Specifications

47
A. O. Smith Water Products Service Handbook
Ashland City, Tennessee 2005
©
Training Department
corresponding to the stage in which the failure occurred. A red stage LED, corresponding to the stage
in which the failure occurred, will also illuminate. The appropriate LED(s) will remain illuminated until
manual reset.
Temperature Probe Fault: If the control detects an open or shorted temperature sensor in the
controlling temperature probe, or in the Appliance Max. Temperature Probe (Outlet Probe), the control
will enter the lockout mode. The appropriate LED will illuminate and an error code is displayed. The
appropriate LED(s) will remain illuminated until the Control receives a manual reset. Unused
temperature probes are not monitored. (Ex. "Temp
Probe Fail" red LED 'On'. Display "Temp Probe Fail
High Limit LOCO 010).
TRIAL FOR IGNITION STATE
Limit String Fault: During trial-for-ignition, if the Control senses a limit string fault, the Control will
enter the lockout mode. The appropriate LED will illuminate and an error code is displayed. If applicable,
a Red stage LED will illuminate. The appropriate LED(s) will remain illuminated until the Control receives
a manual reset, or if a soft lockout has occurred, one hour after the fault occurred.
Temperature Probe Fault: If the control detects an open or shorted temperature sensor in the
controlling temperature probe, or in the Appliance Max. Temperature Probe (Outlet Probe), the control
will enter the lockout mode. The appropriate LED will illuminate and an error code is displayed. The
appropriate LED(s) will remain illuminated until the Control receives a manual reset. Unused
temperature probes are not monitored.
HEATING STATE
Limit String Fault: During heating, if the Control senses a limit string fault, the Control will enter the
lockout mode. The appropriate LED will illuminate and an error code is displayed. If applicable, a Red
stage LED will illuminate. The appropriate LED(s) will remain illuminated until the Control receives a
manual reset, or if a soft lockout has occurred, one hour after the fault occurred.
Gas Valve Relay Failure: After detecting the failure, the blower associated with the stage in which the
failure occurred will proceed to a 15 second (nominal) inter-purge. The stage will then retry for ignition.
If the failure continues after one or three attempts (depending on the trial configuration), all active
blowers will proceed to a 25 second
(nominal) post-purge, and the pump will function per the programmed
post-circulate time. The Control will proceed to a hard lockout. A red Gas Valve LED will illuminate
and the display will show an error code corresponding to the stage in which the failure occurred. A red
stage LED, corresponding to the stage in which the failure occurred, will also illuminate. The appropriate
LED(s) will remain illuminated until manual reset.
Flame Failure (Ignition Failure): After detection of loss of flame, the controller will shut off the stage
gas valve(s), and all other gas valves associated with the subsequent stages, if applicable, and proceed
to a 15 second (nominal) inter-purge. The stage is given one or three retry attempts, depending upon
the trial configuration. If ignition is not successful after one or three attempts, (depending on the trial
configuration), all active blowers will go into a 25 second (nominal) post-purge, and the pump will
function per the programmed post-circulate time. The controller will go into a hard lockout, and the
FAULT CONDITIONS CATEGORIZED BY BOILER