American Water Heater ITCE3-52/80/119 manual Contactors, Contactor Construction - How They Work

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CONTACTORS

OPERATION & SERVICE

CONTACTORS

This section of the manual provides information on how contactors used on Electronic Control Models are constructed, how they work and how to test contactor operation - see Figure 2 on page 9 for location of the contactors on these models. Surface Mount Control Models are not equipped with contactors.

Contactor Construction - How They Work

Magnetic contactors are used on Electronic Control Models to energize and de-energize the heating elements. Power from the fuse blocks is supplied to the heating elements through three switches (3 poles) inside the contactor. Springs located inside the contactor hold the switch contacts open; the springs are compressed and the spring tension forces or holds the switch contacts in their normally open state.

The contactor’s switches are closed by an electromagnetic coil inside the base of the contactor. When a call for heat is activated the electronic control system sends 120 volts to the contactor’s electromagnetic coil. As current runs through the coil it becomes “magnetized” and overcomes the spring tension holding the switch contacts open. The switch contacts then close which in turn sends power to the heating elements. When the call for heat is satisfied the control system de-energizes the contactor coil and spring tension returns the contacts to their open position.

3 Pole Contactor Side View

3 Pole Contactor Internal Wiring

Heating Element

Power Circuit

Wiring Terminals

Electromagnetic

Contactor Coil Wiring

Terminals 120 VAC

T3	T2	T1
		3 Normally
		Open Switch
		Contacts
L3	L2	L1
		Electromagnetic
		Contactor Coil

3 Pole Contactor Side View - Cover Plate Removed

Contactor Springs

Hold Contacts Open

When Electromagnetic

Coil Is Not Energized

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