American Water Heater STCE3-52/80/119 ユーザーズマニュアル

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Servicing should only be performed by a Qualified Service Agent
65
TROUBLESHOOTING
ELECTRONIC CONTROL MODELS
The remainder of the Troubleshooting section covers Electronic Control Models only. 
Fault Conditions
When the control system declares a Fault condition it will display a Fault message on the 
UIM and lock out. Voltage to the contactor coils and heating elements is terminated to 
prevent further heating operation.
Alert Conditions
When the control system declares an Alert condition it will continue heating but will display 
an Alert message on the UIM notifying the user that the water heater requires servicing.
Resetting Control System
Turn the power supply to the water heater off for approximately 20 seconds and then back 
on. If the operational problem that caused the control system to declare a Fault or Alert 
condition has not been corrected the control system will continue to display the Alert or Fault 
message and lock out.
CONTROL SYSTEM UNRESPONSIVE
DISPLAYED MESSAGE
CONDITION/INDICATES
CHECK/REPAIR
UIM Display Is Blank
UIM is not energized - LCD display is blank.
Possible Causes:
No power to water heater
Blown control circuit transformer fuses
120 VAC power problems
24 VAC power problems
Defective transformer(s)
Wiring or plug/socket connection problems
UIM communication cable problems
Important Service Reminder:
When performing any troubleshooting steps outlined 
in this service manual always consider the wiring 
and connectors between components. Perform a 
close visual inspection of all wiring and connectors 
to a given component before replacement. 
Ensure wires were stripped before being crimped in 
a wire connector, ensure wires are crimped tightly in 
their connectors. Ensure pins inside plugs/sockets 
are not damaged or worn, ensure plugs/sockets are 
mating properly & providing good contact.
Check/restore power supply to the water heater 
at Power Distribution Block - see pages 12 - 14.
Check control circuit transformer fuses see Fig-
ure 2 page 9 and checking fuses page 17.
Check communication cable connections at 
UIM’s J2 Socket (page 47) and the CCB’s J11 
Port (page 42). 
Install a new communication cable between 
UIM’s J2 Socket and the CCB’s J11 Port - use 
standard Cat 5 network cable.
Closely inspect communication ports on CCB 
and UIM ensure they are mating properly and 
providing good contact (pages 42 & 47).
Ensure 120 VAC power/ground is supplied to 
CCB’s J2 Socket; follow procedure on page 46.
Check J1 and J2 plug/socket connections on 
the CCB - ensure they are mating properly and 
providing good contact (page 42).
Check 24 VAC transformer: follow procedure 
outlined on page 36.
Call the technical support phone number on the 
back cover of this manual for further assistance 
if the problem has not been corrected after per-
forming the procedure outlined here.