Bosch 125B LP User manual

WARNING: Improper installation,
adjustment, alteration, service or maintenance can
causeinjuryorpropertydamage.Refertothismanual.
For assistance or additional information consult a
qualified installer, service agency or the gas supplier.
Uponcompletionoftheinstallation,theseinstructions
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.
FEATURING:Automatic Variable Power Modulating Gas
Valve
INSTALLATION AND OPERATING INSTRUCTIONS FOR AUTOMATIC
INSTANTANEOUS TYPE WATER HEATERS FOR USE WITH NATURAL AND
LIQUEFIED PETROLEUM GAS
MODEL 125B LP and 125B NG (Flow Modulated)
Suitable for heating potable water only
Not approved for space heating purposes
Intended for variable flow applications with steady cold water inlet temperatures only
WARNING
If the information in this manual is not followed
exactly, a fireorexplosionmayresultcausingproperty
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.
-Immediatelycallyourgassupplierfromaneighbor’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
qualifiedinstaller, serviceagencyorthegassupplier.
Specifications .................................................... Page 2
Rules for safe operation .................................... Page 4
Locating theHeater ............................................ Page 4
CombustionAirRequirements ............................ Page5
MountingtheHeater........................................... Page5
Venting theHeater ............................................. Page 6
GasConnections ............................................... Page7
WaterConnections ............................................ Page9
Safetybefore lighting the pilot ............................ Page9
Lightinginstructions ......................................... Page10
Settingwatertemperature ................................ Page10
Maintenance&Service..................................... Page10
TroubleShooting ...............................................Page11
DiagramofAquaStar......................................... Page14
Componentsand Parts List.............................. Page15
TABLE OF CONTENTS
6 720 606 521 (02.01) AL

2
This well engineered, gas water heater has all the fea-
tures a water heater should have:
Itoperatesontheprinciple ofheatingwaterinstantaneously
“on demand”. When a hot water faucet is opened, cold
waterflows through the coils of theheat exchanger in the
Aquastar. This same flow opens the gas valve, and the
burnersareignitedby the pilot flame. The heatexchanger
coils absorbtheheat generated bytheburners and trans-
fer 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
energyuse. Each timeyou turn off yourhot 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.
- Burner output proportional to hot water flow demand
for maximum energy efficiency.
- Safety thermocouple at pilot burner.
- Automatic overheating protection shut-off sensor.
- Stainless steel burners with stabilized blue flame.
- Built-in corrosion resistant draft inducer.
- Compactspacesaver:mountsonawallwithtwohooks.
- Easily removable one-piece cover.
- Easy one person installation.
- Adjustablewaterflowrestrictortoensurethatwaterflow
demand will not exceed the heating capacity of the
heater.
- Easypilotflame lighting withpushbutton piezo ignition.
BOSCHisconstantly improvingourproducts,therefore
specifications are subject to change without prior
notice.
AquaStar 125B LP and 125B NG Specifications
GasInput max.:117,000Btu/hr
min.: 28,000 Btu/hr
WaterConnection1/2” Thread fitting NPT
H x W x D 29 3/4” x 18 1/4” x 8 3/4"
Vent5”
GasConnection1/2”NPT thread
Min. Water Pressure 18 Psi at 4 GPM
Max. Water Pressure 150 Psi
Shipping Weight 42 LB
Net Weight 39 LB
1.8 GPM at 90°rise
3.7 GPM at 45°rise
Min. Water Flow 1/2 gal/min
LP GAS Supply Pressure min. 11” W.C.
(beforeAquastarregulator) max.14” W.C.*
RequiredLP GASpressure at inlet
tapwhileAquastarisoperating: 10.5” W.C.
LPGASBurner Manifold pressurewhile
Aquastar is operating at maximum input: 9.0” W.C.
NaturalGas Supply Pressure
(beforeAquastarregulator) min.: 7” W.C.
max.: 14”W.C.*
RequiredNaturalGas Pressure at
inlet tap whileAquastar is operating: 5.7”W.C.
NaturalGasBurnerManifold 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 7.
UNPACKING THE AQUASTAR HEATER
Thisheateris packedsecurely.Thebox includes two waterconnection fittings, a controlknob, a gas pressureregulator,
apressurereliefvalve,anincandescentparticle tray,twohooksforhangingtheheater, this manual, a warranty statement
and a warranty registration card. Do not lose this manual, as there is a charge for replacement. Please complete
andreturnthe enclosed warrantyregistration card.

3
D861_059
MINIMUM INSTALLATION CLEARANCES FROM COMBUSTIBLE AND NON
COMBUSTIBLE MATERIALS FOR ALCOVE OR CLOSET INSTALLATIONS
FRONT VIEW SIDE VIEW
AQUASTAR MODEL 125B
* Some local codes require 18” in garage installations
MODEL 125B
TOP (A) 12 "
FRONT (B) 4 "
BACK 0 "
SIDES 4 "
FLOOR (C) 12 " *
VENT DIAMETER 5 "

4
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
conformwithlocal codes or, intheabsence of local codes,
the National Fuel Gas CodeANSI 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. Theplacewhereyouinstalltheheatermusthaveenough
ventilation.TheNationalFire Codes do not allow gasfired
water heater installation in bathrooms, bedrooms or any
occupiedroomsnormallykeptclosed.Seethesectionbelow
onlocating the heater.
4. You must vent your heater. See section on Venting,
Page6.
5. Theappliancemustbedisconnectedfromthegassupply
piping system during any pressure testing at pressures in
excess of 1/2 Psig (3.5 kPa).
Theappliancemustbe isolated from thegassupplypiping
systembyclosingitsindividualmanualshutoffvalveduring
any pressure testing of the gas supply piping system at
test pressures equal to or more than 1/2 Psig (3.5Kpa).
Theappliance and itsgas connection must be leaktested
beforeplacingthe appliance in operation.
6. Keepwaterheaterareaclearandfreefromcombustibles
and flammable liquids. Do not locate the heater over any
materialwhich might burn.
7. Correct gas pressure is critical for the optimum
operationofthisheater(seespecificationsonpage2).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 gassupply.
8. Shouldoverheating occur orthe gas supplyfail to shut
off,turnoff the gassupplyat the manual gasshut off valve
on the gas line.
9. Do not use this appliance if any part has been
underwater. Immediatelycallaqualifiedservicetechnician
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
safetyandforproperheateroperation, you mustprovidean
abundant supply of combustion air and a proper venting
installation.
Theheatermaystilloperateevenwhenimproperlyvented.
Itwill,however,belessefficientandcouldeventuallydamage
theheater.Itcould even result inhumansickness or death
duetooxygendeprivationandcarbon monoxidepoisoning.
Followtheguidelines below:
1. Place your heater as close to a vent or chimney as
possible.
2. National building codes require that you do not install
thisapplianceinbathrooms,bedrooms,unventedclosetor
any occupied rooms normally kept closed.
3. Simultaneous operation of other appliances such as
exhaustfans,ventilationsystemsclothesdryers,fireplaces
orwoodstoves couldcreateavacuumeffectinyourhome
which could cause dangerous combustion by-products to
spillbackintoyour home rather than ventingtotheoutside
through the flue. Confirm that your Aquastar is venting
properlywhenall these otherappliances are running. See
sectiononventing.
Donotobstructtheflowofcombustionandventilation
air to the appliance. If installed near a clothes dryer it is
veryimportantthatthe dryer be properlyvented. Failure to
properlyventadryercouldresultinagradualaccumulation
oflintonthewaterheaterfincoilsandburners, leading to a
dangerous condition of vent blockage and poor unsafe
combustion.
4. Yourhotwaterlinesshouldbekeptshort tosaveenergy.
It is always best to have hot water lines insulated.
Thisproduct 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.
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
WHEREITCOULDFREEZE.
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
disconnectingboth theinlet and outlet elbow connections
at the rear of heater. Additionally, remove the drain plug
underthewater valve. See Fig0.

5
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
TheAquaStar 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.
ThisInstallationManualspecifiesthe minimumverticalvent
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
freezingduetonegativedraftifallthecombustionappliances
inthe area arenot being suppliedwith a sufficientamount
ofmake-upair. Awoodstoveorfurnacecanrobthemake-
upairintheAquaStar’sventpipe,leavingthecoldinfiltrating
aircapable of freezingthe cold waterin theAquaStar heat
exchanger. More make up air is the solution. Follow the
instructionsonventingandcheckingadequacyofmakeup
air. AHVAC specialist should be used to design solutions
forprovidingmoremake-up air if necessary.
Observethefollowinginstructions concerning combustion
air.
Applianceslocated in unconfinedspaces:
a) An unconfined space is one whose volume is greater
than50cubicfeetper1000 Btu perhourofthecombined
ratingofallappliancesinstalled in thespace.Thatwould
be5850 cubic feetfor theAquaStar125Balone.
b) Inunconfinedspacesinbuildingsofconventionalframe,
masonry, or metal construction, infiltration is normally
adequateto provide air forcombustion, ventilation, and
dilutionof flue gasses.
Applianceslocated inconfined spaces:
Theconfinedspace must be providedwithtwo permanent
openings,onecommencingwithin12inchesofthetopand
one commencing within 12 inches of the bottom of the
enclosure.Each openingmust have a minimum free area
ofone square inchper:
- 1000 Btu/hr if all air is taken from inside the building.
- 2000Btu/hrifallairis takenfromtheoutsidebyhorizontal
ducts.
- 4000 Btu/hr if all air is taken from the outside by direct
openingsor vertical ducts.
Ortheconfinedspacemustbeprovidedwithonepermanent
openingorduct that iswithin12 inches of theceiling of the
enclosure. Thisopeningmusthaveaminimumfree area of
onesquare inch per:
- 3000 Btu/hr if all air is taken from the outside by a direct
openingorvertical duct.
Louvers, grills and screens have a blocking effect. If the
effectivefreearea is notknown,increase the sizesofyour
openings by 75% if your louvers are wood and by 30% if
yourlouversaremetal. RefertotheNationalFuelGas Code
forcomplete information. In buildings oftight construction
all air should be taken from outside.
CLEARANCES
TheAquastar 125 B is designcertified forinstallation on a
combustible wall and for installation in an alcove or closet
with the minimum clearances to combustible and non -
combustibleconstruction listed below
A. Top12 inches (306mm)
B. Front 4 inches (102 mm)
C. Back 0 inches
D. Sides 4 inches (102mm)
E. Bottom 12 inches (306 mm)
Clearancefromventisdependentupontheclearancerating
oftheventing material used. For example:typeB-1 vent is
approvedfor1inchclearance.
Note: Minimumclearancetocombustiblematerialsshould
not be less than 6" for single wall flue pipe. Note that this
clearance can be reduced if combustible material are
protectedaspertableVIoftheNationalfuelGasCodeorif
Type B gas vent is used.
MOUNTING INSTALLATION
The Aquastar 125 B is design certified for mounting on a
wall.
Secure the two L shaped hooks, which are provided with
heater,toawallsurface. Placethem13¼”apartasshown
in Fig. 1.
Donotinstallthisapplianceonacarpetedwalloroverfloor
coveringwhichis combustible, such ascarpet.Theheater
must be mounted on a wall using appropriate anchoring
materials.Ifwall is a studwallsheathed 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.

6
Expansionandcontractionofpipingduetochangingwater
temperature in the pipes imparts movement to the heater
which, if mounted directly to a brittle, friable board, such
asplasterboard, can cause failureof mounting.
In earthquake-prone zones, CEC recommends that
installers use a large washer and lag screw through the
existing holes used to hang the heater to affix the upper
thirdofthe heater to themountingboard.Toaffixthelower
third of the heater, CEC recommends that two new holes
bedrilled in theheater’s frame, eachone 16 inchesbelow
the top two holes, and that washers and lag screws be
usedtosecure the lowerportionof the heatertoa spacing
board.
Before installing the unit, be certain you have the correct
heater for your type of Gas – Propane or Natural Gas.
Identificationlabels are foundon the shipping box,and on
the rating plate which is located on the right side panel of
thecover.Also,eachburnerorificeisstampedwithanumber
(79for LPG and 120for Natural Gas).
Fig. 1 - Mounting the Heater
Fig. 2 - Incandescent Particle Tray Illustration
Consult your gas utility or National Fuel Gas Code if
vent will have elbows or share venting with another
appliance. The vent connector should have as much
vertical rise as possible (minimum 12”) before any
horizontal run.
The appliance must be located as close as practicable to
achimneyorvent.Theventpipesectionsmustbesecured
to each other with sheet metal screws. Keep in mind the
minimumclearancefromthetopofyour heater.Remember
also that single wall vent pipe connectors require a 6 inch
clearance from combustibles. National Fuel Gas Code
specifies double wall — Type “B” — vent pipe be used in
coldclimatesand for gasventsrunning through attics. We
consider double wall vent pipe preferable in all
circumstances.Any vent section greater than 45 degrees
fromvertical is consideredhorizontal. Horizontal sections
ofventconnectorsmustslopeupwardsatleast1/4inchfor
everyfootofitshorizontallength.Keepthehorizontalsection
shortand avoid too manyelbows.
Optional powervent available in order to sidewall vent.
Contactyour local dealer.
To check the draft:
Close all doors and windows to the outside.
Turn on all appliances that force air out of the building.
Theseincludeallexhaust/ventilation fans,furnaces,clothes
dryers,wood burning stoves,etc.
Open all doors between the AquaStar and these other
appliances.
Runtheunit for atleast 10 minutes. Thenhold 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
theheaterandfreezingof the heat exchanger in afreezing
environment.
Themirrorwillremainclear withaproperlyfunctioningdraft.
WARNING
Note: Theburnersofaninstantaneous“ondemand”water
heater such as the AquaStar are only on at the time that
hotwater is actuallybeing used, the vent pipeis therefore
coldexceptfor the short durations whenhotwater is being
used,itis therefore very importantthat the venting and air
supplybeadequatetoprovidea goodpositivedraftassoon
asthe burners turn on. See venting guide on back page.
TheAquaStar125Binstantaneouswaterheatershave built-
in draft diverters and are designed for indoor installation
only.Thedraftdiverteroutletmustbeconnectedtoa clear,
unobstructedvent of thesame size, or larger.
InCanada,CAN/CGA-B149InstallationCodefordetailed
requirements
In U.S.A., ANSI Z223.1 - NFPA 54, national Fuel Gas
Codefordetailedrequirements.
The vent connection for the AquaStar 125B is 5 inches.
However, IN CANADA, for installations at high altitude
(2000-4500feetabovesealevel)asixinchflueisrequired.
A 5" by 6" flue adaptor must be affixed to the flue collar of
theAquaStar with at least two screws. See figure 3.
Theincandescentparticletray(shippedlooseinthecarton
with the water heater) must be attached at the bottom of
thewater heater frontcover at the timeof installation. Use
thescrewsprovided.Seefigure2
VENTING
Vent pipe connection.WARNING: Do not reduce
the vent pipe size.
This appliance must be vented to the outside following all
local ordinances and specifications for installing a gas
appliance vent or chimney. The venting system must be
designedand constructed so asto develop apositive flow
adequatetoremovefluegassestotheoutdoors.Minimum
vent size must be 5". Minimum height must be 6 feet,
provided there are no elbows. Termination of vent
must be 2 feet above any obstruction within a 10 foot
radius.
WALL STUDS
1” X 4”
SPACE BOARD
SUPPORT BOARD
13 ¼”
SCREWS
INCANDESCENT PARTICLE TRAY

7
Fig. 3 - Vent Adaptor for High Altitude Canadian
Installations
WARNING: FailureTOINCREASETHEVENTSIZE
TOSIXINCHESAND/orassurethatthemanifoldpressure
issettopropervaluelistedforapplicationsathighaltitudes
willcause unsafe venting, asphyxiation,and will void CSA
Certification.
GAS CONNECTIONS and Gas Regulator
NOTE: The Aquastar 125 B is supplied with a gas
pressureregulatorthatmustbeinstalledontheheater
before attaching the gas supply line. See figure 4.
Failure to install the gas regulator as shown in figure
4 will be a violation of CSA certification of the unit.
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.
GAS LINE SIZING
-It is strongly recommended that the Natural Gas pipe
be Black Iron pipe the entire distance from the outside
meter to the inlet of theAquastar regulator. 1/2” Black
Iron pipe up to 10 feet, 3/4” Black Iron pipe up to 40
feet and 1” Black Iron pipe up to 150 feet distances.
Flex line tubing is NOT recommended, but if used
then oversize it.
-It is strongly recommended that the LP Gas pipe be
semi-rigid copper or Black Iron pipe from the outside
regulator to the inlet of the Aquastar regulator. For
semi-rigid copper piping: 5/8” up to 20 feet and 3/4”
up to 60 feet distances. For Black Iron piping: 1/2 “ up
to 45 feet and 3/4” up to 160 feet distances. Flex line
tubingisNOTrecommended,butifusedthenoversize
it.
THESEFIGURESAREFORAQUASTARSUPPLYONLY,
ALLOTHERAPPLIANCESINTHEBUILDINGWILLNEED
TO BE INCLUDED IN THE PIPE SIZING.
NationalFuelGasCoderequiresthatasediment trap (drip
leg) be installed on gas appliances not so equipped. The
drip leg must be accessible and not subject to freezing
conditions.Installinaccordancewiththe recommendations
oftheserving gas supplier.
WARNING: The heater mustbedisconnected 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.
Thewaterheater, including thepressureregulatorprovided
with it, must not be operated at gas supply pressures in
excess of 0.5 psig. If overpressure has occurred, such as
throughimproper testing ofthe gas linesor malfunction of
the supply system, the gas valve and regulator must be
checked for safe operation. Make sure that the regulator
ventis protected againstblockage.
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
appropriatefittingstostopleak.Turnthe gas on and check
againwithasoapysolution.Nevertestforgasleaks using
a match or flame.
Fig. 4 - Installation of Gas Pressure Regulator
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.
MAXIMUM INLET GAS FLOW PRESSURE SETTING
Altitude Natural Gas Liquid Propane
inches W.C: inches W.C:
0' - 2.000 ft 5.7" 10.5"
2.000 ft - 4.500 ft 4.6" 8.4"
Thepressureregulatorprovidedwiththeheaterisadjusted
to deliver the proper gas pressure (as indicated on the
rating plate and in the manual for altitude up to 2000 feet
(660meters)abovesealevel.Onappliancesbeinginstalled
above2000ft(660meters)elevation, theinletgaspressure
should be set at installation to the value shown below.
Above 4.500 ft consult your local gas supplier.
5”X 6”ADAPTOR
USED ON HIGH ALTITUDE
GAS INLET PIPE
PRESSURE TAP
PRESSUREREGULATOR
(with directional arrow on
reverse side pointing
upward)
PLASTIC VENTCAP
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 4).

8
GAS PIPING, 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
GasCodeANSIZ223.1/NFPA54.
InCanada:TheInstallationshouldconform with CGAB149 INSTALLATION CODES and /orlocal installation codes.
FOR NATURAL GAS
Maximum Capacity of pipe in Cubic Feet of Gas per Hour
forGasPressureof0.5PsigorlessandaPressuredropof
0.3 in Water Column.
Followboxednumbersforpipingjust oneAquastar125B
(example:3/4”B.I.NaturalGaspipefor30 ft. will handle
152,000btu’s).Formultipleappliancescombinethetotal
btuinput load andthen refer toapplicable chart below.
(Basedona0.60Specific Gravity Gas) Btu numbersgiven
inthousands.
FOR LP GAS
MaximumCapacityofPipein Thousands of
BTUperHourofUndilutedPetroleumGases
(at11 inchesWater ColumnInlet Pressure)
(BasedonaPressureDropof0.5InchWater
Column).
MaximumCapacity of Semi-Rigid
Tubing in Thousands of BTU per Hour of
UndilutedLiquified Petroleum Gases(at 11
inchesWater Column Inlet Pressure)
(BasedonaPressureDropof0.5InchWater
Column)
* Source National Fuel Gas Code NFPA 54, ANSI Z223.1 - No
AdditionalAllowance is necessary for an ordinarynumberoffittings
GAS LINE SIZING
Nominal
Iron Length of Black Iron Pipe, Feet
Pipe Internal
Size, Diameter
inches inches 10 20 30 40 50 60 70 80 90 100 125 150 175 200
1/4 0.364 32 22 18 15 14 12 11 11 10 9 8 8 7 6
3/8 0.493 72 49 40 34 30 27 25 23 22 21 18 17 15 14
1/2 0.622 132 92 73 63 56 50 46 43 40 38 34 31 28 26
3/4 0.824 278 190 152 130 115 105 96 90 84 79 72 64 59 55
1 1.049 520 350 285 245 215 195 180 170 160 150 130 120 110 100
1 1/4 1.380 1050 730 590 500 440 400 370 350 320 305 275 250 225 210
1 1/2 1.610 1600 1100 890 760 670 610 560 530 490 460 410 380 350 320
2 2.067 3050 2100 1650 1450 1270 1150 1050 990 930 870 780 710 650 610
2 1/2 2.469 4800 3300 2700 2300 2000 1850 1700 1600 1500 1400 1250 1130 1050 980
3 3.068 8500 5900 4700 4100 3600 3250 3000 2800 2600 2500 2200 2000 1850 1700
4 4.026 17,500 12,000 9,700 8,300 7,400 6,80 6,200 5,800 5,400 5,100 4,500 4,100 3,800 3500
Nominal
Iron Pipe Black Iron Pipe
Size, Length of Pipe, Feet
Inches 10 20 30 40 50 60 70 80 90 100 125 150
1/2 275 189 152 129 114 103 96 89 83 78 69 63
3/4 567 693 315 267 237 217 196 185 173 162 146 132
1 107 732 590 504 448 409 378 346 322 307 275 252
1 1/4 220 149 121 103 913 834 771 724 677 630 567 511
1 1/2 330 229 185 155 141 127 118 108 102 976 866 787
2 622 433 346 299 264 239 220 204 192 1811 1606 1496
Copper
Outside Length of Tubing, Feet
Diameter,
Inch 10 20 30 40 50 60 70 80 90 100
3/8 39 26 21 19 _ _____
1/2 9262 5041 37 3531292726
5/8 199 131 107 90 79 72 67 62 59 55
3/4 329 216 181 145 131 121 112 104 95 90
7/8 501 346 277 233 198 187 164 155 146 138

9
WATER CONNECTIONS
Whenfacingtheheater,the cold water inlet isonyourright
and the hot water outlet is on your left.
Although water piping throughout your structure may be
other than copper, we recommend that copper piping be
usedforatleastthreefeetbeforeandaftertheheater(follow
local codes if more stringent). Keep water inlet pipe to no
less than 1/2 inch diameter to allow the full flow capacity.
Rememberthatwaterpressuremustbe sufficienttoactivate
theheaterwhen drawing hot waterfromthe top floor. If the
hot and cold connections to the heater are reversed, the
heaterwillnotfunction.TheAquaStar125Bisprovidedwith
twoflexibletype connectors that mustbeconnected to the
inlet and outlet fittings of the water valve as shown in Figs
5 and 6. ½” Copper or brass fittings work best when
connectedtotheconnectors.SeeFig6.These connectors
seal to the water valve by means of a union connection
with a washer type gasket at the joint. No pipe dope or
thread tape is to be used at these joints. Be certain there
arenoloose particles or dirtinthe piping. Blow outorflush
thelinesbeforeconnectingtotheAquaStar. Full portvalves
shouldbeinstalledonboththe cold water feed line andthe
hot water outlet line to facilitate servicing the heater.
For installation on a private well system, be sure that the
water pressure is set between 30 and 50 psi.
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.
Openahotwaterfaucettopermitthewatertofilltheheater
andthepipingandtoeliminate the airtrappedinthesystem
Closethe hot waterfaucet after the water flowsfreely and
alltheair has escapedfromthe system. The waterheater
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 oflife.
A. Thisappliance has a piezo-igniter forlighting the pilot
burner. When lighting the pilot, follow these instructions
exactly.
B. BEFORELIGHTINGsmellallaroundtheappliancearea
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 IFYOU SMELL GAS
- Do not try to light any appliance.
- Do not touch any electric switch; do not use any phone
inyourbuilding
- 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.Neveruse tools. Ifa button will notpush 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
qualifiedservicetechnician.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
inspecttheapplianceandto replace any part ofthecontrol
system and any gas control which has been under water.
Fig. 5 - Water valve and water
connectors, top view
Connecting the pressure relief valve (PRV)
Alistedpressure relief valve supplied withtheheater must
be installed at the time of installation. No valve is to be
placed between the PRV and the heater. No reducing
couplingorotherrestrictionmaybeinstalledinthedischarge
line.Thedischargelinemustbeinstalledsuchthatitallows
completedrainageofboththePRVandtheline.Thelocation
of the PRV must be readily accessible for servicing or
Fig. 7 - Pressure Relief Valve
THREADEDASSEMBLY SWEATEDASSEMBLY
replacement,andbemountedas close to the waterheater
as possible. See Fig 7.
To install the PRV, a suitable fitting connected to an
extension on a “T”fitting can be sweated to the hot water
line.
Fig. 6 - Plumbing connections for the Aquastar 125B
1/2”FLEX
PIPEPRV TO
APPROPRIATE
DISCHARGE
S FITTING
PIPEPRV TO
APPROPRIATE
DISCHARGE
1/2”FLEX
PIPEPRV TO
APPROPRIATE
DISCHARGE
WASHER
WATER FILTER
WATER VALVE
WASHER
INLET
OUTLET
FLEX
CONNECTORS

10
LIGHTING INSTRUCTIONS (as seen on front
cover of heater)
1. STOP!Readthesafetyinformation above on thisplate.
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 this instruction
plate.
5. Slide the gas valve button to the right, under the pilot
mark ( ).
6. Fullydepressgasvalvebuttonandlight pilot by pushing
“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
withpilotburning.Whenthe gasvalvebuttonisreleased,
the pilot should continue to burn.
- If the gas valve button does not pop up when released,
stopandimmediately call yourservicetechnician 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
valvebutton to theleft, under the OFF( ) mark andcall
service technician or gas supplier.
8.Oncepilotremains lit, thenslide the gasvalve button to
the right, under the ON mark ( ). The heater will now
fire when water is drawn at a rate greater than the
thresholdflowrate.
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 gas supply to the heater.
SETTING THE WATER TEMPERATURE
TheAquaStar125BLP and 125 B NGwaterheatershave
a gas control that modulates burner input in response to
flow. Itspurposeistoensurethat thehotwatertemperature
will remain steady, although the water flow demand might
vary (down to 1/2 gal/minute). To adjust the temperature
on your AquaStar, turn on a hot water faucet to its
maximum flow. At the water heater, turn the large knob
located beneath the main gas controls on the front of the
heaterall the way to the right (clockwise). SeeFig 8.This
will produce a temperature rise of approximately 90°F at
flow rates between 0.5 and 2.0 gallons per minute. Given
that average incoming water temperatures are 50°F, this
heater will produce approximately 140°F water at these
flow rates. Turning the dial all the way to the left
(counterclockwise) will produce a temperature rise of
approximately 45°F for flow rates between 1.1 and 3.7
gallons per minute. It is safest to select a comfortable
temperature and not have to mix in cold water.
Fig. 8 - Water Flow Control Knob
Thepositionyouselectonthetemperatureadjustmentknob
willdependonthetemperatureoftheincoming water (50°F
isaverageintheU.S.).Inwarmweatherregionswherethe
incomingcold water isgenerally warmer, or duringthe hot
weather months in some other areas a midway setting on
the temperature adjustment knob would produce a
temperature rise of about 70°F, giving an output of
approximately120°F. Atthis setting, if it isstillnecessary,
one could mix a small amount of cold water in a shower
andhavea comfortable shower atabout3gallons/minute.
Duringthecolder months, or incoldclimate areas, itmight
be necessary to set the control to the maximum position,
all the way clockwise to the right.
Do not supply the AquaStar 125B with preheated water.
Forthis type ofapplication, purchase a solar model125 B
LPS or 125 B NGS.
MAINTENANCE AND SERVICE
REVIEW MAINTENANCE TABLE ON
THE BACK OF THIS MANUAL
Approximatelyonceayear,theAquaStarshouldbechecked
and cleaned. To remove the front cover, first remove the
incandescent particle tray, then pull off the temperature
adjustmentknobandunscrewandremovetheplasticcollar.
Pull main cover out toward you and lift up and out. THE
FOLLOWINGOPERATIONS SHOULD BE PERFORMED
BYAQUALIFIED SERVICEPERSON:
Vent System: Should be checked annually. Clean and
repairasneeded.
Water Valve (Part # 8707002499):Thewatervalveonthis
heatershouldbeservicedperiodically.Lubricatecomponent
#24 on page 14 with a small amount of silicon, faucet or
lithiumgreaseeverytwoyearstokeepits o rings freshand
pushrod sliding smoothly. Every 3-5 years replace
components #24 and #25 on page 14. The frequency will
dependonthe mineral content ofthewater and conditions
of use or whenever signs of corrosion appear at the gas
andwatervalvejoint.Periodicallycheckthatthewaterinlet
filter (#28 on page 14) is clean as well.
Pilot Flame: Thepilotflameshouldburn with acleansharp
blueflameandshouldresemblethe diagram in Fig 9. If the
flameisyellow,orifthepilotknobhastoremaindepressed
for a long time in order to keep the pilot lighted, the pilot
burnerandorthepilotburnerorificemayneedtobecleaned,
the orifice may need to be replaced, and or the air screen
may need cleaning. The pilot flame should envelop
approximately 10 mm (3/8") of the tip of the

11
TROUBLE SHOOTING (see maintenance table)
Introduction
TheAquaStar 125B burners are activated by a water flow
valve. Numerous water related problems can cause this
watervalve to malfunctionsuch 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
waterflowrelatedproblemscancausetheheatertodeliver
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
betakenoff.To dothis, remove incandescent particletray,
pulloffthetemperatureadjustmentknobandunscrewand
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.
PILOT LIGHT WILL 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 PILOT.
C. Gas regulator may be shut or damaged.
2. In-line AquaStar gas regulator jammed (usually on
LP gas)
Replace or unlock the regulator. Note: The regulator
furnishedwiththeheater is designed for lowgaspressure.
Excessive pressure will lock it up (propane only). Locking
usuallyhappens if thegas pressure betweenthe gas tank
(propane)andthewaterheater’sgasregulatorhasnotbeen
reduced. See page 2 for recommended correct gas
pressure.To unlock a regulator, consultyour gas supplier.
3. Pilot orifice clogged and/or air screen dirty, or pilot
gas filter is dirty.
Clogging of the pilot burner can be caused by dust and
any suspended matter contained in the ambient air.
To clean the pilot burner and/ or the pilot orifice : Turn
offthegas at theunit. Remove thecover of the heater. To
do so, pull off the temperature adjustment knob and
unscrew and remove the plastic collar and unscrew the
centralscrew locatedat thebottom ofthe frontcover. Pull
main cover out toward you and lift up and out . Pull the air
screen off,wash it and blow any lint off (SeeFig10).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
thatyou can usuallyclean them by blowing throughthem.
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
exposepilot orifice.
Fig. 10 - Pilot burner with air screen/ pilot orifice
Fig. 9 - Characteristic Pilot Flame
thermocouple. If it is too small, the pilot burner must be
cleaned.Toobtainaspark, thepositionof the Piezo igniter
electrode should be approximately 3 mm (1/8") from the
pilot burner tip.
Main Burner Flames: The main burner flames should be
blue, with a more intense blue cone in the center core.
Yellow flames couldbe a signof wrong size gasorifices or
dirty burners, or a blockage on the heat exchangers fins.
Ifsomeburnershaveyellowflameswhileothers have good
flames,itislikelythatdust,lintorspiderwebshavepartially
cloggedthe burner venturis.To cleanthe burners, contact
a gas service person.
Mineral Scale Build-up: The AquaStar heater, when
operatedatlowertemperaturessettings,donotaccumulate
mineralbuild-up.Ifhowever,theheaterisusedatthehigher
temperature settings and the water has a high mineral
content,periodicdescalingmay benecessary.Theheating
coilsshould be flushed witha descaling solution. Consult
yourdealer or Controlled Energyfor instructions.
PILOT ORIFICE
AIR SCREEN
3mm
Correct gap between pilot
burner tip and electrode tip
PiezoElectrode
Air screen filter
10mm
3/8”
Piezo
Electrode
Thermocouple

12
6. Faulty thermocouple (part #8747202083) or
electromagnet ) Unless these 2 parts are at least 8
to10yearsold,itisveryunlikely that they are faulty.
Before testing, reconfirm that #2 is absolutely
correct, and that all connections are clean and
tight.
Totestthe thermocouple,disconnectthethermocouplelead
totheECO.Insertamulti-meterprobeintothethermocouple
lead and attach or hold the other lead to the metal gas
valve(DC common). Lightthe pilot flameand hold button,
meterreading should be24 mVDC or more. Ifthe reading
is24 mVDC or morethe thermocouple isgood.Totest 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 shoulddrop to 19 mVDCor less. If
it does not, replace the electromagnet.
BURNERS DO NOT IGNITE WHEN HOT WATER IS
TURNEDON
1. Pilot is not on.
Light the pilot. See lighting instructions.
2. Gas valve buttonnotpositionedonBurnerPosition
Be sure pilot flame is on. Slide gas valve control to burner
position ( ).
3. Cold incoming water connection made to wrong
side of heater
Make sure cold water inlet connection is on the right side
ofheaterwhen you are facingheater.
4. Water flow rate at hot water tap is too low.
Note:Whentheflowcontrolisturnedall thewayclockwise,
the AquaStar models 125B require 1/2 gallon per minute
flowtoactivatethe burners. This is aflowwhichwould fill a
quart jar in 30 seconds. If the flow control knob is turned
fullycounterclockwise,aflow rate of 1.1gpmisrequired to
activatetheburners.
5. Cold water inlet filter on heater is dirty.
Removefilter and clean. Thisscreen filter islocated at the
inletsideofthe brass water valve (fig.12,#28).Checkand
cleanfaucet aerators too.
6. Crossover in household plumbing
TheAquaStarburneractivateswhen thereissufficientwater
pressuredropintheAquaStarwatervalveassembly—i.e.
whenahotwaterfaucetisopened.Ifthereisacrossoverin
theplumbing,thenecessarypressuredropintheAquaStar
will be insufficient, or totally eliminated. A plumbing
crossovercanbecausedby a bad washer at asinglelever
faucet or incorrect plumbing or a mixing valve in the line,
etc. which permits hot and cold water to mix in the
plumbing.Thecrossoverwill create a backpressureinthe
system preventing the pressure drop in the Aquastar —
i.e.cold water is enteringthe water heaterfrom both sides
and the burners will not come on. To confirm there is no
crossoverintheplumbing,shutoffthe cold water supply to
theAquaStar. Open yourhot water taps.There should not
be any water flowing. If there is water flowing, there is a
crossoverintheplumbing. This is a plumbingproblem,not
anAquastarproblem.Please contact your plumber.
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
likewiseto becleaned orexchanged.
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
thegas valve button to pilotposition ( ) anddepress this
buttonuntilalltheairhasescaped,and the gashasarrived.
Duringthisprocess, press repeatedly onthepiezo ignition
button until the pilot flame has ignited.
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
Once pilot flame has been lighted. Hold button 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“)ofthethermocoupletip.Pilotflamehastobe properly
aimed at the thermocouple. See Fig 9.
3. Poor thermocouple connection at the
electromagnet
Note: Electromagnet is part #8707201012 located on the
right side of the gas valve behind the piezo push-button
assembly. Check the tightness of the thermocouple
connectionnut at theelectromagnet: 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 Cut-
Off overheat protection)
Oxidation or looseness of the ECO terminal connections
canresultinmillivoltcurrentlossthroughthethermocouple
safetycircuit. Clean terminals withvery fine sandpaperor
an eraser and reconnect ECO leads.
5. Faulty ECO (part #8707206040)
If cleaning the terminals attached to the ECO did not fix
the problem,connectajumperwirebetweenthetwowires
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.

13
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
componentsneed tobereplacedimmediately.Note: Water
valve for model 125B is part# 8707002499 for both LP
and NG models. (Contact service person to clean water
valveorreplace if corrosion ispresent).
PILOT LIGHT GOES OUT DURING OR IMMEDIATELY
AFTERHOTWATER 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 linesare undersized, theremay still bethe
specifiedstaticgaslinepressure.Howeverwhenthewater
valveopens,andgasenterstheburners,thepressurecould
dropsharply, causing thepilot flame togo out. Havea gas
technician confirm the gas pressure both static and at
maximumBtuoutput.Specifications foryourheaterare on
page2.
2. Pilot may be dirty or weak
See Page 9 for instructions on pilot maintenance.
3. Burners are not shutting down immediately when
hot water is turned off
Note: Ifburnersdon’tshutdownimmediatelywhenthehot
water is turned off, the heater will overheat and the ECO
will shut-off the gas. Rebuild the water valve assembly.
Contactservicepersonto clean or rebuildwatervalve.
WATER IS TOO HOT
1.Temperature Selection too high
Turnthe temperature adjustmentknob counter-clockwise
(tothe left) tolower the maximum water temperature.
Note: This will increase the activation flow rate.
2. Inlet water temperature is too high (as with solar
preheated water)
Note: OnlytheAquaStar125BS should be used iftheinlet
waterispreheated.
3. Reduce inlet gas supply when inlet water
temperature is very warm (60º-75ºF).
WATER IS NOT HOT ENOUGH
1. Temperature selection too low.
Changethesetting.Turnthetemperatureadjustmentknob
clockwise (to the right).
Note: This will decrease the activation flow rate.
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
specifictemperature rises onpage 2.
3. Btu input is toolowduetoinsufficientgaspressure
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
verypowerful to heatwater instantaneously sincethey do
this only at the time hot water is actually being used. It is
therefore imperative that the gas pressure requirement
bemetexactly. Insufficientgaspressure will directly affect
the water temperature at the time of usage. See page 2
forcorrectgaspressure settings and page13for locations
where gas pressures are taken.
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
ComparewatertemperatureatoutletoftheAquaStar(hold
theAquaStar’s outlet pipe with your hand) and at the tap.
If these two are very different, check for mixing valve or
plumbing crossover (see “MAIN BURNERS WILL NOT
IGNITE...”paragraph #6). Where automatic “anti-scald”
valvesarerequiredbycode, lower the temperature setting
on the AquaStar as much as possible and balance the
pressure between cold and hot water after theAquaStar.
6. Parts in water valve are corroded so that the gas
passage is not fully opening.
HOT WATER TEMPERATURE FLUCTUATES / UNIT
DEACTIVATED
1. Unbalanced pressure in waterlines
The added restriction caused by the Aquastar in the hot
watersystem can result inuneven pressures betweenthe
coldand the hot. In suchcases when mixing cold waterat
thetap,thelowerhot water pressure may beoverpowered
by a much higher cold water pressure, which may cause
theAquastarburnerstoshutdown(deactivate).Makesure
faucet aerators or shower heads are free of minerals. Do
not add any flow restrictor to the shower head.
Typically this deactivation symptom is a result of the
hot water being too hot to use comfortably. Warm inlet
water generally causes this. Lowering the control
knob setting and/or reducing the inlet gas supply to
the heater should correct this deactivation symptom.
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
TurnedOn”.
3. Inlet water pressure is erratic due to inadequate
supply water pressure or saturated pressure tank
on well system
Check the inlet water pressure. On a private well, raise
minimum pressure setting to 30 psi. Confirm that the
pressure tank is not water logged.
4. Gas pressure is too low
See page 2 and 7 for correct specifications.

14
Fig. 11 - Diagram of AquaStar 125 B
5
11
1
4
9
10
1. Heat exchanger
2. Pilot assembly
3. Burner manifold gas
pressure test nipple
4. Main gas burner
5. Pilot gas tubing
6. Gas valve
7. Pressure tap screw
location
8. Gas control slide
9. Piezoigniter
10. Water valve
11. Temperature adjustment
selector
12. Gas inlet gas pressure
test nipple
3
12
2
6
7
8

15
Fig. 12 - INTERIOR COMPONENTS DIAGRAM AND PARTS LIST

16
Fig. 12
INTERIOR COMPONENTS DIAGRAM
AND PARTS LIST 125B
1Cover ¤8 705 421 025
2Temperatureadjustment knobcomp. ¤8 702 000 219
3Temperatureadjustment knob ¤8 702 000 111
4Water connectionsgasket ¤8 710 103 043
5Draft divertor ¤8 705 505 354
6Heat exchanger ¤8 705 406 235
7Hot water pipe ¤8 700 705 556
8Cold water pipe ¤8 700 705 294
9Heat exchanger washer ¤8 710 103 045
10 Overheat sensor (ECO) ¤8 707 206 040
11 Main burner assembly LPG 8 708 120 296
Main burner assembly NG 8 708 120 298
12 Pilotburner assembly ¤8 708 105 337
12a Pilot air screen ¤8 700 507 055
13 Piezo electrode ¤8 708 107 002
14 Pilot orifice NG 8 708 200 005
“LPG 8 748 200 173
15 Pilot Tube ¤8 700 707 320
16 Thermocouple ¤8 747 202 083
17 Burner assembly washer ¤8 710 103 060
18 Throttle disc LPG 8 700 100 174
19 Gas valve LPG 8 707 011 463
Gas valve NG 8 707 011 459
20 Gas supply pipe ¤8 700 705 552
21 Electromagnet ¤8 707 201 012
22 Thermocable ¤8 747 202 209
23 Water valve assembly ¤8 707 002 499
24 Water valve repair kit ¤8 703 406 178
25 Slow ignition valve ¤8 708 503 063
26 Water valve diaphragm ¤8 700 503 053
27 Water valve selector screw assembly ¤8 708 500 251
28 Waterinlet filter ¤8 700 507 059
29 Water valve venturi ¤8 708 205 249
30 Watervalve watergovernor ¤8 707 402 021
31 Water elbowfitting ¤8 700 703 114

17

18

19

Replacement Parts available from North American
Distributor
CONTROLLED ENERGY CORP.
340 Mad River Park
Waitsfield, Vermont 05673
Phone[phone]
Fax [phone]
www.controlledenergy.com
[e-mail]
Recycled paper
GAS LINE SIZE
Natural Gas
Nominal Iron Pipe Size* 1/2" 3/4" 1"
MAXIMUM LENGTH 10' 40' 150'
Liquid Propane
Semi-rigid Tubing 1/2" 5/8" 3/4" 7/8"
MAXIMUM LENGTH NOT
RECOMMENDED 20' 60' 150'
* Flex tubing greatly reduces capacity and, therefore, is not recommended.
Minimum Vent Size* and Height
Minimum Diameter Minimum Height**
5 inches 6 feet**
* NOTE: Vent size must not be restricted. Installation must comply with national fuel gas code venting
requirements for a 117,000 Btu Category I appliance and any applicable local codes.
Water Pressure
For installation on well systems, insure that your water pressure is between 30 - 50 psi.
** NOTE: Minimum vent height must be 6 feet, provided there are no elbows. Termination of the vent must be
2 feet above any obstruction within a 10 foot radius of vent pipe. Consult your gas utility or National Fuel Gas
Code if vent will have elbows or share venting with another appliance. The vent connector should have as much
vertical rise as possible (minimum 12") before any horizontal run.
INSTALLATION CHECKLIST
11&01segapeesELBATECNANETNIAM
RAEYYREVESRAEY2YREVESRAEY5-3YREVE
EVLAVRETAWETACIRBUL
†
EVLAVRETAWDLIUBER
†
NEERCSRETLIFRETAWTCEPSNI
†
YLBMESSATOLIPTCEPSNI
†
YLBMESSATNEVTCEPSNI
†
RENRUBNIAMTCEPSNI
†
VULCANOTermodomésticos S.A.
Estrada de Cacia
3801 - 856 Aveiro - PORTUGAL
© 2001 Controlled Energy Corporation,
Waitsfield, VT all rights reserved