Bosch GWH 2700 ES LP, GWH 2700 ES NG User Manual

Page 1

MODEL GWH 2700 ES NG and GWH 2700 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 2700 ES NG - Natural Gas GWH 2700 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.

6 720 608 542 (2009/03) US

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.

Page 2

Index

1 Warning 3

2 Appliance details 4

2.1 Features 4

2.2 Specifications (Technical data) 5

2.3 Unpacking the heater 6

2.4 General rules to follow for safe operation 7

2.5 Dimensions and Minimum installation clearances 8

3 Installation instructions 9

3.1 Tools required for installation 9

3.2 Introduction 9

3.3 Venting 9

3.4 Combustion air requirements 20

3.5 Proper location for installing your heater 21

3.6 Heater placement and clearances 21

3.7 Mounting installation 21

3.8 Gas piping & connections 22

3.9 Water connections 25

3.10 Water quality 25

3.11 Domestic hot water recirculation 26

3.12 Measuring gas pressure 27

6 Maintenance and service 32

6.1 Annual maintenance 32

6.2 Winterizing for seasonal use 32

6.3 Mineral scale build-up 33

6.4 Adjusting CO2 (carbon dioxide) 33

6.5 Program values 36

6.6 Control board diagnostics 37

7 Troubleshooting 38

7.1 Introduction 38

7.2 Burner do not ignite when hot water is turned ON 38

7.3 Water is too hot 38

7.4 Water is not hot enough 38

7.5 Low water flow/pressure 39

7.6 Hot water temperature fluctuates at tap 39

7.7 Noisy burner/heater during operation 39

8 Problem solving 41

8.1 Error code diagnostics 41

9 Electrical diagram 45

4 Electrical connections 28

4.1 Electrical power supply 28

4.2 Position of the fuses in control unit 28

5 Operation instructions 29

5.1 LCD Display functions 29

5.2 For your safety read before operating your water heater 30

5.3 Power 30

5.4 Temperature selection 30

5.5 Use of optional remote control accessory (part no. TSTAT2) 31

5.6 Operation 31

5.7 Reset button 31

5.8 Program button 31

5.9 Locked condition 31

10 Sensor resistance charts 46

11 GWH 2700 ES Functional scheme 48

12 Interior components diagram

and parts list 49

12.1 Interior components 49

12.2 Components diagram 51

13 Protecting the environment 57

14 Limited Warranty 58

6 720 608 542

Page 3

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: The appliance should be located in an area where leakage of the heater or connections will not result in damage to the area adjacent to the appliance or to lower floors of the structure. When such locations cannot be avoided, it is recommended that a suitable drain pan, adequately drained, be installed under the appliance. The pan must not restrict combustion air flow.

Warning: The maximum inlet gas pressure must not exceed the value specified by the manufacturer and that the minimum value listed is for the purposes of input adjustment.

Warning: If a water heater is installed in a closed water supply system, such as one having a backflow preventer in the cold water supply line, means shall be provided to control thermal expansion. Contact the water supplier or local plumbing inspector on how to control this situation.

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.

Warning: Keeping appliance area clear and free from combustible materials, gasoline and other flammable vapors and liquids.

Warning: Do not obstruct the flow of combustion and ventilation air.

Warning: Precautions must be taken prior to manually operating the relief valve to avoid contact with hot water coming out of the relief valve and to prevent water damage.

Caution: Label all wires prior to disconnection when servicing controls. Wiring errors can use improper and dangerous operation. Verify proper operation after servicing.

Warning: In order for the freeze prevention kit to provide adequate protection,120V AC must always be supplied to the water heater.

6 720 608 542

Page 4

Appliance details

HOT

BURN

D A N G E R

Watertemperatureover125°Fcan causesevereburnsinstantlyor deathfromscalds.

Children,disabledandelderlyare athighestriskofbeingscalded.

Seeinstructionmanualbefore settingtemperatureatwater heater.

Feelwaterbeforebathingor showering.

6720608643-16.1AL

Warning: The anti freeze kit is designed to provide protection for the water heater down to approximately 5°F for short term conditions only. It will not protect the appliance in areas where the temperature is routinely expected to be below freezing.

B The anti freeze kit will not protect

plumbing outside the appliance from freezing. Precautions should be taken.

B Always drain the water heater if it will be

exposed to long term freezing conditions. See Section 6.2 Winterizing for seasonal use.

Warning: If a relief valve discharges periodically, this may be due to thermal expansion in a closed water supply system. Contact the water supplier or local plumbing inspector on how to correct this situation. Do not plug the relief valve.

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.

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: The freeze prevention is designed to provide protection for the water heater down to approximately 5°F for short term conditions only. It will not protect the appliance in areas where the temperature is routinely expected to be below freezing.

- The freeze prevention will not protect plumbing outside

the appliance from freezing. Precautions should be taken. Accessories (Bosch part #)

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

• Cascading kit (TLINK)

• Outdoor kit (AQOK)

• Gas conversion kit (8719002176)

• Vertical vent kit (ESVVT)

• Horizontal vent kit (AQ3ES1))

• Stainless steel bird screen (L2594) (fits into a 3” PCV fitting - Intake vent).

Fig. 1

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

1) AQ3 vent kit is compatible with this appliance but requires the purchase of an additional 12" piece of straight pipe to meet minimum vent length requirements. The aluminum flex piping included with this kit is not permissible for use with this appliance.

6 720 608 542

Page 5

Appliance details

2.2 Specifications (Technical data)

Approved in US/Canada

Capacity

Maximum flow rate: 7.15 GPM (27 l/min) at a 45°F (25°C) rise.

Maximum output

160,500 Btu/h (47.0 kW)

Maximum input

199,000 Btu/h (58.3 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.

Dimensions

• Depth (in): 11¼” (286 mm)

• Width (in): 17

” (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 CO2 analyzer. Call Bosch Water Heating through

thermotechnology corp.

for conversion instructions.

Bosch

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

• 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 ≤ 40 Ng/J

Joule of heat output).

(Nanograms of NOx (calculated as NO2) per

• CO ≤ 250 ppm (measured)

• CO

level set from factory, see chapter 6.4.

Water protection

IP X4 (protection against water drops)

If appliance is installed at elevations above 2000ft, refer to section 3.3.6 Fan speed adjustment.

6 720 608 542

Page 6

Appliance details

2.3 Unpacking the 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 Serial number B Type of gas

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.

The box includes:

• GWH 2700 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 2700 ES is not approved or designed for:

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

• Use above 8000 ft A.S.L. altitude (see page 18)

• Outdoor installation without installation of Outdoor kit (AQOK)

• Space heating purposes

• Preheated inlet water supply.

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

6 720 608 542

Page 7

2.4 General rules to follow for safe operation

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 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

(

page 20

B 4. You must vent your heater. See

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.

3.5

(

3.3 (page 9

page 21

) and

chapter 3.3

). If the

3.4

Appliance details

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

6 720 608 542

Page 8

Appliance details

6720608158-04.2AL

res et

5 ¼"

30 ½"

17 "

5 ¼"

11 ¼"

2 ¾"

6 ½"

2 "

5 ¼"

2 "

4 "

6 "

2.5 Dimensions and Minimum installation clearances

Fig. 6 Dimensions

1 On/Off button 2 Reset button 3 Program key 4 Power ON or stand-by LED 5 LCD display 6 Up button 7 Down button

Fig. 7 Minimum clearances

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

TOP (A) 12”

FRONT (B) 1”

BACK 0”

SIDES 1”

FLOOR (C) 12”

Table 1 Minimum clearances

Model GWH 2700 ES

6 720 608 542

Page 9

3 Installation instructions

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

• 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: 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.

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 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

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

Diam. Material

Exhaust Vent

3 or 4 inches Sealed single wall stainless steel

(AL29-4C)

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.

6 720 608 542

Intake Vent

Table 2 Venting Specifications

3 or 4 inches Sealed PVC or any other rigid pipe

Page 10

Installation instructions

6720608782-09.1Av

6720608782-10.1Av

12"

6720608782-11.1Av

Min. 3 Feet

3” stainless steel pipe

Horizontal venting systems only:

An optional stainless concentric vent/air intake termination can be used to provide only one penetration point through the exterior wall (see Fig. 8, 9 & 10). The concentric vent/air intake kit can be ordered from your local wholesaler. (Part# ESHCK). Note: Vent piping and

terminal used with concentric vent/air intake kit must be from the same vent pipe manufacturer. The appliance can also be installed with separate air intake and exhaust piping (see Fig. 15

Fig. 8 Concentric kit part # ESHCK

3.3.2 Venting Specifications

Install appliance as close to point of vent termination as possible. The exhaust piping must vent directly to the outside of the structure. Horizontal sections of vent must pitch upward 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 other than the termination. Note: Listed thimbles or collars are necessary where venting passes through wall and ceiling partitions. If the vent system passes through combustible areas where the vent clearance requirements cannot be maintained, it is permissible to chase straight sections of sea led 3 inch single wall vent through 4 inch (or greater) T ype-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.

Fig. 9 Concentric kit vent assembly

3”

VENTING

3 or 4"

90° elbow

3”

Horizontal

Terminal

3” Vertical

Terminal

Z flex Protech Heat Fab

2SVEEWCF0390 FSELB9003 9314

2SVSTB03 FSTB3 9390 TEE

2SVSRCF03 FSRC3 5300CI

Table 3 Terminator Part Numbers

Fittings or Piping Equivalent

feet m

45 degree elbow 1.25 0.38

90 degree elbow 2.5 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

Fig. 10 Concentric kit installation

ProTech Industries www.protechinfo.com

800-766-3473

Heat-Fab www.heatfab.com

800-772-0739

Table 5 Vent manufacturers

6 720 608 542

Page 11

Installation instructions

Condensate drain requirements

An external condensate drain (not supplied with the heater) must be installed under the following conditions:

• All vertical terminating vent installations.

• Horizontal terminating vent installations where the

total linear vent length is greater than 10 feet (3.1 m).

• Vent installations where any section of the exhaust

vent pipe passes through an unconditionedspace.

Twin pipe termination clearances

The minimum clearance between exhaust vent and combustion air inlet terminations for twin pipe penetration is 3 feet.

Minimum combustion air and exhaust pipe length

The minimum exhaust pipe length is 3 feet (1m) of straight vent pipe. The minimum combustion air pipe length is one 90° elbow.

Maximum combustion air and exhaust pipe length

The following table (Table 6) displays the maximum allowable straight pipe lengths for combustion air and exhaust piping with consideration to the number of elbows used.

Air intake or

Exhaust

system

0 N/A* 26 21 16 11

1 N/A* 23 18 13 8

2 23 20 15 10 5

# of 45°

elbows

3 20 17 12 7 N/A**

4 17 14 9 4 N/A**

5 14 11 6 N/A** N/A**

6 11 8 3 N/A** N/A**

0 1 2 3 4

Maximum allowable straight pipe length (ft)

# of 90° elbows

Table 6 Maximum allowable straight pipe length

* Not allowed. At least one 90º elbow required. ** Not allowed. Minimum of 3 feet (1m) of straight pipe required.

Note: 90° elbows used for terminations should not be counted in the exhaust and combustion air piping.

Step 1: Total the number of 90° elbows and 45°

elbows used on the exhaust piping.

Step 2: Use this value in the table to determine the

maximum straight exhaust pipe length allowed.

Step 3: Total the number of 90° elbows and 45°

elbows used on the combustion air piping.

Step 4: Use this value in the table to determine the

maximum straight combustion air pipe length allowed.

6 720 608 542

Page 12

Installation instructions

6720608836-23.1Av

Required direct vent terminal clearances (twin pipe / concentric penetration)

Fig. 11

Canadian installations

A Clearance above grade, veranda, porch, deck or balcony 12 in. 12 in.

B Clearance to window or door that may be opened 36 in. 12 in.

C Clearance to permanently closed window * *

D Vertical clearance to ventilated soffit located above the vent

terminator within a horizontal distance of 2 feet (61cm) from the center line of the terminator

E Clearance to unventilated soffit * *

F Clearance to outside corner * *

G Clearance to inside corner * *

H Clearance to each side of center line extended above meter/

regulator assembly

I Clearance to service regulator vent outlet 36 in. *

J Clearance to non-mechanical air supply inlet to building or the

combustion air inlet to any other application

K Clearance to mechanical air supply inlet 72 in. 36 in. above if within 10 feet

L Clearance above paved sidewalk or paved driveway located on

public property

M Clearance under veranda, porch deck or balcony 12 in.

36 in. within a height 15 feet above

meter/ regulator assembly

* *

36 in. 12 in.

84 in.

U.S. installations

horizontally

Table 7

1) In accordance with the current CSA B149.1 Natural Gas and Propane Installation Code

2) In accordance with the current ANSI Z223.1 / NFPA 54 National Fuel Gas Code

3) A vent shall not terminate directly above a sidewalk or paved driveway that is located between two single family dwellings and serves both dwellings.

4) Permitted only if veranda, porch, deck or balcony is fully open on a minimum of two sides beneath the floor.

* For clearances not specified in ANSI Z223.1 / NFPA 54 or CSA-B149.1, one of the following shall be indicated:

a) A minimum clearance value determined by testing in accordance with section 2.20, or; b) A reference to the following footnote: “Clearance in accordance with local installation codes and the requirements of the gas supplier.”

6 720 608 542

Page 13

Required other than direct vent terminal clearances (single pipe penetration)

6720608836-23.1Av

Installation instructions

Fig. 12

Canadian installations

A Clearance above grade, veranda, porch, deck or balcony 12 in. 12 in.

B Clearance to window or door that may be opened 36 in. 4 feet below or to side of opening;

C Clearance to permanently closed window * *

D Vertical clearance to ventilated soffit located above the vent

terminator within a horizontal distance of 2 feet (61cm) from the center line of the terminator

E Clearance to unventilated soffit * *

F Clearance to outside corner * *

G Clearance to inside corner * *

H Clearance to each side of center line extended above meter/

regulator assembly

I Clearance to service regulator vent outlet 36 in. *

J Clearance to non-mechanical air supply inlet to building or the

combustion air inlet to any other application

K Clearance to mechanical air supply inlet 72 in. 36 in. above if within 10 feet

L Clearance above paved sidewalk or paved driveway located on

public property

M Clearance under veranda, porch deck or balcony 12 in.

36 in. within a height 15 feet above

meter/ regulator assembly

* *

36 in. 4 feet below or to side of opening;

84 in.

U.S. installations

1 foot above opening

horizontally

84 in.

Table 8

1) In accordance with the current CSA B149.1 Natural Gas and Propane Installation Code

2) In accordance with the current ANSI Z223.1 / NFPA 54 National Fuel Gas Code

3) A vent shall not terminate directly above a sidewalk or paved driveway that is located between two single family dwellings and serves both dwellings.

4) Permitted only if veranda, porch, deck or balcony is fully open on a minimum of two sides beneath the floor.

* For clearances not specified in ANSI Z223.1 / NFPA 54 or CSA-B149.1, one of the following shall be indicated:

6 720 608 542

Page 14

Installation instructions

6720608542-02.2AL

HORIZONTAL RUN

1/4" PERFOOT

DOWN TO

TERMINATOR.

CONDENSATE

DRAIN

12"

6720608782-11.1Av

Min. 3 Feet

3” stainless steel pipe

6720608542-05.2AL

26ft

FIRESTOP SUPPORT

ELBOW

APPLIANCE

HOSE CLAMP

RAINCAP

STORMCOLLAR

FLASHING

FIRESTOP SUPPORT

4"MIN.

AIRSPACE

6720608158-91.2Av

CONDENSATE

DRAIN

2'MIN.

10'MIN.

3'MIN.

3.3.3 Venting configuration examples

Below are approved examples of horizontal venting installations.

Fig. 13 Horizontal side wall venting installation (single

pipe penetration)*

* Warning: for non-freezing climates only! 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. 15 Horizontal twin pipe penetration

Below are approved examples of vertical venting installations.

Important:

Note: Pitch horizontal runs down toward the heater, 1/4" per foot.

Fig. 14 Horizontal venting installation (concentric

penetration)

Fig. 16 Vertical venting installation (single pipe pene-

tration)*

* Warning: for non-freezing climates only!

6 720 608 542

Page 15

Installation instructions

CHIMNEY

MORTAR

HANGERSTRAP

HORIZONTAL RUN 1/4"RISE/FT

ELBOW

APPLIANCE

MAY BEINSULATED IFNECESSARY

6720608158-14.2AL

HOSE CLAMP

ELBOW

RAINCAP

STORMCOLLAR

SILICONESEAL

FLASHING

CONDENSATE

DRAIN

2'MIN.

10'MIN.

3'MIN.

3.3.4 Vent connections

B Attach the flue gas exhaust accessory (8 705 504

162) 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).

NOTE: Vent pipe must be completely vertical when inserting or gasket inside exhaust accessory can become displaced. Exhaust accessory can be removed with vent pipe attached to check gasket position.

Fig. 17 Vertical venting installation (twin pipe penetra-

tion)

Fig. 19

B Attach the combustion air inlet accessory (8 705

504 116) 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. 18 Vertical venting installation - Masonry Chim-

6 720 608 542

ney (combustion air piping not shown)

Fig. 20

B Ensure that exhaust vent pipe is fully inserted in collar

to enable proper connection.

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

Page 16

Installation instructions

RAIN CAP

STORM COLLAR

FLASHING

4" MIN.

AIR SPACE

CONDENSATE

APPLIANCE

6720608782-04.2Av

ELBOW

FIRESTOP SUPPORT

DRAIN TRAP TO DRAIN - DISPOSE

OF CONDENSATE ACCORDING TO LOCAL CODES

DRAIN TEE

2'MIN.

10'MIN.

3'MIN.

3.3.5 Condensate drain installation 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 silicone 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.

Fig. 21 Condensate drain installation (combustion air

3" Venting Z-flex ProTech Heat Fab

90° Condensate Drain Tee

Horizontal Condensate Drain

Condensate Drain Tube

Table 9 Approved Condensate Drain Part Numbers

piping not shown)

2SVEVWCF03 FST3 &

2SVEDWCF03 FSHDT3 9321

2SVEDTK24 N/A 7000TUBE

93PPLSTEE

FSDF3

6 720 608 542

Page 17

Installation instructions

3.3.6 Fan speed adjustment

IMPORTANT! Installation adjustment:

After installing the water heater, the fan speed values for minimum power (P2) and maximum power (P1) may need adjustment due to variations in altitude and vent pipe length. Failure to make necessary adjustments to fan speed values may result in improper operation of the appliance.

First calculate the total equivalent vent length. Use this value to determine the appropriate fan speed values, found in Table 12 and make any necessary adjustments. After changing fan speed values proceed to Section 6.4 to confirm CO2 values are within specified ranges.

Total equivalent vent length calculation

B Determine the total length of all straight sections of

vent pipe and enter in table 10, line 1.

B Count the number of 90° elbows used and enter that

value in line 2. (Do not count terminals and first elbow used on intake and exhaust).

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 10.

B Add line 4 from Exhaust to line 4 of Intake and enter

result in line 5. This is the total equivalent vent length.

Example

Exhaust

• 7 - 3' straight sections

• 1 - 1' straight section = Total straight pipe length 22’

• 2 - 90° elbow.

Intake

• 5 - 3' straight sections =

Total straight pipe length 15’

• 1 - 90° elbows.

Example

Exhaust

Straight section length (feet)

90° elbows (qty) 1 x 2.5 = 2.5

45° elbows (qty) 0 x 1.25 = 0

Total: 24.5

Intake

Straight section length (feet)

90° elbows (qty) 1 x 2.5 = 0

45° elbows (qty) 0 x 1.25 = 0

22 x 1 = 22

15 x 1 = 15

Exhaust

Straight section length

__ x 1 =

____

(feet)

90° elbows (qty) __ x 2.5 =

45° elbows (qty) __ x 1.25 =

4 Total:

____

Intake

Straight section length __ x 1 =

90° elbows (qty) __ x 2.5 =

45° elbows (qty) __ x 1.25 =

Total equivalent vent length =

Total:

____

Table 10 Determining vent length combination (see

example in Table 11)

Total: 15

Total equivalent vent length = 39.5

Table 11 Determining vent length combination exam-

ple

Note: Do not count terminals and first elbow used on intake and exhaust.

Total equivalent length must not to exceed 57ft.

NOTE: If using concentric terminal include exhaust pipe length that is part of the concentric terminal.

6 720 608 542

Page 18

Installation instructions

Natural Gas Liquid propane

Altitude

(above sea

level)

0 - 2000 ft

(0 - 610 m)

2000 - 4500 ft

(610 - 1372 m)

4500 - 8000 ft

(1372 - 2439 m)

* Above 2000 ft, CO2 levels must be checked with a combustion gas analyzer, see section

Total

equivalent

vent length

5.5 - 32 ft

33 - 57 ft

5.5 - 32 ft 8* 48* 47*

33 - 57 ft 8* 49* 48*

5.5 - 32 ft 9* 49*

33 - 57 ft 9* 50* 49*

Minimum

power fan

speed (P2)

Maximum

power fan speed

(P1)

modification required

power fan speed

modification required

Maximum

(P1)

Table 12 Fan speed adjustment

1) Full equivalent length (inlet + outlet piping + fittings)

Adjusting minimum power fan speed (P2)

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.

Adjusting maximum power fan speed (P1)

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.

48*

6.4

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

for instructions.

level

Fig. 22

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 12.

B Press and hold (± 5 sec.) “Program” button until

the display flashes, then the selected value is memorized.

Fig. 23

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

ton , and the display reads P2.

B Press the minus button to display P1. B Press “Program” button to enter P1 adjustment.

The current setting will appear on the display.

B Press or to choose the fan speed suitable

with your installation, see Table 12.

B Press and hold (± 5 sec.) “Program” button until

Do not set P2 to greater then 9.

the display flashes, then the selected value is memorized.

Proceed directly to Section 6.4 to confirm CO2 values are within range.

6 720 608 542

Page 19

Installation instructions

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

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.

6 720 608 542

Page 20

Installation instructions

3.4 Combustion air requirements

Warning: In areas where outside

temperatures routinely come close to freezing, sealed combustion operation is required. Use twin pipe or concentric terminations for combustion air and exhaust, 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 (e.g. hair salons, car washes) are present the twin pipe system is required.

Twin pipe and Concentric pipe

The water heater is designed as a sealed combustion appliance. It is recommended that the combustion air be provided from the outside by a dedicated pipe (twin pipe) or by connecting to the concentric vent kit (see Fig. 8, 9 & 10). The combustion air pipe may be PVC or any other rigid sealed 3" or 4" pipe. Horizontal sections of the combustion air pipe must pitch down towards termination 1/4" per foot to prevent rain water from entering the appliance. When using the twin pipe method, 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. 11 and Fig. 12 Letter I, page 12. For the maximum length of the combustion air inlet pipe, see table 6.

Warning: Vent terminations must

prevent rain from entering the combustion air and exhaust vent piping.

Single pipe Note: This appliance requires 9950 cubic feet of

available combustion air, or a minimum of 1243 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

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.

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.

6 720 608 542

Page 21

Installation instructions

Studs 16"

(406mm) on

center

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 32 “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.

3.7 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 6.

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.

Warning: In areas where outside temperature is routinely below 32°F and the heater is to be installed on the inside of an exterior wall, a minimum 2" air gap or rigid insulation between the heater back and the wall is recommended.

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. 24.

3.6 Heater placement and clearances

The water heater 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. See Fig. 7 and Table 1 on page 8.

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 9) Venting.

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. 25).

B Hang the appliance on the bracket, see Fig. 26.

Fig. 24 Distance between support boards

6 720 608 542

Page 22

Installation instructions

6720608158-64.1AL

6720608158-05.1AL6720608158-05.1AL

Gas supply

Cap

Minimum

3”

Fig. 25 Leveling the mounting bracket on the studs

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 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.

Fig. 26 Mounting the heater

Warning: Appliance must be installed vertically.

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. 27.

Fig. 27 Gas connection (drip leg)

6 720 608 542

Page 23

Once connections are made, check for gas leaks at all

Gas piping

Inlet gas particle screen (included)

joints. Apply some gas leak detection solution to all gas fittings. Bubbles are a sign of a leak. A combustible gas detector may also be used to detect for leaks.

Danger: If you have a leak, shut off the gas. 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. 29, page 24 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 27 for the procedure to confirm gas pressure. Proper gas pressure must be confirmed at time of installation.

Installation instructions

Fig. 28

6 720 608 542

Page 24

Installation instructions

Follow boxed numbers for piping just one GWH 2700 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.

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

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

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 Length of Black iron Pipe , Feet Pipe Internal

Size, Diameter

inches inches 10 20 30 40 50 60 70 80 90 100 125 150 175 200

1/4 0.364 32 22 18 15 14 12 11 11 10 9 8 8 7 6

3/8 0.493 72 49 40 34 30 27 25 23 22 21 18 17 15 14

1/2 0.622 132 92 73 63 56 50 46 43 40 38 34 31 28 26

3/4 0.824 278 190 152 130 115 105 96 90 84 79 72 64 59 55

1 1.049 520 350 285 245 215 195 180 170 160 150 130 120 110 100

1 1/4 1.380 1050 730 590 500 440 400 370 350 320 305 275 250 225 210

1 1/2 1.610 1600 1100 890 760 670 610 560 530 490 460 410 380 350 320

2 2.067 3050 2100 1650 1450 1270 1150 1050 990 930 870 780 710 650 610

Tube size, inches EHD*

10 20 30 40 50 60

1/2

18 EHD

82 58 47 41 37 34

3/4

23 EHD

161 116 96 83 75 68

30 EHD

330 231 188 162 144 131

1 1/4

37 EHD

639 456 374 325 292 267

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

Nominal

iron

Black Iron Pipe

pipe

Length of Pipe, Feet

Inches

10 20 30 40 50 60 80 100 125 150 200

1/2 291 200 160 137 122 110 94 84 74 67 58

3/4 608 418 336 287 255 231 197 175 155 140 120

1 1145 787 632 541 480 434 372 330 292 265 227

Copper

Outside Length of Tubing, Feet diameter Inch 10 20 30 40 50 60 70 80 90 100

3/8 39 26 21 19 _ _ _ _ _ _

1/2 92 62 50 41 37 35 31 29 27 26

5/8 199 131 107 90 79 72 67 62 59 55

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

Tube size inches EHD*

1020304050

1/2 18 EHD 129 91 74 64 58 53

3/4 23 EHD 254 183 151 131 118 107

1 30 EHD 521 365 297 256 227 207

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

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.

Fig. 29

6 720 608 542

Page 25

Installation instructions

HOT

COLD

3.9 Water connections

Warning: This heater is not approved

for preheated water applications. See chapter 3.11 for approved recirculating application.

Warning:

In applications where inlet water temperature can exceed 140°F (60ºC), a 3-way valve or mixing valve must be installed before the appliance to prevent water exceeding 140°F (60°C) from entering the appliance.

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.

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. 31).

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 consulting a local water treatment professional for water softening/ conditioning options.

Description Max. Levels

pH pH 6.5 - 8.5

Fig. 30

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

TDS (total Dissolved Solids)

Total hardness mg/l or ppm

Aluminum mg/l or ppm 2.0

Chlorides mg/l or ppm 250

Copper mg/l or ppm 1.0

Iron mg/l or ppm 0.3

Manganese mg/l or ppm 0.05

Zinc mg/l or ppm 5.0

Table 13

mg/l or ppm 500

100

(6 grains)

6 720 608 542

Page 26

Installation instructions

6720608158-77.1AL

Ariston Minitank

GWH

2700

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. 31. 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 Domestic hot water recirculation

Although recirculation directly through the tankless water heater is allowed, temperature stability is improved by recirculating through a mini-tank as shown in Fig. 32. By using the design in Fig. 32, there is no recirculation of hot water through the tankless water heater and therefore, does not affect the heat exchanger warranty. Direct recirculation through the tankless water heater is permissible, however, the heat exchanger warranty is reduced; contact Bosch Thermotechnology for further installation requirements. The following drawing is provided to outline one possible recirculation design using the water heater in conjunction with an Ariston mini tank water heater. 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.

Fig. 31 Plumbing Connections (with shutoff valves)

and Pressure Relief Valve

1 Water filter

Fig. 32 Recirculation application

1 Full port isolation valve 2 Circulator (pump) 3 Check valve 4 PRV 5 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 Thermotechnology if further information is needed.

6 720 608 542

Page 27

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. 34).

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 15.

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 15.

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 22.

Fig. 34 Gas pressure test port (left tapping)

Fig. 33

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

Static Gas Pressure Reading (see Chapter 3.12)

enter here: ___________________ Date: ___________

Operating Gas Pressure Reading (see Chapter 3.12)

enter here: ___________________ Date: ___________

Table 15

3.5” WC 8” WC

Table 14 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.

6 720 608 542

Page 28

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 water heater requires an electrical power supply from a 120VAC / 60Hz properly rated receptacle and must be properly grounded. The heater is wired as shown in the wiring diagram (chapter 9, Fig. 59).

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. 36

B Pull control unit free to access and remove the six

screws from the back cover of the control unit, see Fig. 37, pos. 2.

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

37, pos. 3.

Fig. 35 Connecting power supply cord

1 Power cord length: 3ft.

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

Fig. 37 Location of fuses

B After verifying the fuses mount all parts in reverse

order.

6 720 608 542

Page 29

5 Operation instructions

Fig. 38

1 On/Off button 2 Reset button 3 Program Key 4 LCD display 5 Up button 6 Down button 7 LED - Power On indicator or Stand-by

Operation instructions

5.1 LCD Display functions

Warning: Do not use any cleaning or

corrosive agent to clean the window.

Fig. 39 Power bar indicator

Fig. 42 Lock indicator

Fig. 43 Flame indicator

Fig. 44 Remote control

Fig. 40 Temperature indicator

Fig. 41 Error indicator

6 720 608 542

Page 30

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.

5.4 Temperature selection

To select output water temperature:

B Press buttons or in order to reach desired

temperature.

Fig. 46

Setting the water temperature

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

5.3 Power

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

Fig. 45

Off

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

again.

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).

6 720 608 542

Page 31

5.5 Use of optional remote control

accessory (part no. TSTAT2)

Operation instructions

Fig. 50 Reset button

If the problem persists, contact your installer.

5.8 Program button

Fig. 47 Remote control

The wireless remote control accessory (Fig. 71, 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. 71, component 16) is required when programming the remote control with this heater.

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

B LCD blinks until selected temperature is reached.

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. 51 “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

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

After following instructions indicated in “Troubleshooting” section.

B press reset button to return heater to normal

operation.

6 720 608 542

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. 52 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.

Page 32

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.

Annual maintenance table

Every year

1. Inspect venting system X

2. Inspect combustion chamber X

3. Inspect burner X

4. Inspect condensate trap X

Pressure relief valve

• Manually open the pressure relief valve to ensure proper operation.

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. 53, page 32). Close installer supplied cold water shutoff and loosen slotted screw on inlet fitting. Water will drain from the appliance. Remove cylindrical filter inside.

5. Inspect water filter X

Table 16 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. 64, #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. 53 Water filter

1 Inlet water filter 2 Water filter

Descaling

• In areas where the water supply has a high mineral content (see Table 13, page 25), 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 scale 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

6 720 608 542

Page 33

Maintenance and service

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 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.

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.

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. 54).

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.".

Fig. 54

6.4 Adjusting CO2 (carbon dioxide)

The CO2 can only be adjusted by a certified gas technician with a calibrated CO2 analyzer.

Caution: One factor that may affect

CO2 levels is improper gas pressure. Please see Chapter 3.12 for the procedure to measure gas pressure and record your findings below:

6 720 608 542

Page 34

Maintenance and service

Static Gas Pressure: “ WC

P1 Operating Pressure: “ WC

The P1 minimum operating gas pressure is 3.5" WC for Natural Gas and 8" WC for Propane. Do not proceed in adjusting CO

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. 55.

B Insert CO2 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.

B Record the CO2 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 CO2 reading in P1 and P2 below. P2 CO2 Reading: % CO

P1 CO2 Reading: % CO

C. Adjusting CO2: Note: P1 adjustment will change the P2 reading.

Confirm the P1 value BEFORE adjusting the P2 level.

1. If P1 CO2 level is off: B Loosen yellow painted philips screw (1) and cover

should rotate down (2) revealing a recessed brass slotted screw. Fig. 57.

B Turning the slotted screw counter clockwise will

raise P1 CO2 levels and clockwise will lower P1 CO2 levels. Adjustments to the slotted screw will also change P2 CO2 levels.

B After bringing the P1 CO2 readings in proper range,

press the button to enter the P2 mode. Verify CO2 readings in P2 mode.

Fig. 55 Measuring port

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

ON/OFF button to turn ON the heater (see Fig. 56). 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. 56

B. Measuring CO2 (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.

2. If P2 CO2 level is off: B Remove yellow painted #40 Torx cover from the front

of the gas valve. (Fig. 58) A plastic #40 Torx screw will be revealed.

B Turning the plastic #40 Torx screw counter

clockwise will lower P2 CO2 levels and clockwise will raise P2 CO2 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 CO2 readings are within the ranges specified in table 17. Repeat steps 1 and 2 as necesssary until CO2 values are within the specified ranges.

4. Once CO2 values are within the specified ranges, verify the CO readings on P1 and P2 do not exceed values shown in table 17. If values exceed this limit, inspect vent system and fin coils (chapter 6.1, page 32) for blockage.

D. Returning to Service:

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

2. Reinstall Torx cover.

3. Remove CO2 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.

6 720 608 542

Page 35

Max. CO

6720608158-38.1AL

CO2 range (%)

level

(measured)

Nat. Gas

max. input P1 7.5 % - 8.1 % < 250 ppm

min. input P2 2.3 % - 2.6 % < 60 ppm

LP Gas

max. input P1 8.7 % - 9.3 % < 250 ppm

min. input P2 2.7 % - 3.0 % < 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 CO2 values. Changes in these inputs can result in different CO and CO2 values on the same appliance.

Table 17 CO2 & CO target numbers

Final Readings

P2 CO2 Reading: % CO

Maintenance and service

P1 CO2 Reading: % CO

Fig. 57 Adjusting P1 CO2 level

Fig. 58 Adjusting P2 CO2 level

6 720 608 542

Page 36

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.

Program Description Factory Default MIN MAX Comment

P1 Maximum Power NG: 48, LP: 46 21 NG: 50, LP: 49 see chapter 3.12, page 27.

P2 Minimum Power 7 7 20 see chapter 3.3.6, page 17

P3 Remote Con-

trols installed

P4 Access to Diag-

nostic Mode

P5 Cascade Mode NO NO CC contact Bosch for details

_0 _0 6 see chapter 5.5, page 31

E 0d 10f see chapter 6.6, page 37

Refer to chapter 6.6 Control board diagnostics (page

37) regarding how to access these P-modes.

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

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

P6 Temperature

Unit

P7 Appliance Type NO Cd NO Condensing / Non-condensing*

P8 Back light dE dE ON dE turns back light off after 60

P9 Fan Purge runs secondary and primary fan

Table 18 Program values, factory default settings and ranges.

* Incorrect setting causes errors.

°F °F °C

seconds from last button pushed, ON turns backlight on permanently

when P9 is selected by depressing the “P” - button

6 720 608 542

Page 37

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 ' ' button once again and the display should read P4.

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 Set-point temperature (°F)

1d Inlet water temperature (°F)

2d Outlet water temperature (°F)

3d Water flow (gallons/min)

4d Gas type (LP or NG)

5d Fan speed (Hz)

6d Burner power (%)

7d Maximum power (kW)

8d Back flow temperature (°F)

9d Flue gas temperature (°F)

not used, settting 00

1F Most recent error/failure

2F 2nd most recent error

3F 3rd most recent error

4F 4th most recent error

5F 5th most recent error

6F 6th most recent error

7F 7th most recent error

8F 8th most recent error

9F 9th most recent error

10F 10th most recent error

Table 19

1) Available only on model GWH C800 ES

6 720 608 542

Page 38

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 28 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. 30, page 25.

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 32.

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 49 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 30.

2. Clean inlet filter screen per chapter 6.1, page 32.

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 6 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 33 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 30.

2. Clean inlet filter screen. See chapter 6.1, page 32.

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 6 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 27. 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

6 720 608 542

Page 39

Troubleshooting

heater. Then open all of the hot water taps served by 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 27. 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 32.

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 32 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 4060 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 9.

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 20, 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.

6 720 608 542

Page 40

Troubleshooting

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

) to be

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 27 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 CO2 readings per chapter 6.4, page

33. CO2 adjustments must be done by a certified gas technician with a calibrated combustion gas analyzer.

6 720 608 542

Page 41

8 Problem solving

8.1 Error code diagnostics

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

Display Cause Solution

Fault in the flue gas limiter. 1. Check continuity of the flue gas limiter (see Fig.64, page49).

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 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.

Problem solving

3.3

Table 20

Appliance selection on “P7” mode is not correct.

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

Outlet temperature sensor fault (Temperature below freezing or above 210°F).

* By installer or service technician only.

1. Check “P7” mode: water heater requires setting “NC”.

2. Check jumper and connection on sensor at upper right hand corner of heat exchanger.

3. Measure jumper resistance, must be 115-125 ohms.

1. Check backflow temperature sensor connection and resistance. See

Fig. 62, page 47

2. Replace backflow temperature sensor.

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.64, page

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.

and

Fig. 64

, page49.

49.

6 720 608 542

Page 42

Problem solving

Display Cause Solution

(Flashing) Outlet temperature sensor not

sensing expected output temperature.

Primary fan rotation too low on operation.

No rotational speed sensor signal from primary fan.

1. Check that the sensor is firmly attached to the hot water pipe (see Fig.70, page55).

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.71, page56).

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.71, page56).

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.

(Flashing) Water flow signal over specified

maximum value. Water flow > 10 gallon/min.

Internal hardware/software failure. 1. Disconnect power supply cord and check the two wire and

Table 20

* By installer or service technician only.

1. Disconnect power supply cord and check wire connections on water valve and the two connectors on the control board (see Fig.71, page56).

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

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.

6 720 608 542

Page 43

Display Cause Solution

Problem solving

Over-temperature detected by outlet temperature sensor on hot water pipe. Temperature > 185°F

Cold water temperature sensor fault.

Backflow temperature sensor over 309°F. The appliance will close the burner and lock.

1. Check that the sensor is firmly attached to the vertical section of the hot water pipe (see Fig.70, page55).

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

3. Clean inlet filter screen per chapter 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.

1. Check connector on wires coming from top of watervalve for a secure connection. See Fig.64, page

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.

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

6.2, page 32

49.

Fig. 62, page 47

Fig. 60, page

and clear any

6.3, page 32

for

Table 20

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

* By installer or service technician only.

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.64, page

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

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.

chapter 6.3

49.

6 720 608 542

Page 44

Problem solving

Display Cause Solution

No flame ionization detected with water flow.

Ionization failure during operation. 1. Check gas type, see

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

2. Check gas type, see

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

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

Check that the minimum power fan speed has been adjusted to

the proper value. See page

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 CO2 readings per

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.

Check that the minimum power fan speed has been adjusted to

the proper value. See page

5. Check gas pressure, see

6. Check and adjust CO2 readings, see

Fig. 2, page 6

chapter 3.12, page 27

18.

section 6.4

Fig. 2, page 6

18. section 3.12, page 27

section 6.4, page 33.

Table 20

Ionization error at standby. 1. Loose connection to the flame ionization rod. Verify that the

Gas leakage error, gas valve circuit not closing properly.

* By installer or service technician only.

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.64, page

2. Flame ionization rod or control unit may be damaged. Contact Bosch Water Heating for further instruction.

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 instruction.

49.

6 720 608 542

Page 45

9 Electrical diagram

20...1

16...1

JP5

JP6

JP7

JP8

JP2

T=104°C T=220°F

T=110°C T=230°F

Casc. input

Casc. output

Backflow

6720608542-04.1AL

Electrical diagram

Fig. 59 Electrical scheme

1 Intlet water temperature sensor 2 Outlet water temperature sensor 3 Backflow temperature sensor 4 Cascading output connection 5 Cascading input connection 6 Ionization sensor 7 Water flow sensor 8 Flue gas limiter 9 Heat exchanger overheat sensor (ECO) 10 Gas valve 11 Jumper resistance 12 Water valve 13 Primary fan 14 ON/OFF switch 15 Secondary fan 16 AC plug 17 Main connection 18 Ignition electrodes 19 Ground post 20 Antifreeze kit connection 21 Fuse 22 Fuse

6 720 608 542

Page 46

Sensor resistance charts

Outlet temperature sensor characteristics

3 2

3 7

4 2

4 7

6 2

6 7

8 2

8 7

9 2

9 7

10 2

107

112

117

12 2

127

13 2

137

14 2

147

152

157

16 2

167

172

177

18 2

187

19 2

197

2 02

2 07

2 12

2 17

2 22

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 2 0 2 1 2 2 2 3 24 25 26 2 7 2 8 29 3 0 3 1 3 2 33 3 4 3 5 3 6 37

Resistance (Kohm)

Temp ºF

2 0

2 5

3 0

3 5

4 0

4 5

6 0

6 5

8 0

8 5

9 0

9 5

10 0

10 5

110

Temp ºC

Inlet temperature sensor characteristics

3 2

3 7

4 2

4 7

6 2

6 7

8 2

8 7

9 2

9 7

102

107

112

117

122

127

132

137

142

147

152

157

162

167

172

177

182

187

192

197

2 02

2 07

2 12

2 17

2 22

2 27

2 32

2 37

2 42

2 47

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 2 3 24

Resistance (Kohm)

Temp ºF

2 0

2 5

3 0

3 5

4 0

4 5

6 0

6 5

8 0

8 5

9 0

9 5

100

105

110

115

120

Temp ºC

10 Sensor resistance charts

Fig. 60

Fig. 61

6 720 608 542

Page 47

Sensor resistance charts

Back Flow characteristics

102

107

112

117

122

127

132

137

142

147

152

157

162

167

172

177

182

187

192

197

20 2

20 7

212

217

22 2

22 7

23 2

23 7

24 2

24 7

25 2

25 7

26 2

26 7

27 2

27 7

28 2

28 7

29 2

29 7

30 2

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 2 5 26 27 28 29 30 31 32 33 34 35 36 37

Resistance (Kohm)

Temp ºF

2 0

2 5

3 0

3 5

4 0

4 5

6 0

6 5

8 0

8 5

9 0

9 5

100

105

110

115

120

125

130

135

140

145

150

155

Temp ºC

Fig. 62

6 720 608 542

Page 48

GWH 2700 ES Functional scheme

11 GWH 2700 ES Functional scheme

Fig. 63 Functional scheme

6 720 608 542

Page 49

Interior components diagram and parts list

12 Interior components diagram and parts list

12.1 Interior components

Fig. 64 Components

1 Flue gas collector 2 Heat exchanger 3 Flame sensor 4 Primary fan (Mixer) 5 Outlet temperature sensor 6 LCD display 7 On/Off button 8 Reset button 9 Program key 10 Flue gas limiter 11 Heat exchanger overheat sensor (ECO)

6 720 608 542

12 Ignition electrodes 13 Observation window 14 Backflow temperature sensor 15 Secondary air fan 16 Gas valve 17 Water valve with engine and temperature sensor 18 Control unit 19 Up button 20 Down button 21 LED

Page 50

Interior components diagram and parts list

Fig. 65 Appliance overview

6 720 608 542

Page 51

12.2 Components diagram

6720902973.AA JF

12.2.1 Group 1

Interior components diagram and parts list

Fig. 66 Components Diagram

Item Description Reference

1 Front cover 8 705 431 286

2 Cover shield 8 705 506 862

3 Trade mark badge 8 701 103 140

4 Cover screw 8 703 401 170

5 Combustion cover 8 700 506 300

6 Combustion cover gasket 8 704 701 084

7 Observation window 8 705 600 003

8 Holding bracket 8 708 104 103

9 Screw 8 703 403 012

Table 21

Item Description Reference

10 Combustion cover clip 8 701 201 032

11 Grommet set 8 710 203 039

12 Exhaust accessory 8 705 504 162

13 Gasket exhaust 8 700 103 710

14 Inlet air cover 8 708 006 022

15 Inlet air gasket 8 700 103 166

16 Inlet air accessory 8 705 504 116

17 Mounting bracket 8 701 309 164

Table 21

6 720 608 542

Page 52

Interior components diagram and parts list

6720902974.AA JF

12.2.2 Group 2

Fig. 67 Components Diagram

Item Description Reference

1 Heat exchanger 8 705 406 422

2 Heat exchanger top gasket 8 704 701 052

3 Flue gas collector 8 705 700 153

4 Overheat sensor (ECO) 8 707 206 204

5 Heat exchanger bottom gasket 8 704 701 054

Table 22

Item Description Reference

6 Site window 8 701 000 401

7 Ignition group 8 701 302 249

8 Heat exchanger O-ring 8 700 205 147

9 Rubber grommet 8 710 303 027

Table 22

6 720 608 542

Page 53

12.2.3 Group 3

6720902975.AA JF

Interior components diagram and parts list

Fig. 68 Components Diagram

Item Description Reference

1 Main burner 8 708 120 699

2 Burner gasket 8 704 701 087

3 Primary fan 8 707 204 071

4 Backflow temperature sensor 8 707 206 459

5 Washer 8 704 701 097

6 Fan mount nut 2 915 011 006

7 Secondary fan - NG 8 707 204 094

7 Secondary fan - LPG 8 707 204 072

8 Screw 8 703 403 012

9 Gas / Air Mixer 8 705 700 170

Table 23

Item Description Reference

10 Air duct O-ring 8 700 205 149

11 Venturi 8 700 306 226

12 O-ring 8 700 205 224

13 Mixer / Fan gasket 8 704 701 059

14 Screw 2 910 642 150

15 Plate gasket 8 701 004 049

16 Air supply duct 8 705 700 155

17 Screw 2 910 952 122

Table 23

6 720 608 542

Page 54

Interior components diagram and parts list

6720608158-73.1AL

12.2.4 Group 4

Fig. 69 Components Diagram

Item Description Reference

1 Gas valve 8 707 021 019

2 Pressure tapping 8 703 404 219

3 Washer 8 700 203 041

4 Pressure balance tube 8 700 703 136

5 Pressure balance nut 8 703 300 041

6 Gas supply pipe 8 700 715 389

7 Gas valve washer 8 700 103 014

Table 24

Item Description Reference

8 Gas filter 8 700 507 002

9 Gasket 8 704 701 085

10 Gas / Fan connector 8 705 202 140

11 Washer 8 704 701 062

12 Regulation screw 8 703 404 220

13 O-ring 8 700 205 009

14 Screw 2 910 149 181

Table 24

6 720 608 542

Page 55

12.2.5 Group 5

Interior components diagram and parts list

Fig. 70 Components Diagram

Item Description Reference

1 Water valve with engine 8 708 505 024

2 O-ring 8 700 205 147

3 Cold water pipe 8 700 715 394

4 Pipe connection clip 8 701 201 028

5 Hot water pipe 8 700 715 469

6 Temperature sensor 8 700 400 015

7 Outlet fitting 8 703 305 349

8 Inlet / Outlet washer 8 710 103 045

9 Wireform spring 8 701 300 025

Table 25

6 720 608 542

Item Description Reference

10 Inlet fitting with filter 8 703 305 356

11 O-ring 8 700 205 157

12 Watervalve clip 8 716 102 607

13 Water filter 8 700 507 059

14 Washer 8 700 103 764

15 O-ring 8 700 205 231

Table 25

Page 56

Interior components diagram and parts list

6720902978.AA JF

12.2.6 Group 6

Fig. 71 Components Diagram

Item Description Reference

1 Control unit 8 707 207 257

2 Fuse T2.5A 1 904 521 342

3 Fuse T1.6A 8 700 609 008

4 Power supply cables 8 704 401 371

5 Power supply cord 8 704 401 378

6 Fan cables 8 704 401 347

7 Wire harness 8 704 401 348

8 Jumper 8 704 401 376

Table 26

Item Description Reference

9 Electrode cables 8 704 401 346

10 Flue gas limiter 8 700 400 032

11 Cascading kit (optional) 7 709 003 617

12 Anti freeze kit 7 709 003 665

13 Remote control (optional) 8 707 207 153

14 Shaped seal (optional) 8 700 201 012

15 Screw (optional) 8 703 401 109

16 Printed circuit transceiver (optional) 8 708 300 123

Table 26

6 720 608 542

Page 57

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.

Protecting the environment

6 720 608 542

Page 58

Limited Warranty

14 Limited Warranty

General

Aquastar water heaters are warranted by the Manufacturer (BOSCH) through Bosch Thermotechnology Corp.. 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 Corp. 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 Corp. will furnish a replacement heat exchanger. However, if the water heater is used within an approved hot water recirculation and supplied with circulated water, this heat exchanger warranty is limited to three (3) 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 properly install, operate or maintain the unit in 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 five (5) years after original installation and operation, Bosch Thermotechnology Corp. 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, installation or re-installation of the original water heater or a replaced water heater.

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 CORP. 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 Corp.. However, all replacements are made subject to validation by Bosch Thermotechnology Corp. 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 Corp.. It is expressly understood that the replacement warranty of Bosch Thermotechnology Corp. 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 Corp. 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 Corp. 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.

6 720 608 542

Page 59

Limited Warranty

6 720 608 542

Page 60

6720608542

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* Static__________ Operating__________

Building Water Pressure __________ Range if on Well system __________

Installing Company _____________________________________________

Installer name _____________________________________________

Address _____________________________________________

Phone _____________________________________________

* See Chapter 3.12, page 27 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 CORP.

50 Wentworth Avenue Londonderry, NH 03053 Tel. 866-330-2730 www.boschhotwater.com

Bosch Termotecnologia SA

Estrada de Cacia

3801 - 856 Aveiro - PORTUGAL

Bosch GWH 2700 ES LP, GWH 2700 ES NG User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual