Bosch AQUA STAR 2400E LP Specifications


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Bosch AQUA STAR 2400E LP Specifications | Manualzz

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

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 appliance.

Improper installation, adjustment, alteration, 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 supplier.

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 department.

• 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.

Index

Index

1 Warning 3

2 Appliance details 4

2.1

Features 4

2.2

GWH 2400 ES Specifications

(Technical data)

2.3

Unpacking the GWH 2400 ES heater

4

5

2.4

General rules to follow for safe operation

2.5

Dimensions and Minimum installation

6 clearances 7

3 Installation instructions 8

3.1

Tools required for installation 8

3.2

Introduction 8

3.3

Venting

3.4

Combustion air requirements

8

15

3.5

Proper location for installing your heater

3.6

Heater placement and clearances

3.7

Mounting installation

3.8

Gas piping & connections

16

16

16

17

3.9

Water connections

3.10 Water quality

3.11 Recirculation application

3.12 Measuring gas pressure

20

20

21

21

6

6.1

Annual maintenance

6.2

Winterizing for seasonal use

6.3

6.4

6.5

6.6

6.7

7

Maintenance and service

Mineral scale build-up

Adjusting CO2 (carbon dioxide)

Program values

Control board diagnostics

Fan speed adjustment

27

27

27

28

28

31

32

33

7.1

Introduction 35

7.2

Burner do not ignite when hot water

7.3

7.4

7.5

7.6

7.7

8

8.1

9

Troubleshooting 35 is turned ON

Water is too hot

Water is not hot enough

Low water flow/pressure

Hot water temperature fluctuates at tap

Noisy burner/heater during operation

Problem solving

Error code diagnostics

Electrical diagram

4 Electrical connections

4.1

Electrical power supply

4.2

Position of the fuses in control unit

5 Operation instructions 24

5.1

LCD Display functions

5.2

For your safety read before operating

5.4

Temperature selection

5.5

Use of optional remote control accessory

24 your water heater 25

5.3

Power 25

25

(part no. TSTAT2) 26

5.6

Operation 26

5.7

Reset button

5.8

Program button

5.9

Locked condition

26

26

26

23

23

23

10 Sensor resistance charts

11 GWH 2400 ES Functional scheme

12 Interior components diagram and parts list

12.1 Interior components

12.2 Components diagram

13

14

Protecting the environment

Limited Warranty

35

35

35

36

36

36

43

45

46

46

48

54

55

38

38

42

2

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Warning

1 Warning

For your safety

Do not store or use gasoline or other flammable, combustible or corrosive vapors and liquids in the vicinity of this or any other appliance.

Warning: Carefully plan where you install the heater. Correct combustion air supply and flue pipe installation are very important. If a gas appliance is not installed correctly, fatal accidents can result, such as carbon monoxide poisoning or fire.

Warning: Exhaust gas must be vented to outside using stainless steel vent material suitable for category III vent systems and temperatures up to 480°F.

Vent piping must be sealed gas-tight to prevent possibility of flue gas spillage, carbon monoxide emissions and risk of fire, resulting in severe personal injury or death. Approved vent terminators must be used when penetrating to the outside.

Warning: Place the heater in a location where water leaks will do NO DAMAGE to adjacent areas or lower floors.

Warning: Field wiring connections and electrical grounding must comply with local codes, or in the absence of local codes, with the latest edition of the

National Electric Code, ANSI/NFPA 70, or in Canada, all electrical wiring must comply with the local codes and the

Canadian Electrical Code, CSA C22.1

Part 1.

Warning: Shock hazard: line voltage is present. Before servicing the water heater, unplug power supply cord from outlet. Failure to do so could result in severe personal injury or death.

Warning: The heater must be disconnected from the gas supply piping system during any pressure testing of that system at test pressures equal to or more than 0.5 psig.

FCC:

This device complies with Part 15 of the FCC rules.

Operation is subject to the following two conditions: (1)

This device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation.

Fig. 1

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3

Appliance details

4

2 Appliance details

2.1

Features

Parts

• Key Pad interface control

• High power pre-mix compact burner with low NOx emissions

• Modulating Gas Valve with constant gas:air ratio control

• Modulating water valve for improved comfort and temperature control.

High quality materials for long working life

• Copper heat exchanger

• High efficiency Ceramat Burner

• Compact space saver: mounts on a wall with a supplied bracket.

Features

• Real-time diagnostics for troubleshooting/ informational purposes

• LCD Display with backlight

• On/Off and Temperature control switches

• Reset button

• Program button (Selectable temperature default)

• Failure codes for easy diagnostics and repair

• Easily removable one-piece cover

• Built in freeze prevention.

Note: Freeze prevention is not intended to protect plumbing outside the appliance or to keep the appliance from freezing for long periods.

Accessories (Bosch part #)

• Optional wireless remote control accessory to operate with the appliance (TSTAT2)

• Outdoor kit (AQOK).

i

BOSCH is constantly improving its products, therefore specifications are subject to change without prior notice.

2.2

GWH 2400 ES Specifications

(Technical data)

Approved in US/Canada

Capacity

Maximum flow rate: 6.4 GPM (24 l/min) at a 45°F

(25°C) rise.

Maximum output

147,000 Btu/h (43.0 kW)

Maximum input

175,000 Btu/h (51.2 kW)

Efficiency in %

Thermal efficiency > 82%

Min. Input

19,900 Btu/h (5.8 kW)

Temperature Control

Selection range: 100°F (38°C) - 140°F (60°C)

Default temperature: 122°F (50°C)

Stability: +/- 2°F (+/- 1°C)

Gas Requirement

Gas connection (inches) - ¾”

Inlet gas pressure under operation (with a high hot water flow rate)*

• Propane: 8” - 13” water column

• Natural Gas: 3.5” - 10.5” water column.

* To measure gas pressure, see Measuring Gas

Pressure, chapter 3.12.

Water

• Hot water connection (inches) - ¾”

• Cold water connection (inches) - ¾”

• Water valve material: Polymer (PPS) (Polypropylene

Sulfid)

• Minimum water flow: 0.65 gallon/minute (2,5 l/m).

Note: Activation varies with inlet water temperatures from 0.65 - 1.6 gallon/minute.

• Minimum recommended water pressure: 30 PSI

(2.07 bar)

• Minimum recommended well pressure: 40 PSI (2.75 bar), see chapter 3.9.

• Connections:

– Bottom of heater

Combustion

• NOx ≤ 55 ppm

• CO ≤ 250 ppm (measured)

• CO

2

level set from factory, see chapter 6.4.

Dimensions

• Depth (in): 11¼” (286 mm)

• Width (in): 17 7

/

8

” (452 mm)

• Height (in): 30½” (775 mm)

• Weight: 67 pounds (30,5 kg).

Gas types

Natural Gas.

LP Gas.

Converting the gas type can only be done by a certified gas technician with a calibrated CO

2

analyzer.

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Appliance details

Call Bosch Water Heating through Bosch thermotechnology corporation for conversion instructions.

Voltage

120 V AC (60 Hz) nominal

Amperage

Idle - 40 mA

Operation -

≤ 2.5 A

Noise

45 - 65 db (A)

Safety devices

• Flame failure device (ionization flame rod sensor)

• Pressure relief valve (supplied with heater)

• Over heat prevention (temperature limiter)

• Inlet temperature sensor

• Outlet temperature sensor

• Backflow temperature sensor.

Water protection

IP X4 (protection against water drops) i

If appliance is installed at elevations between 2000ft and 4500ft, a combustion gas analyzer is required for proper calibration of appliance. (see page

22).

2.3

Unpacking the GWH 2400 ES heater

Before installing the unit, be certain you have the correct heater for your type of Gas: Propane or

Natural Gas. Identification labels are found on the shipping box, and on the rating plate which is located on the right side panel of the cover.

Fig. 2 Rating plate

A

B

Serial number

Type of gas

The box includes:

• GWH 2400 ES

• Pressure relief valve (150 psi / 200,000 Btu rating)

• Bracket for wall hanging the heater

• Exhaust vent adaptor (with 4 screws and gasket provided)

• Combustion air inlet adaptor (with 3 screws and gasket provided)

• Installation manual (manual can be downloaded at www.boschhotwater.com)

• Product registration card

• Energy Guide label.

Please complete and return the enclosed product registration card.

The GWH 2400 ES is not approved or designed for:

• Manufactured (mobile) homes, boats or any mobile installation (modular homes are acceptable for installation)

• Use above 4500ft A.S.L. altitude

• Outdoor installation without installation of Outdoor kit (AQOK)

• Space heating purposes

• Preheated inlet water supply.

5

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Appliance details

To remove front cover

B Loosen the two Philips head screws located on bottom rear of cover (see Fig. 3).

Fig. 3 Loosen the two screws

B Lift front cover panel upward and remove.

Fig. 4 Removing the front cover

To remove combustion cover (service only)

B Open the four clips and remove the combustion cover see Fig. 5.

Fig. 5 Remove the combustion cover

2.4

General rules to follow for safe operation

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.

In Canada: The Installation must conform with CGA

B149.(1,2) INSTALLATION CODES and /or local installation codes.

B 2. Carefully plan where you install the heater. Correct combustion air supply and vent pipe installation are very important. If not installed correctly, fatal accidents can occur, such as carbon monoxide poisoning or fire.

B 3. When the unit is installed indoors and ROOM

SEALED (twin pipe) it is permitted to be located in bathrooms, bedrooms and occupied rooms that are normally kept closed. See chapter 3.3 (page 8). If the unit will be installed indoors and use indoor combustion air, the place where you install the heater must have enough ventilation. The National Fuel

Gas Code does not allow UNSEALED gas fired water heater installations in bathrooms, bedrooms or any occupied rooms normally

kept closed. See chapter 3.5 (page 16) and 3.4

( page 15).

B 4. You must vent your heater. See chapter 3.3 on

VENTING.

B 5. The appliance and its gas connection must be leak tested before placing the appliance in operation.

The appliance must be isolated from the gas supply piping system by closing its individual manual gas shutoff valve (not supplied with heater) during any pressure testing at pressures in excess of ½ Psig (3.5

kPa).

B 6. Keep water heater area clear and free from combustibles and flammable liquids. Do not locate the heater over any material which might burn.

B 7. Correct gas pressure is critical for the proper operation of this heater. Gas piping must be sized to provide the required pressure at the maximum output of the heater, while all the other gas appliances are in operation. Check with your local gas supplier, and see the section on connecting the gas supply. See

Section 3.8, page 17.

B 8. Should overheating occur or the gas supply fail to shut off, turn off the gas supply at the manual gas shut off valve, on the gas line. Note: manual gas shutoff valve is not supplied with the heater but must be field installed.

B 9. Do not use this appliance if any part has been underwater. Immediately call a qualified service technician to inspect the appliance and to replace any part of the control system and any gas control which has been underwater.

B 10. Failure to install heater correctly may lead to unsafe operation and void the warranty.

6

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2.5

Dimensions and Minimum installation clearances

Appliance details

Fig. 6 Dimensions

5

6

7

3

4

1

2

On/Off button

Reset button

Program key

Power ON or stand-by LED

LCD display

Up button

Down button

TOP (A)

FRONT (B)

BACK

SIDES

FLOOR (C)

Table 1 Minimum clearances

Model GWH 2400 ES

12”

1”

0”

1”

12”

Fig. 7 Minimum clearances

Note: For servicing access, a 2ft clearance to front cover is recommended.

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7

Installation instructions

3 Installation instructions

3.1

Tools required for installation

• Philips head screwdriver

• Flat head screwdriver

• Adjustable wrench

• Level

• Thermometer

• Standard plumbing tools

• Manometer

• Drill

• Pipe wrench

• Adjustable pliers

• Pipe fitting tools

• Hacksaw with metal blades

• Hole saw.

3.2

Introduction

Please follow these instructions. Failure to follow instructions may result in:

B Damage or injury.

B Improper operation.

B Loss of warranty.

If you are unable to perform the tasks required to install this heater properly, please contact a locally licensed plumber or gas technician.

Common installation practice is to determine the venting/intake system layout and penetration and then work back to the heater.

3.3

Venting

Warning: Do not reduce the vent

(exhaust and combustion) pipe sizes and do not common vent with any other vented appliance or stove.

Warning: Failure to vent the exhaust gases to the outside with sealed stainless steel vent pipe (AL29-4C) may result in dangerous flue gases filling the structure in which it is installed.

Warning: Do not mix vent pipe or joining methods from different manufacturers.

Warning: Proper end terminal / rain cap must be used. Failure to do so may result in damage to the appliance.

This damage is not covered under the manufacturer's warranty.

Caution: The vent system must be installed by a qualified installer in accordance with these instructions. If improperly installed, a hazardous condition such as explosion or carbon monoxide poisoning could result.

Bosch Water Heating will not be responsible for improperly installed appliances.

Warning: In areas where outside temperatures routinely come close to freezing, sealed combustion operation is required. Use a concentric termination or separate terminations for combustion and vent, which must be installed on the same wall or roof surface, however never facing the direction of prevailing winds. Failure to do so may result in heat exchanger freezing up and bursting. This failure is not covered under the manufacturer's warranty.

3.3.1

Vent material and specifications

Establish vent clearances that comply with the vent manufacturer's specifications. In all cases, follow local codes. See Table 2.

Diam.

Min. lenght

Max. length

Material

Exhaust

Vent

Intake

Vent

3 or 4 inches

3 or 4 inches

3 feet 26 feet with

1 90° elbow and terminal

Sealed single wall stainless steel

(AL29-4C)

1 90° elbow

26 feet with

1 90°elbow and terminal

Sealed PVC or any other rigid pipe

Table 2 Venting Specifications

The appliance should be located as close to the point of vent termination as possible. The maximum vent length is 26 feet (8 m) with one 90 degree elbow and approved terminator. Subtract 2.5 feet from the total vent length for each additional 90° elbow used (a

maximum of three 90° elbows are permitted in the total exhaust vent length), or subtract 1.25 feet for every

45° elbow used. Horizontal sections of vent must pitch

8

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Installation instructions upwards towards termination ¼" for every foot of 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" per foot.

Note: For horizontal terminations, venting must terminate once it penetrates to the outside of the structure. There must be no sections of vent pipe exposed to the outdoors.

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 vent. The distance to combustibles using this chase technique is 1 inch

1)

. Note: Type-B vent must never be used as the actual exhaust vent system for the appliance, as it is not gas tight and illegal for use

with this appliance. This will create a serious health hazard and void the warranty.

3”

VENTING

Z flex Protech Heat Fab

3”

Horizontal

Terminal

2SVSTB03 FSTB3 9390 TEE

3” Vertical terminator

2SVSRCF03 FSRC3

Table 3 Terminator Part Numbers

Fittings or Piping

5300CI

Equivalent feet m

45 degree elbow

90 degree elbow

1.25

2.5

0.38

0.76

pipe per foot 1 0.30

Table 4 Friction Loss Equivalent in piping and fittings

For specific questions concerning vent material, specifications, usage or installation, please contact the vent manufacturer directly.

Company Contact info

Z-flex www.z-flex.com

800-654-5600

ProTech Industries www.protechinfo.com

800-766-3473

Heat-Fab www.heatfab.com

800-772-0739

Table 5 Vent manufacturers

Minimum exhaust vent length

Fig. 8

Maximum exhaust vent and combustion air inlet lengths

The maximum exhaust vent and combustion air inlet lengths with one elbow are ≥ 26ft.

Fig. 9 Maximum vent and combustion air lenghts

Note: reduce 2.5 ft for each 90° elbow used after the first one, reduce 1.25 ft for each 45° elbow, see table 2, page 8.

Refer to chapter 3.3.2, page 12 for condensate drain requirements.

Vent Safety System

The GWH 2400 ES will shut down if inadequate exhaust venting is detected or a lack of combustion air is provided to the unit; see troubleshooting section on page 35. See error code to confirm error, correct the problem and then reset the heater before operating.

1) in all cases, follow local codes.

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9

Installation instructions

Recommended exhaust vent terminator position

Fig. 10

Ref.

Description

A

B

C

D*

E

F

Directly below an opening; operable windows, doors and any nonmechanical fresh air openings

Below a gutter, sanitary pipework or eaves

Below a gutter, sanitary pipework or eaves, protected by metal shielding

From any internal corner

Above ground or snow pack

Above a paved sidewalk

From an opposing wall or structure facing the termination

From the relief valve of a Ip gas regulator

From a terminator facing a terminator

G Vertically between two exhaust vent terminators on the same wall

Minimum distance

36 in (twin pipe installation)

48 in (single pipe installation)

24 in

12 in

12 in

12 in

7 ft

24 in

60 in

48 in

60 in

H Horizontally between two exhaust vent terminators on the same wall 36 in

Horizontally and vertically from combustion air inlet of a twin pipe system

36 in

I**

J

K

From the gravity combustion air inlet any other equipment

From any external corner

Horizontally from an opening; operable windows, doors and any nonmechanical fresh air openings

6 ft

12 in

12 in (twin pipe installation)

48 in (single pipe installation)

L

Vertically from a wall, roof slope, or obstruction (venting through a flat or pitched roof) see ABOVE THE ROOF requirements on following page

Table 6

* Subject to local codes and anticipated snow level

** Other equipment that operates with a mechanical air inlet may require greater distances, reference manufacturer's instructions

NOTE: terminating exhaust vent under a deck is not permitted

10

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Installation instructions

Venting configuration examples

(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" per foot.

Note: For horizontal terminations, venting must terminate once it penetrates to the outside of the structure. There must be no sections of vent pipe exposed to the outdoors.

Fig. 13 Above the roof clearance requirements from rain cap (combustion air piping not shown)

Fig. 12 Vertical venting installation (combustion air piping not shown)

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Chimney (combustion air piping not shown)

11

Installation instructions

3.3.2

Condensate drain requirements

A condensate drain must be installed under the following conditions:

• All vertical terminating vent installations

• Horizontal terminating vent installations where the total equivalent exhaust vent length is greater than 10 feet. See table 17, page 33.

• Vent installations where any section of the exhaust vent pipe passes through an unconditioned space.

Note: Do not install condensate drain in areas where it may freeze.

1. Install condensate drain as close to heater as possible.

2. Use 3/8" ID high temperature silicone tube to connect to condensate drain port. Do not use copper piping for any portion of the condensate drain.

3. Form a condensate trap by means of a 3" loop partially filled with water.

4. To increase the tube length, connect to end of the high temperature silicon tubing with vinyl tubing, PVC or

CPVC pipe. Do not reduce the internal diameter at any point.

5. Dispose of condensate according to local codes.

Room sealed installation (TWIN PIPE SYSTEM)

Installing this water heater as a room sealed (TWIN

PIPE SYSTEM) is the recommended method. Contact your dealer for available vent termination kits and vent materials for this water heater.

The exhaust and combustion air piping must vent directly to the outside of the structure.

Warning: In areas where outside temperatures routinely come close to freezing, sealed combustion operation is required. Use a concentric termination or separate terminations for combustion and vent, which must be installed on the same wall or roof surface, however never facing the direction of prevailing winds. Failure to do so may result in heat exchanger freezing up and bursting. This failure is not covered under the manufacturer's warranty.

Fig. 16

Combustion air pipe: ≤ 26 ft (8 m) from collar

Exhaust vent pipe: ≤ 26 ft (8 m) from collar

Fig. 15 Condensate drain installation

3" Venting Z-flex ProTech Heat Fab

90°

Condensate

Drain Tee

2SVEVWCF03 FST3 &

FSDF3

93PPLSTEE

Horizontal

Condensate

Drain

Condensate

Drain Tube

2SVEDWCF03 FSHDT3

2SVEDTK24 N/A

9321

7000TUBE

Table 7 Approved Condensate Drain Part Numbers

12

Fig. 17

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Installation instructions

Warning: Approved terminators must be used for inlet and exhaust vent systems to prevent rain from entering the appliance, failure to do so may result in damage to the appliance. This failure is not covered under the manufacturer’s warranty.

Fig. 18

Open combustion installation (SINGLE PIPE

SYSTEM)

Not recommended in cold climate areas, see chapter 3.4, page 15.

first one, reduce 1.25 ft for each 45° elbow.

A maximum of three 90-degree elbows are permitted.

Determining installation adjustment

The GWH 2400 ES comes factory set to accomodate most common venting arrangements. Determine the elbows and straight pipe you will require for exhaust and combustion air. Refer to the the table below to determine if the factory setting for the fan is adequate. If your venting system is longer and exceeds the values listed in Table 8, proceed to Section 6.7, page 33 for fan speed adjustment.

TWIN PIPE

Intake

1 x 90° elbow or

Less

2 x 90° elbow

3 x 90° elbow

SINGLE PIPE

No intake piping

Exhaust

One 90° elbow or Less (feet)

Two 90° elbows

Three 90° elbows

19’

16.5’

14’

19’

16.5’

14’

11.5’

16.5’

14’

11.5’

9’

14’

Maximum combined intake and exhaust vent length without fan speed adjustment.

Table 8

Note: Maximum of three 90° elbows allowed for exhaust and three 90° elbows allowed for intake.

Fig. 19

Connecting a one piece 90 degree elbow pipe to the combustion air inlet adaptor is required. This will prevent debris or objects from falling into the appliance.

The exhaust vent system must vent directly to the outside of the building and an adequate amount of indoor combustion air must be provided for this installation. See chapter 3.4.

Note: reduce 2.5 ft for each 90° elbow used after the

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13

Installation instructions

3.3.3

Vent connections

B Attach the flue gas exhaust accessory (8 705 504

151) to the top of the unit (position 1) using the 4 screws and gasket provided. Fully insert stainless steel vent pipe 1.5” minimum into the accessory and tighten the clamp (position 2).

Fig. 20

B Attach the combustion air inlet accessory (8 705

504 154) to the top of the unit (position 3) using the

3 screws and gasket provided, and install air intake pipe over the accessory. NOTE: The appliance has the option to mount the combustion air inlet accessory on the top right or on the top left side of the heater. The combustion air inlet that is not used must be kept sealed.

Fig. 21

B Ensure that exhaust vent pipe is fully inserted in collar to enable proper connection.

i

Exhaust venting must be 3" or 4" sealed single wall stainless steel (AL29-4C) vent pipe.

Attention residents of the Commonwealth of

Massachusetts:

In the Commonwealth of Massachusetts the following regulation went into effect on 12/30/2005:

(a) For all side wall horizontally vented gas fueled equipment installed in every dwelling, building or structure used in whole or in part for residential purposes, including those owned or operated by the

Commonwealth and where the side wall exhaust vent termination is less than seven (7) feet above finished grade in the area of the venting, including but not limited to decks and porches, the following requirements shall be satisfied:

1. INSTALLATION OF CARBON MONOXIDE

DETECTORS. At the time of installation of the side wall horizontal vented gas fueled equipment, the installing plumber or gasfitter shall observe that a hard wired carbon monoxide detector with an alarm and battery back-up is installed on the floor level where the gas equipment is to be installed. In addition, the installing plumber or gasfitter shall observe that a battery operated or hard wired carbon monoxide detector with an alarm is installed on each additional level of the dwelling, building or structure served by the side wall horizontal vented gas fueled equipment. It shall be the responsibility of the property owner to secure the services of qualified licensed professionals for the installation of hard wired carbon monoxide detectors.

a. In the event that the side wall horizontally vented gas fueled equipment is installed in a crawl space or an at tic, the hard wired carbon monoxide detector with alarm and battery back-up may be installed on the next adjacent floor level.

b. In the event that the requirements of this subdivision can not be met at the time of completion of installation, the owner shall have a period of thirty (30) days to comply with the above requirements; provided, however, that during said thirty (30) day period, a battery operated carbon monoxide detector with an alarm shall be installed.

2. APPROVED CARBON MONOXIDE DETECTORS.

Each carbon monoxide detector as required in accordance with the above provisions shall comply with

NFPA 720 and be ANSI/UL 2034 listed and IAS certified.

3. SIGNAGE. A metal or plastic identification plate shall be permanently mounted to the exterior of the building at a minimum height of eight (8) feet above grade directly in line with the exhaust vent terminal for the horizontally vented gas fueled heating appliance or equipment. The sign shall read, in print size no less than one half (1/2) inch in size, "GAS VENT DIRECTLY

BELOW. KEEP CLEAR OF ALL OBSTRUCTIONS".

4. INSPECTION. The state or local gas inspector of the side wall horizontally vented gas fueled equipment shall not approve the installation unless, upon inspection, the inspector observes carbon monoxide detectors and

14

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Installation instructions signage installed in accordance with the provisions of

248 CMR 5.08(2)(a)1 through 4.

(b) EXEMPTIONS: The following equipment is exempt from 248 CMR 5.08(2)(a)1 through 4:

1. The equipment listed in Chapter 10 entitled

"Equipment Not Required To Be Vented" in the most current edition of NFPA 54 as adopted by the Board; and

2. Product approved side wall horizontally vented gas fueled equipment installed in a room or structure separate from the dwelling, building or structure used in whole or in part for residential purposes.

(c) MANUFACTURERS REQUIREMENTS - GAS

EQUIPMENT VENTING SYSTEM REQUIRED. When the manufacturer of Product Approved side wall horizontally mounted gas equipment provides a venting system design or venting system components with the equipment, the instructions provided by the manufacturer for the installation of the equipment and the venting shall include:

1. Detailed instructions for the installation of the venting system or the venting system components: and

2. A complete parts list for the venting system design or venting system.

(d)MANUFACTURER REQUIREMENTS - GAS

EQUIPMENT VENTING SYSTEM NOT PROVIDED.

When the manufacturer of a product approved side wall horizontally vented gas fueled equipment does not provide the parts for the venting of flue gases, but identifies "special venting systems," the following requirements shall be satisfied by the manufacturer:

1. The referenced "special venting system" instructions shall be included with the appliance or equipment installation instructions; and

2. The "special venting systems" shall be product approved by the Board, and the instructions for that system shall include a parts list and detailed installation instructions.

(e) A copy of all installation instructions for all products approved side wall horizontally vented gas fueled equipment, all venting instructions, all parts lists for venting instructions, and/or all venting design instructions shall remain with the appliance or equipment at the completion of the installation.

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3.4

Combustion air requirements

Warning: In areas where outside temperatures routinely come close to freezing, sealed combustion operation is required. Use a concentric termination or separate terminations for combustion and vent, which must be installed on the same wall or roof surface, however never facing the direction of prevailing winds. Failure to do so may result in heat exchanger freezing up and bursting. This failure is not covered under the manufacturer's warranty.

Warning: When installed in an environment where corrosive chemicals or dirty air are present the twin pipe system is required.

Twin pipe

The GWH 2400 ES is designed as a sealed combustion appliance. It is recommended that the combustion air be provided by a dedicated 3” or 4” pipe from the outside. The combustion air pipe may be PVC or any other rigid sealed 3” or 4" pipe. The combustion air piping must pitch down 1/4 inch per foot towards termination to prevent rain water from entering the appliance. The combustion air inlet, whether terminating vertically or horizontally, must be located in such a manner as to provide a minimum 3 foot clearance

from the exhaust vent terminator. See Fig. 10

Letter I, page 10.

The maximum length of the combustion air inlet is 26 feet with one elbow. Subtract 2.5 feet for each additional 90° elbow and 1.25 feet for each additional 45° elbow. Maximum number of

elbows permitted is 3.

Warning: Vent terminations must prevent rain from entering the combustion air and exhaust vent piping.

Single pipe

Note: This appliance requires 8750 cubic feet of available combustion air, or a minimum of 1094 square feet of space with an 8 foot ceiling to operate. If the large amount of air space, which equates to about half of most average sized homes, is not available, the appliance must pull air from outside (see twin pipe system above).

Although it is permissible to draw combustion air from inside the structure, it is not the manufacturer’s 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 unit.

If a single pipe installation is utilized, follow guidelines

15

Installation instructions below for providing adequate combustion air for the water heater as well as any other appliances that may consume air in the space. Always follow local codes if they are more stringent.

This Installation Manual specifies the minimum exhaust vent length (Fig. 8, page 9) and the amount of combustion air required for this unit. When all requirements are followed, the unit will operate properly and safely. However, there may still be a risk of freezing due to negative draft if the other combustion appliances in the building are not supplied with sufficient combustion air. A wood stove or furnace can pull its combustion air from the heater's vent pipe, allowing the cold incoming air to freeze the cold water in the heat exchanger. Supplying more combustion air for all combustion appliances is the solution. A HVAC specialist should be consulted to design solutions for providing more combustion air. Observe the following guidelines:

Installations in structures that have been tightly constructed (air infiltration rate of 0.40 ACH or less) must be provided with combustion air per the National

Fuel Gas Code. Consult a HVAC specialist if your air infiltration rate is questionable.

The space must have two permanent openings, one commencing within 12 inches of the top and one commencing within 12 inches of the bottom of the enclosure.

Each opening must have a minimum free area of one square inch per:

• 1000 Btu/hr if all air is taken from inside the building

• 2000 Btu/hr if all air is taken from the outside by horizontal ducts

• 4000 Btu/hr if all air is taken from the outside by direct openings or vertical ducts.

Or the space must be provided with one permanent opening or duct that is within 12 inches of the ceiling of the enclosure.

This opening must have a minimum free area of one square inch per:

• 3000 Btu/hr if all air is taken from the outside by a direct opening or vertical duct.

Louvers, grills and screens have a blocking effect. If the effective free area is not known, increase the sizes of your openings by 300% if your louvers are wood and by

43% if your louvers are metal. Refer to the National Fuel

Gas Code for complete information.

3.5

Proper location for installing your heater

Carefully select the location of the water heater. For your safety and for proper heater operation, you must provide combustion air to the heater and a proper exhaust vent system.

Follow the guidelines below:

B 1. Locate the heater where venting, gas and plumbing connections are feasible and convenient.

B 2. The hot water lines should be kept short and insulated to save energy. Centrally locating the water heater is recommended to keep hot water distribution times even throughout the structure.

Warning: The water in this water heater is cold and always remains cold except for the times the burner is on. In the event of power outage in conjunction with freezing temperatures, it is recommended that the heater be drained.

See chapter 6.2, page 27 “Winterizing” for draining instructions.

Warning: Flammable materials, gasoline, pressurized containers, or any other items or articles that are potential fire hazards must NOT be placed on or adjacent to the heater. The appliance area must be kept free of all combustible materials, gasoline and other flammable vapors and liquids.

3.6

Heater placement and clearances

The GWH 2400 ES is approved for installation on

a combustible wall (see chapter 3.7 Mounting installation) provided the floor covering below

the heater is noncombustible. For installations in an alcove or closet, maintain the minimum clearances to combustible and non-combustible materials listed below. See also Fig. 7 and Table 1 on page 7.

Clearances from any exhaust vent pipe are dependent upon the clearance requirements of the stainless steel vent pipe manufacturer. Single wall stainless steel

(AL29-4C) vent pipe (vent type rated for Category III appliances) must be used when exhaust venting this appliance. See chapter 3.3 (page 8) Venting.

3.7

Mounting installation

Warning: before starting installation

B Check that there are no loose or damaged parts inside the appliance

B Confirm the gas type of the heater matches the gas supply you will be

connecting the heater, see Fig. 2, page 5.

16

6 720 608 782

Installation instructions i

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” or

1/2" (minimum) plywood first be attached across a pair of studs, see Fig. 22.

B Secure the wall mounting bracket provided with the heater to the wall surface. The heater must be kept level on the wall surface (see Fig. 23).

B Hang the appliance on the bracket, see Fig. 24.

Fig. 23 Leveling the mounting bracket on the studs

Studs 16"

(406mm) on center

Fig. 22 Distance between support boards

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Fig. 24 Mounting the heater

Warning: Appliance must be installed vertically.

3.8

Gas piping & connections

Before connecting the gas supply, check the rating plate on the right side of the heater to be sure that the heater is rated for the same gas to which it will be connected.

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.

In Canada: The Installation must conform to CSA B149

17

Installation instructions

INSTALLATION CODES and/or local installation codes.

Warning: DO NOT connect to an unregulated or high pressure propane line or to a high pressure commercial natural gas line.

Warning: The heater must be isolated from the gas supply piping system during any pressure testing of that system at test pressures equal to or more than 0.5 psig. If overpressure has occurred, such as through improper testing of the gas lines or malfunction of the supply system, the gas valve must be checked for safe operation.

GAS CONNECTIONS

B Install a manual gas shut off valve on the gas supply line within easy reach of the appliance.

B Install a union when connecting gas supply.

B The minimum internal diameter required for any appliance connector is ¾”.

B Undersized flexible appliance connectors not permitted.

B National Fuel Gas Code requires that a sediment trap (drip leg) be installed on gas appliances not so equipped. The drip leg must be accessible and not subject to freezing conditions. Install in accordance with the recommendations of the serving gas supplier, see Fig. 25.

Danger: If you have a leak, shut off the gas. Tighten appropriate fittings to stop leak. Turn the gas on and check again with a gas leak detection solution.

Never test for gas leaks using a match or flame.

GAS LINE SIZING

The gas supply piping for a single heater should be sized for a maximum draw of 199,000 BTUH. Measure the length of gas supply line and use the tables in

Fig. 27, page 19 or the gas line manufacturer’s sizing tables to determine the pipe diameter necessary to accommodate the 199,000 BTU demand of the heater.

If there are more gas appliances on the line, size the gas line according to the total maximum amount of BTU input rating for all appliances.

Note: Undersizing the gas line may result in diminished hot water flow rate and temperature. See chapter 3.12, page 22 for the procedure to confirm gas pressure.

Proper gas pressure must be confirmed at time of installation.

Gas piping

Inlet gas particle screen

(included)

Fig. 26

Minimum

3”

Gas supply

Cap

Fig. 25 Gas connection (drip leg)

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.

18

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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.

1/4

3/8

1/2

3/4

1

1 1/4

1 1/2

2

Follow boxed numbers for piping just one GWH 2400 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.

Nominal

Iron

Pipe Internal

Size, Diameter inches inches 10 20 30 40

Length of Black iron Pipe , Feet

50 60 70 80 90 100 125 150 175 200

0.364

0.493

0.622

0.824

1.049

1.380

1.610

2.067

32

72

132

22

49

92

18

40

73

15

34

63

14

30

56

12

27

50

11

25

46

11

23

43

10

22

40

9

21

38

278

520

190

350

152 130

285 245

1050 730 590 500

1600 1100 890 760

115

215

440

670

105

195

400

610

96

180

370

560

90

170

350

530

84

160

320

490

79

150

305

460

3050 2100 1650 1450 1270 1150 1050 990 930 870

8

18

34

72

130

275

410

780

8

17

31

64

120

250

380

710

7

15

28

6

14

26

59 55

110 100

225 210

350 320

650 610

Length of Flexible Corrugated Stainless Steel Tubing (CSST), Feet

Tube size, inches EHD*

10 20 30 40 50 60

1/2 18 EHD 82 58 47

3/4 23 EHD 161 116 96

41

83

37

75

34

68

1 30 EHD 330 231 188

1 1/4 37 EHD 639 456 374

162

325

144

292

131

267

* EHD = Equivalent Hydraulic Diameter. The greater the value of EHD, the greater the gas capacity of the tubing .

FOR LP GAS

Maximum Capacity of Pipe in Thousands of BTU per Hour of Undiluted Petroleum Gases (at 11 inches Water Column Inlet

Pressure) (Based on a Pressure Drop of 0.5 Inch Water Column).

* EHD = Equivalent Hydraulic Diameter. The greater the value of EHD, the greater the gas capacity of the tubing.

Nominal iron pipe

Inches

1/2

3/4

1

40

Black Iron Pipe

Length of Pipe, Feet

50 60 80 100 125 150 200 10 20 30

291 200 160 137 122 110 94 84 74 67 58

608 418 336 287 255 231 197 175 155 140 120

1145 787 632 541 480 434 372 330 292 265 227

Tube size inches

Length of Flexible Corrugated Stainless Steel Tubing (CSST), Feet

EHD*

10 20 30 40 50 60

1/2 18 EHD 129 91 74 64 58 53

3/4

1

23 EHD 254 183 151

30 EHD 521 365 297

131

256

118

227

107

207

Maximum Capacity of Semi-Rigid (flexible, non corrugated) Tubing in Thousands of BTU per Hour of

Undiluted Liquefied Petroleum Gases (at 11 inches

Water Column Inlet Pressure).

(Based on a Pressure Drop of 0.5 Inch Water Column)

* Source National Fuel Gas Code NFPA 54, ANSI

Z223.1 - No Additional Allowance is necessary for an ordinary number of fittings

Fig. 27

Outside diameter

Inch

Copper

Length of Tubing, Feet

10 20

3/8 39 26

30 40 50

21 19 _

1/2 92 62 50 41 37

5/8 199 131 107 90 79

60

_

35

72

70

_

31

67

80

_

29

62

90

_

27

59

100

_

26

55

3/4 329 216 181 145 131 121 112 104 95 90

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19

Installation instructions

3.9

Water connections

Warning: This heater is not approved for preheated water applications.

See chapter 3.11 for approved recirculating application.

B When facing the heater, the ¾” cold connection is on the bottom right and the hot connection is on the bottom left. Centrally locating the water heater is recommended to keep hot water distribution times even throughout the structure.

HOT

COLD

Fig. 28

B The use of unions when connecting both water pipes to the inlet and outlet connections is required. This will facilitate any necessary servicing.

B Plastic or PEX type plumbing line materials are not suitable for connecting directly to the water heater.

B Although water piping throughout the building may be other than copper, we recommend that copper or suitably rated stainless steel flex line piping be used for the water connections for 1.5’ on either side of the water heater (follow local codes if more stringent).

B Never sweat any piping directly to or beneath the water connections, as damage can occur to the internal water valve from heating of the pipe.

B Keep water inlet and outlet pipes to no less than ¾" (19.05mm) diameter to allow the full flow capacity.

B If the cold and hot connections to the heater are reversed, the heater will not function. Be certain there are no loose particles or dirt in the piping. Blow out or flush the lines before connecting to the water heater.

B Full port shutoff valves should be installed on both the cold water supply and hot water outlet lines to facilitate servicing the heater (see Fig. 29).

B For installation on a private well system with the use of a pressure tank, the lowest pressure range setting recommended is 40-60 psi (2.75 and 4.15 bar).

3.10

Water quality

Water quality can have an impact on appliance longevity and may not be covered under the manufacturer's warranty.

For water analysis data call your local water department, or if on a well, have well water analyzed periodically. If water quality exceeds one or more of the values specified below, Bosch recommends installing a water conditioner or softener.

Description Max. Levels pH

TDS (total Dissolved

Solids)

Total hardness

Aluminum pH 6.5 - 8.5

mg/l or ppm mg/l or ppm mg/l or ppm

500

100

(6 grains)

2.0

Chlorides

Copper mg/l or ppm mg/l or ppm

250

1.0

Iron

Manganese mg/l or ppm mg/l or ppm mg/l or ppm Zinc

Table 9

0.3

0.05

5.0

20

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Installation instructions

Connecting the pressure relief valve (PRV)

A listed pressure relief valve supplied with the heater must be installed at the time of installation. No valve is

to be placed between the PRV and the heater. No reducing coupling or other restriction may be installed in the discharge line. The discharge line must be a minimum of 4” above a drain and installed such that it allows complete drainage of both the PRV and the line.

The discharge line must be placed where it will not cause any damage.

The location of the PRV must be readily accessible for servicing or replacement, and be mounted as close to the water heater as possible. See Fig. 29. To install the

PRV, a suitable fitting connected to an extension on a

“T” fitting can be sweated to the hot water line.

Support all piping.

3.11

Recirculation application

The following drawing is provided to outline one possible recirculation design using the water heater in conjunction with an Ariston mini tank water heater.

Recirculation directly through the tankless water heater not allowed. This schematic is for illustration only and must not be used for actual installation without appropriate engineering and technical advice from a properly licensed professional in the locality where the installation is made.

GWH

2400

ES

Fig. 29 Plumbing Connections (with shutoff valves) and Pressure Relief Valve

1 Water filter

Ariston Minitank

Fig. 30 Recirculation application

3

4

1

2

5

Full port isolation valve

Circulator (pump)

Check valve

PRV

Expansion tank

The use of a small electric mini-tank water heater (4-6 gallon size) should be used for this application and designed so the pump will circulate the water through the mini-tank and the building's hot water return loop only. Timed or thermostatically controlled operation of the pump is commonly done. Contact Bosch Water

Heating if further information is needed.

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21

Installation instructions

3.12

Measuring gas pressure

Confirm gas pressure upon installation.

Connecting manometer

B Shut off gas supply at installer supplied shutoff valve for this water heater.

B Remove front cover and locate inlet gas pressure measuring point (see Fig. 32).

B Loosen screw inside left test point fitting (do not remove) and connect manometer tube to test point.

Remove screw completely if correct size tapping is available.

Static Pressure Test

B Turn gas supply back on.

B Record static gas pressure reading in table 11.

Operating Pressure Test

B Press ON/OFF button to turn off the appliance.

B Press and hold "Program" (P) button and press ON/

OFF button to turn appliance ON.

B Record lowest operating gas pressure reading in table 11.

Gas pressures lower than 3.5" W.C. for Natural Gas or

8" W.C. for LPG will result in insufficient degree rise to the hot water being used, reduced hot water volume, possible error code faults and must be corrected. See

Gas Connections, chapter 3.8, page 17.

Fig. 31

B As soon as '188' is displayed, release "Program"

, button and the display should read P2.

B Press or until P1 appears.

Note: While in this mode the appliance will run constantly at maximum power and allow maximum water flow.

For inlet gas pressure adjustment consider the following table:

Gas type NG LPG

3.5” WC 8” WC

Table 10 Minimum inlet gas pressure under full operation

B Turn on high volume of hot water flow (at least 6 gpm) and heater will ignite. If heater display reverts to

P2, open more hot water fixtures to allow sufficient flow. Press until P1 reappears on display.

B Operate all other gas appliances on the same gas piping system at maximum output.

Fig. 32 Gas pressure test port (left tapping)

Static Gas Pressure Reading (see Chapter 3.12)

enter here: ___________________ Date: ___________

Operating Gas Pressure Reading (see Chapter 3.12)

enter here: ___________________ Date: ___________

Table 11

HIGH ALTITUDE OPERATION (see chapter 6.4 page 28, for details)

Altitude above sea level

Natural

Gas:

Liquid

Propane:

0 - 2,000 ft

(0 - 610 m)

2,000 ft - 4,500 ft

(610 m - 1,372 m)

Above 4,500 ft

(above 1,372 m)

Table 12 no modification no modification

CO

2

adjustment with flue gas analyzer required See section

6.4

for instructions.

For operation at elevations above 2,000 ft

(610 m) the equipment ratings shall be reduced at the rate of 4% for each 1,000 ft

(305 m) above sea level

Not approved

22

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Electrical connections

4 Electrical connections

4.1

Electrical power supply

Warning: For safety reasons, disconnect the power supply cord to the heater before any service or testing is performed.

Warning: This heater must be electrically grounded in accordance with the most recent edition of the

National Electrical Code. NFPA 70. In

Canada, all electrical wiring to the heater should be in accordance with local codes and the Canadian Electrical

Code, CSA C22.1 Part 1. Do not rely on the gas or water piping to ground the metal parts of the heater.

The GWH 2400 ES requires an electrical power supply from a 120VAC / 60Hz circuit (with a dedicated outlet) and must be properly grounded.

The heater is wired as shown in the wiring diagram

(chapter 9, Fig. 58).

4.2

Position of the fuses in control unit

To check fuses, proceed as follows:

B Remove the front cover, see Fig. 4, page 6.

B Remove the three screws on front of the control unit.

Fig. 34

B Pull control unit free to access and remove the six screws from the back cover of the control unit, see

Fig. 35, pos. 2.

B Check the fuses in the printed circuit board, see Fig.

35, pos. 3.

1

Fig. 33 Connecting power supply cord

1 Power cord length: 3ft.

Note: Outlet appliance is plugged in to should be clear from possible water damage.

2

3

6720608158-78.1AL

Fig. 35 Location of fuses

B After verifying the fuses mount all parts in reverse order.

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23

Operation instructions

5 Operation instructions

Fig. 36

5

6

7

3

4

1

2

On/Off button

Reset button

Program Key

LCD display

Up button

Down button

LED - Power On indicator or Stand-by

5.1

LCD Display functions

Warning: Do not use any cleaning or corrosive agent to clean the window.

Fig. 40 Lock indicator

Fig. 41 Flame indicator

Fig. 37 Power bar indicator

Fig. 42 Remote control

Fig. 38 Temperature indicator

Fig. 39 Error indicator

24

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Operation instructions

5.2

For your safety read before operating your water heater

Warning: If you do not follow these instructions exactly, a fire or explosion may result causing property damage, personal injury or loss of life.

A. This appliance is equipped with electronic ignition for lighting the main burner. When turning the heater on, follow these instructions exactly.

B. Before operating the unit, press the On/Off button.

WHAT TO DO IF YOU SMELL GAS

B Do not try to light any appliance.

B Do not touch any electric switch; do not use any phone in your building.

B Immediately call your gas supplier from a neighbors phone. Follow the gas supplier’s instructions.

B If you cannot reach your gas supplier, call the fire department.

C. Use only your hand to press the on/off control switch.

Never use tools. Follow these instructions exactly. If control switch is jammed, close the gas supply and call a qualified service technician. Attempted forceful repair may result in a fire or explosion.

D. Do not use this appliance if any part has been under water. Immediately call a qualified service technician to inspect the appliance and to replace any part of the control system and any gas control which has been under water.

5.3

Power

On

B To start the appliance press the On/Off button.

5.4

Temperature selection

To select output water temperature:

B Press buttons temperature.

or in order to reach desired

Fig. 44

Setting the water temperature

The desired temperature of the hot water can be adjusted on the front control panel of the heater.

The GWH 2400 ES has an electronically controlled gas valve that modulates the burner input in response to both varying hot water flow rates and/or changes in any incoming and outgoing water temperatures.

Note: The water heater, running at minimum BTU, may still achieve temperatures above the desired set temperature. Low flowing fixtures are the leading cause of this type of temperature overshoot. To combat this symptom, clean fixtures or replace with higher flowing ones.

Saving water resources:

B Make sure you close all the taps after any use. Avoid leaving the taps dripping. Repair any leaking tap.

B Define the temperature you want, in the appliance or with the remote control. This way you have the precise water flow needed (mixing cold water to regulate temperature will increase the water flow with consequent waste of water).

Fig. 43

Off

B To shut down the appliance press the On/Off button again.

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25

Operation instructions

5.5

Use of optional remote control accessory (part no. TSTAT2)

Fig. 45 Remote control

The wireless remote control accessory (Fig. 70, component 13) and the temperature selector buttons on the front of the water heater operate identically.

Contact your distributor to order the remote control accessory. Modification of the water heaters interior control unit (Fig. 70, component 16) is required when programming the remote control with this heater.

i

NOTE: up to 6 remote controls can be programmed for one single water heater, each with a range distance of 98 ft (30 m).

5.6

Operation

B When a hot water tap is opened, main burner ignites and LCD displays the symbol .

Fig. 48 Reset button

If the problem persists, contact your installer.

5.8

Program button

Program button can be used on the appliance and in the remote control.

Programming “Program” function

Programming actions are similar for both controls

(appliance control pad and wireless remote control).

Fig. 46

B LCD blinks until selected temperature is reached.

5.7

Reset button

If the LCD shows the error symbol do not shut off power or unplug the heater.

See the error code on LCD and consult

“Troubleshooting” section.

Fig. 49 “Program” key

Memorizing selected temperature

B Press buttons or to select temperature to be memorized.

B Hold “Program” button for 3 seconds to save temperature.

When LCD stops blinking, temperature is saved in memory.

Using “Program” function

In order to select memorized temperature

B Press “Program” key.

LCD shows pre-memorized temperature, which is now the hot water selected temperature.

5.9

Locked condition

This condition is only valid for appliances with remote controls.

Fig. 47

After following instructions indicated in

“Troubleshooting” section.

B press reset button to return heater to normal operation.

Fig. 50 Locked condition

Whenever LCD shows the temperature setting cannot be adjusted because the appliance is in use by a user which already selected a different temperature.

Appliance will be automatically unlocked five minutes after closing the hot water tap.

26

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Maintenance and service

6 Maintenance and service

Warning: Always turn off the electrical power supply, turn off the manual gas shut off valve and turn off the water shut off valves whenever servicing.

Caution:

B Check and clean the complete water heating system once a year.

B Carry out a maintenance overhaul if necessary. Immediately repair defects to avoid damage to the system.

Inlet water filter

• Verify the inlet filter screen is clean and undamaged.

The inlet water filter is located inside the cold water inlet fitting on the right side of the appliance (See

Fig. 51, page 27). Close installer supplied cold water shutoff and loosen slotted screw on inlet fitting.

Water will drain from the appliance. Remove cylindrical filter inside.

Annual maintenance table

Every year

1.

Inspect venting system

2.

Inspect heat exchanger

3.

Inspect burner

4.

Inspect condensate trap

X

X

X

X

5.

Inspect water filter X

Table 13 Annual maintenance

The unit should be checked once a year by a gas technician. If repairs are needed, the repairs should be done by a gas technician.

6.1

Annual maintenance

(To remove front cover, see page 6.)

Venting System

• Venting system - inspect inside of flue pipe for any blockage or restriction. Observe burner flames during heater operation. (Vent pipe must be removed). Inspect the combustion air inlet pipe for blockage or debris. Inspect combustion air and exhaust terminations for blockage or debris.

Combustion chamber

• Inspect burner observation window (Fig. 63, #10) for cracks or spillage of flue gases. Observe burner flames during heater operation. Flames should be steady and blue with no signs of yellowing. Yellow burner flames are an indication of improper combustion. Refer to Section 3.4 & 3.3 of this manual to ensure that exhaust system and combustion air supply meets manufacturer's specifications.

Fig. 51 Water filter

1

2

Inlet water filter

Water filter

Descaling

• In areas where the water supply has a high mineral content (see Table 9, page 20), the heat exchanger should be periodically flushed with a descaling solution. Scale build up will shorten the life of the water heater and damage resulting from is not covered under warranty. Refer to section 6.3 for detailed instructions on descaling the heat exchanger.

Heat exchanger fin coils

• Inspect heat exchanger fincoil for soot build-up or blockage. To access fincoil, venting must be removed from flue gas exhaust accessory. With venting removed and inspect fincoil below with a flashlight. If there is evidence of soot build-up or blockage, the heat exchanger should be removed by a professsional and cleaned thoroughly. To remove the heat exchanger, consult service bulletin at www.boschhotwater.com.

6.2

Winterizing for seasonal use

Installation instructions state that the water heater must not be installed in a location where it may be exposed to freezing temperatures. If the heater must be left in a space which is likely to experience freezing temperatures, all water must be drained from the heater.

If precautions are not taken, resulting damage will not be covered under the warranty. NOTE: Use of agents

6 720 608 782

27

Maintenance and service such as anti-freeze is not permitted as they may cause damage to the water heater's internal components.

1. Press ON/OFF switch on the water heater to turn

OFF the heater and unplug power supply cord. The display should be blank.

2. Shut off gas supply to heater.

3. Shut off the water supply to the water heater using installer supplied shutoff valve.

4. Open hot water taps to drain the plumbing system. If water continues to flow after 5 minutes, a plumbing crossover is present and must be corrected before proceeding.

5. Open service valves (if available) or disconnect inlet and outlet water pipes from the water heater. Place a small bucket underneath the water heater to catch residual water remaining inside the water heater.

6. Using an air compressor, blow short bursts of air

(100psi max) through the outlet water connection until there is no water present coming through the inlet water connection of the heater.

7. Reconnect water fittings and return heater to service when danger of freezing has past.

6.3

Mineral scale build-up

Periodic descaling may be necessary in areas with high mineral content in the water. Scale buildup in the heat exchanger may result in lower flow rates, error codes of

A7 and E9 and boiling sounds (knocking and banging) in the heat exchanger.

Descaling using a pump

1. Disconnect electrical supply from the water heater.

2. Shut off the water supply to the water heater using

(installer supplied) shutoff valve.

3. Open hot water taps to drain and relieve pressure from the plumbing system.

4. Drain water from the unit's heat exchanger by disconnecting inlet and outlet water connections from the heater.

5. Connect a line (A) from the outlet of the circulating pump (installer supplied) to the inlet water fitting on the water heater (see Fig. 52).

6. Using another line (B), connect to the water outlet 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, connect to the inlet side of circulating pump. Install a filter on the end of this line in the descaling reservoir.

8. Make sure all connections are "water tight.".

9. Fill tank with descaling solution so both lines inside are submersed. We recommend straight white vinegar. If using a commercial descalant, refer to manufacturer's instructions on dilution with water.

10.Operate the circulating pump.

11.Make sure there are no leaks and the solution is flowing from the descaling reservoir through the heater and returning to the reservoir.

12.Run solution through the heater until the solution returning to the descaling reservoir comes out clear.

(Changing to a fresh solution may be necessary during this process).

13.Disconnect all lines and drain all solution from heat exchanger. Properly discard of solution.

14.Position a container below the hot water outlet and connect cold water supply. Open cold water supply isolation valve and flush heat exchanger with clean water.

15.Shut cold water shutoff valve and reconnect hot water supply to the water heater.

16.Reconnect electrical supply to unit, open water shutoff valves, and return the unit to service.

Fig. 52

6.4

Adjusting CO

2

(carbon dioxide)

The CO

2

can only be adjusted by a certified gas technician with a calibrated CO

2

analyzer.

Caution: One factor that may affect

CO

2

levels is improper gas pressure.

Please see Chapter 3.12 for the procedure to measure gas pressure and record your findings below:

Static Gas Pressure:

P1 Operating Pressure:

“ WC

“ WC

The P1 minimum operating gas pressure is 3.5" WC for

Natural Gas and 8" WC for Propane. Do not proceed in

28

6 720 608 782

Maintenance and service adjusting CO

2

until pressure is at or above these levels, but not to exceed 10.5” WC for Natural Gas and 13”

WC for Propane.

A. Once Gas Pressure is adequate

B Press ON/OFF button to turn off the heater.

B Remove brass flat head screw on the exhaust collar as seen in Fig. 53.

B Insert CO

2

analyzer probe into the measuring port.

The tip of the probe should be in the center of the flue pipe (approx 1.5" inserted). Avoid air gaps between probe and measuring port as they can alter readings.

Fig. 53 Measuring port

B While holding the Program (P) button in, press the

ON/OFF button to turn ON the heater (see Fig. 54).

As soon as ‘188’ flashes on the display, release the

Program button. The display should now read P2.

Press button until “P1” appears on display.

Fig. 54

B. Measuring CO

2

(combustion cover must be installed):

B Open all hot water taps to achieve a flow rate of at least 6 gallons per minute. (1 tub and 2 sinks should be sufficient). If heater display reverts to P2, open more hot water fixtures to allow sufficient flow. Press

‘ ’ until P1 reappears on the display.

B Record the CO

2

reading in P1 below. (Analyzer reading may take several minutes to stabilize).

B Press the ‘ ’ button until P2 appears. Unit will ramp down to low fire and the flow should decrease.

B Record the CO

2

reading in P1 and P2 below.

P2 CO

2

Reading: % CO

2

P1 CO

2

Reading: % CO

2

C. Adjusting CO

2

:

Note: P1 adjustment will change the P2 reading.

Confirm the P1 value BEFORE adjusting the P2 level.

1. If P1 CO

2

level is off:

B Loosen yellow painted philips screw (1) and cover should rotate down (2) revealing a recessed brass slotted screw. Fig. 55.

B Turning the slotted screw counter clockwise will raise P1 CO

2

levels and clockwise will lower P1

CO

2

levels. Adjustments to the slotted screw will also change P2 CO

2

levels.

B After bringing the P1 CO

2

readings in proper range, press the button to enter the P2 mode. Verify

CO

2

readings in P2 mode.

2. If P2 CO

2

level is off:

B Remove yellow painted #40 Torx cover from the front of the gas valve. (Fig. 56) A plastic #40 Torx screw will be revealed.

B Turning the plastic #40 Torx screw counter clockwise will lower P2 CO

2

levels and clockwise will raise P2 CO

2

levels.

Note: This screw adjustment is very sensitive and should be made in small increments. It may take several minutes for readings to stabilize.

3. Verify both P1 and P2 CO

2

readings are within the ranges specified in table 14. Repeat steps 1 and 2 as necesssary until CO

2

values are within the specified ranges.

4. Once CO

2

values are within the specified ranges, verify the CO readings on P1 and P2 do not exceed values shown in table 14. If values exceed this limit, inspect vent system and fin coils (chapter 6.1, page 27) for blockage.

D. Returning to Service:

1. Return slotted screw cover to original position and tighten philips screw.

2. Reinstall Torx cover.

3. Remove CO

2

analyzer probe and reinstall flathead screw with gasket in exhaust collar.

4. Press ON/OFF button to turn OFF the heater and then turn ON the heater.

5. Heater is ready for normal operation.

6 720 608 782

29

Maintenance and service

CO

2

range (%) max. input min. input

P1

P2

Nat. Gas

6.9 % - 7.5 %

2.3 % - 2.6 %

LP Gas

< 250 ppm

< 60 ppm max. input min. input

P1

P2

8.1 % - 8.7 %

2.5 % - 2.8 %

< 250 ppm

< 60 ppm

* Values above are for climate controlled conditions.

Inputs such as gas pressure, heating value of the gas, humidity and temperature of combustion air all impact CO and CO

2

values. Changes in these inputs can result in different CO and CO

2

values on the same appliance.

Table 14 CO

2

& CO target numbers

Final Readings

P2 CO

2

Reading: % CO

2

P1 CO

2

Reading: % CO

2

Max. CO level

(measured)

Fig. 55 Adjusting P1 CO

2

level

Fig. 56 Adjusting P2 CO

2

level

6720608158-38.1AL

30

6 720 608 782

Maintenance and service

6.5

Program values

This section describes details on programming the appliance. For most applications the factory default values will robust and stable operation. Only adjust the factory settings if the installation requires changes as indicated in the appropriate section of this manual.

Refer to chapter 6.6 Control board diagnostics (page

32) regarding how to access these P-modes.

Caution: Misadjusted program values can lead to appliance malfunction, errors, and service calls.

Program Description Factory Default MIN MAX Comment

P1 Maximum Power NG:40, LP:37 21

P2

P3

Minimum Power 6

Remote Controls installed

_0

6

_0

20

6

P4 Access to Diagnostic Mode

E 0d 10f

P6 Temperature

Unit

°F °F °C

Table 15 Program values, factory default settings and ranges.

NG:40, LP:37 see chapter 3.12, page 22.

note: reducing P1 values below maximum will reduce maximum power of the appliance.

see chapter 6.7, page 33 see chapter 5.5, page 26 see chapter 6.6, page 32

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31

Maintenance and service

6.6

Control board diagnostics

1. Turn on/off switch on water heater to off (O) position.

2. Press and hold the program ( ) button while turning the on/off switch to the on (I) position. The display will cycle through a startup procedure including the software version.

3. Release the ' ' button when '188' appears on the display. The display should read 'P2' when the program button is released. If not, repeat process.

4. Press and release the ' ' button on the control panel until the display reads 'P4'. You are now in the diagnostic mode of the control board.

5. When the display reads 'P4', press and release the

' ' button once again and the display should read

'E'.

6. Use the ' ' and ' ' button on the control board to cycle through different diagnostic modes available.

7. Once in the selected diagnostic mode of your choice, press and release the ' ' button to display the diagnostic information.

EXAMPLE: to read the flow rate in gallons per minute while the unit is flowing water, cycle to the '3d' mode and press the ' ' button. A reading of 25 on the display would indicate the heater is reading a flow rate of 2.5 gallons/minute.

8. Once the information is obtained, press the ' button again to return to the diagnostic mode menu

' and scroll to addition diagnostic information.

9. To exit the diagnostic mode of the heater, use the

' ' or ' ' button until the display reads 'E'.

10.Press the ' should read P4.

' button once again and the display

11.Turn the on/off switch off (O) and back on (I) again to return heater to normal function.

Diagnostic menu

E Entry/Exit into sub-modes

0d

1d

2d

3d

Set-point temperature (°F)

Inlet water temperature (°F)

Outlet water temperature (°F)

Water flow (gallons/min)

4d

5d

6d

7d

8d

9d

1F

2F

3F

4F

Gas type (LP or NG)

Fan speed (Hz)

Burner power (%)

Maximum power (kW)

Back flow temperature (°C)

Flue gas temperature (°F)

1)

Most recent error/failure

2nd most recent error

3rd most recent error

4th most recent error

5F

6F

7F

8F

9F

5th most recent error

6th most recent error

7th most recent error

8th most recent error

9th most recent error

10F

Table 16

1)

10th most recent error

Available only on model GWH C800 ES

32

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Maintenance and service

6.7

Fan speed adjustment

Installation adjustment: Flue pipe length setting for minimum power - P2.

After installing the GWH 2400 ES, the minimum power fan speed must be selected to compensate for variation in vent pipe length.

Total vent length calculation

B Determine the total length of all straight sections of vent pipe and enter in table 17, line 1.

B Count the number of 90° elbows used and enter that value in line 2. (Do not count end terminal and first elbow after the appliance).

B Count the number of 45° elbows used and enter that value in line 3.

B Repeat steps 1 through 3 for air intake pipe and enter those values in the intake section of table 17.

B Add line 4 from Exhaust to line 4 of Intake and enter result in line 5.

This is the total equivalent vent length.

Exhaust

1 Straight section length

2 90° elbows (qty)

3 45° elbows (qty)

4

Intake

__ x 1 =

__ x 2.5 =

__ x 1.25 =

____

____

____

Total: ____

1

2

3

4

Straight section length

90° elbows (qty)

45° elbows (qty)

__ x 1 = ____

__ x 2.5 = ____

__ x 1.25 = ____

Total: ____

5 Total equivalent vent length = ____

Table 17Determining vent length combination (see example in Table 18)

Example

Exhaust

• 7 - 3' straight sections

• 1 - 1' straight section

Total length 22'

• 2 - 90° elbow.

Intake

• 5 - 3' straight sections

Total length 15'

• 2 - 90° elbows.

Example

Exhaust

Straight section length

(feet)

90° elbows (qty)

45° elbows (qty)

Total:

Intake

22 x 1 =

1 x 2.5 =

0 x 1.25 =

22

2.5

0

24.5

15 x 1 = 15 Straight section length

(feet)

90° elbows (qty)

45° elbows (qty)

Total:

1 x 2.5 =

0 x 1.25 =

2.5

0

17.5

Total equivalent vent length = 42

Table 18Determining vent length combination example

Note: Do not count 1st elbow and terminators i

Total maximum length not to exceed 52 ft.

33

6 720 608 782

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 or to choose the fan speed suitable with your installation, see Table 19.

B Press and hold (± 5 sec.) “Program” button until the display flashes, then the selected value is memorized.

Mode

“P2”

Pipe Length for 3 ft up to 19 ft for 20 ft until 46 ft

1)

Fan speed

6

7 for 47 ft until 52 ft

Table 19Fan speed adjustment

1)

8

Full equivalent length (inlet+outlet+fittings). Do not count terminals and first elbow used on intake and exhaust.

34

6 720 608 782

Troubleshooting

7 Troubleshooting

Warning: If you are unable to perform the tasks listed below, or need additional assistance please contact your original installer or licensed gas technician.

7.1

Introduction

Many of the questions customers ask regarding operation of this unit can be answered by following the troubleshooting steps as outlined below. Visit our web site at www.boschhotwater.com for more detailed troubleshooting and service bulletins. For best results, perform each step before proceeding to the next. The suggested solutions may require that the cover be taken off. (See Page 6. Fig. 3).

7.2

Burner do not ignite when hot water is turned ON

1. If the display is blank, verify power to outlet.

(120VAC/60Hz properly grounded circuit required).

Verify that the heater ON/OFF button is turned ON.

2. Verify the fuses in the control board are good. See

Section 4.2, page 23 of the installation manual for fuse locations.

3. Make sure cold water inlet connection is plumbed to the right side of heater when facing unit. See Fig. 28, page 20.

4. A minimum of 0.65 gallons per minute (GPM) (2.5 l/ m) is required to activate the heater. A quart container should fill in 25 seconds or less to activate heater. In areas of warm inlet water temperatures, the heater may increase activation rate to as high as 1.6

gallons per minute (GPM) to prevent overshooting of set temperature.

5. Clean inlet filter screen per chapter 6.2, page 27.

6. Inspect the water path for obstructions. Make sure all showerheads, faucet aerators and whole house filters are clear of debris.

7. The heater activates when the water flow through the unit is at or above the required minimum of 0.65

GPM (2.5 l/m). A crossover in the plumbing creates back pressure on the water flowing through the heater. Therefore, a higher flow rate than normal is needed to force the heater to activate. To check for a plumbing crossover, shut off the cold water supply to the water heater. Then open all of the hot water taps served by the heater. Wait 10 minutes and check for water flow at taps. There should be no water flowing. Any continuous flow of water, small or large, indicates a crossover is present and must be corrected. Consult a professional plumber for help in correcting a crossover. Failing single lever faucets and mixing valves are common causes of plumbing crossovers.

8. With the ON/OFF switch turned to OFF (O) position and the power supply cord unplugged, remove the unit's front cover (See Page 6. Fig 3). Check wire connections between the water valve, control unit and electrode set. See chapter 12.1, page 46 for location of these parts.

7.3

Water is too hot

1. Selected temperature on the unit is set too high. To lower output temperature, see chapter 5.4, page 25.

2. Clean inlet filter screen per chapter 6.1, page 27.

3. Inspect the water path for obstructions. Make sure all showerheads, faucet aerators and whole house filters are clear of debris.

4. Confirm the heater's gas type coincides with the type of gas being supplied. See Fig. 2, page 5 for location of rating plate.

5. Avoid restrictive outlets. Clean all showerheads and faucet aerators. It may be necessary to upgrade to higher flow rate shower heads if allowable by local code.

6. In areas where the water has a high mineral content, periodic descaling may necessary. See chapter 6.3, page 28 for directions.

7. Ensure the outlet temperature sensor is making contact and firmly mounted on the hot water pipe.

7.4

Water is not hot enough

1. Selected temperature on the unit is too low. To raise output temperature, see chapter 5.4, page 25.

2. Clean inlet filter screen. See chapter 6.1, page 27.

3. Inspect the water path for obstructions. Make sure all showerheads, faucet aerators and whole house filters are clear of debris.

4. Confirm the heater's gas type coincides with the type of gas being supplied. See Fig. 2, page 5 for location of rating plate.

5. Check inlet gas particle screen for blockage at gas inlet connection on bottom of unit.

6. Verify gas pressure is in accordance with specifications in chapter 3.12, page 22. A gas pressure reading is needed to proceed further.

Contact your original installer or a local certified gas technician to obtain this reading.

7. Cold water is mixing into the hot water lines

(plumbing crossover). A plumbing crossover can unintentionally mix cold water with the hot water leaving the heater. The end result is a cooler water temperature than desired. To check for a plumbing crossover, shut off the cold water supply to the water heater. Then open all of the hot water taps served by

6 720 608 782

35

Troubleshooting the heater. Wait 10 minutes and check all taps for water flow. There should be no water flowing. Any continuous flow of water, small or large, indicates a crossover and must be corrected. Consult a professional plumber for help in correcting a crossover. Failing single lever faucets and mixing valves are common causes of plumbing crossovers.

8. Ensure the outlet temperature sensor is making contact and firmly mounted on the hot water pipe.

7.5

Low water flow/pressure

1. Too many hot water applications are being used simultaneously or too much flow is demanded. The water heater will effectively support two 2.0-2.5

GPM shower heads simultaneously or multiple sink applications. Greater draws will result in a water pressure drop and reduced flow at taps.

2. Ensure that gas pressure is in accordance with specifications in chapter 3.12, page 22. A gas pressure reading is needed to proceed further.

Contact your original installer or a local certified gas technician to obtain this reading. If gas pressure is inadequate, the water heater will close its motorized water valve, reducing the hot water flow rate in an attempt to reach the selected output temperature.

3. If selected temperature on the unit is set too high for the demanded flow rate, the water heater will close its motorized water valve, reducing the hot water flow rate in an attempt to reach the selected output temperature. Lowering the selected temperature will allow the motorized water valve to open up for increased water flow rate.

4. Clean inlet filter screen per chapter 6.1, page 27.

5. Inspect the water path for obstructions. Make sure all showerheads, faucet aerators and whole house filters are clear of debris.

7.6

Hot water temperature fluctuates at tap

1. Hot water is very hot out of the tap, requiring mixing of cold water in order to attain a useable hot water temperature. The addition of too much cold water will overpower the hot water flow from the tankless water heater.

This slows the flow within the tankless water heater, decreasing it below activation point, which shuts off the burners. The end result is nothing but cold water coming out of the outlet.

Consult www.boschhotwater.com for a detailed service bulletin on overcoming temperature fluctuations.

2. Unbalanced pressure in water lines. Any restriction in the water heater, such as a clogged inlet filter screen, can result in unequal pressures between the cold and hot water lines. In such cases, when mixing in the higher pressure cold water at the tap, the lower pressure hot water can be overpowered. This will shut down the burners because the hot water flow rate fell below the minimum flow rate required for activation. Verify inlet filter screen is clean and clear of debris. See chapter 6.1, page 27 for inlet filter cleaning instructions.

3. Heater deactivated by temperature balancing valves.

If the outlet water temperature is set too high, the heater can produce temperatures that are too hot. A temperature balance shower valve will automatically mix in cold water to reduce the hot water temperature. In the event of any temperature instability at a fixture using a temperature balancing valve, refer to the valve manufacturer for instructions on internal adjustment setting. An adjustment should be made to minimize the amount of cold water the valve is adding. Additionally, the temperature setting on the heater can be lowered to prevent the temperature balance valve from mixing in too much cold water.

4. Inlet water pressure is erratic due to fluctuating supply water pressure. For installation on a private well system with the use of a pressure tank, the lowest pressure range setting recommended is 40-

60 psi (2.75 - 4.15 bar). Consult your installer or local plumber for effective ways to maintain constant water pressure to the water heater when on a well system.

7.7

Noisy burner/heater during operation

1. Sealed combustion leak. Make sure combustion cover is securely fastened. Ensure the exhaust vent adaptor is properly sealed with supplied gasket.

Leaky seals create improper combustion resulting in noise.

2. Improper venting. Venting that is unsealed, the wrong material, too big in diameter or too long in run will result in unstable burner flames and noise. Ensure venting is proper and in accordance with specifications in chapter 3.3, page 8.

3. Lack of adequate combustion air. Drawing combustion air from a room area of inadequate size will result in unstable burner flames and noise.

Improper use of piping for combustion air will result in unstable burner flames and noise. Ensure adequate combustion air is provided to the unit in accordance with specifications in Section 3.4, page

15, Combustion Air Requirements.

4. Cross contamination. Ensure that intake and exhaust terminations maintain minimum required clearances stated in the manual. Cross contamination between intake and exhaust may cause unstable burner flames and noise.

5. Lack of adequate gas pressure. Inadequate gas pressure will cause the fuel-to-air mixture (CO

2

) to be

36

6 720 608 782

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.

6. Verify proper CO

2

readings per chapter 6.4, page

28. CO

2

adjustments must be done by a certified gas technician with a calibrated combustion gas analyzer.

Troubleshooting

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37

Problem solving

8 Problem solving

8.1

Error code diagnostics

i

To remove error code from the display, press the reset button.

Display Cause

Fault in the flue gas limiter.

Jumper connection is not correct.

Solution

1. Check continuity of the flue gas limiter (see Fig.

63 , page 46 ).

Go to steps two and three to determine air box temperature sensor fault and replace it.

2. Check for flue gas leakage around the top and bottom seals of heat exchanger as well as the viewing window.

3. Check that venting is within specifications (see Section 3.3

).

Long vent lengths, venting with more than three elbows, blocked vent or combination venting may cause this failure.

4. Check that flue gas limiter connector and spade connections are secure.

5. Unplug heater and check the two main plug connections inside the control board.

1. Check jumper connection on connector at upper right hand corner of heat exchanger.

Backflow temperature sensor defect - happens if sensor is disconnected or short circuit.

1. Check backflow temperature sensor connection and resistance.

See Fig. 61 , page 44 and Fig. 63 , page 46 .

2. Replace backflow temperature sensor.

Outlet temperature sensor fault

(Temperature below freezing or above 210°F).

1. Check red wire connections at hot water temperature sensor.

Clean terminals with an eraser. If badly corroded, replace sensor and wire harness. See Fig.

63 , page 46.

2. Sensor may trip if water temperature drops below freezing to protect heater from freezing conditions. Any damage due to freezing conditions is not covered under warranty.

3. Clean inlet filter screen and clear any debris out of shower heads, faucet aerators and whole house filters.

4. In areas where water has a high mineral content, periodic descaling may be necessary.

Table 20

* By installer or service technician only.

38

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Problem solving

Display

(Flashing)

(Flashing)

Cause Solution

Outlet temperature sensor not sensing expected output temperature.

Primary fan rotation too low on operation.

No rotational speed sensor signal from primary fan.

Water flow signal over specified maximum value.

Water flow > 10 gallon/min.

1. Check that the sensor is firmly attached to the hot water pipe

(see Fig.

69 , page 52 ).

2. Clean inlet filter screen and clear any debris out of shower heads, faucet aerators and whole house filters.

3. Check venting specifications are met. Long vent lengths, venting with more than three elbows, blocked vent or combination venting may cause this failure.

4. Check gas pressure. Low gas pressure may prevent the heater from reaching desired output temperature.

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.

1. Disconnect power supply cord and check wire connections on back side of primary fan and the two connectors on the control board (see Fig.

70 , page 53 ).

2. Check supply voltage. It must be 120VAC and properly grounded.

3. Check venting specifications are met. Long vent lengths, venting with more than three elbows, blocked vent or combination venting may cause this failure.

4. Ensure intake and exhaust terminations maintain the required minimum clearances stated in the manual. Cross contamination between intake and exhaust may cause the fan to alter its rotational speed.

5. Check gas pressure. Low gas pressure may cause the fan to change its speed to meet desired temperature.

6. Possible defective control unit call Bosch Water Heating for further instructions.

1. Disconnect power supply cord and check wire connections on back side of primary fan and the two connectors on the control board (see Fig.

70 , page 53 ).

2. Check supply voltage. It must be 120VAC and properly grounded.

3. Possible defective component in fan or defective control unit call Bosch Water Heating for further instructions.

1. Disconnect power supply cord and check wire connections on water valve and the two connectors on the control board (see

Fig.

70 , page 53 ).

2. Excessive water pressure and flow. Ensure water pressure is less than 150psi and flow rate is below 10 gallons per minute.

Internal hardware/software failure.

1. Disconnect power supply cord and check the two wire and ground connections on control board as well as ground connection on heater chassis.

2. Pushing the wrong combination of buttons on the control unit can create confusion among the microprocessors inside. In this case, the error code should not happen more than once or twice.

Turn off the water heater. Turn water heater back on and try resetting error code. Use the reset button ( ) to reset any error codes.

3. Possible defective control unit. Call Bosch Water Heating for further instructions.

Table 20

* By installer or service technician only.

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39

Problem solving

Display Cause Solution

Over-temperature detected by outlet temperature sensor on hot water pipe.

Temperature > 185°F

1. Check that the sensor is firmly attached to the vertical section of the hot water pipe (see Fig.

69 , page 52 ).

2. Check red wire connections at outlet temperature sensor.

Clean terminals with an eraser. If badly corroded, replace sensor and wire harness. Check sensor resistance (see Fig. 59 , page

43 .

3. Clean inlet filter screen per chapter 6.2

, page 27 and clear any debris out of shower heads, faucet aerators and whole house filters.

4. In areas where water has a high mineral content, periodic descaling may be necessary. See chapter directions.

6.3

, page 27 for

Cold water temperature sensor fault.

1. Check connector on wires coming from top of watervalve for a secure connection. See Fig.

63 , page 46.

2. Sensor may trip if water temperature drops below freezing to protect heater from freezing conditions Any damage due to freezing conditions is not covered under warranty.

Backflow temperature sensor over

309°F.

The appliance will close the burner and lock.

1. Check combustion air and backflow vent piping for blockage.

2. Check if secondary fan connections are disconnected.

3. Check venting specifications are met. Long vent lengths, venting with more than three elbows, blocked vent or combination venting may cause this failure.

4. Check sensor resistance (see Fig. 61 , page 44 ).

Overheat sensor (ECO) open circuit (should reset when cooler temperatures are detected).

1. Disconnect power supply cord and check wire connections on overheat sensor (top right of heat exchanger) and the two connectors on the control board. See Fig.

63 , page 46.

2. Check white wire connections at overheat sensor. Clean terminals with an eraser. If badly corroded, replace sensor and wire harness.

3. Check venting specifications are met. Long vent lengths, venting with more than three elbows, blocked vent or combination venting may cause this failure.

4. Clean inlet filter screen and clear any debris out of shower heads, faucet aerators and whole house filters.

5. In areas where water has a high mineral content, periodic descaling may necessary, see chapter 6.3

.

6. Unplug power supply cord to the water heater. Open a hot water tap for several minutes to allow cold water to pass through heat exchanger. Close hot water tap and disconnect lead wires to overheat sensor. Using a multimeter, check continuity through overheat sensor contacts. Replace sensor if open.

Table 20

* By installer or service technician only.

40

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Problem solving

Display Cause Solution

No flame ionization detected with water flow.

1. Verify that all manual gas shut off valves are open.

2. Check gas type, see Fig. 2 , page 5 .

3. Reset error code and open a water tap to cycle the heater in an effort to purge air on new installations. Cycling hot water tap on and off multiple times may be necessary. If heater still faults with

EA error code, have a licensed gas technician properly purge air out of the gas line leading to the water heater.

4. Check three wire connections to ignition group on the lower front of the heat exchanger are secure.

5. Check gas pressure, see chapter 3.12

, page 22 .

6. Check venting specifications are met. Improper venting may cause premature failure of the flame sensor rod.

7. Check that the minimum power fan speed has been adjusted to the proper value. See page 34.

8. Observe inside the viewing window of the heat exchanger when a hot water tap is opened. Sparking should be followed by a steady blue flame. If flame is unstable or yellow with proper gas pressure, confirm CO

2

readings per section 6.4

.

Ionization failure during operation.

1. Check gas type, see Fig. 2 , page 5 .

2. Check three wire connections to ignition group on the lower front of the heat exchanger are secure.

3. Check venting specifications are met. Improper venting may cause unstable burner flames and loss of flame ionization.

4. Check that the minimum power fan speed has been adjusted to the proper value. See page 34.

5. Check gas pressure, see section 3.12

, page 22 .

6. Check and adjust CO

2

readings, see section 6.4, page 28.

Ionization error at standby.

1. Loose connection to the flame ionization rod. Verify that the thinner wire leading from the control unit is securely connected to the flame sensor located on the lower front of the heat exchanger.

See Fig.

63 , page 46.

2. Flame ionization rod or control unit may be damaged. Contact

Bosch Water Heating for further instruction.

Gas leakage error, gas valve circuit not closing properly.

1. Disconnect power supply cord and check wire connections on gas valve and the two connectors on the control board.

2. Flow water out of a hot water tap above the minimum activation point of 0.65 GPM. Measure voltage at the gas valve wire plug connection. 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.

Table 20

* By installer or service technician only.

6 720 608 782

41

Electrical diagram

9 Electrical diagram

Fig. 58 Electrical scheme

14

15

16

17

9

10

12

13

18

19

20

21

22

7

8

5

6

3

4

1

2

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

Secondary fan

AC plug

Main connection

Ignition electrodes

Ground post

Antifreeze Kit connection

Fuse

Fuse

42

6 720 608 782

Sensor resistance charts

10 Sensor resistance charts

Outlet temperature sensor characteristics

12 2

117

112

10 7

10 2

9 7

9 2

8 7

8 2

77

72

6 7

6 2

57

52

4 7

4 2

3 7

3 2

2 2 2

2 17

2 12

2 0 7

2 0 2

19 7

19 2

18 7

18 2

177

172

16 7

16 2

157

152

14 7

14 2

13 7

13 2

12 7

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37

0

10

5

3 0

2 5

2 0

15

75

70

6 5

6 0

55

50

4 5

4 0

3 5

9 5

9 0

8 5

8 0

110

10 5

10 0

Resistance (Kohm)

Fig. 59

Inlet temperature sensor characteristics

2 4 7

2 4 2

2 3 7

2 3 2

2 2 7

2 2 2

2 17

2 12

2 0 7

2 0 2

19 7

19 2

18 7

18 2

177

172

16 7

16 2

12 2

117

112

10 7

10 2

9 7

9 2

8 7

8 2

77

72

6 7

6 2

57

52

4 7

4 2

3 7

3 2

157

152

14 7

14 2

13 7

13 2

12 7

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

Resistance (Kohm)

15 16 17 18 19 20 21 22 23

8 0

75

70

6 5

6 0

55

50

4 5

4 0

3 5

5

24

0

3 0

2 5

2 0

15

10

12 0

115

110

10 5

10 0

9 5

9 0

8 5

Fig. 60

6 720 608 782

43

Sensor resistance charts

Back Flow characteristics

2 4 2

2 3 7

2 3 2

2 2 7

2 2 2

2 17

2 12

2 0 7

2 0 2

19 7

19 2

18 7

18 2

17 7

17 2

16 7

16 2

3 0 2

2 9 7

2 9 2

2 8 7

2 8 2

2 7 7

2 7 2

2 6 7

2 6 2

2 5 7

2 5 2

2 4 7

10 7

10 2

9 7

9 2

8 7

8 2

7 7

7 2

6 7

6 2

5 7

5 2

4 7

4 2

3 7

3 2

15 7

15 2

14 7

14 2

13 7

13 2

12 7

12 2

117

112

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

Resistance (Kohm)

23 24 25 26 27 28 29 30 31 32 33 34 35 36

155

150

14 5

115

110

10 5

10 0

9 5

14 0

13 5

13 0

12 5

12 0

9 0

8 5

8 0

75

70

6 5

37

0

10

5

3 5

3 0

2 5

2 0

15

6 0

55

50

4 5

4 0

Fig. 61

44

6 720 608 782

11 GWH 2400 ES Functional scheme

GWH 2400 ES Functional scheme

Fig. 62 Functional scheme

6 720 608 782

45

Interior components diagram and parts list

12 Interior components diagram and parts list

12.1

Interior components

Fig. 63 Components

7

8

5

6

3

4

1

2

9

10

11

Flue gas collector

Heat exchanger

Flame sensor

Primary fan (Mixer)

Outlet temperature sensor

LCD display

On/Off button

Reset button

Program key

Flue gas limiter

Heat exchanger overheat sensor (ECO)

46

16

17

18

19

12

13

14

15

20

21

Ignition electrodes

Observation window

Backflow temperature sensor

Secondary air fan

Gas valve

Water valve with engine and temperature sensor

Control unit

Up button

Down button

LED

6 720 608 782

Interior components diagram and parts list

Fig. 64 Appliance overview

6 720 608 782

47

Interior components diagram and parts list

12.2

Components diagram

12.2.1 Group 1

9

15

16

9

12

13 15

9

14

17

5

6

8

9

10

3

7

11

2

4

1

Fig. 65 Components Diagram

Item Description

7

8

5

6

9

3

4

1

2

Table 21

Front cover

Cover shield

Trade mark badge

Cover screw

Combustion cover

Combustion cover gasket

Observation window

Holding bracket

Screw

48

Reference

8 705 431 286

8 705 506 862

8 701 103 140

8 703 401 170

8 700 506 300

8 704 701 084

8 705 600 003

8 708 104 103

8 703 403 012

Item Description

14

15

16

17

10

11

12

13

Table 21

Combustion cover clip

Grommet set

Exhaust accessory

Gasket exhaust

Inlet air cover

Inlet air gasket

Inlet air accessory

Mounting bracket

6720902973.AA JF

Reference

8 701 201 032

8 710 203 039

8 705 504 162

8 700 103 710

8 708 006 022

8 700 103 166

8 705 504 116

8 701 309 164

6 720 608 782

Interior components diagram and parts list

12.2.2 Group 2

3

2

1

5

4

9

8

6

7

Fig. 66 Components Diagram

Item Description Reference

1

2

3

4

5

Table 22

Heat exchanger

Heat exchanger top gasket

Flue gas collector

8 705 406 356

8 704 701 052

8 705 700 153

Overheat sensor (ECO) 8 707 206 204

Heat exchanger bottom gasket 8 704 701 054

6 720 608 782

6720902974.AA JF

Item Description

8

9

6

7

Table 22

Site window

Ignition group

Heat exchanger O-ring

Rubber grommet

Reference

8 701 000 401

8 701 302 249

8 700 205 147

8 710 303 027

49

Interior components diagram and parts list

12.2.3 Group 3

3

5

4

2

1

6

16

10

17

14

15

9

12 11

13

8

7

Fig. 67 Components Diagram

Item Description

1

4

5

2

3

6

7

8

9

Table 23

Main burner

Burner gasket

Primary fan

Backflow temperature sensor

Washer

Fan mount nut

Secondary fan

Screw

Gas / Air Mixer

Reference

8 708 120 642

8 704 701 087

8 707 204 071

8 707 206 459

8 704 701 097

2 915 011 006

8 707 204 072

8 703 403 012

8 705 700 170

50

Item Description

14

15

16

17

10

11

12

13

Table 23

Air duct O-ring

Venturi

O-ring

Mixer / Fan gasket

Screw

Plate gasket

Air supply duct

Screw

6720902975.AA JF

Reference

8 700 205 149

8 700 306 226

8 700 205 224

8 704 701 059

2 910 642 150

8 701 004 049

8 705 700 155

2 910 952 122

6 720 608 782

Interior components diagram and parts list

12.2.4 Group 4

14

11

7

6

13

12

11

10

8

9

1

3

4

2

5

Fig. 68 Components Diagram

Item Description

5

6

7

3

4

1

2

Table 24

Gas valve

Pressure tapping

Washer

Pressure balance tube

Pressure balance nut

Gas supply pipe

Gas valve washer

Reference

8 707 021 019

8 703 404 219

8 700 203 041

8 700 703 136

8 703 300 041

8 700 715 389

8 700 103 014

Item Description

12

13

14

8

9

10

11

Table 24

Gas filter

Gasket

Gas / Fan connector

Washer

Regulation screw

O-ring

Screw

6720608158-73.1AL

Reference

8 700 507 002

8 704 701 085

8 705 202 140

8 704 701 062

8 703 404 220

8 700 205 009

2 910 149 181

6 720 608 782

51

Interior components diagram and parts list

12.2.5 Group 5

Fig. 69 Components Diagram

Item Description

7

8

9

5

6

3

4

1

2

Water valve with engine

O-ring

Cold water pipe

Pipe connection clip

Hot water pipe

Temperature sensor

Outlet fitting

Inlet / Outlet washer

Wireform spring

Table 25

52

Reference

8 708 505 024

8 700 205 147

8 700 715 394

8 701 201 028

8 700 715 392

8 700 400 015

8 703 305 349

8 710 103 045

8 701 300 025

Item Description

10 Inlet fitting with filter

11

12

13

14

15

Table 25

O-ring

Watervalve clip

Water filter

Washer

O-ring

Reference

8 703 305 356

8 700 205 157

8 716 102 607

8 700 507 059

8 700 103 764

8 700 205 231

6 720 608 782

Interior components diagram and parts list

12.2.6 Group 6

4

5

6

7

9

10

3

2

1

13

14

15

11

Fig. 70 Components Diagram

Item Description

3

4

1

2

5

6

7

8

Table 26

Control unit

Fuse T2.5A

Fuse T1.6A

Power supply cables

Power supply cord

Fan cables

Wire harness

Jumper

6 720 608 782

12

6720608782-08.1AL

Reference

8 707 207 296

1 904 521 342

8 700 609 008

8 704 401 371

8 704 401 378

8 704 401 347

8 704 401 348

8 704 401 376

Item Description Reference

9

10

11

12

13

14

15

Table 26

Electrode cables

Flue gas limiter

Anti freeze kit

Remote control (optional)

Shaped seal (optional)

Screw (optional)

8 704 401 346

8 700 400 032

7 709 003 665

8 707 207 153

8 700 201 012

8 703 401 109

Printed circuit transceiver (optional) 8 708 300 123

53

Protecting the environment

13 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.

54

6 720 608 782

Limited Warranty

14 Limited Warranty

General

Aquastar water heaters are warranted by the

Manufacturer (BOSCH) through Bosch thermotechnology corporation.

Bosch thermotechnology corporation will furnish a replacement heat exchanger and will furnish a replacement of any other part which fails in normal use and service within the applicable periods specified below, in accordance with the terms of this warranty.

The Bosch thermotechnology corporation replacement will be warranted for the unexpired portion of the original warranty. This warranty will be valid only for water heaters in possession of the original purchaser as recorded on the warranty card.

The Heat Exchanger

If the heat exchanger fails within twelve (12) years after the original installation and operation, Bosch thermotechnology corporation will furnish a replacement heat exchanger. However, if the water heater is in an approved domestic hot water recirculation application, this heat exchanger warranty is limited to five (5) years from date of original installation and operation. If the water heater is installed in other than a single family dwelling, this heat exchanger warranty is limited to two (2) years from date of original installation and operation.

Exceptions

This warranty will not apply:

1. to defects or malfunctions resulting from failure to accordance with the printed instructions provided;

2. to damage or abuse, accident, neglect or freezing and other acts of nature;

3. to damage resulting from operation with either the flame sensor rod or overheat sensor removed;

4. to failure of the heat exchanger resulting from the operation of the water heater in a corrosive atmosphere or at water temperatures exceeding the maximum rating, or if the water heater is not supplied with potable water;

5. to defects or damage cause by any attachment or modification, including any energy-saving device.

• 6. to damage resulting from scale deposits and/or highly mineralized / unsoftened water supply.

All Other Parts

If any other part fails within two (2) years after original installation and operation, Bosch thermotechnology corporation will furnish a replacement part free of charge.

Service Labor Costs

This warranty does not cover any labor costs associated with service, removal or re-installation of part(s). All such costs must be borne by the Purchaser.

Additionally, this warranty does not cover any labor costs associated with service, removal or re-installation of the original water heater or a replaced water heater.

i

NOTE: the water heater must be free of damaging scale deposits and not subject to gas pressures greater than those shown on the rating plate, which must not be altered, defaced or removed.

How to Make a Claim

Any claim for warranty parts should be made to your local dealer or distributor:

BOSCH THERMOTECHNOLOGY CORPORATION

Bosch Water Heating

340 Mad River Park

Waitsfield, VT 05673

TEL. 800-642-3111 www.boschhotwater.com

In most cases, the dealer or distributor will be able to promptly honor your claim and subsequently notify

Bosch thermotechnology corporation. However, all replacements are made subject to validation by Bosch thermotechnology corporation of in-warranty coverage.

The damaged or defective item must be made available in exchange for the replacement.

Miscellaneous

No one is authorized to make any other warranties on behalf of Bosch thermotechnology corporation. It is expressly understood that the replacement warranty of

Bosch thermotechnology corporation shall be in lieu of any and all other warranties, express or implied, including warranties of merchantability or fitness for a particular use or purpose, and further that Bosch thermotechnology corporation shall not be liable for any loss or damage directly or indirectly arising from the use of the hot water heater, or for any consequential damages arising from such use (including damages from water leakage). Bosch thermotechnology corporation sole liability with respect to any defect shall be for the replacement of the defective part(s). Some states do not allow such limitations and exclusions, so the above may not apply to you.

This warranty gives specific legal rights. You may also have other rights which vary from state to state.

55

6 720 608 782

Installer Checklist to be completed by installer upon installation

Serial Number ___ ___ ___ ___ ___ ___ ___ ___

(8 digit serial number is located on rating plate on right side panel)

Gas Pressure Reading*

Building Water Pressure

Installing Company

Installer name

Static__________

__________

Operating__________

Range if on Well system __________

_____________________________________________

_____________________________________________

Address

Phone

_____________________________________________

_____________________________________________

* See Chapter 3.12, page 22 and gas pressure table (to be filled out by installer)

Installation manual should be left with the owner after the installation is tested and completed

Replacement Parts available from:

BOSCH THERMOTECHNOLOGY

CORPORATION

Bosch Water Heating

340 Mad River Park

Waitsfield, VT 05673

TEL. 800-642-3111 www.boschhotwater.com

Recycled paper

Bosch Termotecnologia, S.A.

Estrada de Cacia

3801 - 856 Aveiro - PORTUGAL

© 2008 Bosch Thermotechnology Corp.,

Waitsfield, VT all rights reserved

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