(PDF 1.9 MB)

Applications manual

For tankless and point-of-use water heaters

2 |

Bosch applications manual

Bosch applications manual | 06.2009

BOSCH THERMOTECHNOLOGY CORPORATION

Bosch applications manual

Table of Contents

1 Introduction

2 Bosch Water Heating Model Certifi cations

3 Bosch Water Heater Accessories

4 Water Quality

5 Pump Sizing

5.1 Pressure drop curves

5.2 Domestic hot water circulation

5.3 Tank loading

6 Bosch Water Heating Models & Specifi cations

6.1 Sizing tankless water heaters

6.2 Outdoor Installation

6.3 Bosch gas tankless water heater specifi cations

6.4 Bosch electric tankless water heater specifi cations

2.5 Ariston electric mini-tank water heater specifi cations

7 Domestic Water Heating Applications

7.1 Point-of-use applications

7.2 Whole house applications

8 High Volume Potable Water Heating

8.1 Cascading unit applications

8.2 Parallel unit applications

9 Residential Solar Applications

9.1 Tankloading

9.2 Booster applications

10 Commercial Solar Applications

26

27

29

23

25

26

13

13

16

22

8

8

10

11

12

12

5

5

6

6

7

7

4

4

11 Commercial Water Heating Applications

11.1 Commercial kitchen applications

11.2 Basic tank loading with domestic recirculation

11.3 Advanced tank loading commercial hot water system

30

30

32

33

BOSCH THERMOTECHNOLOGY CORPORATION

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1 Introduction

Bosch applications manual

The Bosch Applications Manual is intended to present some of the most common applications of the Bosch line of tankless and point of use water heaters. Application drawings are shown with both piping and corresponding electrical schematics where applicable. Auxiliary equipment depicted does not necessarily represent any one manufacturer or specifi c model number. There are a wide variety of techniques, practices and piping strategies possible when installing water heating appliances. It is the responsibility of the installing contractor to determine the most suitable arrangement for the application.

All drawings are conceptual in nature and does not address

all design, installation or safety considerations. Additional

safety and/or auxiliary equipment may be needed.

Drawings are for reference use by offi cials, designers and licensed installers. It is expected that installers have adequate knowledge of accepted industry practices for the equipment, procedures, and applications involved. It is the responsibiltiy of the installer to ensure that the installation

is in accordance with local building codes.

Although this manual covers many common applications for our products, system possibilities are virtually endless. Should you encounter an application that is not covered in this manual or have any questions regarding any of its content, we encourage you to contact your local sales representative or us directly at Bosch

Thermotechnology .

Certifi ed by Underwriters Laboratories Inc.

Energy effi ciency certifi ed by Gas

Appliance Manufacturers Association

(GAMA), www.gamanet.org

For Models GWH C 920 ES, GWH C 920 ESC only

These models are built in accordance with the

requirements of the ASME Boiler and Pressure

Vessel Code and received the Certifi cate of

Authorization from the National Board. The heat

exchanger has the NB and the HLW stamps.

Plumbing-Heating-Cooling Contractors

Association

This manual is not a substitute for any of the product’s installation manuals. All specifi cations subject to change.

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: Installation must conform with CGA B149.(1,2)

INSTALLATION CODES and/or local installation codes.

2 Bosch Water Heating Model Certifi cations

Other certifi cations:

Met the California Energy Commission (CEC) standards

Approved by the Commonwealth of Massachusetts

South Coast Air Quality Management

The following are certifi cation stamps and explanations that are specifi c to one or more Bosch tankless water heaters. These certifi cations bring the appliances in accordance with the requirements of the National Fuel Gas Code ANSI Z223.1/NFPA 54.

Certifi ed to applicable U.S. standards for

appliances using gas or other petroleum fuel.

Certifi ed to applicable Canadian standards for

appliances using gas or other petroleum fuel.

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Bosch applications manual

3 Tankless Water Heater accessories

See Table 1 for available accessories for the Bosch line of tankless water heaters.

NOTE: Only models that have accessories available are listed in the table below.

Available accessories

Concentric Vent/air Intake kit - stainless steel (part# ESHCK )

Concentric termination kit - PVC (part# 196016)

Exhaust / intake bird screen (part# L2594)

Vertical vent kit (part# ESVVT)

Horizontal vent kit (part# 4TWHVK3SII)

Outdoor kit (part# PTOK)

Wireless remote control (part# TSTAT2)

Cascading kit (part# TLINK)

Freeze prevention kit (part# 7709003665)

External water fi lter (part# 8703305356)

Gas conversion kit (part# 8719002176)

PVC Condensate drain tee (part# 196061)*

Condensate neutralization cartridge kit (part# JM-2KIT)

* Also included in the Concentric termination kit (part# 196016)

4 Water Quality

Poor water quality will have an impact on appliance longevity and may void 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 specifi ed below, Bosch recommends consulting a local water treatment professional for water softening/conditioning options.

Water quality max. levels

Description pH

TDS (Total Dissolved Solids)

Total hardness

Aluminum

Chlorides

Copper

Iron

Manganese

Zinc

Table 2

Max. Levels

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

6.5 - 8.5

500

100 (6 grains)

2.0

250

1.0

0.3

0.05

5.0

715 ES

BOSCH THERMOTECHNOLOGY CORPORATION

C 800 ES

Table 1

C 920 ES/ESC

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70

60

50

40

30

20

10

0

0 .

0

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5 Pump sizing

The following section outlines sizing pumps for domestic hot water circulation and tank loading. Only models approved for such applications are listed in this section.

Pump must be bronze or stainless steel.

Size the pump according to the system pressure drop chart

below.

Maximum flow allowed through the recirc loop is 5 GPM.

If the water heater is used within an approved hot water

recirculation application and supplied with circulated

water, the heat exchanger warranty is decreased. Please

refer to the installation manual for detailed warranty

period information.

Run the system for 30 minutes to remove debris from the

plumbing. Then remove the unit‘s inlet water fi lter to

decrease pressure drop through the system.

If the inlet water fi lter, when removed, contains debris

install a Y-strainer (installer supplied) on the cold water

inlet.

5.1 Pressure drop curves

GWH C 800 ES GWH C 920 series GWH 715 ES

1 .

0 2 .

0

Flow (GPM)

3 .

0

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4 .

0

Bosch applications manual

5 .

0

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5.2 Domestic hot water circulation

Must provide a recirculation flow above 1.7 GPM. This can be verified in the control unit diagnostics section of the installation manual; mode P4 – 3d.

Note: The Grundfos model 15-55 has been tested and shown to work on recirculating systems up to 120 feet of total pipe length.

System conditions vary and each pump must be sized by a professional to insure performance.

Refer to pump manufacturers flow vs pressure specifications to select a pump that can provide the flow rate greater than 1.7 gpm while overcoming the pressure loss through:

• Tankless water heater (see Chapter 6.1)

• All building supply and return plumbing in the circulation loop

(reference local plumbing codes, standards, or practices)

System pressure drop

90 degree elbow

45 degree elbow

10 ft of straight pipe ½"

10 ft of straight pipe ¾"

Pressure drop ¾" copper (PSI)

0.088

0.053

1.3

0.35

Source: International Plumbing Code 2003 edition.

Examples:

1) Average house (less than 2500 square feet) a) Total loop length approximately 120 ft b) Pump recommendation: Grundfos UP 15-55 or equivalent.

2) Large house (2500 to 5000 square feet) a) Total loop length approximately 240 ft b) Pump recommendation: Grundfos UP 25-64 or equivalent.

NOTE: Use only bronze or stainless steel pumps. Do not use pumps of iron construction as they will oxidize and clog the inlet fi lter on the appliance.

5.3 Tank loading

3

4

1

2

# of heaters

Pressure drop vs. fl ow

Models: C800ES,

C920ES, C920ESC

Table 2

Pressure drop vs. fl ow

Model: 715ES

4gpm @ 40 feet of head

8gpm @ 40 feet of head

12gpm @ 40 feet of head

16gpm @ 40 feet of head

4gpm @ 32 feet of head

8gpm @ 32 feet of head

12gpm @ 32 feet of head

16gpm @ 32 feet of head

These guidelines should be followed to maximize system output:

Ensure fl ow through each water heater is between 3.5-5.0 gpm

Isolation valves or boiler drains should installed to facilitate

descaling in applications with hard water.

Whenever possible, plumb the system or confi gure the tank to

draw cold supply water into the water heater during hot water

use.

We recommend Grundfos UP26-99, Taco 009 or equivalent potable water circulators.

Recommendations for domestic hot water recirculation

An Aquastat, with a 5° F differential to control the pump, is

recommended.

The usage of a timer is recommended to limit the energy

consumption. The timer should also limit recirculation pump

operation to the time of day when occupants are home and likely

to use hot water.

Water heater set point must be minimum of 14° F above the

Aquastat setpoint.

Example: Tankless water heater setpoint = 122°F

Aquastat setpoint = 108°F

Keep hot water piping insulated to limit heat loss.

Set temperature on the GWH 920 ESC must not exceed 140°F.

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Bosch applications manual

6 Bosch Water Heating Models and

Specifi cations

This section describes the water heaters available from Bosch

Thermotechnology Corporation and provides a general overview to the specifi cations of that particular model. More detailed information is contained in the installation manuals. Download these manuals at www.BoschPro.com.

6.1 Sizing tankless water heaters

Defi nitions

Major applications (2 GPM or more): Washing machine, bath tub, shower nozzle

Minor applications(2 GPM or less): Low fl ow shower head, bathroom sink, kitchen sink

Rule of thumb sizing

The tables below provide a general rule of thumb when sizing for most residential applications. For commercial applications or for a more detailed sizing method, use the Sizing by Chart instructions below in conjunction with the charts on the next page.

Figure 1 Average ground water temperatures

This example requires a fl ow rate of 2.0 GPM at a 65˚F rise. Refer to the graphs on the following page. Since the demand is above the GWH 260 PN capacity, this application would require a GWH

425 HN/PN gas tankless water heater. The electrical model used for this application would be the RP27PT electric tankless water heater.

Model Number

Rule of Thumb Sizing

Number of Major

Applications

GWH C 920 ES/ESC

GWH 715 ES

GWH C 800 ES

GWH 425 HN/PN

GWH 425 HN/PN

GWH 260 PN

RP17PT

RP27PT

3

2

2

1

0

1

1

1

Number of Minor

Applications

0

0

1

2

1

1

0

1

Sizing by Chart

Measure the fl ow rates at each fi xture that will be used

simultaneously and add them together. If only one application will

rate observed

Using a known volume container, record several fi ll times. Perform the calculation below to determine the fl ow rate (a one gallon fi ll time of 30 seconds is 2.0 gallons per minute (GPM):

Flow rate (GPM) =

Volume (gallons)

Fill time (sec) x

60 sec min

Using a thermometer, measure the incoming water temperature.

For reference, see average ground water temperature map. Subtract this temperature from the desired hot water temperature to get the degree rise. If the desired hot water temperature is 120F and incoming temperature is 55F, the desired degree rise is 65F.

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GPM

10

9

6

5

8

7

4

3

2

1

0

10 20

GWH C 920 ES/ESC

GWH C 800 ES

GWH 715 ES

GWH 425 PN/HN

GWH 260 PN/HN

30 40 50 60

Gas Appliance Sizing Chart

70 80 90

Degree rise (°F)

GPM

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

RP7P

0.0

10 20 30 40 50 60

Electric Appliance Sizing Chart

Note: Maximum flow rates dependent on site conditions

BOSCH THERMOTECHNOLOGY CORPORATION

70 80 90

Degree rise (°F)

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6.2 Outdoor Installation

All models listed in this manual are designed to be installed indoors.

However, the following models are approved for outdoor installation with the use of the Outdoor Kit (part# PTOK):

GWH 715 ES

GWH C 800 ES

GWH C 920 ES

GWH C 920 ESC

Outdoor Kit (PTOK) installation:

The installation of this outdoor kit (PTOK) is required when installing any of the above appliances outdoors.

Outdoor cap easily retrofi ts to these indoor models.

Outdoor kit comes with Freeze Prevention which must be installed.

Exterior water piping should be protected if short term freezing conditions could exist.

Not for use in areas routinely exposed to freezing temperatures.

Installation on wood siding

Minimum clearances:

Bosch applications manual

Installation on vinyl siding:

Ref.

Description

Min. distances

A

B

C

Directly below or adjacent to an opening; operable windows, doors and any fresh air openings

D

E

From any adjacent wall

Below a gutter, sanitary pipework, eaves or overhang

Above ground F

G

From a gas meter or gas regulator

Outdoor Installation Clearances

Source: NFPA 54 National Fuel Gas Code

ANSI Z223.1

≥ 1 ft

≥ 4 ft

≥ 3 ft

≥ 1 ft

≥ 5 ft

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≥12"

≥12"

≥12"

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6.3 Bosch Gas Tankless Water Heater Specifi cations

Technical Specifi cations

Model 260 PN

Gas input

(BTU/hr)

Min: 30,735

Minimum fl ow to activate (GPM)

Max: 74,900

0.6

Maximum fl ow rate at 45° rise (GPM)

Maximum fl ow rate at 90° rise (GPM)

2.6

1.3

Thermal Effi ciency NG: 78%

LP: 78%

Dimensions

(inches)

H: 28¾

W: 12¼

D: 8½

Weight (lbs.) 25

Modulating gas valve yes

425 PN

Min: 31,000

Max: 117,000

0.6

4.2

2.1

NG: 78%

LP: 78%

H: 25¾

W: 16¾

D: 8½

33 yes

425 HN

Min: 30,735

Max: 117,000

0.6

715 ES

Min: 19,900

Max: 199,000

0.65

4.2

2.1

NG: 80%

LP: 80%

H: 25¾

W: 16¾

D: 8½

33 yes

7.2

3.6

NG: 82%

LP: 82%

H: 30½

W: 17⅞

D: 11¼

67 yes

C 800 ES

Min: 19,900

Max: 199,000

0.65

C 920 ES/ESC

Min: 25,000

Max: 225,000

0.65

8.0

3.9

NG: 92%

LP: 92%

H: 30½

W: 17⅞

D: 11¼

74 yes

9.2

4.6

NG: 94%

LP: 94%

H: 30½

W: 17⅞

D: 11¼

88 yes

Ignition Standing pilot

Gas connection

Water connections

NG gas pressure

(inches of W.C.)

LP gas pressure

(inches of W.C.)

Water pressure

Static - (PSI)

Electrical supply

½" Male NPT

½" Male NPT

Min: 7

Max: 14

Min: 11

Max: 14

Min: 30

Min (well): 40

Max: 150

N/A

Venting options Vertical natural draft

* horizontal termination not allowed

Standing pilot

¾" Male NPT

¾" Male NPT

Min: 7

Max: 14

Min: 11

Max: 14

Min: 30

Min (well): 40

Max: 150

N/A

Vertical natural draft

* horizontal termination only with AQ4 vent kit

5

Hydrogenerated

¾" Male NPT

¾" Male NPT

Min: 7

Max: 14

Min: 11

Max: 14

Min: 30

Min (well): 40

Max: 150

N/A

Vertical natural draft

* horizontal termination only with AQ4 vent kit

5

Electronic

¾" Male NPT

¾" Male NPT

Min: 3.5

Max: 10.5

Min: 8

Max: 13

Min: 30

Min (well): 40

Max: 150

120VAC direct vent room-sealed combustion

Electronic

¾" Male NPT

¾" Male NPT

Min: 3.5

Max: 10.5

Min: 8

Max: 13

Min: 30

Min (well): 40

Max: 150

120VAC direct vent room-sealed combustion

Electronic

¾" Male NPT

¾" Male NPT

Min: 3.5

Max: 10.5

Min: 8

Max: 13

Min: 30

Min (well): 40

Max: 150

120VAC direct vent room-sealed combustion

Venting diameter

(inches)

Vent material

4

Type B-vent recommended

Type B-vent recommended

3 or 4 3 or 4 3 or 4

Type B-vent recommended

Stainless steel

(AL29-4C)

PVC, CPVC, or ABS

(Schedule 40)

PVC, CPVC, or ABS

(Schedule 40)

Note:

C 920 ES (residential model) has a maximum setpoint temperature of 140°F.

C 920 ESC (commercial model) has a maximum setpoint temperature of 180°F.

Note:

For specifi cations and details on the Bosch GWH 345 ESR and

GWH 450 ESR models, see the GWH 345 ESR and GWH 450 ESR applications manual.

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Bosch applications manual

6.4 Bosch Electric Tankless Water Heater Specifi cations

Technical Specifi cations

Model RP1P

Volts 240

Kilowatts 9.50

Amps 40

Minimum wire size

(AWG)

8

RP2P

277

6.00

22

10

RP3P

120

3.40

29

10

Phase Single

Minimum fl ow to activate (GPM)

0.75

Maximum fl ow rate at 45° rise (GPM)

Maximum fl ow rate at 80° rise (GPM)

1.4

n/a

Thermal Effi ciency 99%

Dimensions

(inches)

H: 6½

W: 12¼

D: 3

Weight (lbs.) 6

Water connections ½" Male

NPT

Single

0.50

0.9

0.5

99%

H: 6½

W: 12¼

D: 3

6

½" Male

NPT

Single

0.50

0.5

n/a

RP7P

240

7.20

30

10

Single

0.75

1.1

n/a

RP9P

277

9.50

35

8

Single

0.75

1.4

n/a

RP12PT

240

12.00

50

6

Single

0.75

RP17PT

240

17.25

U.S.A: 80

(2 x 40)

Canada: 80

(1 x 80)

U.S.A: 8

Canada: see

Canadian

Electrical Code

Single

0.6

RP27PT

240

26.85

U.S.A: 120

(3 x 40)

Canada: 120

(1 x 120)

U.S.A: 8

Canada: see

Canadian

Electrical Code

Single

0.8

2.0

n/a

2.6

1.5

99%

H: 6½

W: 12¼

D: 3

6

½" Male

NPT

99%

H: 6½

W: 12¼

D: 3

6

½" Male

NPT

99%

H: 6½

W: 12¼

D: 3

6

½" Male

NPT

99%

H: 6½

W: 12¼

D: 3

6

½" Male

NPT

90%

H: 15½

W: 15¼

D: 4½

20

¾" Male

NPT

4.0

2.2

94%

H: 15½

W: 15¼

D: 4½

22

¾" Male

NPT

6.5 Ariston Electric Mini-tank Water Heater

Specifi cations

Technical Specifi cations

Model GL2.5Ti

Volts 120

Watts 1500

Amps 12.5

Wire size Plug-in

Tank volume (gallons)

Dimensions

(inches)

Recovery at 90° F rise

(gallons per hour)

2.75

H: 14

W: 14

D: 10¼

6.8

Temperature range 65 - 145° F

Water connections ½" Male NPT

Operating pressure (PSI) 150

GL4Ti

120

1500

GL8Ti

120

1500

12.5 12.5

Plug-in Plug-in

3.85

H: 14

W: 14

D: 12¼

6.8

7.00

H: 17½

W: 17½

D: 14½

6.8

65 - 145° F

½" Male NPT

150

65 - 145° F

¾" Male NPT

150

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Bosch applications manual

7 Domestic Water Heating Applications

Potable water

Potable water is water that is suitable for drinking. Bosch Water

Heating appliances are approved to heat potable water only. Heating any other liquid other than potable water will void the manufacturer’s warranty covering the appliance.

Introduction

This chapter covers the various application techniques Bosch Water

Heating recommends. The schematics are to be used by professional contractors in designing a domestic water heating system. The applications covered range from single sink point-of-use applications to multi-appliance central domestic recirculation applications.

7.1 Point-of-use applications

Point-of-use applications cover the small applications in which a large water heater would be ineffi cient. Installing a smaller heater at a point-of-use puts the heater near the hot water demand and reduces the wait for hot water. Common applications for these appliances include homes, offi ces, warehouses, service stations, stores, concession stands and summer camps.

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7.1.1 Ariston mini tank

Simply tap into the cold water line and install the water heater directly at the sink. All models plug into a standard 120 volt outlet.

Heater can be wall mounted, or sit on the fl oor.

hot cold

Ariston Pro GL2.5 Ti

Ariston Pro GL4 Ti

hot cold

Ariston Pro GL8 Ti

Note:

Drawing is not to scale.

Cold water piping to fixtures not shown for clarity purposes.

Bosch applications manual

Symbols

Temperature and pressure relief valve

Sink

Flow direction

Service valve

Drain pan

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Bosch applications manual

7.1.2 Powerstream Pro electric point-of-use tankless water heater

PowerstreamPro point-of-use water heaters come in four models to serve a wide range of applications. Finding the right model depends upon your desired temperature and fl ow rate. See Section 2.1 to fi nd the model best suited to your customer‘s needs. Flow controls and faucet aerators can greatly enhance performance.

Note: Water heater must be fi lled with water and purged of air prior to supplying power.

hot cold supply hot

Powerstream Pro

RP1P, RP2P, RP3P,

RP7P, RP9P, RP12PT cold

hot

Powerstream Pro

RP1P, RP2P, RP3P,

RP7P, RP9P

cold hot

cold supply

Symbols

Service valve

Sink

Flow direction

Note:

Drawing is not to scale.

RP12PT cannot be mounted sideways.

Cold water piping to fixtures not shown for clarity purposes.

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7.2 Whole house applications

Whole house applications cover the typical home applications up to a 2 or 3 bedroom house. See the sizing guide (Section 6.1) to determine the best Bosch water heater model for your application.

An enhanced design including an Ariston mini tank in line to the hot water source will reduce the wait time for hot water and improve temperature stability.

7.2.1 Low volume tankless water heater applications

The Bosch GWH 260 PN gas tankless water heater and the RP17PT electric tankless water heater offer a compact and lightweight design for easy installation.

Both appliances are intended for low volume applications

(e.g. camps, cottages, cabins).

Bosch GWH 260 PN

BOS CH

hot cold

Bosch applications manual

Hot

Note:

Drawing is not to scale.

Cold water piping to fixtures not shown for clarity purposes.

Powerstream Pro

RP17PT

Cold

Symbols

Pressure relief valve

Sink

Service valves

Low flow shower

Flow direction

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Bosch applications manual

7.2.2 Powerstream Pro whole house applications

The RP27PT must be hard wired.

hot cold

Ariston Pro GL4Ti

- for pipe runs over

100 ft between tankless heater and Ariston, use

GL8Ti

Note: place Ariston close to the point of

use to reduce wait time for hot water.

| 17

Hot

Powerstream Pro

RP27PT

Cold

Hot

Note:

Drawing is not to scale.

Cold water piping to fixtures not shown for clarity purposes.

Powerstream Pro

RP27PT

Cold

Symbols

Standard tub fixture

Flow direction

Pressure & temperature relief valve

Service valve

Sink

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Bosch applications manual

7.2.3 Powerstream Pro whole house application with domestic recirculation loop

The circulator should be controlled by an external aquastat, or with a timer to run only during times of expected hot water usage.

Insulate piping in hot water recirculation loop to limit heat loss.

See Chapter 5.1 for recirculation pump parameters

Powerstream Pro

RP17PT or RP27PT

Hot Cold

Ariston Pro mini-tank

(2.5, 4 and 8 gallon sizes)

Symbols

Bronze or stainless steel circulator pump sized according to UPC standards

(Taco Bronze 007 or Grundfos 15-42B will cover most homes up to 3 bathrooms)

Potable water expansion tank

Service valve

Flow check valve

Sink

Timer

Aquastat

Note:

Drawing is not to scale.

Cold water piping to fixtures not shown for clarity purposes.

Flow direction

Standard tub fixture

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Bosch applications manual

7.2.4 Bosch ProTankless gas water heater

Below are two examples of Bosch ProTankless gas water heater installations for the whole house. One example shows an Ariston mini tank in line for reduced hot water wait time and increased temperature stability.

hot

Bosch GWH 425 PN,

Bosch GWH 425 HN,

Bosch GWH 715 ES,

Bosch GWH C 800 ES,

Bosch GWH C 920 ES

cold

Hot

Ariston Pro GL4Ti

- for pipe runs over

100 ft between tankless heater and Ariston, use

GL8Ti

Note: place Ariston close to the point of

use to reduce wait time for hot water.

Bosch GWH 425 PN,

Bosch GWH 425 HN,

Bosch GWH 715 ES,

Bosch GWH C 800 ES,

Bosch GWH C 920 ES

Cold

| 19

Hot

Cold

Symbols

Standard tub fixture

Flow direction

Service valve

Pressure relief valve

Sink

Note:

Drawing is not to scale.

Cold water piping to fixtures not shown for clarity purposes.

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7.2.5 Bosch ProTankless gas water heater with domestic recirculation loop

The circulator should be controlled by an external aquastat or with a timer to run only during times of expected hot water usage.

Insulate piping in hot water recirculation loop to limit heat loss.

See Chapter 5.1 for recirculation pump parameters

Bosch GWH 425 PN,

Bosch GWH 425 HN,

Bosch GWH 715 ES,

Bosch GWH C 800 ES,

Bosch GWH C 920 ES

Hot

Ariston Pro mini-tank

(2.5, 4 and 8 gallon sizes)

Bronze or stainless steel circulator pump sized according to UPC standards

(Taco Bronze 007 or Grundfos 15-42B will cover most homes up to 3 bathrooms)

Potable water expansion tank

Service valve

Symbols

Flow check valve

Sink

Timer

Aquastat

Note:

Drawing is not to scale.

Cold water piping to fixtures not shown for clarity purposes.

Flow direction

Standard tub fixture

Cold

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Bosch applications manual

7.2.6 Bosch ProTankless gas water heater with direct recirculation loop

Use a circulator, aquastat and/or timer, to keep a loop of hot water constantly hot and ready to use. This limits wait time for hot water delivery to the tap and excessive waste of water. Insulate piping in hot water recirculation loop to limit heat loss.

If the water heater is used within an approved hot water

recirculation application and supplied with circulated

water, the heat exchanger warranty is decreased. Please

refer to the installation manual for detailed warranty

period information.

See Chapter 5.1 for recirculation pump parameters

Bosch GWH 715 ES,

Bosch GWH C 800 ES,

Bosch GWH C 920 ES/ESC,

Cold water supply

Domestic hot water tap

| 21

Hot

Cold

Domestic hot water tap

Y-strainer

Domestic hot water tap

Aquastat Timer

Flow check valve

Note:

Drawing is not to scale.

Cold water piping to fixtures not shown for clarity purposes.

Domestic hot water tap

Symbols

Potable water expansion tank

Service valves

Pressure relief valve

Flow direction

Bronze or stainless steel circulator/ pump

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8 High Volume Potable Water Heating

Potable water

Potable water is water that is suitable for drinking. Bosch Water

Heating appliances are approved to heat potable water only. Heating any other liquid other than potable water will void the manfucturer’s warranty covering the appliance.

Introduction

This section lays out the options for high volume water heating for large residential and light commercial applications including continuous fl ows.

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8.1 Cascading unit applications

A cascading application should be considered if the potential hot water demand exceeds the capacity of one GWH 715 ES, GWH C

800 ES, or GWH C 920 ES/ESC. The cascading set up supports variable fl ow inputs and is designed for large homes and commercial applications. Cascading, unlike parallel applications, maintains the activation fl ow rate of a single appliance.

8.1.1 GWH 715 ES, GWH C 800 ES, GWH C 920 ES/ESC cascading with domestic hot water recirculation

Cascading allows up to four appliances to be connected. One of the appliances will serve as the controlling Master appliance and will attempt to meet the hot water demand. If the hot water demand is beyond the capacity of the Master appliance, a signal is sent to one or more of the Slave appliances to begin operation.

System parameters:

• For applications with 200ft of pipe or more.

• The plumbing must be connected in the reverse return method

with a minimum number of elbows to aid in balancing

pressures between the appliances.

• Locate appliances close together for improved performance.

- Maximum distance between appliances: 36”.

- Minimum distance between appliances: 1”.

• Minimum pipe diameter: ¾” (2 appliances or less).

• Minimum pipe diameter: 1” (3 appliances or more).

• Minimum water pressure: 50 psi.

• Insulate pipes to prevent heat loss.

See Chapter 5.1 for recirculation pump parameters

Bosch GWH 715 ES, Bosch GWH C 800 ES, or Bosch GWH C 920 ES/ESC

hot cold tankless link hot cold tankless link hot cold tankless link hot cold cold hot

Note:

Drawing is not to scale.

BOSCH THERMOTECHNOLOGY CORPORATION

Domestic hot water recirculation return line

Electric buffer Tank

outlet inlet

Flow direction

Symbols

Potable water expansion tank

Pressure relief valve

Timer

Service valve

Tankless

link

Flow check valve

Bronze or stainless steel circulator

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8.1.2 GWH 715 ES, GWH C 800 ES, GWH C 920 ES/ESC cascading with domestic hot water recirculation

System parameters:

• For applications with 200ft of pipe or less.

See Chapter 5.1 for recirculation pump parameters

Bosch GWH 715 ES, Bosch GWH C 800 ES, or Bosch GWH C 920 ES/ESC

hot cold tankless link hot cold tankless link hot cold tankless link hot cold

DHW outlet

Note:

Drawing is not to scale.

DHW outlet

Ariston GL8Ti

DHW outlet

Domestic hot water recirculation return line cold

Symbols

Potable water thermal expansion tank

Pressure relief valve

Bronze or stainless steel circulator

Flow direction

Flow check valve

Service valves

Aquastat

Timer

Tankless

link

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Bosch applications manual

8.2 Parallel unit applications

Two Bosch ProTankless units will have double the activation rate of a single unit. The activation rate will continue to double with each additional unit added in parallel. hot cold

Bosch GWH 425 PN,

Bosch GWH 425HN,

Bosch GWH 715 ES,

Bosch GWH C 920 ES/ESC,

Bosch GWH C 800 ES,

*see text above about activation rate

hot cold

| 25

Note:

Drawing is not to scale.

cold hot

Symbols

Pressure relief valves

Flow direction

Service valve

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9 Residential Solar Applications

Introduction

This section gives a general overview of tank loading and in line booster applications for domestic hot water in conjuction with solar water heating. For additional system details, consult the Bosch

Solar Technical Guide.

9.1 Tank loading

9.1.1 Solar DHW system with gas tankless water heater tank loading

In this system the gas tankless water heater keeps the comfort zone at top of tank at desired temperature.

Use GWH 715 ES, GWH C 800 ES, or GWH C 920 ES with

aquastat that activates circulator.

Timer recommended to interrupt reheating during night time.

Aquastat / Water Heater setpoints

Model Number Aquastat setpoint Water heater setpoint

GWH C 920 ESC ≤140°F 14°F above

Aquastat setpoint

GWH C 920 ES ≤126°F* 140°F

GWH 715 ES ≤126°F* 140°F

GWH C 800 ES ≤126°F* 140°F

* If local codes require higher setpoint or to increase the recovery

capacity of the water heater, contact Bosch Thermotechnology.

See Chapter 5.2 for tank loading pump parameters

Collector sensor

Domestic

Hot

Water

Bosch GWH 715 ES,

Bosch GWH C 800 ES,

Bosch GWH C 920 ES/ESC

Thermostatic valve

Setpoint 120°F

Solar

Controller

Twin tube

Solar

Pump

Station

Aquastat or tank sensor

Cold

Water

Supply

Tank sensor

Honeywell

Am-1 series thermostatic mixing valve

Well thermometer

Service valve

Pressure relief valve

Bosch applications manual | 06.2009

Symbols

Solar storage tank

Potable water expansion tank

Flow direction

Circulator

Drain valve

Expansion tank

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9.2 Booster applications

9.2.1 Solar DHW system with gas tankless water heater booster

The tankless water heater only runs when solar water needs a boost.

The Ariston mini tank provides small amounts of DHW instantly and increases comfort by buffering DHW temperature. Recommended appliances: Bosch GWH 715 ES, GWH C 800 ES, GWH C 920 ES/ESC

Thermostatic valve 1 ensures that warm solar water bypasses the

water heater and directs cooler water through the appliance

when reheating is needed.

Thermostatic valve 2 acts as a tempering valve that brings

potentially hot water temperatures down to a level that is safe for

the inhabitants.

System parameters:

Honeywell AM101 Thermostatic Valves required for proper

operation;

Remove check valves from Thermostatic Valve 1 as it is used as a

diverter valve;

Thermostatic Valve 2 is a tempering valve;

Recommended setpoint 120°F for both Valves;

Set tankless water heater temperature to

140° F

Ariston mini tank will provide increased

temperature stability and quicker hot water

delivery. (recommended but not required)

Bosch GWH 715 ES,

Bosch GWH C 800 ES,

Collector sensor

Solar

Controller

Solar

Pump

Station

Hot Cold

Ariston GL8ti mini tank

Thermostatic valve 1

Domestic hot water

Thermostatic valve 2

Tank sensor

Water supply

Honeywell

Am-1 series thermostatic mixing valve

Well thermometer

Service valve

Pressure relief valve

Symbols

Solar storage tank

Expansion tank

Flow direction

Circulator

Drain valve

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9.2.3 Solar DHW system with gas tankless water heater booster and recirculation loop

Similar to 4.3.2 with domestic hot water recirculation added. The tankless water heater only runs when solar heated water needs a boost. Buffer tank provides small amounts of DHW instantly and increases comfort by smoothing out DHW temperature.

Recommended appliances: Bosch GWH 715 ES, GWH C 800 ES.

Thermostatic valve 1 ensures that warm solar water bypasses the

water heater and directs cooler water through the appliance

when reheating is needed.

Thermostatic valve 2 acts as a tempering valve that brings

potentially hot water temperatures down to a level that is safe for

the users.

System parameters:

Honeywell AM101 Thermostatic Valves required for proper

operation;

Remove check valves from Thermostatic Valve 1 as it is used as a

diverter valve;

Thermostatic Valve 2 is a tempering valve;

Recommended setpoint 120°F for both Valves;

Set tankless water heater temperature to 140° F

Ariston mini tank will provide increased temperature stability and

quicker hot water delivery. (recommended but not required)

Choose size of the Ariston mini tank to match the volume of the

recirculation loop

See Chapter 5.1 for recirculation pump parameters

Collector sensor

Bosch GWH 715 ES,

Bosch GWH C 800 ES,

Bosch GWH C 920 ES/ESC

Solar

Controller

Solar

Pump

Station

Hot Cold

Thermostatic valve 1

Domestic hot water

Thermostatic valve 2

Tank sensor

Water supply

Ariston GL8ti mini tank

Honeywell

Am-1 series thermostatic mixing valve

Well thermometer

Service valve

Pressure relief valve

Symbols

Solar storage tank

Potable water expansion tank

Flow direction

Circulator

Flow check valve

Drain valve

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10 Commercial Solar Applications

Introduction

This section provides a general overview for commercial hot water systems in conjuction with solar water heating (e.g. schools, fi tness centers). For additional system details, consult the Bosch Solar

Technical Guide.

System parameters:

Honeywell AM101 Thermostatic Valves required for proper

operation.

For optimal performance, the fl ow through the water heater

should be between 3.5 -5 gpm

See Chapter 5.1 and 5.2 for recirculation pump parameters

Collector sensor

Solar

Controller

Domestic

Hot

Water

Thermostatic valve

Setpoint 120°F

Twin tube

Aquastat or tank sensor

Solar

Pump

Station

Aquastat or tank sensor

Hot water recirculation return line

DHW recirculation pump

Symbols

Honeywell

Am-1 series thermostatic mixing valve

Well thermometer

Pressure relief valve

Service valve

Solar storage tank

Drain valve

Potable water expansion tank

Expansion tank

Flow direction

Flow check valve

Circulator

Cold

Water

Supply

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11 Commercial Water Heating Applications

Introduction

This section gives a general overview of high volume, high temperature water heating for commercial applications.

11.1 Commercial Kitchen applications

11.1.1 Commercial kitchen

This design allows for temperature stability with short, repeated hot water demands such as a super sprayer. It also provides high temperature water for a commercial dishwasher.

When using the super sprayer, hot water draws must be

longer than 15 seconds to avoid temperature fl uctuations.

System parameters:

Set Ariston mini-tank to maximum temperature.

Set tankless water heater temperature per dishwasher temperature requirements.

Bosch GWH C 920 ESC

Sink

Dish sprayer

Cold

Water

Supply

Y-strainer

Dishwasher with heating element

Ariston GL8Ti

Honeywell

Am-1 series thermostatic mixing valve

Note:

Drawing not to scale.

Cold water piping to fixtures not shown for clarity purposes.

Bosch applications manual | 06.2009

Well thermometer

Symbols

Service valve

Pressure relief valve

Potable water expansion tank

Flow direction

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Bosch applications manual

11.1.2 Commercial kitchen with domestic hot water recirculation

System parameters:

For optimum performance in applications involving a commercial dishwasher, a hot water circulation loop is recommended.

See Chapter 5.1 for recirculation pump parameters

Bosch GWH C 920 ESC

Sink

Dish sprayer

Cold

Water

Supply

| 31

Y-strainer

Dishwasher with heating element

Ariston GL8Ti

Domestic hot water recirculation return line

Circulator

(stainless steel or bronze)

Honeywell

Am-1 series thermostatic mixing valve

Well thermometer

Service valve

Symbols

Pressure relief valve

Note:

Drawing not to scale.

Cold water piping to fixtures not shown for clarity purposes.

Potable water expansion tank

Flow direction

Flow check valve

Aquastat

Timer

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11.2 Basic tank loading with domestic recirculation

The following application outlines general tank loading with one or more gas tankless water heaters in parallel. Domestic hot water recirculation shown is optional.

System parameters:

• Aquastat/tank sensor Tset 120-140°F, <10°F differential.

• 30-119 gallon storage tank recommended

• DHW return line can tie directly into tank if fi ttings are available.

• Individual pumps (i.e. UP26-99) can be used on supply to each

heater or one pump (as shown) for the entire system

See Chapter 5.1 and 5.2 for pump parameters

Aquastat / Water Heater setpoints

Model Number Aquastat setpoint Water heater setpoint

GWH C 920 ESC ≤140°F 14°F above

Aquastat setpoint

GWH C 920 ES

GWH 715 ES

≤126°F*

≤126°F*

140°F

140°F

GWH C 800 ES ≤126°F* 140°F

* If local codes require higher setpoint or to increase the recovery

capacity of the water heater, contact Bosch Thermotechnology.

Bosch GWH 715 ES, Bosch GWH C 800 ES, Bosch GWH C 920 ES/ESC

Domestic

Hot Water supply

Aquastat or tank sensor

Cold

Water

Supply

Hot water recirculation return line

DHW recirculation pump

Well thermometer

Service valve

Pressure relief valve

Symbols

Solar storage tank

Drain valve

Flow direction

Bronze or stainless steel circulator

Potable water expansion tank

Flow check valve

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11.3 Advanced tank loading commercial hot water system

The following application outlines an advanced tank loading application for commercial hot water systems (e.g. hotels, fi tness centers). This design allows for complete isolation of the system for maintenance reasons and gives the ability to bypass certain system components in case of failure. A second hot water storage tank is shown for additional hot water supply and back up in case of tank failure.

System parameters:

See Chapter 5.1 and 5.2 for pump parameters

Aquastat / Water Heater setpoints

Model Number Aquastat setpoint Water heater setpoint

GWH C 920 ESC ≤140°F 14°F above

Aquastat setpoint

GWH C 920 ES ≤126°F* 140°F

GWH 715 ES ≤126°F* 140°F

GWH C 800 ES ≤126°F* 140°F

* If local codes require higher setpoint or to increase the recovery

capacity of the water heater, contact Bosch Thermotechnology.

Bosch GWH 715 ES, Bosch GWH C 800 ES, or Bosch GWH C 920 ES/ESC

cold supply hot cold hot cold hot cold hot cold

Thermostatic mixing valve

Note:

Drawing is not to scale.

Service valves

Symbols

Tankless

link

Pressure relief valve

Flow direction

Circulator

DHW

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BOSCH THERMOTECHNOLOGY CORPORATION Bosch applications manual | 06.2009

Bosch Thermotechnology Corp.

50 Wentworth Avenue

Londonderry, NH 03053

Tel: 1-866-642-3198

Fax: 1-603-584-1681 www.boschpro.com

BTC 710001101 A | 06.2009

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