American Water Heater STCE3-52/80/119, ITCE3-52/80/119 Heating Element Resistance & Ground Tests

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Heating Element Resistance & Ground Tests

OPERATION & SERVICE

Heating Element Resistance & Ground Tests

This is a two part test. In the first part of this test the actual resistance (ohms) of each heating element is measured. In the second part of this test each heating element is tested for any continuity to ground to ensure the heating element is not shorted to ground. These tests should be considered as third and fourth diagnostic procedures to be performed whenever the results from the Heating Element Amperage Test showed a heating element was not drawing the correct amps AND the results from the Heating Element Voltage Test showed the element had the proper voltage applied.

Measuring Resistance

1Determine what the actual voltage and KW rating is for the heating elements in the water heater being serviced - see Heating Element Ratings and Heating Element Configurations on page 21. Replace any elements that are not the proper rating for the water heater being serviced.

2Secure power to the water heater at the main breaker or disconnect switch.

3Verify with an AC volt meter that there is not any voltage present at the Power Distribution Block (see Figures 1 and 2 on pages 8 and 9) and at the two wiring terminals on the ends of all heating elements.

4Disconnect both power wires from the terminals on the top of all heating elements to be tested.

5Using an ohm meter: set the ohm meter to a range just above the expected ohms (200 ohm range initially).

6Touch the ohm meter probes between the two terminals on each heating element - see the image below. Measure and record the resistance (ohms) at all heating elements being tested.

7Compare the resistance value (ohms) measured to the values given in the Heating Element Resistance table on page 22.

8If the measured resistance (ohms) matches the values in the Heating Element Resistance table on page 22 the heating element resistance is correct.

9If the resistance reading is infinite - no continuity at all between the two terminals - the heating element is defective and must be replaced. During heating element replacement be sure to check fuses (page 17), inspect contactors on Electronic Control Models (see page 31) and check all wiring and connections between the heating elements, contactors, fuses and the power distribution block. Ensure all wiring and connections are tight and making good contact - replace any wiring, fuses, contactors that are damaged or show signs of excessive wear.

Measuring resistance (ohms) on an electric heating element. Touch the two ohm meter probes to the two terminals on the end of each heating element.

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 TABLE OF CONTENTS SERVICE MANUALCOMMERCIAL ELECTRIC WATER HEATER INTRODUCTION QUALIFICATIONS - QUALIFIED SERVICE AGENTSERVICE WARNING IMPORTANT SERVICE REMINDERTOOLS REQUIRED INSTRUCTION MANUALINSTALLATION CONSIDERATIONS CLOSED WATER SYSTEMSTHERMAL EXPANSION Power Supply ELECTRICAL REQUIREMENTSGrounding PRE SERVICE CHECKS WIRING CONNECTIONSSERVICE 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 applied to “SINGLE PHASE” 1Ø power Ohms LawCalculating 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 BlockPHASE CONVERSIONS - SURFACE MOUNT CONTROL MODELS Surface Mount Control Models Three Phase to Single PhaseSurface Mount Control Models Single Phase to Three Phase PHASE CONVERSIONS - ELECTRONIC CONTROL MODELS Electronic Control Models Three Phase to Single PhaseElectronic Control Models Single Phase to Three Phase FUSES Ohm Meter MethodVolt Meter Method SURFACE MOUNT THERMOSTATS Thermostat & ECO Test HEATING ELEMENTS Heating Element ConstructionWire 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 TRANSFORMERS120 VAC Control Circuit Transformer Test Primary Winding Voltage TestSecondary Winding Voltage Test 24 VAC Transformer Test ECO High Temperature Limit Switch IMMERSION TEMPERATURE PROBETemperature 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 Power and Ground To The CCB Checking for 120 VACChecking 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 Settings Daily Operating Mode Settings Economy Mode All DayNormal 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 MENU Restore Factory DefaultsFactory Default User Settings Not Enough Hot Water TROUBLESHOOTINGCOMMON SERVICE PROBLEMS No Hot WaterAlert Conditions Fault ConditionsResetting Control System CONTROL SYSTEM UNRESPONSIVEHeating Cycle Disabled Control System Unresponsive contUIM is Inoperable “No Current Detected” FAULT AND ALERT MESSAGESFault & Alert Messages “Temp Probe Open”“Temp Probe Short” “Energy Cut Out ECO” Page Page Page Page Technical Support and Parts
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