
H or L