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Bosch 940 ES Installation Manual

Temperature modulated with electronic ignition
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940 ES
Temperature Modulated with Electronic Ignition
Suitable for heating potable water only and space heating
(Intended for variable flow applications)
940 ES - Natural Gas
940 ES - Liquefied Petroleum (LP) Gas
Warning: If the information in this manual is not
followed exactly, a fire or explosion may result
causing property damage, personal injury or death.
Do not store or use gasoline or other flammable
vapors and liquids in the vicinity of this or any other
service or maintenance can cause injury or
property damage. Refer to this manual. For
assistance or additional information consult a
qualified installer, service agency or the gas
In the Commonwealth of Massachusetts this
product must be installed by a licensed plumber or
gas fitter.
Upon completion of the installation, these
instructions should be handed to the user of the
appliance for future reference.
What to do if you smell gas
• Close gas valve. Open windows.
• Do not try to light any appliance.
• Do not touch any electrical switch; do not use any
phone in your building.
• Immediately call your gas supplier from a neighbor's
phone. Follow the gas supplier's instructions.
• If you cannot reach your gas supplier, call the fire
• Installation and service must be performed by a
qualified installer, service agency or the gas supplier.



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  Summary of Contents for Bosch 940 ES

  • Page 1 Suitable for heating potable water only and space heating (Intended for variable flow applications) 940 ES - Natural Gas 940 ES - Liquefied Petroleum (LP) Gas Warning: If the information in this manual is not What to do if you smell gas followed exactly, a fire or explosion may result •...
  • Page 2: Table Of Contents

    For your safety read before operating your water heater Protecting the environment Power Temperature selection LIFETIME LIMITED WARRANTY Use of optional remote control accessory FOR BOSCH TANKLESS (part no. TSTAT2) WATER HEATERS Operation Reset button Program button Locked condition 6 720 644 930...
  • Page 3: Warning

    Warning Warning Warning: The appliance should be located in an area where leakage of the For your safety heater or connections will not result in damage to the area adjacent to the Do not store or use gasoline or other flammable, appliance or to lower floors of the combustible or corrosive vapors and liquids in the structure.
  • Page 4: Appliance Details

    Appliance details Warning: If a relief valve discharges periodically, this may be due to thermal D A N G E R expansion in a closed water supply system. Contact the water supplier or local plumbing inspector on how to correct this situation. Do not plug the relief valve.
  • Page 5: Specifications (Technical Data)

    • Recess box kit (7736500043) * To measure gas pressure, see Measuring Gas • Pressure relief valve (FWL-2). Pressure, chapter 3.14, page 33. BOSCH is constantly improving its Water products, therefore specifications are • Hot water connection (inches) - ¾”...
  • Page 6: Unpacking The Heater

    Please complete and return the enclosed product 120 V AC (60 Hz) nominal registration card. Amperage The 940 ES is not approved or designed for: Idle - 40 mA • Recreational vehicle (RV) or boat installations. Operation -  2.5 A •...
  • Page 7: General Rules To Follow For Safe Operation

    Appliance details B Lift front cover panel upward and remove. bathrooms, bedrooms and occupied rooms that are normally kept closed. See chapter 3.3 ( page 9 ). If the unit will be installed indoors and use indoor combustion air, the place where you install the heater must have enough ventilation.
  • Page 8: Dimensions And Minimum Installation Clearances 8

    11 ¼" " 5 ¼" r e s e t 6720608158-04.2AL Fig. 6 Dimensions On/Off button Reset button Model 940 ES Program key TOP (A) 12” Power ON or stand-by LED LCD display FRONT (B) 1” Up button Down button BACK 0”...
  • Page 9: Installation Instructions

    • Multi-meter monoxide poisoning could result. Bosch Water Heating will not be • Combustion Gas Analyzer. responsible for improperly installed appliances. Introduction Please follow these instructions. Failure to follow Warning: In areas where outside...
  • Page 10 Installation instructions structure. There must be no sections of vent pipe exposed to the outdoors other than the termination. Note: Listed thimbles or collars are necessary where venting passes through wall and ceiling partitions. If the vent system passes through combustible areas where the vent clearance requirements cannot be maintained, it is permissible to chase straight sections of sealed 3 inch single wall vent through 4 inch (or greater) Type-B...
  • Page 11 Installation instructions Use of elbows Company Contact info It is recommended to limit the amount of elbows used in Z-flex the exhaust and combustion air piping to reduce friction 800-654-5600 in the air flow. The following lists the maximum amount of 90°...
  • Page 12 Installation instructions Calculation example for 3" venting: Calculation example for 4" venting: Exhaust Exhaust System used Concentric System used Twin pipe Number of 90° elbows needed: Number of 90° elbows needed: Number of 45° elbows needed: Number of 45° elbows needed: Table 8 Table 12 Calculation of example...
  • Page 13 Installation instructions Required direct vent terminal clearances (twin pipe / concentric penetration) 6720608836-23.1Av Fig. 11 Canadian installations U.S. installations Clearance above grade, veranda, porch, deck or balcony 12 in. 12 in. Clearance to window or door that may be opened 36 in.
  • Page 14 Installation instructions Required other than direct vent terminal clearances (single pipe penetration) 6720608836-23.1Av Fig. 12 Canadian installations U.S. installations Clearance above grade, veranda, porch, deck or balcony 12 in. 12 in. Clearance to window or door that may be opened 36 in.
  • Page 15 Installation instructions 3.3.3 Venting configuration examples Below are approved examples of horizontal venting installations. 12" 4" HORIZONTAL RUN 1/4" PER FOOT DOWN TO TERMINATOR. CONDENSATE DRAIN 6720608542-02.2AL Fig. 13 Horizontal side wall venting installation (single 6720608782-11.2V pipe penetration) Fig. 15 Horizontal venting installation (concentric penetration) 4"...
  • Page 17 Installation instructions any point. 5. Dispose of condensate according to local codes. RAIN CAP 10' MIN. 2' MIN. STORM COLLAR 3' MIN. FLASHING FIRESTOP SUPPORT 4" MIN. AIR SPACE ELBOW CONDENSATE Fig. 20 DRAIN TEE B Attach the combustion air inlet accessory (8 705 DRAIN TRAP TO DRAIN - DISPOSE 504 154) to the top of the unit (position 3) using the...
  • Page 18 Installation instructions Solution One • To allow accessibility, damper must not be installed in an enclosed section of vent pipe. The Z-flex vent termination hood is the preferred option for limiting backdraft under the following conditions • Do not install damper in unconditioned spaces (e.g. (see Fig.
  • Page 19 Installation instructions Preferred damper position for vertical terminations 3" Venting Z-flex Venting 24" Drain Tube Kit 2SVEDTK24 3" x 45° Elbow 2SVEEWCF0345 3" x 90° Elbow 2SVEEWCF0390 Unconditioned space. Do not 3" x 6" Pipe 2SVEPWCF03.5 install damper. 3" x 12" Pipe 2SVEPWCF0301 3"...
  • Page 20 Installation instructions 3.3.8 Fan speed adjustment IMPORTANT! Installation adjustment: After installing the water heater, the fan speed values for minimum power (P2) and maximum power (P1) may need adjustment due to variations in altitude and vent pipe length. Failure to make necessary adjustments to fan speed values may result in improper operation of the appliance. First calculate the total equivalent vent length.
  • Page 21 Installation instructions Adjusting minimum power fan speed (P2) Adjusting maximum power fan speed (P1) To select fan speed: To select fan speed: B Press ON/OFF button into OFF. B Press ON/OFF button into OFF. B Press and hold "Program" button B Press and hold "Program"...
  • Page 22 Installation instructions Attention residents of the Commonwealth of signage installed in accordance with the provisions of Massachusetts: 248 CMR 5.08(2)(a)1 through 4. In the Commonwealth of Massachusetts the following (b) EXEMPTIONS: The following equipment is exempt regulation went into effect on 12/30/2005: from 248 CMR 5.08(2)(a)1 through 4: (a) For all side wall horizontally vented gas fueled 1.
  • Page 23: Combustion Air Requirements

    Installation instructions Combustion air requirements recommended installation method. Always install a 3 inch elbow on the top of the combustion air inlet adaptor to prevent foreign objects from falling into the Warning: In areas where outside unit. temperatures routinely come close to If a single pipe installation is utilized, follow guidelines freezing, sealed combustion operation below for providing adequate combustion air for the...
  • Page 24: Proper Location For Installing Your Heater

    Installation instructions Proper location for installing your Mounting installation heater Warning: before mounting Carefully select the location of the water heater. For appliance your safety and for proper heater operation, you must B Check that there are no loose or provide combustion air to the heater and a proper damaged parts...
  • Page 25 Installation instructions Studs 16" (406mm) on center Fig. 29 Distance between support boards 6720608158-05. 1 AL 6720608158-05. 1 AL Fig. 31 Mounting the heater Warning: Appliance must be installed vertically. 6720608158-64.1AL Fig. 30 Leveling the mounting bracket on the studs 6 720 644 930...
  • Page 26 Installation instructions Mounting installation for Gas piping & connections manufactured (mobile) homes Before connecting the gas supply, check the rating plate on the right side of the heater to be sure that the When installing this appliance in a mobile home the unit heater is rated for the same gas to which it will be must be additionally secured at the bottom of the water connected.
  • Page 27 Installation instructions Once connections are made, check for gas leaks at all joints. Apply some gas leak detection solution to all gas fittings. Bubbles are a sign of a leak. A combustible gas detector may also be used to detect for leaks. Danger: If you have a leak, shut off the gas.
  • Page 28 0.3” in Water Column (0.75mbar).(Based on a 0.60 Specific Gravity Gas) Btu numbers given in thousands. Follow boxed numbers for piping just one 940 ES (example: ¾” B.I. Natural Gas pipe for 10 ft (3.0m). will handle 278,000 btu’s (81.5 kWh). For multiple appliances combine the total maximum btu input load and then refer to applicable chart below.
  • Page 29: Water Connections

    For water analysis data call your local water department, or if on a well, have well water analyzed periodically. If Fig. 36 water quality exceeds one or more of the values specified below, Bosch recommends consulting a local water treatment professional for water softening/ conditioning options. Description Max.
  • Page 30: Domestic Hot Water Recirculation

    Timed or thermostatically controlled operation of the pump is commonly done. Contact Bosch Thermotechnology if further information is needed. 6 720 644 930...
  • Page 31: Space Heating Applications

    (automotive antifreeze). determining the size of the primary pump. Warning: The use of a flow switch is Bosch tankless water heaters are approved for use in recommended to ensure DHW priority combination DHW and space heating applications and to prevent “cold-blow” situations (open-loop setup).
  • Page 32 Installation instructions 6720644887-02.1V Fig. 41 Space heating diagram Hot water outlet Cold water inlet Pressure relief valve Gas supply Shut off gas valve Thermal expansion tank (as required) Atmospheric vacuum breaker Cold inlet Check valve Pump Thermostatic mixing valve Thermometer (optional) DHW outlet Water to water heat exchanger Backflow preventer...
  • Page 33: Measuring Gas Pressure

    Installation instructions B Record lowest operating gas pressure reading in 3.14 Measuring gas pressure table 24. Confirm gas pressure upon installation. Gas pressures lower than 3.5" W.C. for Natural Gas or 8" W.C. for LPG will result in insufficient degree rise to Connecting manometer the hot water being used, reduced hot water volume, B Shut off gas supply at installer supplied shutoff valve...
  • Page 34: Electrical Connections

    Electrical connections Electrical connections Electrical power supply Position of the fuses in control unit To check fuses, proceed as follows: Warning: safety reasons, B Remove the front cover, see Fig. 4, page 7. disconnect the power supply cord to the heater before any service or testing B Remove the three screws on front of the control unit.
  • Page 35: Operation Instructions

    Operation instructions Operation instructions Fig. 47 On/Off button Reset button Program Key LCD display Up button Down button LED - Power On indicator or Stand-by Description LCD display Fig. 51 Lock indicator (only with remote control) Warning: Do not use any cleaning or corrosive agent to clean the window.
  • Page 36: Power

    Operation instructions For your safety read before Temperature selection operating your water heater To select output water temperature: B Press buttons in order to reach desired Warning: If you do not follow these temperature. instructions exactly, a fire or explosion may result causing property damage, personal injury or loss of life.
  • Page 37: Operation

    Operation instructions Solar mode control unit (Fig. 80, component 16) is required when programming the remote control with this heater. The water heater will not ignite if inlet water temperature exceeds the set temperature on the appliance. In this NOTE: up to 6 remote controls can be condition, the solar mode indicator will show on the programmed for one single water heater, LCD display.
  • Page 38: Locked Condition

    Maintenance and service Programming “Program” function Caution: Programming actions are similar for both controls B Check and clean the complete water (appliance control pad and wireless remote control). heating system once a year. B Carry out a maintenance overhaul if necessary.
  • Page 39: Winterizing For Seasonal Use

    6. Using another line (B), connect to the water outlet the heat exchanger, consult service bulletin at fitting on the water heater. Route the other end of this line into a descaling reservoir. 7. Using a 3rd line (C) from the descaling reservoir, Winterizing for seasonal use connect to the inlet side of circulating pump.
  • Page 40: Adjusting Co2

    Maintenance and service B Insert CO 16.Reconnect electrical supply to unit, open water analyzer probe into the measuring port. shutoff valves, and return the unit to service. The tip of the probe should be in the center of the flue pipe (approx 1.5"...
  • Page 41 Maintenance and service D. Returning to Service: Max. CO 1. Return slotted screw cover to original position and range (%) level tighten philips screw. (measured) 2. Reinstall Torx cover. 3. Remove CO analyzer probe and reinstall flathead Nat. Gas screw with gasket in exhaust collar. max.
  • Page 42: Program Values

    “P” - button Cascading type This menu is only available when cascade mode is selected CC. Contact Bosch Water Heating for details. Master/Slave mode Table 27 Program values, factory default settings and ranges. * Incorrect setting causes errors.
  • Page 43: Diagnostic Menu

    Maintenance and service Diagnostic menu Most recent error/failure 1. Turn on/off switch on water heater to off (O) position. 2nd most recent error B Press and hold the program ' ' button while 3rd most recent error turning the on/off switch to the on (I) position. The display will cycle through a startup procedure 4th most recent error including the software version.
  • Page 44: Troubleshooting

    Many of the questions customers ask regarding operation of this unit can be answered by following the Water is too hot troubleshooting steps as outlined below. Visit our web site more detailed 1. Selected temperature on the unit is set too high. To lower output temperature, see chapter 5.4 , page 36 .
  • Page 45: Low Water Flow/Pressure

    Measuring Gas out of the outlet. Pressure. A gas pressure reading is needed to proceed Consult for a detailed service further. Contact your original installer or a local certified bulletin on overcoming temperature fluctuations. gas technician to obtain this reading.
  • Page 46: Problem Solving

    Problem solving Problem solving Error code diagnostics To remove error code from the display, press the reset button. Display Cause Solution Fault in the flue gas limiter. 1. Check continuity of the flue gas limiter (see Fig. , page Temperature above 230°F Go to steps two and three to determine air box temperature...
  • Page 47 2. Check supply voltage. It must be 120VAC and properly (Status message, not an error). grounded. 3. Possible defective control unit call Bosch Water Heating for further instructions. Primary fan rotation too low on 1. Disconnect power supply cord and check wire connection on operation.
  • Page 48 4. Call Bosch Water Heating for further instruction. Overheat sensor (ECO) open 1. Disconnect power supply cord and check wire connections on circuit...
  • Page 49 The voltage should measure 24VDC between the left pair of wires and 24VDC between the right pair of wires when the unit is operating. If voltage is not proper, contact Bosch Water Heating for further instruction. 3. Gas valve may be defective, contact Bosch Water Heating for further instrucation.
  • Page 50: Electrical Diagram

    Electrical diagram Electrical diagram T=104°C T=220°F T=110°C T=230°F Casc. input Casc. output Back flow 6720608158-92.1AL Fig. 69 Electrical scheme Intlet water temperature sensor Outlet water temperature sensor Backflow temperature sensor Cascading output connection Cascading input connection Ionization sensor Water flow sensor Flue gas limiter Heat exchanger overheat sensor (ECO) Gas valve...
  • Page 51: Sensor Resistance Charts

    Sensor resistance charts Sensor resistance charts Outlet / Inlet Immersion Sensor characteristics 12 0 2 4 7 2 4 2 2 3 7 2 3 2 2 2 7 10 5 2 2 2 2 17 10 0 2 12 2 0 7 2 0 2 19 7...
  • Page 52: Functional Scheme

    Functional scheme Functional scheme Fig. 72 Functional scheme 6 720 644 930...
  • Page 53: Interior Components Diagram And Parts List

    Interior components diagram and parts list Interior components diagram and parts list 12.1 Interior components 6720608158-39.2V Fig. 73 Components Flue gas collector Ignition electrodes Heat exchanger Observation window Flame sensor Backflow temperature sensor Primary fan (Mixer) Secondary air fan Outlet temperature sensor Gas valve LCD display Water valve with engine and temperature sensor...
  • Page 54 Interior components diagram and parts list Fig. 74 Appliance overview 6 720 644 930...
  • Page 55: Components Diagram

    Interior components diagram and parts list 12.2 Components diagram 12.2.1 Group 1 13 15 6720902973.AA JF Fig. 75 Components Diagram Item Description Reference Item Description Reference Combustion cover clip 8 701 201 032 0 Front cover 8 705 431 412 0 Grommet set 8 710 203 039 0 Cover shield...
  • Page 56 Interior components diagram and parts list 12.2.2 Group 2 6720902974.AA JF Fig. 76 Components Diagram Item Description Reference Item Description Reference Site window 8 701 000 401 0 Heat exchanger 8 738 701 985 0 Ignition group 8 701 302 249 0 Heat exchanger top gasket 8 704 701 052 0 Heat exchanger O-ring...
  • Page 57 Interior components diagram and parts list 12.2.3 Group 3 6720902975.AA JF Fig. 77 Components Diagram Item Description Reference Item Description Reference Gas / Air Mixer 8 705 700 170 0 Main burner 8 708 120 699 0 Air duct O-ring 8 700 205 149 0 Burner gasket 8 704 701 087 0...
  • Page 58 Interior components diagram and parts list 12.2.4 Group 4 6720608158-73.1AL Fig. 78 Components Diagram Item Description Reference Item Description Reference Gas filter 8 700 507 002 0 Gas valve 8 707 021 019 0 Gasket 8 704 701 085 0 Pressure tapping 8 703 404 219 0 Gas / Fan connector...
  • Page 59 Interior components diagram and parts list 12.2.5 Group 5 6720608158-74.2V Fig. 79 Components Diagram Item Description Reference Item Description Reference O-ring 8 700 205 157 0 Water valve with engine 8 708 505 024 0 Watervalve clip 8 716 102 607 0 O-ring 8 700 205 147 0 Water filter...
  • Page 60 Interior components diagram and parts list 12.2.6 Group 6 6720644956-09.1V Fig. 80 Components Diagram Item Description Reference Item Description Reference Electrode cables 8 704 401 346 0 Control unit 8 707 207 366 0 Flue gas limiter 8 700 400 032 0 Fuse T2.5A 1 904 521 342 0 Kit inteligent cascading...
  • Page 61: Protecting The Environment

    Protecting the environment Protecting the environment Packing The packing box may be fully recycled as confirmed by the recycling symbol Components Many parts in the heater can be fully recycled in the end of the product life. Contact your city authorities for information about the disposal of recyclable products.
  • Page 62: For Bosch Tankless Water Heaters

    LIFETIME LIMITED WARRANTY FOR BOSCH TANKLESS WATER HEATERS LIFETIME LIMITED WARRANTY FOR BOSCH TANKLESS WATER HEATERS MODELS COVERED ITEMS NOT COVERED This limited warranty provided Bosch This limited warranty does not cover the following cir- Thermotechnology Corp. (BTC) and covers model 940 cumstances: ES (hereinafter referred to as "Water Heater").
  • Page 64 Installation manual should be left with the owner after the installation is tested and completed Replacement Parts available from: BOSCH THERMOTECHNOLOGY CORP. Bosch Termotecnologia SA 50 Wentworth Avenue Estrada de Cacia Londonderry, NH 03053 3800 - 533 Cacia - PORTUGAL Tel. 866-330-2730 © 2012 Bosch Thermotechnology Corp., Londonderry, NH...

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