Bosch 38B LP, 38B NG Installation And Operating Instructions Manual

WARNING

: 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.
Upon completion of the installation, these instructions
should be handed to the user of the appliance for future
reference.
In the Commonwealth of Massachusetts this product
must be installed by a licensed plumber or gas fitter.

INSTALLATION AND OPERATING INSTRUCTIONS FOR AUTOMATIC
INSTANTANEOUS TYPE WATER HEATERS FOR USE WITH NATURAL AND
LIQUEFIED PETROLEUM GAS

MODEL 38B LP and NG

Suitable for heating potable water only

Not approved for space heating purposes

Intended for low flow domestic hot water applications with steady cold water inlet temperatures

WARNING

If the information in this manual is not followed exactly, a
fire or explosion may result causing property damage,
personal injury or death.

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.

WHAT TO DO IF YOU SMELL GAS

- Do not try to light any appliance.

- Do not touch any electrical switch; do not use any

phone in your building.

- Immediately call your gas supplier from a neighbor’s
phone. Follow the gas supplier’s instructions.

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

- Installation and service must be performed by a
qualified installer, service agency or the gas supplier.

Specifications................................................................. Page 2

Rules for safe operation ...............................................Page 4

Locating the Heater ......................................................Page 4

Combustion Air Requirements ....................................Page 5

Mounting the Heater .....................................................Page 5

Venting the Heater ........................................................Page 7

Gas Connections .......................................................... Page 9

Water Connections .................................................... Page 10

Safety before lighting the pilot ................................ Page 11

Lighting instructions ................................................... Page 11

Setting water temperature ........................................ Page 12

Maintenance & Service ............................................. Page 12

Trouble Shooting ......................................................... Page 13

Diagram of AquaStar ................................................. Page 16

Components and Parts List ...................................... Page 19

Warranty ....................................................................... Page 21

TABLE OF CONTENTS

6 720 606 446 US (06.01) AL

http://waterheatertimer.org/Troubleshoot-Bosch-Tankless-water-heater.html

2 6 720 606 446

This well engineered, gas water heater has all the fea­tures a water heater should have:

It operates on the principle of heating water instantaneously
“on demand”. When a hot water faucet is opened, cold water
flows through the coils of the heat exchanger in the Aquastar.
This same flow opens the gas valve, and the burners are
ignited by the pilot flame. The heat exchanger coils absorb
the heat generated by the burners and transfer heat to the
water. When the hot water faucet is shut off, the gas valve
automatically closes and the burners turn off. Your hot wa­ter faucet is an ignition key to turn on the water heater,
giving you control over your hot water energy use. Each
time you turn off your hot water faucet, you also shut off
the water heater.

FEATURES

- High Quality Materials for Long Working Life.

- Copper heating coils for endless supply of hot water.

- Safety thermocouple at pilot burner.

- Automatic overheating protection shut-off sensor.

- Stainless steel burners with stabilized blue flame.

- Built-in corrosion resistant draft inducer.

- Compact space saver: mounts on a wall with two hooks.

- Easily removable one-piece cover.

- Easy one person installation.

- Adjustable water flow restrictor to ensure that water flow
demand will not exceed the heating capacity of the heater.

- Easy pilot flame lighting with push button piezo ignition.

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

AquaStar 38B LP and 38B NG Specifications

Gas Input max.: 40,000 Btu/hr

min.: 20,000 Btu/hr

Water Connection 1/2” Thread fitting NPT

H x W x D 25 3/8” x 10 5/8” x 9 1/8"

Vent 4”

Gas Connection 1/2” NPT thread

Min. Water Pressure 13 Psi at 1.3 GPM

Max. Water Pressure 150 Psi

Shipping Weight 20 LB

Net Weight 18 LB

0.5 GPM at 90° rise

1.3 GPM at 45° rise

Min. Water Flow 1/2 gal/min

LP GAS Supply Pressure
(before Aquastar regulator) min.: 11” W.C.

max.: 14” W.C.*

Required LP GAS Pressure at inlet tap while
Aquastar is operating: 10.5” W.C.

LP GAS Burner Manifold pressure while Aquastar is
operating at maximum input: 9.0” W.C.

Natural Gas Supply Pressure
(before Aquastar regulator) min.: 7” W.C.

max.: 14” W.C.*

Required Natural Gas Pressure at inlet tap
while Aquastar is operating: 5.7” W.C.

Natural Gas Burner Manifold pressure while Aquastar is
operating at maximum input: 3.3” W.C.

* Inlet gas pressure before Aquastar regulator must not
exceed this value. Pressure may need to be adjusted for
high altitudes, see page 10.

UNPACKING THE AQUASTAR HEATER

This heater is packed securely. The box includes two water connection fittings, a gas pressure regulator, a gas supply elbow
with gasket, a gas shut off valve, a pressure relief valve, two hooks for hanging the heater, this manual, a warranty
statement and a warranty registration card. Do not lose this manual, as there is a charge for replacement. Please
complete and return the enclosed warranty registration card.

36 720 606 446

MINIMUM INSTALLATION CLEARANCES FROM COMBUSTIBLE AND

NON COMBUSTIBLE MATERIALS

FRONT VIEW

SIDE VIEW

AQUASTAR MODEL 38B

MODEL 38B

TOP (A) 12 "
FRONT (B) 4 "
BACK 0 "
SIDES 4 "
FLOOR (C) 12 "
VENT DIAMETER 4 "

4 6 720 606 446

GENERAL RULES TO FOLLOW
FOR SAFE OPERATION

1. You should 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 should conform with CGA
B149.(1,2) INSTALLATION CODES and /or local installation
codes.

2. Carefully plan where you install the heater. Correct

combustion air supply and flue pipe installation are very
important. If not installed correctly, fatal accidents can be
caused by lack of air, carbon monoxide poisoning or fire.

3. The place where you install the heater must have enough

ventilation. The National Fire Codes do not allow gas fired
water heater installation in bathrooms, bedrooms or any
occupied rooms normally kept closed. See the section below
on locating the heater. The 38B is not approved for boat or
RV installations.

4. You must vent your heater. See section on VENTING,

Page 6.

5. The appliance must be disconnected from the gas supply

piping system during any pressure testing at pressures in
excess of 1/2 Psig (3.5 kPa).
The appliance must be isolated from the gas supply piping
system by closing its individual manual shutoff valve during
any pressure testing of the gas supply piping system at test
pressures equal to or more than 1/2 Psig (3.5Kpa). The
appliance and its gas connection must be leak tested before
placing the appliance in operation.

6. Keep water heater area clear and free from combustibles

and flammable liquids. Do not locate the heater over any
material which might burn.

7. Correct gas pressure is critical for the optimum

operation of this heater (see specifications on page 2). 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.

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.

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.

PROPER LOCATION FOR INSTALLING YOUR
HEATER

Carefully select the location of your new heater. For your
safety and for proper heater operation, you must provide an
abundant supply of combustion air and a proper venting
installation.
The heater may still operate even when improperly vented.
It will, however, be less efficient and could eventually damage
the heater. It could even result in human sickness or death
due to oxygen deprivation and carbon monoxide poisoning.

Follow the guidelines below:

1. Place your heater as close to a vent or chimney as
possible.

2. National building codes require that you do not install
this appliance in bathrooms, bedrooms, unvented closet or
any occupied rooms normally kept closed. The 38B is not
approved for boat or RV installations.

3. Simultaneous operation of other appliances such as
exhaust fans, ventilation systems clothes dryers, fireplaces
or wood stoves could create a vacuum effect in your home
which could cause dangerous combustion by-products to
spill back into your home rather than venting to the outside
through the flue. Confirm that your Aquastar is venting
properly when all these other appliances are running. See
section on venting.

Do not obstruct the flow of combustion and ventilation
air to the appliance. If installed near a clothes dryer it is

very important that the dryer be properly vented. Failure to
properly vent a dryer could result in a gradual accumulation
of lint on the water heater fin coils and burners, leading to a
dangerous condition of vent blockage and poor unsafe
combustion.

4. Your hot water lines should be kept short to save energy.
It is always best to have hot water lines insulated.

WARNING: The water in this water heater is cold

and always remains cold exept for the times that hot water
is being used DO NOT INSTALL IN AN AREA WHERE IT

COULD FREEZE.
This heater is neither designed for nor approved for
outside installation.

Drain the heater entirely if freezing temperatures are
anticipated in area where heater is installed by disconnecting
both the inlet and outlet water connections. Additionally,
remove the drain plug under the water valve. See Fig 0.

WARNING: Flammable materials, gasoline,
pressurized containers, or any other items or articles
that are potentially 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.
This product is not approved for manufactured homes
(mobile home), recreational vehicles (RV) or boats.
Reference ANSI Z21.10.3.
This product is neither designed or approved for outside
installations.

Fig. 0 - Water heater drain plug

WATER VALVE

DRAIN PLUG

TO HEAT

EXCHANGER

56 720 606 446

COMBUSTION AIR REQUIREMENT

The AquaStar water heater holds cold water in its copper
heat exchanger and brass water valve when not in use.
Because of this, any cold air that comes in through the
unit’s vent pipe is capable of freezing these components.
This Installation Manual specifies the minimum vertical vent
pipe and the amount of combustion air required for this unit.
When all requirements are followed, the unit will operate
properly and safely. However, there may still be a risk of
freezing due to negative draft if all the combustion appliances
in the area are not being supplied with a sufficient amount
of make-up air. A wood stove or furnace can rob the make­up air in the AquaStar’s vent pipe, leaving the cold infiltrating
air capable of freezing the cold water in the AquaStar heat
exchanger. More make up air is the solution. Follow the
instructions on venting and checking adequacy of make up
air. A HVAC specialist should be used to design solutions
for providing more make-up air if necessary.

Observe the following instructions concerning combustion
air.
Appliances located in confined spaces:
The confined space must be provided with 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 confined 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 75% if your louvers are wood and by 30% if
your louvers are metal. Refer to the National Fuel Gas Code
for complete information. In buildings of tight construction
all air should be taken from outside. That would be 2000

cubic feet for the Aquastar 38B alone.

CLEARANCES

The Aquastar 38 B is design certified for installation on a
combustible wall and for installation in an alcove or closet
with the minimum clearances to combustible and non ­combustible construction listed below

A. Top 12 inches ( 305 mm)
B. Front 4 inches (102mm)
C. Back 0 inches
D. Sides 4 inch (102mm)
E. Bottom 12 inches (306 mm)

Clearance from vent is dependent upon the clearance rating
of the venting material used. For example: type B-1 vent is
approved for 1 inch clearance.

Note: Typically, the minimum clearance to combustible
materials should not be less than 6” for single wall flue
pipe. Note that this clearance can be reduced if combustible
materials are protected as per table VI of the National Fuel
Gas Code or if Type B gas vent is used.

MOUNTING INSTALLATION

The Aquastar 38 B is design certified for mounting on a
wall.
Secure the two L shaped hooks, which are provided with
heater, to a wall surface. Place them 5 ½” apart as
shown in Fig. 1.
Do not install this appliance on a carpeted wall or over floor
covering which is combustible, such as carpet. The heater
must be mounted on a wall using appropriate anchoring
materials. If wall is a stud wall sheathed with plasterboard, it

is recommended that support board(s), either 1x4’s or
1/2" (minimum) plywood first be attached across a pair
of studs and then the heater should be attached to the
support boards. See Fig 1.

Expansion and contraction of piping due to changing water
temperature in the pipes imparts movement to the heater
which, if mounted directly to a brittle, friable board, such as
plasterboard, can cause failure of mounting.

In earthquake-prone zones, BBTNA recommends that
installers use a large washer and lag screw through the
existing holes used to hang the heater to affix the upper
third of the heater to the mounting board. To affix the lower
third of the heater, BBTNA recommends that two new holes
be drilled in the heater’s frame, each one 16 inches below
the top two holes, and that washers and lag screws be used
to secure the lower portion of the heater to a spacing board.

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

AQ38B

AQ38B

Air Vents

(10¾ X 10¾ in. each)

Air Vents

(5½ X 5½ in. each)

6 6 720 606 446

Appliances located in unconfined spaces:
a) An unconfined space is one whose volume is greater

than 50 cubic feet per 1000 Btu per hour of the combined
rating of all appliances installed in the space. That would
be 2000 cubic feet for the AquaStar 38B alone.

b) In unconfined spaces in buildings of conventional frame,

masonry, or metal construction, infiltration is normally
adequate to provide air for combustion, ventilation, and
dilution of flue gasses.

Identification labels are found on the shipping box, and on
the rating plate which is located on the right side panel of
the cover. Also, each burner orifice is stamped with a number
(79 for LPG and 120 for Natural Gas).

Fig. 1 - Mounting the Heater

WALL STUDS

1” X 4”

SPACE BOARD

SUPPORT BOARD

5 ½”

76 720 606 446

VENTING

Vent pipe connection. WARNING: Do not reduce the vent pipe size.

The heater must be vented to the outside following all local ordinances and specifications for installing a gas appliance
vent or chimney. The heater must be located as close as practicable to a vertically rising chimney or vent that has a listed
vent cap at its termination point. The venting system must be designed and constructed so as to develop a positive flow
adequate to remove flue gasses to the outdoors.

Consult the National Fuel Gas Code if the vent will have elbows or share venting with another natural draft appliance.
The heater should never be common vented with a mechanically vented appliance. Single wall vent pipe is not
recommended, if used consult the National Fuel Gas Code.

Horizontally venting to a sidewall vent terminator or a vertically constructed vent stack along an outside wall of a building
is not permissible. A Powervent with a proof-of-draft safety interlock device, is required and is available in order to sidewall
vent. Contact your dealer. In the Commonwealth of Massachusetts: Powervented applications must utilize proof-of-

draft safety interlock device.

VERTICAL GAS VENT: A 4 inch diameter gas vent constructed of double wall Type B gas vent is recommended. Any gas vent

section that is greater than 45 degrees from the vertical is considered horizontal. Horizontal sections must slope upwards
at least ¼ inch for every foot of its horizontal length and be properly supported. Keep the horizontal section short and avoid
too many elbows. The minimum vertical gas vent height allowed is 6 feet; horizontal vent connectors and elbows are not
to be considered in the total gas vent height. All gas vent sections must be secured to each other with sheet metal screws
and be properly supported.

The gas vent constructed of double wall Type B gas vent must terminate above the roof surface with a listed vent cap at
a height that’s in accordance with Figure A or B and their table, provided they are at least 8 feet (2.4 m) from a vertical wall
or similar obstruction. All other gas vents that are not able to terminate within the minimum specified height allowed must
terminate not less than 2 feet (0.6 m) above the highest point where it’s passed through the roof and at least 2 feet (0.6
m) higher than any vertical wall or similar obstruction within 10 feet (3.1 m).

Roof pitch H (minimum) feet meters

Flat to 6/12

1.0 0.30

6/12 to 7/12 1.25 0.38
Over 7/12 to 8/12

1.5 0.46

Over 8/12 to 9/12 2.0 0.61
Over 9/12 to 10/12

2.5 0.76

Over 10/12 to 11/12

3.25 0.99

Over 11/12 to 12/12 4.0 1.22
Over 12/12 to 14/12

5.0 1.52

Over 14/12 to 16/12 6.0 1.83
Over 16/12 to 18/12

7.0 2.13

Over 18/12 to 20/12 7.5 2.27
Over 20/12 to 21/12 8.0 2.44

GAS VENT TERMINATIONS FOR LISTED VENT CAPS

LISTED VENT CAP

LISTED VENT CAP

LISTED GAS VENT

LOWEST DISCHARGE OPENING

H (minimum) height
from roof to lowest
discharge opening

Figure A Figure B

ROOF PITCH

IS X/12

12

X

8 6 720 606 446

MASONRY CHIMNEY: Masonry chimneys shall be built and installed in accordance with NFPS 211 or local codes. A

minimum 4” diameter gas vent pipe (metal double wall Type B), or an approved clay flue liner or a listed chimney lining
system must be used when venting into a naturally drafting, internal masonry chimney. Local codes may require the use of
both gas vent and an approved lining system when venting into a masonry chimney. The Commonwealth of Massachusetts
requires the use of a listed liner. Lining systems include approved clay flue lining, a listed chimney lining system or other
approved material that will resist corrosion, erosion, softening, or cracking from exhaust flue gases at temperatures up to
1800 degrees F. The lining system must be listed for use with naturally drafting, draft hood equipped gas appliances.
Follow local codes and refer to NFGC 54 and NFPA 58.

When connecting the water heater to a masonry chimney the following connector guidelines must be followed for
safe and proper operation: An approved gas vent connector must be attached to the top of the water heater and rise

vertically at least 12” before entering into an approved gas vent connector elbow. Any gas vent section that is greater than
45 degrees from the vertical is considered horizontal. If a horizontal vent connector is to be used to connect the vertical
gas vent connector on the top of the water heater to the masonry chimney, that approved horizontal gas vent connector
must be kept as short as possible and must be sloped upwards at least ¼” per foot of its length. This connector must be
supported throughout its horizontal length. This horizontal gas vent connection may be no greater than 75% of the total
vertical gas flue vent within the chimney. Also, an approved thimble or collar must be used when penetrating a masonry
chimney.

A) Existing INTERIOR Masonry Chimney

The metal gas vent pipe should be permanently mounted inside the masonry chimney. Double wall Type B gas vent is
recommended. The masonry chimney may have to be tile or metal lined before the insertion of the gas vent pipe; check
local codes for clarification. The lining material must be listed for use only with naturally drafting, draft hood equipped gas
appliances. Follow manufactures instructions for installation of listed lining material. You may not vent any other fuel
burning appliances into any free space remaining in the chimney. The minimum vertical gas vent length within the masonry
chimney should be no less than 5 ft (1.5 m); the vent terminator should extend at least 3 feet (0.9 m) above where the
chimney meets the roofline and at least 2 feet (0.6 m) higher than any vertical wall or similar obstruction within 10 feet (3.1
m). The top of the gas vent should have an approved vent terminator. See Figure C.

B) Tile Lined INTERIOR Masonry Chimney

The masonry chimney must have an approved liner, ceramic tile, clay or metal. The masonry chimney must be able to
accommodate the spent fuel gasses; consult a HVAC engineer for chimney capacity. A common venting like-fuel appliance
into this lined masonry chimney is permissible. The chimney’s diameter must be large enough to adequately draft the spent
fuel gasses. See NFPA 54 for guidelines. A HVAC engineer will be required to spec a chimney system. The minimum
vertical chimney length should be no less than 5 ft (1.5 m); the termination point should extend at least 3 feet (0.9 m)
above where the chimney meets the roofline and at least 2 feet (0.6 m) higher than any vertical wall or similar obstruction
within 10 feet (3.1 m). See Figure C.

C) EXTERIOR masonry Chimney

Refer to the National Fuel Gas Code and consult a local HVAC professional.

MASONRY CHIMNEYS

GAS

VENT

LISTED VENT CAP

VENT CONNECTOR

ESTABLISH A ONE

FOOT RISE BEFORE

ANY ELBOWS

Figure C

96 720 606 446

WARNING

Note: The burners of an instantaneous “on demand” water

heater such as the AquaStar are only on at the time that
hot water is actually being used, the vent pipe is therefore
cold except for the short durations when hot water is being
used, it is therefore very important that the venting and air
supply be adequate to provide a good positive draft as soon
as the burners turn on.
The AquaStar 38B instantaneous water heaters have built­in draft diverters and are designed for indoor installation
only. The draft diverter outlet must be connected to an
unobstructed vent of the same size, or larger.

In Canada, CAN/CGA-B149 Installation Code for detailed
requirements
In U.S.A., ANSI Z223.1 - NFPA 54, National Fuel Gas
Code for detailed requirements.

To check the draft:

Close all doors and windows to the outside.
Turn on all appliances that force air out of the building.
These include all exhaust/ventilation fans, furnaces, clothes
dryers, wood burning stoves, etc.
Open all doors between the AquaStar and these other
appliances.
Run the unit for at least 10 minutes. Then hold an ordinary
mirror at the side above the front shell. Any flue gases
backdrafting will cause the mirror to fog. This is a serious
health hazard and must be corrected. Poor venting can result
in soot building up inside the heater, overheating of the heater
and freezing of the heat exchanger in a freezing environment.
The mirror will remain clear with a properly functioning draft.

GAS CONNECTIONS
and Gas Regulator

Before connecting the gas supply, check the rating plate on
the right side of the front cover 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 should conform with CGA B149
INSTALLATION CODES and /or local installation codes.

NOTE: The Aquastar 38 B is supplied with a gas pressure
regulator that must be installed on the heater before
attaching the gas supply line. See figure 2. Place the gas
regulator between the gas supply connection (which
comes with a manual shutoff valve) and the gas fitting
wich is connected to the heater’s gas inlet. There is a
pressure tap on this gas fitting. The regulator supplied
with the heater is preset for the gas shown on the rating
plate to the correct pressure. It is an appliance level
regulator designed for low inlet pressure (less than 1/2
Psig or 15” W.C.) DO NOT connect to an unregulated or
high pressure propane line or to a high pressure
commercial natural gas line.

Fig. 2 - Gas Pressure Regulator

APPLIANCE GAS

REGULAT OR

1/2” BRASS

BUSHING

GAS SHUT-OFF

COCK

INLET GAS FITTTING

WITH GASKET

PLASTIC VENT CAP

PRESSURE
REGULAT OR
(with directional
arrow on reverse
side pointing upward)

PRESSURE T AP

The pressure regulator provided with the heater is adjusted
to deliver the proper gas pressure (as indicated on the rating
plate and in the manual for altitude up to 2000 feet (660
meters) above sea level. On appliances being installed above
2000 ft (660 meters) elevation, the inlet gas pressure should
be set at installation to the value shown below.

NOTE: The gas pressures specified below refer to
pressures taken at the pressure tap on the gas inlet pipe
just above the regulator (See Fig 2). These readings
should be taken while the heater is operating at full input
— i.e. maximum water flow with the temperature dial
selector turned all the way clockwise.

10 6 720 606 446

Connecting the pressure relief valve (PRV)

A listed pressure relief valve supplied with the heater must
be installed at the time of installation. Should a discharge
line be added to the PRV 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 installed such that it allows complete
drainage of both the PRV and the line. 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 4. To install the PRV, a suitable fitting connected to
an extension on a “T” fitting can be sweated to the hot
water line.

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.

WARNING: The heater and its individual shutoff
valve must be disconnected from the gas supply piping
system during any pressure testing of that system at
test pressures in excess of 0.5 psig.

The water heater must be isolated from the gas supply piping
system by closing the manual shutoff valve during any
pressure testing of the gas supply piping system at test
pressures equal to or more than 0.5 psig.
The water heater, including the pressure regulator provided
with it, must not be operated at gas supply pressures in
excess of 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 and regulator must be
checked for safe operation.
Make sure that the regulator vent is protected against
blockage.
When your connections are made, check for gas leaks at
all joints (not just the ones you made). Apply some soapy
water to all gas fittings and gas valve. Soap bubbles are a

sign of a leak.
NOTE: Do not apply soap solution to pilot filter screen or

pilot orifice area. If you have a leak, shut off the gas. After
verifying that required gaskets are in place, tighten
appropriate fittings to stop leak. Turn the gas on and check
again with a soapy solution. Never test for gas leaks using

a match or flame.

MAXIMUM INLET GAS FLOW PRESSURE SETTING

Above 4.500 ft consult your local gas supplier.

Fig. 3 - Water connections

HOT OUTLET LINE

(CONNECTED TO HEAT

EXCHANGER)

3/8” WASHER

3/8” x 1/2”

BRASS FITTING

COLD WA TER

INLET

WATER CONNECTIONS

Install the heater centrally in the building if possible and
make hot water piping runs as short as possible When facing
the heater, the cold water inlet will be on the right and the
hot water outlet on the left.
Although water piping throughout the building may be other
than copper, copper or galvanized piping should be used
when connecting to the heaters ½” male NPT connectors
(follow local codes if more stringent). Plastics or other PEX
type plumbing line materials are not suitable for connecting
directly to the water heater. Keep water inlet pipe to no less
than ½” (19.05mm) diameter to allow the full flow capacity.
If the cold and hot connections to the heater are reversed,
the heater will not function.
The 38B is provided with one rigid elbow connector that
must be connected to the cold inlet fitting of the brass water
valve, no pipe dope or thread tape is to be used at this joint.
The outlet flexible connector is supplied attached to the
heat exchanger, the supplied 3/8” washer and 3/8”x1/2”
brass fitting should be attached to it to allow a ½” NPT
connection to be made. See Fig. 3.
Be certain there are no loose particles or dirt in the piping.
Blow out or flush the lines before connecting to the water
heater. Full port valves should be installed on both the cold
water supply and hot water outlet lines to facilitate servicing
the heater. For installation on a private well system with the
use of a pressure tank, the lowest pressure range setting
recommended is 30-50 psi (2.07-3.45 bar).

Altitude Natural Gas Liquid Propan

e

inches W.C: inches W.C:

0' - 2.000 ft 5.7" 10.5"

2.000 ft - 4.500 ft 4.6" 8.4"

116 720 606 446

LIGHTING INSTRUCTIONS (as seen on front cover

of heater)

1. STOP! Read the safety information on the front panel of

the heater.

2. The Gas valve must be turned off by sliding the gas valve

button ( ) to the far left under the OFF ( ) mark.

3. Wait five (5) minutes to clear out any gas. If you smell

gas, STOP! Follow “B” in the safety information above
on this plate. If you don’t smell gas, go to next step.

4. The pilot burner is located behind the peephole in the

front center of the jacket directly below the lighting
instructions on the front panel of the heater.

5. Slide the gas valve button to the right, to the pilot position

( ).

6. Fully depress gas valve button ( )and light pilot by

pressing hard on pilot igniter button ( ). This step may
have to be repeated.

7. Observe the pilot flame through the peephole. The gas

valve button should be held down at least 15 seconds
with pilot burning. When the gas valve button is released,
the pilot should continue to burn.

- If the gas valve button does not pop up when released,
stop and immediately call your service technician or gas
supplier.

- If pilot does not stay lit, repeat steps 1 through 7.

- If pilot will not stay lit after several tries, slide the gas
valve button to the left, under the OFF ( ) mark and call
service technician or gas supplier.

8. When the pilot remains on, slide the gas valve button to

the right, to the ON ( ) position. The heater will now
fire when water is drawn at a rate of 1/2 gallon or more
per minute.

NOTE: If main burner should fail to ignite, make sure pilot is
burning. If not, repeat lighting steps 1 through 7.

TO TURN OFF GAS TO APPLIANCE

Slide the gas valve button ( ) to the far left, under the OFF
( ) mark and close the heater’s individual shut-off valve.

OPERATING INSTRUCTIONS

Before proceeding with the operation of the heater make
sure that the system is filled with water.

Open the cold water inlet supply to the heater fully.
Open a hot water faucet to permit the water to fill the heater
and the piping and to eliminate the air trapped in the system
Close the hot water faucet after the water flows freely and
all the air has escaped from the system. The water heater is
now ready to operate.

FOR YOUR SAFETY READ BEFORE LIGHTING
THE PILOT

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 has a piezo-igniter for lighting the pilot
burner. When lighting the pilot, follow these instructions
exactly.
B. BEFORE LIGHTING smell all around the appliance area
for gas. Be sure to smell next to the floor because some gas
is heavier than air and will settle on the floor.

WHAT TO DO IF YOU SMELL GAS

- Do not try to light any appliance.

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

Fig. 5 - Water Piping

Fig. 4 - Pressure Relief Valve

- Immediately call your gas supplier from a neighbor’s
phone. Follow the gas supplier’s instructions.

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

C. Use only your hand to push in or turn the gas control
buttons. Never use tools. If a button will not push in, check
to make sure the buttons are being pushed in the proper
sequence. Follow these instructions exactly. If control
button(s) are 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.

12 6 720 606 446

Fig. 6 - Water Flow Control Knob

The position you select on the temperature adjustment knob
will depend on the temperature of the incoming water (50°F
is average in the U.S.). If you plan to supply the AquaStar
38 B, with preheated water (i.e.) solar installation, the unit
could overheat. It will then shut off on safety when the
outlet temperature reaches 185°F. For a lower temperature
rise, the heater can be set for minimum burner output by
sliding the gas valve control to the pilot setting symbol ( ).

MAINTENANCE AND SERVICE (see maintenance

table on back)

Approximately once a year, the AquaStar should be checked
and cleaned. To remove the front cover, first remove the
incandescent particle tray, then pull off the temperature
adjustment knob, unscrew and remove the plastic collar and
unscrew the central screw located at the bottom of the front
cover. Pull main cover out toward you and lift up and out.
THE FOLLOWING OPERATIONS SHOULD BE
PERFORMED BY A QUALIFIED SERVICE PERSON:

Vent System: Should be checked annually. Clean and repair
as needed.

Water Valve (Part # 8707002497): The water valve on
this heater should be serviced periodically. Lubricate com­ponent #19 on page 18 with a small amount of silicon,
faucet or lithium grease every two years to keep its o rings
fresh and pushrod sliding smoothly. Every 3-5 years replace
components #19 and #21 on page 18. The frequency will
depend on the mineral content of the water and conditions
of use or whenever signs of corrosion appear at the gas and
water valve joint. Periodically check that the water inlet fil­ter (#25 on page 18) is clean as well.

3mm

Correct gap between pilot
burner tip and electrode tip

Piezo Electrode

Air screen filter

Fig. 7 - Characteristic Pilot Flame

10mm

3/8”

Piezo

Electrode

Thermocouple

To clean the pilot burner and/ or the pilot orifice : Turn
off the gas at the unit. Remove the cover of the heater. To
do so, remove the incandescent particle tray, pull off the
temperature adjustment knob and unscrew and remove the
knob collar. Unscrew the central screw located at the bottom
of the front cover. Pull main cover out toward you and lift up
and out. Pull the air screen off, wash it and blow any lint off
(See Fig 8). The pilot orifices should also be cleaned or
replaced. Do not enlarge the orifice. Do not use any wire
or sharp object to clean orifices. Natural gas orifices are
large enough that you can usually clean them by blowing
through them. LP orifices, on the other hand, are too small
to clean and should be replaced. See #3 in Trouble Shooting
Section. To access the pilot orifice, remove 2 screws holding
pilot assembly in place. Then loosen compression fittings to
expose pilot orifice.

Pilot Flame: The pilot flame should burn with a clean sharp
blue flame and should resemble the diagram in Fig 7. If the
flame is yellow, or if the pilot knob has to remain depressed
for a long time in order to keep the pilot lighted, the pilot
burner and or the pilot burner orifice may need to be cleaned,
the orifice may need to be replaced, and or the air screen or
pilot gas filter may need cleaning. The pilot flame should
envelop approximately 10 mm (3/8") of the tip of the
thermocouple. If it is too small, the pilot burner must be
cleaned. The position of the Piezo igniter electrode should
be approximately 3 mm (1/8") from the pilot.

SETTING THE WATER TEMPERATURE

To adjust the temperature on your AquaStar, turn on a hot
water faucet to its maximum flow.At the water heater, turn
the large temperature adjustment knob located beneath the
main gas controls on the front of the heater all the way to
the right (clockwise). See Fig 6. This will produce a
temperature rise of approximately 90°F at a flow rate of .5
gallons per minute (gpm). Turning the dial all the way to the
left (counterclockwise) will increase the water flowing through
the heater, and will produce a temperature rise of
approximately 45°F at a flow rate of 1.3 gpm. Given that
average incoming water temperatures are 50°F, this heater
will produce water between 140° and 95° at these flow
rates. Thus one can obtain a higher flow rate, but at cooler

temperatures.

136 720 606 446

PILOT DOES NOT LIGHT

1. No gas to the Aquastar

A. Gas cock on gas line may not be open.
B. Gas valve button has not been moved to “PILOT

POSITION”. Slide button to right to single flame position
( ).

2. In-line Aquastar gas regulator jammed (usually on LP

gas)

Replace or unlock the regulator. Note: The regulator
furnished with the heater is designed for low gas pressure.
Excessive pressure will lock it up (propane only). Locking
usually happens if the gas pressure between the gas tank
(propane) and the water heater’s gas regulator has not been
reduced. See page 2 for recommended correct gas pressure
and check with gas service person.
To unlock a regulator, consult your gas supplier.

3. Pilot orifice clogged and/or air screen dirty

Clogging of the pilot burner can be caused by dust and any
suspended matter contained in the ambient air. Although
the filters can lengthen the cleaning intervals, they can never
completely prevent such clogging. In consequence the gas
jet issuing from the pilot orifice is reduced and or the air
mixture is reduced. The pilot flame is weak and thus can no
longer heat the thermocouple sufficiently. For cleaning
purposes, the air filter screen is pulled off, washed and blown
out. The pilot orifice has likewise to be cleaned or exchanged.
See page 12.

4. Air in the Gas Line

Note: Normally this is a problem only at the time of initial

installation, after the pipes have been worked on, or after a
propane tank has been allowed to empty, or after the heater
has been shut down for a long time.
Bleed all the air trapped in the gas line. Because of the very
small pilot orifice (especially on LP gas models), bleeding
out all the air could take several minutes. Slide the gas
valve button ( ) to pilot position ( ) and depress this
button until all the air has escaped, and the gas has arrived.
During this process, press on the piezo ignition
button separately until the pilot flame has ignited.

Main Burner Flames: The main burner flames should be
blue, with a more intense blue cone in the center core. Yellow
flames could be a sign of wrong size gas orifices or dirty
burners, or a blockage on the heat exchangers fins. If some
burners have yellow flames while others have good flames,
it is likely that dust, lint or spider webs have partially clogged
the burner venturis. To clean the burners contact a gas service
person.

Mineral Scale Build-up: The AquaStars heater, when
operated at lower temperature settings, do not accumulate
mineral build-up. If however, the heater is used at the higher
temperature settings and the water has a high mineral
content, periodic descaling may be necessary. The heating
coils should be flushed with a descaling solution. Consult
your service person.

TROUBLE SHOOTING (see maintenance table on

back)

Introduction

The AquaStar 38 burners are ignited by a water flow valve.
Numerous water related problems can cause this water valve
to malfunction such as: Insufficient water flow volume to
activate the burners at its minimum flow requirement; Dirt
in the water flow valve causing it to malfunction; Sediment
build-up in faucet aerators, or shower heads; Uneven
pressures between cold and hot. (with single lever faucets)
Plumbing cross overs. These water flow related problems
can cause the heater to deliver less than its full output, or
to fail to ignite or to shut down completely.

Problems are stated in upper case, bold face. Most common
causes for the problems follow in order of likelihood. The
suggested solutions require that the cover be taken off. To
this, remove incandescent particle tray, pull off the
temperature adjustment knob and unscrew and remove the
plastic collar and unscrew the central screw located at the
bottom of the front cover. Pull main cover out toward you
and lift up and out.

Fig. 8 - Pilot burner with air screen/ pilot orifice

PILOT ORIFICE

AIR SCREEN

14 6 720 606 446

BUR NERS DO NOT IGNITE WH EN HOT WATER IS TURNED
ON

1. Pilot is not on.

Light the pilot. See lighting instructions.

2. Pilot lighting push button not turned to proper
position

Be sure that once the pilot flame is on, that the gas valve
button ( ) is slid all the way to the right to the ON position
( ).

3. Cold incoming water connection made to wrong side
of heater

Make sure cold water inlet connection is on the right side of
heater when you are facing heater.

4. Water flow rate at hot water tap is too low.

With the control knob set fully clockwise the Aquastar
model 38B requires ½ gallon per minute flow to activate
the burners. This is a flow which would fill a quart jar in
30 seconds.

5. Cold water inlet filter on heater is dirty.

Remove the filter and clean. This screen filter is located at
the inlet side of the brass water valve (fig. 10, #25). Check
and clean faucet aerators too.

6. Crossover in household plumbing

The AquaStar burner activates when there is sufficient water
pressure drop in the AquaStar water valve assembly — ie.
when a hot water faucet is opened. If there is a crossover in
the plumbing, the necessary pressure drop in the AquaStar
will be insufficient, or totally eliminated. A plumbing crossover
can be caused by a bad washer at a single lever faucet or
incorrect plumbing or a mixing valve in the line, etc. which
permits hot and cold water to mix in the plumbing. The
crossover will create a back pressure in the system preventing
the pressure drop in the Aquastar (i.e. cold water is entering
the water heater from both sides and the burners will not
come on). To confirm there is no crossover in the plumbing,
shut off the cold water supply to the AquaStar. Open your
hot water taps. There should not be any water flowing. If
there is water flowing, there is a crossover in the plumbing.
This is a plumbing problem, not an Aquastar problem. Please
contact your plumber.

7. Water valve parts may be dirty or components
damaged.

Water valve and component parts must be totally free of
dirt. First check that the venturi is free of dirt particles. In
hard water areas, mineral deposits can eventually (3 to 5
years in hard water areas) corrode the water valve parts to
a point where they will need replacing. Any sign of moisture

or corrosion at the joint of the water valve and the gas valve
is a sign that the water valve assembly components need to
be replaced immediately. (Contact service person to clean

water valve or replace if corrosion is present).

PILOT LIGHTS BUT FLAME GOES OUT WHEN BUTTON
IS RELEASED

1. Pilot push button was not pushed in far enough or
was not held in long enough

Slide the gas valve button ( ) to pilot position ( ) and
depress this button. Hold it pushed in for at least 15 seconds
to give time for the pilot flame to properly heat the tip of the
thermocouple.

2. Pilot flame improperly aimed or is too weak so it is
not properly heating the tip of the thermocouple.

The Pilot flame should be a sharp blue flame and aimed at
the tip of the thermocouple so that it envelops 10 mm (3/8
“) of the thermocouple tip. Pilot flame has to be properly
aimed at the thermocouple. See Fig 7.

3. Poor thermocouple connection at the electromagnet

Note: Electromagnet is part #8707201012 located on the

right side of the gas valve behind the piezo pushbutton
assembly. Check the tightness of the thermocouple
connection nut at the electromagnet: The Electro-magnet
connection is a large aluminum 17mm hex head nut. The
thermocouple end is a 5 mm brass nut which screws into
the 17 mm nut. Tighten the thermocouple nut snugly but not
too tight.

4. Poor circuit connections at the ECO. (Energy Cut­Off overheat protection)

Oxidation or looseness of the ECO terminal connections
can result in millivolt current loss through the thermocouple
safety circuit. Clean terminals with very fine sand paper or
an eraser and reconnect ECO leads.

5. Faulty ECO (part #8707206040)

If cleaning the terminals attached to the ECO did not fix the
problem, connect a jumper wire between the two wires and
try to relight the pilot. If the pilot flame now remains on,
replace the ECO. If the flame still goes out when the button
is released, the ECO is not defective. Go to next step.

6. Faulty thermocouple (part #8747202083) or
electromagnet ) Unless these 2 parts are at least 8 to
10 years old, it is very unlikely that they are faulty.
Before testing, reconfirm that #2 is absolutely correct,
and that all connections are clean and tight.

To test the thermocouple, disconnect the thermocouple lead
to the ECO. Insert a multi-meter probe into the thermocouple
lead and attach or hold the other lead to the metal gas
valve (DC common). Light the pilot flame and hold button,
meter reading should be 24 mVDC or more. If the reading is
24 mVDC or more the thermocouple is good. To test the
electromagnet, re-connect the thermocouple lead to the
ECO, light pilot and hold button while taking a reading
between the ECO leads and the metal gas valve (DC
common). The reading should drop to 19 mVDC or less. If it
does not, replace the electromagnet.

156 720 606 446

4. Btu input is too low due to insufficient gas supply

Make sure your main gas line is fully opened. If using LP
gas, be sure that the size of the propane tank is adequate to
supply the required gas pressure.

5. Cold water is mixing with the hot water between the
AquaStar and the outlet

Compare water temperature at outlet of the AquaStar (hold
the AquaStar’s outlet pipe with your hand) and at the tap. If
these two are very different, check for mixing valve or
plumbing crossover (see “BURNERS DO NOT IGNITE
WHEN HOT WATER IS TURNED ON” paragraph # 6).
Where automatic “anti-scald” valves are required by code,
lower the temperature setting on the AquaStar as much as
possible and balance the pressure between cold and hot
water after the AquaStar.

6. Parts in water valve are dirty or damaged, which will
prevent the gas valve from being fully opened.

Water valve maintenance needs to be performed, see #7
under BURNERS DO NOT IGNITE WHEN HOT WATER
IS TURNED ON

HOT WATER TEMPERATURE FLUCTUATES

1. Unbalanced pressure in waterlines

The added restriction caused by the Aquastar in the hot
water system can result in uneven pressures between the
cold and the hot. In such cases when mixing cold water at
the tap, the lower hot water pressure may be overpowered
by a much higher cold water pressure, which may cause the
Aquastar burners to shut down. Make sure faucet aerators
or shower heads are free of minerals. Do not add any flow

restrictor to the shower head.

2. Cold water is mixing with the hot water between the
AquaStar and the outlet

See # 6 under “Burners do Not Ignite When Hot Water is
Turned On”.

3. Inlet water pressure is erratic due to inadequate supply
water pressure or saturated pressure tank on well
system

For installation on a private well system with the use of a
pressure tank, the lowest pressure range setting
recommended is 30-50 psi (2.07-3.45 bar). Confirm that
the pressure tank is not water logged.

4. Insufficient gas pressure

Check gas pressure requirements (page 2) and consult gas
service person.

PILOT LIGHT GOES OUT DURING OR IMMEDIATELY
AFTER HOT WATER HAS BEEN USED

1. Gas pressure too low

Very low gas pressure may be caused by low delivered gas
pressure, a jammed gas regulator or undersized gas lines. If
the gas lines are undersized, there may still be the specified
static gas line pressure. However when the water valve
opens,and gas enters the burners, the pressure could drop
sharply, causing the pilot flame to go out. Have a gas
technician confirm the gas pressure both static and at
maximum Btu output. Specifications for your heater are on
page 2.

2. Pilot may be dirty or weak

See Page 12 for instructions on pilot maintenance.

3. Burners are not shutting down immediately when hot
water is turned off

Note: If burners don’t shut down immediately when the hot

water is turned off, the heater will overheat and the ECO
will shut-off the gas. Rebuild the water valve assembly repair
kit from BBTNA (part#8 703 406 204).

4. Water is too hot causing overheat sensor to shut
heater down

Reduce burners by sliding gas control to single flame
position or set control knob to a lower setting.

WATER IS TOO HOT

1. Burners are too strong

Note: If the inlet water is quite warm, slide gas valve control
to single flame symbol ( ) and the heater will function on
a minimum burner output.

2. Temperature selection is too hot

Turn the temperature adjustment knob to the left.

WATER IS NOT HOT ENOUGH

1. Temperature adjustment knob is set too low.

Change the setting. Turn the temperature adjustment knob
clockwise (to the right).

2. Water flow through the heater is higher than the
capacity of the AquaStar to heat it

Reduce the flow demand at the faucet. See flow rates at
specific temperature rises on page 2.

3. Btu input is too low due to insufficient gas pressure

It is extremely important for a tankless instantaneous
water heater to have the right size gas line to obtain
the correct gas pressure

See specifications on page 2. Unlike storage tank water
heaters, the burners of a tankless water heater must be very
powerful to heat water instantaneously since they do this
only at the time hot water is actually being used. It is
therefore imperative that the gas pressure requirement be
met exactly. Insufficient gas pressure will directly affect the
water temperature at the time of usage. See pages 2 and
10 respectively for correct gas pressure settings and where
gas pressures are taken.

16 6 720 606 446

Fig. 9 - Diagram of AquaStar 38 B

2

4

8

10

1

7

9

11

1. Heat exchanger

2. Pilot assembly

3. Burner manifold gas
pressure test nipple

4. Pilot gas tubing

5. Main gas burner

6. Inlet gas pressure test nipple

7. Gas valve

8. Gas control slide

9. Piezo igniter

10. Temperature adjustment knob

11. Water valve

3

5

6

176 720 606 446

18 6 720 606 446

Fig. 10 - INTERIOR COMPONENTS DIAGRAM AND PARTS LIST

196 720 606 446

Fig. 10

INTERIOR COMPONENTS DIAGRAM

AND PARTS LIST 38B

1 Cover 8 705 421 021
2 Temperature adjustment knob 8 702 000 182
4 Draft divertor 8 705 505 361
5 Heat exchanger 8 705 406 149
6 Overheat sensor (ECO) 8 707 206 040
7 Hot water pipe 8 700 703 038
8 Main burner assembly 8 708 120 301 LPG

Main burner assembly 8 708 120 011 NG

9 Burner assembl

y

washer 8 700 103 008
10 Piezo electrode 8 708 107 002
11 Pilot burner assembly 8 718 105 051

11a Pilot air screen 8 700 507 055

12 Pilot orifice 8 708 200 005 NG

“ 8 748 200 173 LPG
13 Pilot Tube 8 710 707 166
14 Thermocouple 8 747 202 083
15 Gas valve 8 707 011 456 LPG

Gas valve 8 707 011 466 NG
16 Electromagnet 8 707 201 012
17 Thermocable 8 747 202 209
18 Water valve assembly 8 707 002 497
19 Pushrod 8 703 406 204
20 Water valve diaphragm 8 700 503 050
21 Slow i

g

nition valve 8 708 503 063
22 Water valve water governor 8 707 402 018
23 Water valve selector screw 8 708 500 166
25 Water inlet filter 8 700 507 001
26 Water valve venturi 8 708 205 210
27 Throttle Disc 8 700 100 169 NG
28 Piezo igniter 8 708 108 040
29 Screw 8 703 401 051

20 6 720 606 446

Fig. 11 - Flow chart of Aquastar 38 B

216 720 606 446

LIMITED WARRANTY

Aquastar

General

Aquastar water heaters are warranted by the Manufacturer
(BOSCH) through BBT North America. BBT North America
(BBTNA) 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
BBTNA 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 BBTNA will furnish a
replacement heat exchanger. However, 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.

All other parts

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

Shipping costs

In addition to supplying the replacement part(s), BBTNA
will provide ground service delivery for these parts. Expedited
or upgraded shipping will be charged to the customer.

Service labor costs

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

How to Make a Claim

Any claim for warranty parts should be made to your local
dealer, distributor or to BBTNA. If BBTNA, please contact
the Technical Support Department:

Controlled Energy Corp.
340 Mad River Park
Waitsfield, VT 05673
Phone: [phone]
www.controlledenergy.com/tech

In most cases, the dealer or distributor will be able to promptly
honor your claim and subsequently notify BBTNA. However,
all replacements are made subject to validation by BBTNA
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 BBTNA. It is expressly understood that the replacement
warranty of BBTNA 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 BBTNA 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). BBTNA’s
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.

22 6 720 606 446

236 720 606 446

Bosch Heating

System Co. Foschan Guangdong

C. T. 528315 P.R. China

Recycled paper

31&21segapeesELBATECNANETNIAM

RAEYYREVESRAEY2YREVESRAEY5-3YREVE

EVLAVRETAWETACIRBUL

†

EVLAVRETAWDLIUBER

†

NEERCSRETLIFRETAWTCEPSNI

†

YLBMESSATOLIPTCEPSNI

†

YLBMESSATNEVTCEPSNI

†

RENRUBNIAMTCEPSNI

†

Replacement Parts available from:

BBT NORTH AMERICA

Bosch Group

Bosch Water Heating
340 Mad River Park
Waitsfield, VT 05673
Phone [phone]
Fax [phone]
www.boschhotwater.com
[e-mail]

© 2006 BBT NORTH AMERICA,
Waitsfield, VT all rights reserved