Bosch 125B LPL, 125B NGL User Manual

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

MODEL 125B LPL and 125B NGL (Non-Modulated)

Suitable for heating potable water

Certified for space heating in combination with potable water only

Not certified for space heating only. Intended for either recirculation to storage or cold water inlet flow that

is non-varying. For variable flow, install the 125 B or the 125 X model.

W ARNING

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.

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.

6 720 606 522 (01.10) AL

Upon completion of the installation, these instructions
should be handed to the user of the appliance for
future reference.

Warning: If you do not follow these instructions exactly , a

fire or explosion may result causing property damage,
personal injury or loss of life

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

T ABLE OF CONTENTS

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

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

Locating the Heater ............................................ Page 5

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

Mounting the Heater........................................... Page 6

Venting the Heater ............................................. Page 6

Gas Connections ............................................... Page 7

Water Connections ............................................ Page 8

Safety before lighting the pilot ............................ Page 9

Lighting instructions ........................................... Page 9

About Water Temperature .................................. Page 9

Maintenance & Service....................................... Page 9

Trouble Shooting .............................................. Page 10

Diagram of AquaS tar......................................... Page 13

Components and Parts List.............................. Page 14

This well engineered, gas water heater has been
specially designed to operate as a circulating 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.

- Easy pilot flame lighting with push button piezo ignition.

AquaStar 125B LPL and 125B NGL Specifications

Gas Input max.: 117,000 Btu/hr

min.: 60,000 Btu/hr
Water Connection 1/2” Thread fitting
H x W x D 29 3/4” x 18 1/4” x 8 3/4"
Vent 5”
Gas Connection 1/2” NPT thread
Min. Water Pressure 8 Psi at 1.8 GPM
Min. Water Pressure 18 Psi at 3.7 GPM
Max. Water Pressure 150 Psi
Shipping Weight 46 LB
Net Weight 44 LB

1.8 GPM at 90° rise

3.7 GPM at 45° rise
Min. Water Flow 1.8 gal/min
LP GAS Supply Pressure

(before Aquastar regulator) min.: 1 1” W .C.

max.: 14” W.C.*

Required LP GAS Pressure at inlet
tap while Aquast ar 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 Aquast ar is operating: 5.7” W.C.

Natural Gas Burner Manifold pressure while Aquastar
is operating at maximum input: 4.2” W.C.

* Inlet gas pressure before Aquastar regulator must not
exceed this value. Pressure may need to be adjusted for
high altitudes, see page 8.

UNPACKING THE AQUASTAR HEATER

This heater is packed securely . The box includes two water connection fittings, a gas pressure regulator , a pressure relief
valve, an incandescent particle tray , 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.

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D861_059

FRONT VIEW SIDE VIEW

MINIMUM INST ALLA TION CLEARANCES FROM COMBUSTIBLE AND NON

COMBUSTIBLE MATERIALS FOR ALCOVE OR CLOSET INSTALLA TIONS

MO DE L 125B L

TOP (A) 12"
FRONT (B) 4"
BACK 0"
SIDES 4"
FLOOR (C) 12" *
FLUE DIAMETER 5"

* Some local codes require 18” in garage installations

AQUASTAR MODEL 125BL

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If you are using the AquaStar for combined space heating and potable water heating (see
schematic diagram below), all piping and other components connected to the system must

be suitable for potable water, (b) toxic chemicals such as those commonly used for boiler
treatment to prevent corrosion and freezing must not be introduced into the system, and
(c) if the space heating requires water temperatures higher than those required for do­mestic, potable water, a mixing valve or other similar device must be provided to reduce
scald hazard potential, (d) maximum system water temperature must not exceed 140°F
(60°C). DO NOT CONVERT AN EXISTING, CLOSED HOT WATER HEATING SYSTEM TO A
COMBINATION SPACE AND POTABLE WATER HEATING SYSTEM USING THE AQUASTAR
OR ANY OTHER HEAT SOURCE.

Open loop potable water and combination space heating system*

* T o be used with a tank, check local codes. May not be permitted in some jurisdictions.

Notes

1. Maximum to tank water temperature from 125 BL 140°F

2. Maximum heating capacity: 40°F rise 20°F rise

AquaStar 125BL - 80,000 BTU/hr 40,000 BTU/hr

3. System shown is electric storage tank with recirculating supply
drawn from the tapping for the lower heating element.

4. If circulation flow to the Aquastar 125BL is restricted, it may be
necessary to adjust the temperature slide control to prevent
overheating.

5. Schematic is for illustration and example only and must not be used
for actual installation without appropriate engineering and technical
advice from a professional properly licensed in the locality where
the installation is made.

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/NFP A 54.
In Canada: The Installation should conform with CGA
B149.(1,2) INST ALLA TION 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.

*Pipe PRV to appropriate discharge
**Tempering valve is required when tank water temperature is over
130 F.

occupied rooms normally kept closed. See the section below
on locating the heater.

4. Y ou 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 less than 1/2 Psig (3.5kPa).
The appliance and its gas connection must be leak tested
before placing the appliance in operation.

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

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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

WARNING: The water in this water heater is cold

and always remains cold except 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 elbow connections
at the rear of heater. Additionally remove the drain plug
under the water valve. See Fig 0.

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 ef ficient 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.

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

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

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.

COMBUSTION AIR REQUIREMENTS

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. The vent pipe must not be restricted and its 6 foot
minimum height (provided there are no elbows) must
terminate 2 feet above any obstruction within a 10 foot
radius.
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 AquaS tar’s vent pipe, leaving the cold infiltrating
air capable of freezing the cold water in the AquaS tar 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 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 5850 cubic feet for the AquaS tar 125BL 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

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