MASCOT MSTWW User manual

Installation and Operation Instructions Document 1316
H2372600-
WARNING
If the information in this manual is not
followed exactly, a re or explosion may
result causing property damage, personal
injury or loss of life.
Do not store or use gasoline or other
ammable 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
nearby phone. Follow the gas supplier's
instructions.
• If you cannot reach your gas supplier, call
the re department.
Installation and service must be performed
by a qualied installer, service agency, or gas
supplier.
FOR YOUR SAFETY: This product must be installed and serviced by a professional service technician,
qualied in hot water boiler and heater installation and maintenance. Improper installation and/or operation
could create carbon monoxide gas in ue gases which could cause serious injury, property damage, or
death. Improper installation and/or operation will void the warranty.
AVERTISSEMENT
Assurez-vous de bien suivres les instructions
données dans cette notice pour réduire au
minimum le risque d’incendie ou d’explosion
ou pour éviter tout dommage matériel, toute
blessure ou la mort.
Ne pas entreposer ni utiliser d’essence ou ni
d’autres vapeurs ou liquides inammables dans
le à proximité de cet appareil ou de tout autre
appareil.
QUE FAIRE SI VOUS SENTEZ UNE ODEUR DE
GAZ:
• Ne pas tenter d’allumer d’appareils.
• Ne touchez à aucun interrupteur. Ne pas vous servir
des téléphones dans le bâtiment où vous vous
trovez.
• Appelez immédiatement votre fournisseur de
gaz depuis un voisin. Suivez les instructions
du fournisseur.
• Si vous ne pouvez rejoindre le fournisseur de
gaz, appelez le sservice des incendies.
L’installation et l’entretien doivent être assurés par
un installateur ou un service d’entretien qualié
ou par le fournisseur de gaz.
Installation and Operation
Instructions for
MASCOT ® ST
Wall-Mounted, Modulating
Gas Condensing Water Heater
Model MSTWW
199,000 BTU/hr
• Natural Gas (NG) - Factory Conguration
• Propane Gas (LP) - Field-Convertible

LAARS Heating Systems
TABLE OF CONTENTS
SECTION 1
Product Accessories
1.1 Introduction .......................................................... 1
1.1 Included with the Appliance ................................... 1
SECTION 2
Product Characteristics
2.1 Model Nomenclature ................................................2
2.2 Specications ...........................................................3
2.3 Dimensions ..............................................................4
2.4 Names of Components ............................................5
SECTION 3
Safety Regulations
3.1 Safety Symbols ..................................................... 6
3.2 Safety Precautions and Proper Use ...................... 8
SECTION 4
Installation
4.1 Location and Clearances .......................................10
4.2 Wall Mount Bracket ................................................. 11
4.2.1 Installation Height and Location ................. 11
4.2.2 Hang the Water Heater .............................. 11
4.3 Combustion Air .......................................................12
4.3.1 Combustion Air from Room ..........................12
4.3.2 Ducted Combustion Air ................................12
4.4 Venting (exhaust) ...................................................14
4.5 General Location Guideline ................................... 15
4.6 Locations for Vent Pipe Terminator ........................ 15
4.6.1 Direct Venting Clearances ........................... 16
4.6.2 Non-Direct Venting Clearances .....................17
4.6.3 Venting Requirements in Massachusetts ......18
4.7 Air / Vent Connections at the Appliance .................20
4.7.1 Vent / Air Pipe Lengths .................................20
4.7.2 Direct Venting ...............................................20
4.7.3 Indoor Combustion Air .................................21
4.8 Vent / Air Pipe Termination ..................................... 21
4.9 Gas Supply and Piping .......................................... 23
4.10 Gas Supply Pressure ............................................26
4.11 Gas Set Up and Adjustment .................................. 26
4.12 Gas High Altitude Setting ......................................27
4.13 Natural Gas to Propane Conversion .....................28
4.14 Plumbing Guideline ...............................................32
4.15 Disposal of Condensate ........................................33
4.16 Pressure Relief Valve ............................................ 34
4.17 Electrical Wiring Connections ...............................34
4.18 DIP Switches .........................................................35
4.19 Control Board, Electrical Diagram ........................ 36
4.20 Ladder Diagram ....................................................37
4.21 Electrical Connections .......................................... 38
SECTION 5
Control Display and Operation
5.1 Control Dial and Buttons ....................................... 40
5.2 LCD Overview ....................................................... 41
5.3 Operating Mode .................................................... 42
5.5 Status Display Mode ........................................... 43
5.4 DHW Set Point Change Mode .............................. 44
5.6 Installer Mode ...................................................... 45
5.7 Error Mode .......................................................... 46
SECTION 6
Error Codes
6.1 Error Codes ......................................................... 47
6.2 Fault Tree Analysis .............................................. 50
SECTION 7
Trouble Shooting
7.1 Diagnostics .......................................................... 52
7.1 Failure Modes ..................................................... 53
SECTION 8
Maintenance
8.1 Annual Startup and General Maintenance .......... 56
SECTION 9
Installation Check
9.1 Quick View .......................................................... 57
9.2 Final Check Lists ................................................. 57
SECTION 10
Repair Part Diagram
10.1 Part List ............................................................... 62
10.2 Notes: ................................................................. 66

Mascot ST Tankless Water Heater Page 1
SECTION 1. Product Accessories
Items Descriptions Qty
LAARS Tankless Water Heater 1
Installation Instructions and
Users Manual 1
Condensate Hose 1
Wall Mount Bracket 1
Bolts w/Anchors 4
Vent terminal cap 3” 2
Parts Kit 1
Installationand Operation Instructions Document1316
H2372600-
WARNING
Ifthe information in this manual is not
followed exactly, a  re or explosion may
result causing property damage, personal
injuryor loss of life.
Donot store or use gasoline or other
 ammable vapors and liquids in the vicinity of
this or any other appliance.
WHATTO 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
nearby phone. Follow the gas supplier's
instructions.
• If you cannot reach your gas supplier, call
the  re department.
Installation and service must be performed
by a quali ed installer, service agency, or gas
supplier.
FORYOUR SAFETY: This product must be installed and serviced by a professional service technician,
qualiedinhotwaterboilerandheaterinstallationandmaintenance.Improperinstallationand/oroperation
couldcreatecarbonmonoxidegasinuegaseswhichcouldcauseseriousinjury,propertydamage,or
death.Improperinstallationand/oroperationwillvoidthewarranty.
AVERTISSEMENT
Assurez-vous de bien suivres les instructions
données dans cette notice pour réduire au
minimum le risque d’incendie ou d’explosion
ou pour éviter tout dommage matériel, toute
blessure ou la mort.
Ne pas entreposer ni utiliser d’essence ou ni
d’autres vapeurs ou liquides in ammables dans
le à proximité de cet appareil ou de tout autre
appareil.
QUEFAIRE SI VOUS SENTEZ UNE ODEUR DE
GAZ:
• Ne pas tenter d’allumer d’appareils.
• Ne touchez à aucun interrupteur. Ne pas vous servir
des téléphones dans le bâtiment où vous vous
trovez.
• Appelez immédiatement votre fournisseur de
gaz depuis un voisin. Suivez les instructions
dufournisseur.
• Si vous ne pouvez rejoindre le fournisseur de
gaz, appelez le sservice des incendies.
L’installation et l’entretien doivent être assurés par
un installateur ou un service d’entretien quali é
ou par le fournisseur de gaz.
Installation and Operation
Instructions for
M ASCOT
®
ST
Wall-Mounted, Modulating
Gas Condensing Water Heater
Model MSTWW
199,000 BTU/hr
• NaturalGas(NG)-FactoryConguration
• Propane Gas (LP) - Field-Convertible
User’s Manual - Mascot ST Water Heater
Page1
User’s Manual Document1317
H2372700-
WARNING
Ifthe information in this manual is not
followed exactly, a  re or explosion may
result causing property damage, personal
injuryor loss of life.
Donot store or use gasoline or other
 ammable vapors and liquids in the vicinity
of this or any other appliance.
WHATTO 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
nearby phone. Follow the gas supplier’s
instructions.
• If you cannot reach your gas supplier, call
the  re department.
Installation and service must be performed
by a quali ed installer, service agency, or gas
supplier.
FORYOUR SAFETY: This product must be installed and serviced by a professional service technician,
qualiedinhotwaterboilerandheaterinstallationandmaintenance.Improperinstallationand/oroperation
couldcreatecarbonmonoxidegasinuegaseswhichcouldcauseseriousinjury,propertydamage,or
death.Improperinstallationand/oroperationwillvoidthewarranty.
AVERTISSEMENT
Assurez-vous de bien suivres les instructions
données dans cette notice pour réduire au
minimum le risque d’incendie ou d’explosion
ou pour éviter tout dommage matériel, toute
blessure ou la mort.
Ne pas entreposer ni utiliser d’essence ni
d’autres vapeurs ou liquides in ammables dans
le voisinage de cet appareil ou de tout autre
appareil.
QUEFAIRE SI VOUS SENTEZ UNE ODEUR DE GAZ:
• Ne pas tenter d’allumer d’appareils.
• Ne touchez à aucun interrupteur. Ne pas vous servir
des téléphones dansle bâtiment où vous êtes.
• Appelez immédiatement votre fournisseur de
gaz depuis un voisin. Suivez les instructions
dufournisseur.
• Si vous ne pouvez rejoindre le fournisseur de
gaz, appelez le sservice des incendies.
L’installation et l’entretien doivent être assurés par
un installateur ou un service d’entretien quali é ou
par le fournisseur de gaz.
User’s Manual
M ASCOT
®
ST
Wall-Mounted, Modulating
Gas Condensing Water Heater
Model MSTWW
199,000 BTU/hr
• NaturalGas(NG)-FactoryConguration
• Propane Gas (LP) - Field-Convertible
1.1 Introduction
This manual provides information necessary for the
installation, operation, and maintenance of the LAARS
Heating Systems Mascot ST.Allapplicationandinstallation
procedures must be read and reviewed completely before
proceedingwiththeinstallation.ConsulttheLAARSHeating
Systems factory, or your local factory representative, with any
problemsorquestionsregardingthisequipment.Experience
has shown that most operating problems are caused by
improperinstallation.
All installations must be made in accordance with
1)AmericanNationalStandardZ223.1/NFPA54-Latest
Edition“NationalFuelGasCode”or
2)CSAB149.1“NaturalGasandPropaneInstallationCode”and
with the requirement of the local utility or other authorities having
jurisdiction.Suchapplicablerequirementstakeprecedenceoverthe
generalinstructionscontainedherein.
All electrical wiring is to be done in accordance with the local
codes, or in the absence of local codes, with: 1) The National
ElectricalCodeANSI/NFPANo.70-latestEdition,or2)CSASTD.
C22.1“CanadianElectricalCode-Part1”.Thisappliancemustbe
electricallygroundedinaccordancewiththesecodes.
1.2 Included with the Appliance

LAARS Heating Systems
Page 2
Figure 1. Model Nomenclature
2 3 4 5 6 7 8 9 10 11 12 13
S T W W 1 9 9 A 1 X X
SERIES
Mascot ST W - Condensing
Water
Heater
SIZE
MBTU/h
199
FUEL
N - Natural
P - Propane
CONFIG
W -Wall Hung
ALTITUDE
A - 0-10,000 Feet
REVISION
1 - First
OPTIONS
X - Standard
PUMP
X - no Pump
1
M
SECTION 2.
Product Characteristics
2.1 ModelNomenclature
The Model Nomenclature is shown on your Rating Plate
and consists of a series of letters and numbers
( Nomenclature )thatfurtheridentiesthe
characteristicsofyourMascotST.

Mascot ST Tankless Water Heater Page 3
Model Name MSTWW199
Gas Input Rate MAX 199,000 Btu/h
MIN 19,900 Btu/h
Hot Water Capacity
35°FRise 11.0GPM
45°FRise 8.5GPM
77°FRise 5.0GPM
Installation Indoor Wall Hung
Flue System Sealed Combustion Direct & Single Vnet
Vent Run 2″(50ft)/3″(100ft)Schedule40PVC,CPVC,PP,ABS
Gas Supply Pressure NG 3.5˝WCto10.5˝WC
LP 8.0˝WCto13.0˝WC
Manifold Pressure
Gas Type NG LP
MAX Fire
-0.11”to-0.17”WC -0.07”to-0.11”WC
MIN Fire
-0.10”to-0.16”WC -0.06”to-0.10”WC
Power Supply
Main Supply 120V 60Hz / 4A
Maximum
Power Consumption 135W(82W+53W_Ceramicheater)
Ignition System DirectElectronicIgnition/AutomaticFlameSensing
Burner System SingleOricePremixedFuelModulationMetalFiberInfrared
Gas Valve System Air ratio valve
Minimum Flow Rate 0.5GPM
Internal Pipe Material STS 304
Dimensions W17.3″–H28.7″–D14.8″
Weight 88lbs
SubHeatExchangerWaterCapacity Under 2 Gallon
Control Panel / Main Controller P-920C/GTH-9500C
Water Pressure MAX Hotwater150psi
MIN 15psi
Connection Sizes
Cold Water Inlet /
Hot Water Outlet 3/4″NPT
Gas Inlet 3/4″NPT
Materials
Casing Cold Rolled Carbon Steel
HeatExchanger PrimaryHeatExchanger:STS304
SecondaryHeatExchanger:STS304
Safety Devices
Flame Rod, Overheat Cut Off Limit Switch , Gas Leak Detector
sensor,ExhaustTemperatureHighLimitSwitch,WaterTem-
perature High Limit Switch, Frost Protection Ceramic Heater
2.2 Specications
• Temperature
 OperatingambientTemperatureRange:-10to60°C.
 OperatingRelativeHumidityupto:90%at40°C.
 Shipping&StorageTemperatureRangeof:-20to80°C.

LAARS Heating Systems
Page 4
Description Diameter
A
Vent Pipe Collar
3"
B
Air Intake Collar
3"
C Gas Inlet 3/4"
D DHW Outlet 3/4"
EDHW Inlet 3/4"
F Condensate Drain 1/2"
G Cold Water Inlet Filter _
2.3Dimensions
Air Intake
Vent

Mascot ST Tankless Water Heater Page5
2.4NamesofComponents
# Name of Component
1
Vent Pipe Collar
2
Combustion Air Intake Assembly
3
Air Gas Mixture (AGM) Actuator
4
Ignition Transformer
5
Igniter
6
Operating Temperature Sensor
7
Switch High Limit
8
Sight Glass
9
Primary Heat Exchanger
11
Mixing Valve
12
Frost Protection
13
Air Pressure Switch
14
Gas Inlet
15
Gas Inlet Pipe
16
Freeze Protector Sensor
17
Domestic Hot Water (DHW) Outlet
18
Condensate Trap Cleanout
# Name of Component
19
Cold Water Inlet
20
Cold Water Inlet Filter
21
Manual Power Switch
22
DHW Temperature Sensor
23
Water Adjustment Valve
24
Condensate Trap Hose
25
Main Controller
26
Control Panel
27
Secondary Heat Exchanger
28
Flame Detection Sensor
29
Burner Case
30
Burner Overheat Switch
31
Gas Valve
32
Venting (exhaust) Duct
33
Gas Manifold
34
Blower
35
Air Intake Collar
Vent Combustion
Air

LAARS Heating Systems
Page 6
SECTION 3.
Safety Regulations
3.1SafetySymbols
WARNING WARNING
Toavoidproductdamage,personalinjury,oreven
possible death, carefully read, understand, and
follow all the instructions in the Installation and
Operation manual before installation, operation
andservicetheWaterHeater.
Laars cannot anticipate every circumstance
thatmightinvolveapotentialhazard.Therefore,
all possible incidents are not included in our
warnings.Properinstallation,operation,and
serviceareyourresponsibility.
You must make sure that the operation and
settings of the Water Heater are safe for you and
forothers.
ThismanualprovidesSafetySymbols.Whenthe
user fails to adhere to the following requirement,
itmaycausedeath,seriousinjury,andsubstantial
propertydamage.
Forsafetysymbols,‘DANGER’,‘WARNING’,
CAUTION’areindicatedandthedenitionsforthese
terms are as follow:
DANGER
Indicates an imminently hazardous situation
which, if not avoided, will result in death or
seriousinjury.Thissignalwordislimitedtothe
mostextremesituations.
WARNING
Indicates a potentially hazardous situation
which, if not avoided, could result in death or
seriousinjury.
CAUTION
Indicates a potentially hazardous situation
which, if not avoided, may result in minor or
moderateinjury.Itisalsousedtoalertagainst
unsafe practices and hazards involving only
propertydamage.
FORYOURSAFETYREADBEFORE
OPERATING
Ifyoudonotfollowtheseinstructionsexactly,are
or explosion could result causing property dam-
age,personalinjuryorlossoflife.
A.Thisappliancedoesnothaveapilot.It
is equipped with an ignition device which
automaticallylightstheburner.Donottryto
lighttheburnerbyhand.
B.BEFOREOPERATINGsmellallaroundthe
applianceareaforgas.Besuretosmellnext
totheoorbecausesomegasisheavierthan
airandwillsettleontheoor.
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.
• 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
redepartment.
C.Useonlyyourhandtopushinorturnthegas
controlknob.Neverusetools.Iftheknobwill
not push in or turn by hand, don’t try to repair
it,callaqualiedservicetechnician.Force
orattemptedrepairmayresultinareor
explosion.
D.Donotusethisapplianceifanyparthas
beenunderwater.Immediatelycallaqualied
service technician to inspect the appliance and
to replace any part of the control system and
anygascontrolwhichhasbeenunderwater.
This appliance must be installed in accordance with
localcodesifany;ifnot,followANSIZ224.1/NFPA
54orCAN/CSAB149.1,NaturalGasandPropane
InstallationCode,asapplicable.
Thisapplianceiscertiedforuseataltitudesup
to4,500ft(1,370m)inaccordancetothelatestCSA/
CGA2.17-M91Gas-FiredAppliancesforUseat
HighAltitudes.

Mascot ST Tankless Water Heater Page 7
DANGER
Vaporsfromammableliquidswillexplodeand
catchonre.Thesewillcausedeathorsevere
burns.
Donotuseorstoreammableproductssuchas
gasoline, solvents or adhesives in the same room
orareaneartheappliance.
Keepammableproducts
Far away from water heater
In approved containers
Tightly closed
Out of children’s reach
Vapors
Cannot be seen
are heavier than air
spreadontheoor
Can spread from other rooms to the main burner
by air currents
Donotinstalltheappliancewhereammable
productswillbestored.
Read and follow water heater warnings and
instructionsthoroughly.Ifowner’smanualis
missing,contacttheretailerormanufacturer.
The Laars Water Heater must be installed by a
qualiedplumber,alicensedgastter,and/ora
professionalservicetechnician.
Improper installation and/or operation will cause a
potentiallyhazardoussituation,suchasseriousinjury
ordeath.Also,itwillvoidthewarranty.
 •TheNationalFuelGasCodeNFPA54/ANSIZ224.1
 •NationalElectricCodeANSI/NEPA70
• All applicable local, state, national and provincial
codes,regulationsandlaws.
Propercareisyourresponsibility.Carefullyreadand
understand the Operating Information in this manual
beforeoperatingtheLaarsWaterHeater.
Be aware of the location of the gas shut-off valve
andoperationmethod.Closethegasshut-offvalve
immediatelyiftheapplianceissubjectedtore,
overheating,ood,physicaldamage,oranyother
damaging condition that might affect the operation of
theunit.WaterHeatermustbecheckedbyaqualied
technicianbeforeresumingoperation.
DO NOT use this Water Heater if any part has been
underwater.Immediatelycallaqualiedtechnician
for inspecting the Water Heater and replacing any
part of the control system and gas control which have
beenunderwater.
Do not power up the unit until the gas and water
supplyvalvesarefullyopened.Makesurethatthe
fresh air intake port and exhaust gas port are opened
andfunctional.
DO NOT attempt to install, repair, or service this
WaterHeaterbyyourself.
 DonotchangeanypartoftheWaterheater.
 ContactaqualiedtechnicianiftheWaterHeater
needsrepairormaintenance.
 Askyourgassupplierforalistofqualiedservice
providers.
DO NOT use spray paint, hair spray, or any other
ammablespraynearWaterHeaterornearthe
exteriorfreshairinletport.DONOTplaceanyitems
in or around the exterior exhaust gas outlet port and/
orfreshairinletport.Thesecouldrestrictorblockthe
owinoroutoftheventsystem.
“Caution:Whilerepairingcontrol,allwiresare
labeled.Youmustconnectthewiresinaccordance
withtheinstruction.
Wiring errors can cause improper and dangerous
operation.
“Verifyproperoperationafterservicingoperation”
This consists of the gas ignition system components
which are protected from water (dripping, spraying, rain,
etc.)duringoperationandservice(circulatorreplacement,
condensatetrap,controlreplacement,etc.).
After installing the heater, safety device must be
tested.
This water heater is equipped with a blocked vent
shutoffsystem.
If the error code ‘41’ occurs, follow the instructions
below.
-First,turnoffthemanualgasvalve.
-Makesurethatthereisnoforeignobjectinthevent
passageorrodentscreen.
-Ifyoudonotndanyproblem,dothefollowing.
- Turn off the error state by pressing the power button
ofcontrolpanel.
- If the error occurs repeatedly, call your service
technicianorgassupplier.

LAARS Heating Systems
Page8
Before Operation
1.ChecktheGasType(NG/LP)
Whenusingormovingtheunitforthersttime,check
if gas type matches with the gas type of the Water
Heater.Checkwhetherthegastypewhichissupplied
is NG (Natural Gas) or LP (Propane) and also check
theWaterHeatergastype.
The gas type is indicated on the rating plate on side of
theWaterHeater.
2.CheckthePower(120V60Hz)
Checkthattheapplianceisconnectedproperly.
3.ChecktheColdWaterInlet
valve
Please keep the
appliance water inlet
valveopenatalltimes.
The appliance will not
ignitewheninsufcient
water or no water is
intheheatingpipes.
(valve: always open
position)
4.ChecktheGasValve
Check that the manual gas shut-off valve
thatsuppliestheMascotSTisopened.
5.Checktheareaaroundtheapplianceandremove
anycombustibleorammablematerials.Remove
laundry or any other items that are on or near the
waterheaterorexhaustvent.
open
When in Operation
CAUTION
1.CautionforGasleak
Frequently check for a gas leak at the gas connection
portionwithsoapywater.
2.CautionforVentilation
Makesurethatthereissufcientinowandoutowofair
ventilationwhileusingtheunit.
If the ventilation is improper, combustion quality may
deteriorate inside the appliance and cause shortened life
oftheappliance.
3.BurnWarning
Becarefulnottoburnyourselfontheueorpipes.They
becomeextremelyhotduringoperation.
SECTION 3.
Safety Regulations
3.2SafetyPrecautionsandProperUse

Mascot ST Tankless Water Heater Page 9
WARNING
Do not use the appliance for any other purpose than for heating
and hot water.
Do not store combustibles or ammable material such as
gasoline near the appliance.
Do not store other items on or near this water heater.
Do not store combustible (ammable) materials such as papers.
Do not hang clothes on the exhaust stack. This may start a re.
Burn Protection
Be cautious when opening the
hotwatertap.Thewaterisvery
hot.Especially,childrenorthe
elderly whose skin is liable to
burn must not use the hot water
withouthelpofaguardian.
Gasleakagetest.
Gassupplylinemustbeinspectedregularly.
DonotshutofftheWaterHeater.
When you leave home for a long time, do not shut
offWaterHeater.TheWaterHeaterhasafreeze
protectionfunction.Theceramicheaterisinstalled
inside of the heater’s internal pipe to protect the
heaterfromfreezing.
Do not wipe the appliance or control panel with
wetcloth.Electricshockmayoccur,orinternalparts
mayfailduetotheexposuretomoisture.
DonotdisassembletheWaterHeater.
Ifrepairisrequired,callyourlocalqualied
technician.
After repair of gas pipeline or gas regulator
replacement,callaqualiedcontractorforinspection
beforestartingitup.
Carbon monoxide poisoning
If exhaust fumes enter the room, it could cause
poisoningbycarbonmonoxidegas.Checkthatthe
exhausttubesareproperlyconnected.Openwindows
forventilation.Callaqualiedservicetechnicianfor
immediaterepair.
StepstotakeifyouhaveaGasleak.
1.Shutdownthewaterheaterassoonasgasfumes
aredetected.
2.Closetheintermediategasvalve.
3.Openwindowsforventilation.
4.Callaqualiedservicetechnicianforimmediate
repair.

LAARS Heating Systems
Page 10
SECTION 4.
Installation
4.1 Location and Clearances
The Mascot ST must be mounted to a suitable wall by
aqualiedheatingcontractorundertheguidelinesofa
wallmountedwaterheater.
Thewallmaybeofconcreteorwood.Suitablefasteners
forconcreteorwoodmustbeused.Failuretowall
mount this water heater using correct fasteners will
affect the performance and life expectancy of the water
heaterandwillvoidthewarranty.
Figure 2. Locating the Appliance
9
23
3
8
3
8
6
15
12
30
Table 1. Minimum Clearances
Installations must comply with
• All the local, state, provincial, and national codes,
laws,regulationsandordinances.
 •National Fuel Gas Code,ANSIZ224.1 –Thelatest
version.
 •NationalElectricalCode.
 •ANationalStandardofCanadaCAN/CSA-B149.1-05
Check before placing the Water Heater
• Always check the connected components which are
neartotheheater.Thecomponentsarebelow.
Water piping position / Venting adapter / Gas supply
piping/Electricalpower/Condensatedrainhose.
 •Conrm area around Water Heater. Remove any
combustiblematerials,gasolineandotherammable
liquids.FailuretokeepWaterHeaterareaclearand
free of combustible materials, gasoline and other
ammable liquids and vapors can result in severe
personalinjury,deathorsubstantialpropertydamage.
• The Water Heater which has gas control system
components must be protected from any possible
dangerduringoperationandservice.
• If new Water Heater replaces the existing appliance,
check and correct system problems, for example:
- Do not install : System leaks causing oxygen
corrosion or heat exchanger cracks from hard water
deposits.
Provide clearances as outlined in Table 1
• As for vent connector and hot water pipe from
combustible construction, please consult with a
qualiedtechnician.
• If the heater was installed in a narrow space or
corner, please ensure that there is sufcient space
for service and maintenance access. For regular
maintenance, there should not be any problem to
approachgasandwaterline.
The water heater must be installed on a wall that can
bearitsweight.
WARNING
WARNING
CLEARANCESFORSERVICEACCESS
• The water heater must be installed on a wall that
canbearitsweight.
 •Adequateserviceclearancemustbeconsidered.
• The Water heater can be installed on any suitable
internalwall(soundproongmayberequiredwhen
installingontoastudpartitionwall).
MinimumclearancestoCombustibles.
to Combustibles and for Service.
For installation from
Non-Combustibles and
Combustibles
Suggested
Service
Clearance
TOP of appliance 9 in
(23 cm)
18in
(46 cm)
BACK of appliance 5/8in
(1.5cm)
5/8in
(1.5cm)
FRONT of appliance 6 in
(15cm)
40 in
(101 cm)
SIDEof appliance 3 in
(7 cm)
8in
(20 cm)
BOTTOM of
appliance
12 in
(30 cm)
24 in
(61 cm)

Mascot ST Tankless Water Heater Page 11
4.2 Wall Mount Bracket
• 4.2.1 The installation height and location for your
MascotSTdependsonyourinstallationscenario.Withall
clearances considered, and given adequate positioning for
air supply and venting, you will need to determine the best
positiontomounttheWallMountBracket.Thewallmust
be concrete, wood, or plywood over studs, and must be
strong enough to hold the water heater!
• Start by familiarizing yourself to how the
included Wall Mount Bracket hooks underneath
the two Hangers that are attached to the back
ofthewaterheater.The‘hooks’oftheWallMount
Bracket will be 3” from the Top of the water heater once
thewaterheaterishung.
• Position the Wall Mount Bracket at the location that it will
go,beingsurethatitislevel,andthendrill4holes(0.47”dia)
witha1/2”drillbit,intothewallthroughtheBracket.
• Ifmountingtoaconcretewall,thenusetheconcreteanchors.If
ontowoodor5/8”(16mm)plywood,thenusethewoodscrews.
Do not hang the Mascot ST onto
sheetrock unless it is possible to
fasten directly into the structural
studs.Iftheincludedanchors
do not suit your installation,
you must use ‘Field Supplied’
anchors that are appropriate
forthewall’sconstruction.
Wall Mount
Bracket
Bolts (4) Wall Mount
Bracket
Anchors*
(4)
3" to Top
of Unit
Concrete,
Wood,
or5/8"Plywood
4.2.2 Hang the Water Heater
• Lift the water heater up, align the Hangers
on the back of the water heater with the hooks
on the Wall Mount Bracket, and hang the water
heaterontotheWallMountBracket.Doavisual
inspection to make sure that the water heater
is hanging properly onto the hooks of the Wall
MountBracket.
• Fasten the bottom of the water heater to the
wallusing2suitablewallanchors(eldsupplied).
Hangers (2)
(fastened to the back of unit)

LAARS Heating Systems
Page 12
Table 2. Required Combustion Air Pipe Material.
COMBUSTION AIR INSTALLATION STANDARDS
 MATERIAL UNITEDSTATES CANADA
 ABS ANSI/ASTMD1527
 PVC,sch40 ANSI/ASTMD1785orD2665 Airpipematerialmustbechosen
CPVC, sch 40 ANSI/ASTM F441 CPVC, sch 40, ANSI/ASTM, Polypropylene
 Polypropylene UL1738,ULCS636. basedupontheintendedapplicationofthewaterheater.
Singlewallgalv.steel 26gauge
SECTION 4.
Installation (continued)
4.3 Combustion Air
Mascot ST water heaters must have provisions for
combustion and ventilation air in accordance with the
applicable requirements for Combustion Air Supply and
Ventilation in the National Fuel Gas Code, ANSI Z223 1;
or in Canada, the Natural Gas and Propane Installation
Code,CSAB149.1.Allapplicableprovisionsoflocal
buildingcodesmustalsobeadheredto.
A Mascot ST unit can take combustion air from the
space in which it is installed, or the combustion air
can be ducted directly to the unit. Ventilation air
must be provided in either case.
4.3.1 Combustion Air from Room
In the United States, the most common requirements
specify that the space shall communicate with the
outdoorsinaccordancewithmethod1or2,whichfollow.
Where ducts are used, they shall be of the same cross-
sectional area as the free area of the openings to which
theyconnect.
Method 1: Two permanent openings, one commencing
within 12” (300mm) of the top and one commencing
within 12” (300mm) of the bottom, of the enclosure
shallbeprovided.Theopeningsshallcommunicate
directly, or by ducts, with the outdoors or spaces
thatfreelycommunicatewiththeoutdoors.When
directly communicating with the outdoors, or when
communicating to the outdoors through vertical ducts,
each opening shall have a minimum free area of 1
squareinchper4000Btu/hr(550squaremm/kW)of
totalinputratingofallequipmentintheenclosure.When
communicating to the outdoors through horizontal ducts,
each opening shall have a minimum free area of not
less than 1 square inch per 2000 Btu/hr (1100 square
mm/kW) of total input rating of all equipment in the
enclosure.
Method 2: One permanent opening, commencing
within 12” (300mm) of the top of the enclosure, shall
bepermitted.Theopeningshalldirectlycommunicate
with the outdoors or shall communicate through a
vertical or horizontal duct to the outdoors or spaces
that directly communicate with the outdoors and shall
have a minimum free area of 1 square inch per 3000
Btu/hr (734 square mm/kW) of the total input rating of
allequipmentlocatedintheenclosure.Thisopening
must not be less than the sum of the areas of all vent
connectorsintheconnedspace.
Other methods of introducing combustion and
ventilation air are acceptable, providing they conform to
therequirementsintheapplicablecodeslistedabove.
In Canada, consult local building and safety codes or, in
absenceofsuchrequirements,followCAN/CGAB149.
4.3.2 Ducted Combustion Air
The combustion air can be taken through the wall, or
throughtheroof.Whentakenfromthewall,itmust
be taken from out-of-doors by means of the LAARS
horizontalwallterminal.Whentakenfromtheroof,a
eld-suppliedraincaporanelbowarrangementmust
beusedtoprevententryofrainwater.
Use ABS, PVC, CPVC, polypropylene, or galvanized
pipeforthecombustionairintake.Routetheintaketo
thewaterheaterasdirectlyaspossible.Sealalljoints.
Provideadequatehangers.Theunitmustnotsupport
theweightofthecombustionairintakepipe.Maximum
linear pipe length allowed is shown in Table 6.Subtract
5allowablelinearft.(1.5m)foreveryelbowused.
The connection for the intake air pipe is at the top of
theunit.
In addition to air needed for combustion, air shall also
be supplied for ventilation, including air required for
comfortandproperworkingconditionsforpersonnel.

Mascot ST Tankless Water Heater Page 13
NOTICE
The instructions for the installation of the venting
system shall specify that the horizontal portions of
the venting system shall be supported to prevent
sagging; the methods of and intervals for support
shallbespecied.Theseinstructionsshallalso
specify that the venting system:
Category I, II and IV water heaters must be installed
so that horizontal sections have a slope of at least ¼
inch per foot (21 mm/m) to prevent accumulation of
condensate; and
For Category II and IV water heaters, where
necessary, have means provided for drainage of
condensate.
AVIS
Les instructions d'installation du système
d'évacuation doivent préciser que les sections
horizontales doivent être supportées pour prévenir
leéchissement.Lesméthodesetlesintervalles
desupportdoiventêtrespéciés.Lesinstructions
doivent aussi indiquer les renseignements suivants:
les chaudières de catégories I, II et IV doivent
présenter des tronçons horizontaux dont la pente
montante est d'au moins ¼ po par pied (21 mm/m)
entre la chaudière et l'évent; les chaudières de
catégories II et IV doivent être installées de façon à
empêcher l'accumulation de condensat;
et si nécessaire, les chaudières de catégories II et IV
doivent être pourvues de dispositifs d'évacuation du
condensat.
The Mascot ST is standard as a Natural Gas Water
Heater and must be converted if propane is the desired
gas,unlessspecicallymanufacturedforpropane.
Adequate drainage
• The appliance should be installed not to damage
theadjacentarea.Ifsuchlocationscannotbe
avoided, it is recommended that a suitable drain
pan, adequately drained, be installed under the
appliance.Thepanmustnotblockcombustionair
ow.
Connecting the Water Supply
• To conserve water and energy, insulate all water
piping—especially the hot and recirculation water
lines.Nevercoverthedrainorpressurereliefvalve.
  Havingabackowpreventerinthecoldwater
supply line means that it prevent from thermal
expansionbackow.Contactthewatersupplieror
local plumbing inspector for information about how
tocontrolthissituation.Ifoverheatingoccursor
the gas supply fails to shut off, turn off the manual
gasvalve.
This installation must conform with below section
 •“AirforCombustionandVentilation”ofthe
NationalFuelGasCode,ANSIZ224.1/NFPA54,
orSections8.2,8.3or8.4ofNaturalGasand
PropaneInstallationCode,CAN/CSAB149.1,or
applicableprovisionsofthelocalbuildingcodes.
CAUTION

LAARS Heating Systems
Page 14
Table 3. Required Exhaust Vent Material.
VENTING INSTALLATION STANDARDS
MATERIAL UNITED STATES CANADA
 StainlessSteel UL1738 VentingmustbeULC-S636certiedforuseas
PVC, sch 40 ANSI/ASTM D1785 ventingmaterial.Theventingmaterialmustbechosen
CPVC, sch 40 ANSI/ASTM F441 basedupontheintendedapplicationofthewaterheater.
 Polypropylene UL1738orULC-S636
4.4 Venting (Exhaust)
The ue temperature of the Mascot ST changes
dramatically with changes in operating water
temperature. Therefore, it is necessary to assess
the application of the water heater to determine
the required certied vent class. If the Mascot ST
is installed in an application where the ambient
temperature is elevated, and/or installed in a closet/
alcove, CPVC, polypropylene, or stainless steel
material is required. If the system temperatures
are unknown at the time of installation, stainless,
polypropylene or CPVC material is recommended.
TheMascotSTisaCategoryIVapplianceandmay
beinstalledwithPVC,CPVCorpolypropylenethat
complieswithULC-S636, ANSI/ASTM D1785 F441
(see Table 3) orastainlesssteelventingsystemthat
complieswithUL1738Standard.
WARNING
UseofcellularcorePVC(ASTMF891),cellularcore
CPVC,orRadel®(polyphenolsulfone)inventing
systemsshallbeprohibited.
WARNING
Failuretousetheappropriateventmaterial,installation
techniques,glues/sealantscouldleadtoventfailure
causingpropertydamage,personalinjuryordeath.
WARNING
Allventingmustbeinstalledaccordingtothismanual
andanyotherapplicablelocalcodes,includingbut
notlimitedto,ANSIZ224.1/NFPA54,CSAB149.1,
CSAB149.2andULC-S636.Failuretofollowthismanual
andapplicablecodesmayleadtopropertydamage,
severeinjury,ordeath.
INSTALLATIONS IN CANADA require the use of
venting material certied to ULCS636. All Gas vents
connected to the Mascot ST, plastic, stainless
steel or otherwise must be certied to this ULC
standard. Appropriate selection of vent material is
very important for proper performance and safe
operation of the Mascot ST.
The ue temperature of the Mascot ST changes
dramatically with changes in operating water
temperature. Therefore, it is necessary to assess
the application of the water heater to determine
the required certied vent class. If the Mascot ST
is installed in an application where the outlet water
temperature exceeds 145°F, and/or installed in a
closet, class IIB or higher vent material is required.
If the system temperatures are unknown at the time
of installation, class IIB or higher venting material
is recommended.
IN CANADA all venting used must meet the
following requirements:
1. ULC-S636 certied and marked
2. The rst 3 feet of venting must be accessible
for visual inspection.
3. All components used in the vent system must
be from a certied manufacturer.
4 . Vent system components must not be mixed
with alternate manufacturers certied
components and/or unlisted components.
5 . The venting must be installed according to the
vent manufacturers installation instructions.
Theunit’sventcanterminatethroughtheroof,or
NOTICE
DO NOT COMMON VENT MASCOT ST UNITS.
Mascot ST units are never permitted to share a
vent with Category I appliances.
AVIS
NE PAS ÉVENT COMMUNE MASCOTTE ST UNITÉS.
Mascotte ST unités ne sont jamais autorisés à
partager un évent Catégorie I avec les appareils.

Mascot ST Tankless Water Heater Page 15
4.5 General Location Guideline
1.Ventsysteminstallationmustbeinaccordance
withLocalcodesor,intheabsenceoflocalcodes,
theNationalFuelGasCode,ANSIZ224.1/NFPA
54and/orCSAB149.1,NaturalGasandPropane
InstallationCode.
2.TheWaterHeaterisdesignedtobeinstalledasa
DirectVent(sealedcombustion)type.
  Theairforcombustionmustbesupplieddirectly
fromtheoutsidetotheburner.Also,theuegases
mustbeventeddirectlytotheoutdoors(through
wallorroof).
3.Donotinstallventingsystemcomponentsonthe
exteriorofbuildingexceptasspecicallyrequiredby
theseinstructions
 -Ventterminalsmustbeatleast1footfromanydoor,
window,orgravityinletintothebuilding.
 -Maintainthecorrectclearanceandorientation
betweentheventandairintaketerminals.
  Theventandairintaketerminalsmustbeatthe
sameheightandtheircenterlinesmustbespaced
apart12˝minimum.
 -Thebottomoftheventandairintaketerminalmust
beatleast12˝abovethenormalsnowline.Inno
WARNING
FailuretoventthisWaterHeaterinaccordance
with these instructions could cause a re,
resulting in severe property damage, personal
injuryordeath.
Do not interchange vent systems or materials
unlessitisspecied.
Theuseofthermalinsulationcoveringpipeand
ttingsisprohibited.
Do not apply an electric damper, draft hood or
ventdamperwiththisWaterHeater.
Do not locate vent termination where exposed
to prevailing winds. Moisture and ice may fall
on surface around vent termination. To prevent
deterioration,surfacemustbeingoodrepair
 (sealed,painted,etc.).
caseshouldtheybelessthan12˝abovegrade
level.
 -Donotinstalltheventterminaldirectlyover
windowsordoors.
 -Airintaketerminalmustnotterminateinareasthat
mightcontaincombustionaircontaminates,suchas
nearswimmingpools.
 -Forsidewallventing,theminimumhorizontal
distancebetweenanyadjacentindividualModule
(WaterHeater)ventterminationsistwelve(12)
inches.Itisbettertobefarmorethan12inchesfor
avoidingfrostdamagetobuildingsurfaceswhere
ventterminationsareplaced.
 -Theminimumhorizontaldistancebetweenany
adjacentindividualmodule(waterheater)roofvent
endpieceisone(1)foot.
throughanoutsidewall.
Ventpipemustpitchupward,towardthevent
terminal,notlessthan1/4”perfoot,sothat
condensatewillrunbacktotheMascotSTtodrain.
Routeventpipetotheheaterasdirectlyaspossible.
Sealalljointsandprovideadequatehangersas
requiredintheventingsystemmanufacturer’s
InstallationInstructions.Horizontalportionsof
theventingsystemmustbesupportedtoprevent
saggingandmaynothaveanylowsectionsthat
couldtrapcondensate.Theunitmustnotsupportthe
weightoftheventpipe.

LAARS Heating Systems
Page 16
4.6 Locations for Vent Pipe Terminator
Description US Direct Vent Instal-
lations
Canadian Direct Vent
Installations
AClearance above grade, veranda, porch, deck, or balcony 12 in (30 cm) 12 in (30 cm)
BClearance to window or door that may be opening 12 in (30 cm) 36 in (91 cm)
CClearance to permanently closed window * *
D
Verticalclearancetoventilatedsoftlocatedabovetheterminal
within
a horizontal distance of 2 feet from the center line of the terminal
* *
EClearancetounventilatedsoft * *
FClearance to outside corner * *
GClearance to inside corner * *
HClearance to each side of center line extended above meter/
regulator assembly *
3 ft (91 cm) within a
height15ftabovethe
meter/regulator as-
sembly
IClearance to service regulator vent outlet * 3 ft (91 cm)
JClearance to non-mechanical air supply inlet to building or the
combustion air inlet to any other appliance 12 in (30 cm) 36 in (91 cm)
KClearance to a mechanical air supply inlet
3 ft (91 cm) above if
within 10 ft (3 m) hori-
zontally
6ft(1.83m)
LClearance above paved sidewalk or paved driveway located on
public property *7ft(2.13m)
MClearance under veranda, porch, deck, or balcony * 12 in (30 cm)
*For clearances not specied inANSI Z224.1 / NFPA 54 or CAN/CSA-B 149.1, please use clearances in
accordancewithlocalinstallationcodesandtherequirementofthegassupplier.
4.6.1 Direct Venting Clearances
Table 4. Direct Vent Clearances

Mascot ST Tankless Water Heater Page 17
Description US Non-Direct Canadian Non-Direct
AClearance above grade, veranda, porch, deck, or balcony 12 in (30 cm) 12 in (30 cm)
BClearance to window or door that may be opening
48in(120cm)below
or to side of opening;
12 in (30 cm) above
opening
36 in (91 cm)
CClearance to permanently closed window * *
D
Verticalclearancetoventilatedsoftlocatedabovetheterminal
within a horizontal distance of 2 feet from the center line of the
terminal
* *
EClearancetounventilatedsoft * *
FClearance to outside corner * *
GClearance to inside corner * *
HClearance to each side of center line extended above
meter / regulator assembly *
36 in (91 cm) within a
height15ft(4.57m)
above the meter/ regu-
lator assembly
IClearance to service regulator vent outlet * 36 in (91 cm)
JClearance to non-mechanical air supply inlet to building or the
combustion air inlet to any other appliance
48in(120cm)below
or to side of opening;
12 in (30 cm) above
opening
36 in (91 cm)
KClearance to a mechanical air supply inlet
36 in (91 cm) above
if within 10 ft (3 m)
horizontally
6ft(1.83m)
LClearance above paved sidewalk or paved driveway located on
public property *7ft(2.13m)
MClearance under veranda, porch, deck, or balcony * 12 in (30 cm)
4.6.2 Non-Direct Venting (Single Pipe) Clearances
Table 5. Non-Direct Vent Clearances

LAARS Heating Systems
Page18
4.6.3 Venting Requirements in the
Commonwealth of Massachusetts
In Massachusetts the following items are required if
the side-wall exhaust vent termination is less than
seven(7)feetabovenishedgradeinthearea
of the venting, including but not limited to decks
andporches.FromMassachusettsRulesand
regulations248CMR5.08
1. InstallationofCarbonMonoxideDetectors
At the time of installation of the side wall
vented gas fueled appliance, the installing plumber
orgasttershallobservethatahard-wiredcarbon
monoxide detector with an alarm battery back-up is
installedontheoorlevelwherethegasappliance
istobeinstalled.Inaddition,theinstallingplumber
orgasttershallobservethatabatteryoperatedor
hard-wired carbon monoxide detector with an alarm
is installed on each additional level of the dwelling,
building or structure served by the side-wall
horizontallyventedgasfueledequipment.Itshall
be the responsibility of the property owner to secure
theservicesofqualiedlicensedprofessionals
for installation of hard-wired carbon monoxide
detectors.
 a.Intheeventthattheside-wallhorizontally
vented gas fueled equipment is installed in a crawl
space or an attic, the hard-wired carbon monoxide
with alarm and battery back-up may be installed on
thenextadjacentoorlevel.
 b.Intheeventthattherequirementsofthe
subdivision cannot be met at the time of completion
of installation, the owner shall have a period of thirty
(30) days to comply with the above requirements,
provided, however, that during said thirty (30)
day period, a battery operated carbon monoxide
detectorwithanalarmbeinstalled.
2. ApprovedCarbonMonoxideDetectors
 Eachcarbonmonoxidedetectorshallcomply
with NFPA 720 and be ANSI/UL 2034 listed and IAS
certied.
3. Signage.Ametalorplasticidenticationplate
shall be permanently mounted to the exterior of
thebuildingataminimumheightofeight(8)feet
above grade directly in line with the exhaust vent
terminal for horizontally vented gas fueled heating
applianceorequipment.Thesignshallread,in
printnolessthanone-half(1/2)inchinsize:“GAS
VENTDIRECTLYBELOW,KEEPCLEAROFALL
OBSTRUCTIONS”.
4. InspectionThestateorlocalgasinspectorof
the side-wall horizontally vented gas fueled appliance
shall not approve the installation unless, upon
inspection, the inspector observes carbon monoxide
detectors and signage installed in accordance with the
provisionsof248CMR5.08(2)(a)1-4.