A.O. Smith 100 Series Service Handbook page 62

CODE
67 ILK OFF
68 ILK ON
69 Pilot test hold
70 Wait for leakage test completion
71 - 77 RESERVED
78 Demand Lost in Run
79 Outlet high limit
80 DHW high limit
81 Delta T limit
82 Stack limit
83 Delta T exchanger/outlet limit
84 Delta T inlet/exchanger limit
85 Inlet/outlet inversion limit
86 Exchanger/outlet inversion limit
87 Inlet/exchanger inversion limit
88 Outlet T-rise limit
89 Exchanger T-rise limit
90 Heat exchanger high limit
Sensor Faults
91 Inlet sensor fault
92 Outlet sensor fault
93 DHW sensor fault
62
DESCRIPTION
Servicing should only be performed by a Qualified Service Agent
RECOMMENDED TROUBLESHOOTING OF
LOCKOUT CODES
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.
1. Verify Run/Test is changed to Run.
2. Reset Module.
3. If fault repeats, replace module.
1. Internal Fault. Reset Module.
2. If fault repeats, replace module.
1. Check wiring and correct any possible errors.
2. If previous steps are correct and fault persists,
replace the module.
1. Check wiring and correct any possible errors.
2. Replace the Outlet high limit.
3. If previous steps are correct and fault persists,
replace the module.
1. Check wiring and correct any possible errors.
2. Replace the DHW high limit.
3. If previous steps are correct and fault persists,
replace the module.
1. Check Inlet and Outlet sensors and pump circuits
for proper operation.
2. Recheck the Delta T Limit to confirm proper
setting.
3. If previous steps are correct and fault persists,
replace the module.
1. Check wiring and correct any possible errors.
2. Replace the Stack high limit.
3. If previous steps are correct and fault persists,
replace the module.
Not Applicable.
Not Applicable.
Not Applicable.
Not Applicable.
Not Applicable.
1. Check for adequate flow.
Not Applicable.
Not Applicable.
1. Check wiring and correct any possible errors.
2. Replace the Inlet sensor.
3. If previous steps are correct and fault persists,
replace the module.
1. Check wiring and correct any possible errors.
2. Replace the Outlet sensor.
3. If previous steps are correct and fault persists,
replace the module.
1. Check wiring and correct any possible errors.
2. Replace the DHW sensor.
3. If previous steps are correct and fault persists,
replace the module.
NOTE
H or L
H or L
H
H
H
H or L
H or L
H or L
H or L
H or L
H or L
H or L
H or L
H or L
H or L
H or L
H or L
H
H
H