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Bosch GWH 2400 ES NG User Manual

Indoor model temperature modulated with electronic ignition suitable for heating potable water only
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MODEL GWH 2400 ES NG and GWH 2400 ES LP -
Temperature Modulated with Electronic Ignition
Suitable for heating potable water only
Not approved for space heating purposes
(Intended for variable flow applications)
GWH 2400 ES NG - Natural Gas
GWH 2400 ES LP - 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
vapor 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.
• If you cannot reach your gas supplier, call the fire
• Immediately call your gas supplier from a neighbor's
phone. Follow the gas supplier's instructions
• 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 GWH 2400 ES NG

  • Page 1 MODEL GWH 2400 ES NG and GWH 2400 ES LP - INDOOR MODEL Temperature Modulated with Electronic Ignition Suitable for heating potable water only Not approved for space heating purposes (Intended for variable flow applications) GWH 2400 ES NG - Natural Gas...
  • Page 2: Table Of Contents

    Index Index Warning Maintenance and service Annual maintenance Winterizing for seasonal use Appliance details Mineral scale build-up Features Adjusting CO2 (carbon dioxide) GWH 2400 ES Specifications Program values (Technical data) Control board diagnostics Unpacking the GWH 2400 ES heater Fan speed adjustment General rules to follow for safe operation Dimensions and Minimum installation clearances...
  • Page 3: Warning

    Warning Warning FCC: This device complies with Part 15 of the FCC rules. Operation is subject to the following two conditions: (1) For your safety This device may not cause harmful interference, and (2) Do not store or use gasoline or other flammable, this device must accept any interference received, combustible or corrosive vapors and liquids in the including interference that may cause undesired...
  • Page 4: Appliance Details

    (TSTAT2) – Bottom of heater • Outdoor kit (AQOK). Combustion • NOx ≤ 55 ppm BOSCH is constantly improving its products, therefore specifications are • CO ≤ 250 ppm (measured) subject to change without prior notice. • CO level set from factory, see chapter 6.4.
  • Page 5: Unpacking The Gwh 2400 Es Heater

    Appliance details Call Bosch Water Heating through Bosch Unpacking the GWH 2400 ES thermotechnology corporation conversion heater instructions. Before installing the unit, be certain you have the Voltage correct heater for your type of Gas: Propane or Natural Gas. Identification labels are found on the...
  • Page 6: General Rules To Follow For Safe Operation

    Appliance details To remove front cover General rules to follow for safe operation B Loosen the two Philips head screws located on bottom rear of cover (see Fig. 3). B 1. You must follow these instructions when you install your heater. In the United States: The installation must conform with local codes or, in the absence of local codes, the National Fuel Gas Code ANSI Z223.1/ NFPA 54.
  • Page 7: Dimensions And Minimum Installation Clearances

    Appliance details Dimensions and Minimum installation clearances Fig. 6 Dimensions On/Off button Reset button Model GWH 2400 ES Program key TOP (A) 12” Power ON or stand-by LED LCD display FRONT (B) 1” Up button Down button BACK 0” SIDES 1”...
  • Page 8: Installation Instructions

    • Drill condition such as explosion or carbon monoxide poisoning could result. • Pipe wrench Bosch Water Heating will not be • Adjustable pliers responsible for improperly installed • Pipe fitting tools appliances. • Hacksaw with metal blades • Hole saw.
  • Page 9 Installation instructions upwards towards termination ¼" for every foot of Minimum exhaust vent length horizontal length, to prevent the pooling of condensate, and be supported at 4 foot intervals with overhead hangers. Exception: horizontal run between last elbow and termination must pitch down to termination 1/4"...
  • Page 10 Installation instructions Recommended exhaust vent terminator position Fig. 10 Ref. Description Minimum distance Directly below an opening; operable windows, doors and any non- 36 in (twin pipe installation) mechanical fresh air openings 48 in (single pipe installation) Below a gutter, sanitary pipework or eaves 24 in Below a gutter, sanitary pipework or eaves, protected by metal 12 in...
  • Page 11 Installation instructions Venting configuration examples Fig. 13 Above the roof clearance requirements from rain cap (combustion air piping not shown) Fig. 11 Horizontal side wall venting installation (combustion air piping not shown) Important: Note: Pitch horizontal runs down toward the heater, except horizontal run between last elbow and termination which must slope down to termination 1/4"...
  • Page 12 Installation instructions 3.3.2 Condensate drain requirements Room sealed installation (TWIN PIPE SYSTEM) A condensate drain must be installed under the Installing this water heater as a room sealed (TWIN following conditions: PIPE SYSTEM) is the recommended method. Contact your dealer for available vent termination kits and vent •...
  • Page 13 Installation instructions first one, reduce 1.25 ft for each 45° elbow. Warning: Approved terminators must A maximum of three 90-degree elbows are permitted. be used for inlet and exhaust vent systems to prevent rain from entering Determining installation adjustment the appliance, failure to do so may result The GWH 2400 ES comes factory set to accomodate in damage to the appliance.
  • Page 14 Installation instructions 3.3.3 Vent connections Attention residents of the Commonwealth of Massachusetts: B Attach the flue gas exhaust accessory (8 705 504 In the Commonwealth of Massachusetts the following 151) to the top of the unit (position 1) using the 4 regulation went into effect on 12/30/2005: screws and gasket provided.
  • Page 15: Combustion Air Requirements

    Installation instructions signage installed in accordance with the provisions of Combustion air requirements 248 CMR 5.08(2)(a)1 through 4. (b) EXEMPTIONS: The following equipment is exempt Warning: In areas where outside from 248 CMR 5.08(2)(a)1 through 4: temperatures routinely come close to freezing, sealed combustion operation 1.
  • Page 16: Proper Location For Installing Your Heater

    Installation instructions B 1. Locate the heater where venting, gas and below for providing adequate combustion air for the water heater as well as any other appliances that may plumbing connections are feasible and convenient. consume air in the space. Always follow local codes if B 2.
  • Page 17: Gas Piping & Connections

    Installation instructions Front cover should be removed (see instructions on page 6) in order to inspect components visually. Warning: Do not install this appliance on a carpeted wall. The heater must be mounted on a wall using appropriate anchoring materials. If wall is sheathed with plaster or drywall, it is recommended that two support boards, either 1”x4”...
  • Page 18 Installation instructions INSTALLATION CODES and/or local installation Danger: If you have a leak, shut off the codes. gas. Tighten appropriate fittings to stop leak. Turn the gas on and check again Warning: DO NOT connect to an with a gas leak detection solution. unregulated or high pressure propane Never test for gas leaks using a match line or to a high pressure commercial...
  • Page 19 Installation instructions FOR NATURAL GAS Maximum Capacity of pipe in Cubic Feet of Gas per Hour for Gas Pressure of 0.5 Psig or less and a Pressure drop of 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 GWH 2400 ES (example: ¾”...
  • Page 20: Water Connections

    B When facing the heater, the ¾” cold connection is on specified below, Bosch recommends installing a water the bottom right and the hot connection is on the conditioner or softener.
  • Page 21: Recirculation Application

    Pressure Relief Valve the mini-tank and the building's hot water return loop only. Timed or thermostatically controlled operation of Water filter the pump is commonly done. Contact Bosch Water Heating if further information is needed. 6 720 608 782...
  • Page 22: Measuring Gas Pressure

    Installation instructions B Record lowest operating gas pressure reading in 3.12 Measuring gas pressure table 11. 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 23: 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 6. 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 24: Operation Instructions

    Operation instructions Operation instructions Fig. 36 On/Off button Reset button Program Key LCD display Up button Down button LED - Power On indicator or Stand-by LCD Display functions Fig. 40 Lock indicator Warning: Do not use any cleaning or corrosive agent to clean the window. Fig.
  • Page 25: For Your Safety Read Before Operating Your Water Heater

    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 26: Operation

    Operation instructions Use of optional remote control accessory (part no. TSTAT2) Fig. 48 Reset button If the problem persists, contact your installer. Program button Program button can be used on the appliance and in the Fig. 45 Remote control remote control. The wireless remote control accessory (Fig.
  • Page 27: Maintenance And Service

    Maintenance and service Maintenance and service Inlet water filter Warning: Always turn off the electrical • Verify the inlet filter screen is clean and undamaged. power supply, turn off the manual gas The inlet water filter is located inside the cold water shut off valve and turn off the water shut inlet fitting on the right side of the appliance (See off valves whenever servicing.
  • Page 28: Mineral Scale Build-Up

    Maintenance and service such as anti-freeze is not permitted as they may cause 11.Make sure there are no leaks and the solution is damage to the water heater's internal components. flowing from the descaling reservoir through the heater and returning to the reservoir. 1.
  • Page 29 Maintenance and service B Record the CO adjusting CO until pressure is at or above these levels, reading in P1 and P2 below. but not to exceed 10.5” WC for Natural Gas and 13” P2 CO Reading: % CO WC for Propane. P1 CO Reading: % CO...
  • Page 30 Maintenance and service Max. CO range (%) level (measured) Nat. Gas max. input 6.9 % - 7.5 % < 250 ppm min. input 2.3 % - 2.6 % < 60 ppm LP Gas max. input 8.1 % - 8.7 % <...
  • Page 31: Program Values

    Maintenance and service Program values Refer to chapter 6.6 Control board diagnostics (page 32) regarding how to access these P-modes. This section describes details on programming the appliance. For most applications the factory default Caution: Misadjusted program values will robust and stable operation. Only adjust the values lead appliance...
  • Page 32: Control Board Diagnostics

    Maintenance and service Control board diagnostics Diagnostic menu 1. Turn on/off switch on water heater to off (O) position. Entry/Exit into sub-modes 2. Press and hold the program ( ) button while Set-point temperature (°F) turning the on/off switch to the on (I) position. The display will cycle through a startup procedure Inlet water temperature (°F) including the software version.
  • Page 33: Fan Speed Adjustment

    Maintenance and service Fan speed adjustment Example Installation adjustment: Flue pipe length setting Exhaust for minimum power - P2. After installing the GWH 2400 ES, the minimum power Straight section length 22 x 1 = fan speed must be selected to compensate for variation (feet) in vent pipe length.
  • Page 34 Maintenance and service To select fan speed: B Press ON/OFF button into OFF. B Press and hold "Program" button and press ON/OFF button to turn appliance ON. Fig. 57 B As soon as '188' is displayed, release "Program" button , and the display should read P2. B Press to choose the fan speed suitable with your installation, see Table 19.
  • Page 35: Troubleshooting

    Troubleshooting Troubleshooting and mixing valves are common causes of plumbing Warning: If you are unable to perform crossovers. the tasks listed below, or need 8. With the ON/OFF switch turned to OFF (O) position additional assistance please contact and the power supply cord unplugged, remove the your original installer or licensed gas unit's front cover (See Page 6.
  • Page 36: Low Water Flow/Pressure

    Troubleshooting the heater. Wait 10 minutes and check all taps for pressure hot water can be overpowered. This will water flow. There should be no water flowing. Any shut down the burners because the hot water flow continuous flow of water, small or large, indicates a rate fell below the minimum flow rate required for crossover and must be corrected.
  • Page 37 Troubleshooting out of adjustment. This will result in unstable burner flames and noise. Ensure gas pressure is in accordance with specifications in section 3.12, page 22 Measuring Gas Pressure. A gas pressure reading is needed to proceed further. Contact your original installer or a local certified gas technician to obtain this reading.
  • Page 38: 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 Go to steps two and three to determine air box temperature sensor fault and replace it.
  • Page 39 5. Check supply voltage. It must be 120VAC and properly grounded. 6. Possible defective control unit call Bosch Water Heating for further instructions. 7. Ensure that outlet temperature sensor is not placed on any bends in the hot water pipe or misreading may occur.
  • Page 40 Problem solving Display Cause Solution Over-temperature detected 1. Check that the sensor is firmly attached to the vertical section of outlet temperature sensor on hot the hot water pipe (see Fig. , page water pipe. 2. Check red wire connections at outlet temperature sensor. Temperature >...
  • Page 41 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 42: Electrical Diagram

    Electrical diagram Electrical diagram Fig. 58 Electrical scheme Intlet water temperature sensor Outlet water temperature sensor Exhaust temperature sensor Cascading output connection Cascading input connection Ionization sensor Water flow sensor Flue gas limiter Heat Exchanger Overheat Sensor (ECO) Gas valve Water valve Primary fan ON/OFF switch...
  • Page 43: Sensor Resistance Charts

    Sensor resistance charts Sensor resistance charts Outlet temperature sensor characteristics 2 2 2 2 17 10 5 2 12 10 0 2 0 7 2 0 2 19 7 19 2 18 7 18 2 16 7 16 2 14 7 14 2 13 7 13 2...
  • Page 44 Sensor resistance charts Back Flow characteristics 3 0 2 2 9 7 2 9 2 14 5 2 8 7 2 8 2 14 0 2 7 7 2 7 2 13 5 2 6 7 2 6 2 13 0 2 5 7 12 5 2 5 2...
  • Page 45: Gwh 2400 Es Functional Scheme

    GWH 2400 ES Functional scheme GWH 2400 ES Functional scheme Fig. 62 Functional scheme 6 720 608 782...
  • Page 46: Interior Components Diagram And Parts List

    Interior components diagram and parts list Interior components diagram and parts list 12.1 Interior components Fig. 63 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 47 Interior components diagram and parts list Fig. 64 Appliance overview 6 720 608 782...
  • Page 48: Components Diagram

    Interior components diagram and parts list 12.2 Components diagram 12.2.1 Group 1 13 15 6720902973.AA JF Fig. 65 Components Diagram Item Description Reference Item Description Reference Combustion cover clip 8 701 201 032 Front cover 8 705 431 286 Grommet set 8 710 203 039 Cover shield 8 705 506 862...
  • Page 49 Interior components diagram and parts list 12.2.2 Group 2 6720902974.AA JF Fig. 66 Components Diagram Item Description Reference Item Description Reference Site window 8 701 000 401 Heat exchanger 8 705 406 356 Ignition group 8 701 302 249 Heat exchanger top gasket 8 704 701 052 Heat exchanger O-ring 8 700 205 147...
  • Page 50 Interior components diagram and parts list 12.2.3 Group 3 6720902975.AA JF Fig. 67 Components Diagram Item Description Reference Item Description Reference Air duct O-ring 8 700 205 149 Main burner 8 708 120 642 Venturi 8 700 306 226 Burner gasket 8 704 701 087 O-ring 8 700 205 224...
  • Page 51 Interior components diagram and parts list 12.2.4 Group 4 6720608158-73.1AL Fig. 68 Components Diagram Item Description Reference Item Description Reference Gas filter 8 700 507 002 Gas valve 8 707 021 019 Gasket 8 704 701 085 Pressure tapping 8 703 404 219 Gas / Fan connector 8 705 202 140 Washer...
  • Page 52 Interior components diagram and parts list 12.2.5 Group 5 Fig. 69 Components Diagram Item Description Reference Item Description Reference Inlet fitting with filter 8 703 305 356 Water valve with engine 8 708 505 024 O-ring 8 700 205 147 O-ring 8 700 205 157 Cold water pipe...
  • Page 53 Interior components diagram and parts list 12.2.6 Group 6 6720608782-08.1AL Fig. 70 Components Diagram Item Description Reference Item Description Reference Electrode cables 8 704 401 346 Control unit 8 707 207 296 Flue gas limiter 8 700 400 032 Fuse T2.5A 1 904 521 342 Anti freeze kit 7 709 003 665...
  • Page 54: 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 55: Limited Warranty

    Exceptions Bosch thermotechnology corporation. However, all replacements are made subject to validation by Bosch This warranty will not apply: thermotechnology corporation of in-warranty coverage. • 1. to defects or malfunctions resulting from failure to...
  • Page 56 BOSCH THERMOTECHNOLOGY CORPORATION Bosch Termotecnologia, S.A. Bosch Water Heating Estrada de Cacia 340 Mad River Park 3801 - 856 Aveiro - PORTUGAL Waitsfield, VT 05673 TEL. 800-642-3111 Recycled paper © 2008 Bosch Thermotechnology Corp., Waitsfield, VT all rights reserved...