Bosch GWH C 920 ESC Specifications

GWH C 920 ES/ESCINDOOR RESIDENTIAL AND COMMERCIAL MODELSTemperature Modulated with Electronic IgnitionSuitable for heating potable water - Not approve

6 720 608 83610Installation instructions3.3.1 Vent materialAll combustion air and vent pipe materials and fittings must comply with the following:For

6 720 608 836Installation instructions113.3.2 Vent specificationsEstablish vent clearances that comply with the ventmanufacturer's specif

6 720 608 83612Installation instructionsRequired direct vent terminal clearances (twin pipe / concentric penetration)Fig. 9* For clearances not specif

6 720 608 836Installation instructions13Required other than direct vent terminal clearances (single pipe penetration)Fig. 10* For clearances not speci

6 720 608 83614Installation instructions3.3.3 Vent configuration examplesBelow are approved examples of vertical and horizontal venting installations.

6 720 608 836Installation instructions153.3.4 Vent connectionsAttaching the exhaust and air inlet connection adaptors to the top of the heaterB Attach

6 720 608 83616Installation instructionsExternal condensate drain installationIf an external condensate drain (installer supplied) mustbe installed

6 720 608 836Installation instructions17Concentric Pipe ExampleExhaust• 3 - 3’ straight sections• 1 - 2’ straight section– Total length 11'• 1 -

6 720 608 83618Installation instructionsAdjusting minimum power fan speed P2To select fan speed:B Press ON/OFF button into OFF.B Press and hold &

6 720 608 836Installation instructions19Attention residents of the Commonwealth of Massachusetts:In the Commonwealth of Massachusetts the followingreg

6 720 608 8362IndexIndex1 Warning 32 Appliance details 42.1 Features 42.2 GWH C 920 ES and GWH C 920 ESC Specifications (Technical data) 52.3 Unpa

6 720 608 83620Installation instructions3.4 Combustion air requirementsTwin pipeThe tankless water heater is designed as a sealedcombustion a

6 720 608 836Installation instructions213.5 Proper location for installing your heaterCarefully select the location of the water heater. Forsa

6 720 608 83622Installation instructionsFig. 21 Leveling wall mounting bracketFig. 22 Mounting the heater3.8Gas piping & connections Before conne

6 720 608 836Installation instructions23Fig. 23 Gas connectionOnce connections are made, check for gas leaks at all joints. Apply some gas leak detect

6 720 608 83624Installation instructionsFOR NATURAL GASMaximum Capacity of pipe in Cubic Feet of Gas per Hour for Gas Pressure of 0.5 Psig or less and

6 720 608 836Installation instructions253.9 Water connections B When facing the heater, the ¾" cold connection ison the bottom right and the hot

6 720 608 83626Installation instructions3.10 Water qualityWater quality can have an impact on appliancelongevity and may void the manufacturer&

6 720 608 836Installation instructions273.11 Domestic hot water recirculationAlthough recirculation directly through the tanklesswater heater i

6 720 608 83628Installation instructions3.12 Filling the condensate trapThe condensate trap can be filled before or afterconnecting the vent p

6 720 608 836Installation instructions293.13 Measuring gas pressureGas pressure must be measured upon installation.Connecting manometerB Shut off gas

6 720 608 836Warning31 WarningFor your safetyDo not store or use gasoline or other flammable,combustible or corrosive vapors and liquids

6 720 608 83630Electrical connections4 Electrical connections4.1 Electrical power supplyThe tankless water heater requires an electrical powersupply

6 720 608 836Operation instructions315 Operation instructionsFig. 401 On/Off button2 Reset button3 Program button4 LCD display5 Up button6 Down button

6 720 608 83632Operation instructions5.2 For your safety read before operating your water heaterA. This appliance is equipped with electronic ignition

6 720 608 836Operation instructions33Solar modeThe water heater will not ignite if inlet water temperatureexceeds the set temperature on the applia

6 720 608 83634Maintenance and service5.8.1 Memorizing selected temperatureB Press buttons or to select desiredtemperature.B Hold “Program”

6 720 608 836Maintenance and service35Inlet Water Filter• Verify the inlet filter screen is clean and undamaged.The inlet water filter is located betw

6 720 608 83636Maintenance and service13. Disconnect all lines and drain all solution from heatexchanger. Properly discard of solution.14. Position a

6 720 608 836Maintenance and service37P1 Operating Pressure: “ WCThe P1 minimum operating gas pressure is 3.5" WC for Natural Gas and 8" W

6 720 608 83638Maintenance and serviceFinal ReadingsP1 CO2 Reading: % CO2P2 CO2 Reading: % CO2D. Returning to Service:1. Return slotted screw cove

6 720 608 836Maintenance and service396.6 Program valuesThis section describes details on programming the appliance. For most applications the factory

6 720 608 8364Appliance detailsFCC:This device complies with Part 15 of the FCC rules.Operation is subject to the following two conditions: (

6 720 608 83640Maintenance and service6.7 Control unit diagnostics1. Press ON/OFF button to turn off the appliance.2. Press and hold "Program&

6 720 608 836Troubleshooting417 Troubleshooting7.1 IntroductionMany of the questions customers ask regardingoperation of this unit can be answer

6 720 608 83642TroubleshootingContact your original installer or a local certified gastechnician to obtain this reading.7. Cold water is mixing in

6 720 608 836Troubleshooting43specifications in Section 3.4, page 20 CombustionAir Requirements.4. Cross contamination. Ensure that intake and exhaust

6 720 608 83644Error codes8 Error codes8.1 Error code diagnosticsiTo remove error code from thedisplay, press the reset button.Display Cause Solu

6 720 608 836Error codes45Primary fan rotation too low inoperation.1. Reset errors, disconnect power supply cord and check wireconnectio

6 720 608 83646Error codesExhaust temperature sensor - theappliance will close the burner andlock if it gets over 194°F; (onlyapplied for co

6 720 608 836Error codes47Ionization failure during operation. 1. Check gas type, Fig. 2, page 6.2. Check three wire connections to ignition gr

6 720 608 83648Electrical diagram9 Electrical diagramFig. 64 Electrical scheme1 Inlet water temperature sensor2 Outlet water temperature sensor3 Backf

6 720 608 836Sensor resistance charts4910 Sensor resistance chartsFig. 65Fig. 66Outlet sensor characteristics3 23 74 24 752576 26 772778 28 79 29 710

6 720 608 836Appliance details52.2 GWH C 920 ES and GWH C 920 ESC Specifications (Technical data)Approved in US/CanadaCapacityMaximum flow rate: 9.

6 720 608 83650Sensor resistance chartsFig. 67Back Flow and Exhaust sensor characteristics3 23 74 24 75 25 76 26 77 27 78 28 79 29 710 210 711211712 2

6 720 608 836Functional scheme5111 Functional schemeFig. 68 Functional scheme

6 720 608 83652Interior components diagram and parts list12 Interior components diagram and parts list12.1 Interior componentsFig. 69 Components1 Exha

6 720 608 836Interior components diagram and parts list53Fig. 70 Appliance overview6720608836-02.1AL

6 720 608 83654Interior components diagram and parts list12.2 Components diagram12.2.1 Group 1Fig. 71 Components Diagram998512367910129141617111315154

6 720 608 836Interior components diagram and parts list5512.2.2 Group 2Fig. 72 Components Diagram10142815123025202122171628312681816131917272819132713

6 720 608 83656Interior components diagram and parts listItem Description Reference1 Heat exchanger 8 705 406 4192 Heat exchanger top gasket 8 704 701

6 720 608 836Interior components diagram and parts list5712.2.3 Group 3Fig. 73 Components Diagram151413467821291113161756720902988.AA JF6Item Descript

6 720 608 83658Interior components diagram and parts list12.2.4 Group 4Fig. 74 Components Diagram9214134567811111213106720902990.AA JFItem Description

6 720 608 836Interior components diagram and parts list5912.2.5 Group 5Fig. 75 Components Diagram91112131012344567891114151617126720902989.AA JF(optio

6 720 608 8366Appliance details2.3 Unpacking the tankless water heaterBefore installing the unit, be certain you have thecorrect heater for your type

6 720 608 83660Interior components diagram and parts list12.2.6 Group 6Fig. 76 Components Diagram151237695111316141012846720902978.AA JFItem Descripti

6 720 608 836Protecting the environment6113 Protecting the environment PackingThe packing box may be fully recycled as confirmed bythe recycling symbo

6 720 608 83662Limited Warranty14 Limited Warranty14.1 Limited warranty for GWH C 920 ES residential modelGeneralBOSCH tankless water heaters are

6 720 608 836Limited Warranty6314.2 Limited warranty for GWH C 920 ESC commercial modelGeneralBOSCH tankless water heaters are warranted by theMa

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6 720 608 836Appliance details72.4 General rules to follow for safe operationB 1. You must follow these instructions when youinstall your hea

6 720 608 8368Appliance details2.5 Dimensions and minimum installation clearancesFig. 6 Dimensions1 On/Off button2 Reset button3 Program button4 Power

6 720 608 836Installation instructions93 Installation instructions3.1 Specialized toolsThe following specialized tools may be required for installatio