Appendix I—Troubleshooting Guide
S811+ Soft Starter MN03900001E—November 2012 83
56
Internal Comm2 Fault Fault Trip Internal communications error. 
Excessive electrical noise or 
hardware failure.
Try a 24 Vdc control voltage power cycle to attempt to clear problem. 
Contact EatonCare for service.
Notes
This fault concerns communication of devices located on the 2 printed circuit boards (PCB’s) inside the unit. It is not relevant to an external 
communications to networks faults.
57
Internal Fault Fault trip Corrupted firmware or memory. Cycle 24 Vdc control power to the S811+. 
Contact EatonCare for service.
58
SCR Not Firing Fault Trip
Fault Warning
Disable
SCR is not conducting when 
gated. Incoming phase lost. 
Special application—undersized 
or high impedance motor
Load disconnected.
SCR failure.
Re-apply lost phase.
Review S811+ application.
Circuitry damaged by megger testing.
Contact EatonCare for service.
Notes:
Verify that both mains and load lines are connected and secure. Verify that any isolation and/or reversing contactors are properly engaged prior to the 
soft starter receiving a START command. If the current draw is significantly less than the frame size of the soft starter (less than 1/16 of motor FLA), not 
enough current may be flowing to allow the SCRs to fire. If this fault occurs immediately when the START command is issued, isolation contactors may 
be open and/or in transition. This feature may be disabled (not recommended).
59
Shorted SCR Fault Trip
Fault Warning
Disable
SCR is shorted.
Internal bypass contactor welded 
shut.
No load on the SCRs when START 
command is issued.
Test resistance of each phase.
Contact EatonCare for service.
Notes:
Shorted SCRs are the most common mode of SCR failure. With power completely removed from the unit, measure the resistance of each pole, line to 
load. If the resistance is near zero (less than 5 ohms), it is most likely that the SCR is shorted. Resistance of a serviceable SCR is approximately 10k ohms. 
Resistance typically moves to a lower value as the SCR ages. This feature may be disabled (not recommended).
60
SCR Over Current 
(Stall Disabled)
Fault Trip Excessive SCR Current during the 
start ramp.
Only active when Stall Fault is 
disabled. 
Increase Soft Start Time and/or Initial Torque parameters in Soft Start 
Config menu.
Reduce starting load. 
Verify S811+ is properly rated for current (undersized unit).
Notes: 
The maximum RMS value of the three phase currents is monitored. The current values observed in the Monitoring Menu should be within ± 5% of each 
other The SCR Over Current Trip threshold is 3 X FLA and is not user settable.
61
Mains AC Voltage 
Loss
Fault Trip Fuses or breaker open.
Disconnect open.
Replace fuses, close disconnect, or reset breaker.
Notes:
The Mains Loss Fault trip threshold is 80 Volts AC and is not user settable.
63
Motor Stall Fault Trip
Fault Warning
Disable
Motor not at rated RPM at end of 
start ramp time and/or current is 
in excess of 2 X FLA.
Bypass contactors not closed at 
the end of the start time (start 
current low/ramp time short). 
Lengthen Soft Start Time and/or increase Initial Torque in the Soft 
Start Config Menu. 
Loads that are heavily loaded (high inertia) during a start such as fans 
will often need an initial torque setting much greater than the factory 
default.
Set Kick Start parameters.
Notes:
Motor rpm is monitored for a synchronous speed condition. A Motor Stall fault will occur at the end of the ramp time (default is 20 seconds) if the motor 
is not at synchronous speed and the current is in excess of 2 X FLA. This feature is not user settable. Verify that the motor is properly sized for the load.
S811+ Fault Codes, continued
Code Fault Status Condition Solution