American Water Heater STCE3-52/80/119 manual Immersion Temperature Probe, Temperature Sensor

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IMMERSION TEMPERATURE PROBE

OPERATION & SERVICE

IMMERSION TEMPERATURE PROBE

This section of the manual provides information on how test the Immersion Temperature Probe on Electronic Control Models - see Figure 2 on page 9 for location. The Immersion Temperature Probe contains the ECO (energy cut out) and a Temperature Sensor. The Immersion Temperature Probe plugs into the CCB circuit board at the J5 socket. See the CCB circuit board layout and identification illustration and tables on pages 42 - 44.

ECO High Temperature Limit Switch

Immersion Temperature Probe

The ECO (energy cut out) is a high

temperature limit switch designed to protect against excessively high water temperatures inside the water heater. The ECO is a normally closed switch located inside the Immersion Temperature Probe (two red wires). The ECO temperature setting is non adjustable; the contacts open at 202°F/94°C and will close at approximately 140°F/60°C.

The control system constantly monitors the state of the ECO switch contacts. If the ECO activates (contacts open) due to abnormally high water temperature the control system will lock out and display a “Energy Cut Out (ECO)” Fault message on the UIM (page 49). Voltage to the contactor coils (page 32) and heating elements is terminated to prevent further heating operation.

Should the ECO activate, the water temperature must drop below 140°F/60°C before the control system can be reset. Once the water temperature has cooled below this point the power supply to the water heater must be turned off and on again to reset the control system.

Temperature Sensor

The temperature sensor located inside the Immersion Temperature Probe is a “thermistor” (two black wires). Thermistors are thermally sensitive resistors. As the water temperature rises the resistance (in ohms) of the sensor will decrease; as the temperature falls the resistance will increase - see the Temperature Sensor Resistance Data table on page 38. The control system interprets the changes in resistance as changes in water temperature.

The control system constantly monitors the temperature sensor (thermistor) for temperature. The control system is also programmed to declare a Fault condition if the resistance of the temperature sensor drops below 390 ohms (shorted) or above 56,000 ohms (open).

If the resistance of the temperature sensor is below 390 ohms the control system will lock out and display a “Temp Probe Short” Fault message on the UIM (page 49). If the resistance of the temperature sensor is above 56,000 ohms the control system will lock out and display a “Temp Probe Open” Fault message on the UIM. Voltage to the contactor coils (page 32) and heating elements is terminated during lock out to prevent further heating operation.

If the control system locks out the condition that caused the lock out must be corrected before the control system can be reset by cycling power off and on again.

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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