American Water Heater ITCE3-52/80/119, STCE3-52/80/119 Fuses, Ohm Meter Method, Volt Meter Method

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FUSES

OPERATION & SERVICE

FUSES

The water heaters covered in this manual have power circuit fuses to protect the heating element circuits. Electronic Control models will have two additional fuses to protect the primary winding of the 120 Volt Control Circuit Transformer. See Figures 1 and 2 on pages 8 and 9 for location. Testing fuses requires an ohm meter, an AC volt meter and an insulated fuse puller - see Tools Required page 3.

Service Note - Replacement Fuses: Replacement power circuit fuses MUST BE of the same value and type as the factory installed fuses - Class G/SC-30 Amp/Time Delay. Replacement 120 Volt Control Circuit Transformer fuses MUST BE of the same value and type as the factory installed fuses - Class G/SC-3 Amp.

Ohm Meter Method

1Secure power to the water heater at the main breaker or disconnect switch.

2Remove each fuse to be tested with an insulated fuse puller.

3Set the Ohm meter to it’s lowest resistance range (< 200) or to an audible beep continuity test setting if so equipped.

4Touch the meter probes to both ends of each fuse simultaneously.

5If the fuse being tested shows a low resistance (< 1 ohms) or the continuity test feature sounds an audible beep the fuse being tested is good and can be re-installed.

6If the fuse being tested shows infinite resistance (open circuit) or the continuity test feature does not sound an audible beep the fuse being tested is blown and must be replaced.

Ohm Meter Method

Volt Meter Method

 

 

 

Volt Meter Method

Fuses can also be checked using an AC volt meter. The power supply must be turned on and a call for heat must be active (all thermostats/contactors must be closed) during this test. Touch the two test probes to both ends of all fuses while still in their fuse blocks.

•A high voltage (at or above 120 VAC) reading indicates the fuse is blown.

•A zero volt reading generally indicates the fuse is good. Next check for voltage between each end of the fuse and ground to ensure voltage is present at both ends of the fuse. If no voltage is present between either end of the fuse and ground the test has not been conclusive - secure power to the water heater and perform the ohm meter test method described above.

The voltage test method is a good way to quickly identify fuses that are blown but it is not always conclusive due to the dependence on power being present at both ends of the fuse, the switch contacts in thermostats/contactors being closed and correct wiring. Keep this in mind as there may be times when a fuse that is blown tests good due to one of these dependencies not being met. The ohm meter method described above is 100% conclusive.

Servicing should only be performed by a Qualified Service Agent

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Contents Technical Support and Parts Service HandbookCOMMERCIAL ELECTRIC WATER HEATERS MODELS STCE3-52/80/119 & ITCE3-52/80/119Page SERVICE MANUAL TABLE OF CONTENTSCOMMERCIAL ELECTRIC WATER HEATER INTRODUCTION QUALIFICATIONS - QUALIFIED SERVICE AGENTSERVICE WARNING IMPORTANT SERVICE REMINDERTOOLS REQUIRED INSTRUCTION MANUALCLOSED WATER SYSTEMS INSTALLATION CONSIDERATIONSTHERMAL EXPANSION ELECTRICAL REQUIREMENTS Power SupplyGrounding WIRING CONNECTIONS PRE SERVICE CHECKSSERVICE PRECAUTIONS ELECTRONIC CONTROL MODELS HEATING ELEMENT CONFIGURATIONSWATER HEATER CONSTRUCTION SURFACE MOUNT CONTROL MODELSWATER HEATER CONSTRUCTION SURFACE MOUNT CONTROL MODELSWATER HEATER CONSTRUCTION Amperage OPERATION & SERVICEPRINCIPLES OF ELECTRICITY VoltageOhms Law Ohms Law applied to “SINGLE PHASE” 1Ø powerCalculating Amps/Ohms/Volts/Watts L1 L2 L3 SINGLE AND THREE PHASE POWERChecking Single Phase 1Ø Power 3 L1 and L3 terminals of the water heater’s Power Distribution Block Checking Three Phase 3Ø Power1 L1 and L2 terminals of the water heater’s Power Distribution Block 2 L2 and L3 terminals of the water heater’s Power Distribution BlockSurface Mount Control Models Three Phase to Single Phase PHASE CONVERSIONS - SURFACE MOUNT CONTROL MODELSSurface Mount Control Models Single Phase to Three Phase Electronic Control Models Three Phase to Single Phase PHASE CONVERSIONS - ELECTRONIC CONTROL MODELSElectronic Control Models Single Phase to Three Phase Ohm Meter Method FUSESVolt Meter Method SURFACE MOUNT THERMOSTATS Thermostat & ECO Test Heating Element Construction HEATING ELEMENTSWire conductor inside tube TOTAL Heating Element ConfigurationsNUMBER OF FACTORY INSTALLED Heating Element Ratings208 VAC Heating Element AmperageELEMENT APPROXIMATE CURRENT - AMPSHeating Element Amperage Test Heating Element Voltage Test Measuring Resistance Heating Element Resistance & Ground TestsReplacing Heating Elements Heating Element Ground TestThree Current Sensors Element Sensor Functions ELEMENT SENSORSElement Sensor Construction Element SensorElement Sensor Operation Contactor Construction - How They Work CONTACTORSContactors Contactor ConfigurationsPower Connection Terminals Element Numbers/Connections Wire Colors to ElementsPhysically Operate Mechanical Contactor InspectionContactor Coil Voltage - At Contactor Contactor Coil Voltage - At CCB H1 H2 H3 H4 H5 N/A Primary Winding Secondary Winding 120 VAC Control Circuit Transformer WiringX1 120 VAC TRANSFORMERSPrimary Winding Voltage Test 120 VAC Control Circuit Transformer TestSecondary Winding Voltage Test 24 VAC Transformer Test IMMERSION TEMPERATURE PROBE ECO High Temperature Limit SwitchTemperature Sensor WATER TEMPERATURE Temperature Sensor Resistance TestTemperature Sensor Resistance Data Checking Temperature Sensor ResistanceDC Voltage To Temperature Sensor Temperature Sensor DC Voltage TestECO Continuity Test Checking ECO Switch ContinuityGround Connection ECO Voltage Test120 VAC To ECO 120 VAC From ECOUIM User Interface Module CCB Central Control Board ELECTRONIC CONTROLSCCB - CENTRAL CONTROL BOARD J4 Wiring Terminals - Contactor Coils CCB Socket & Wiring Terminal IdentificationJ2 Socket - 120 VAC Power Supply J3 Wiring Terminals - Alarm Output Relay see pageJ13 Socket - Heating Element Sensors Bank J7 Socket - Enable / Disable Circuits 1 & 2 see pages 45J16 Socket - Not Used J17 Wiring Terminals - Not Used J8 Socket - Not Used J9 Socket - Not Used J10 Socket - Not UsedCCB Enable/Disable Circuits Test Checking for 120 VAC Checking Power and Ground To The CCBChecking for Ground UIM Circuit Board Front Service Notes - Button Pad Ribbon CableUIM - USER INTERFACE MODULE UIM Circuit Board BackUIM - User Interface Module CONTROL SYSTEM FEATURESELECTRONIC CONTROL SYSTEM CONTROL SYSTEM NAVIGATIONTHE DESKTOP SCREEN ICON Table 1 Status IconsMENUS† Table 2 - Operating StatesTable 3 - Control System Menus STATETank Temperature Differential SettingsTEMPERATURES MENU Operating Set PointTemperature Settings HEATER STATUS MENU Enable / Disable 1Alarm Condition Alarm Relay OutputCurrent Time ECONOMY MODE SETUP MENUSetpoint Adjustment Desktop Screen During Economy Mode Economy Mode Setup MenuEconomy Mode Settings Setpoint Adjustment Value Economy Mode Settings Time Clock Settings Economy Mode All Day Economy Mode Settings Daily Operating Mode SettingsNormal Operation Between Alarm Output Settings ALARM OUTPUT SETUP MENUTemp Alarm SP Used for external Alarm SPBacklight Delay DISPLAY SETTINGS MENUDisplay Settings Temperature UnitsBank # Cycles HEATER INFORMATION MENUElapsed Time Total Heating TimeMain Menu - Current Fault Selected Fault History Menu CURRENT FAULT / ALERT MENUFAULT HISTORY MENU FAULT OCCURRENCE MENURestore Factory Defaults RESTORE FACTORY DEFAULTS MENUFactory Default User Settings Not Enough Hot Water TROUBLESHOOTINGCOMMON SERVICE PROBLEMS No Hot WaterAlert Conditions Fault ConditionsResetting Control System CONTROL SYSTEM UNRESPONSIVEControl System Unresponsive cont Heating Cycle DisabledUIM is Inoperable “No Current Detected” FAULT AND ALERT MESSAGES“Temp Probe Open” Fault & Alert Messages“Temp Probe Short” “Energy Cut Out ECO” Page Page Page Page Technical Support and Parts
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