Intellihot iN199A User manual

Installation & Operation Manual
iN199/iN199A
iN199
WARNING
If the information in these instructions is not followed
exactly, a re or explosion could result causing
property damage, personal injury, or death.
— 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
neighbor’s 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 the gas
supplier.
— Ne pas entreposer ni utiliser d’essence ou
ni d’autres vapeurs ou liquides inammables
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’appareil.
• Ne touchez à aucun interrupteur; ne pas vous
servir des téléphones se trouvant dans
le bâtiment.
• Appelez immédiatement votre fournisseur de gaz
depuis un voisin. Suivez les instructions
du fournisseur.
• Si vous ne pouvez rejoindre le fournisseur,
appelez le service 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.
AVERTISSEMENT
Assurez-vous de bien suivre 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.

Thank you for purchasing this Intellihot unit.
This unit is designed for years of trouble-free operation, and I urge you to read and follow the
instructions in this “Installation & Operation Manual.”
Our mission to create a better heating system began in the winter of 2005 when a tank water
heater broke down and ooded my basement. By combining the principles of a diesel engine’s
robustness, robotics intelligence, and marine environment durability, we set out to design a unit
from the ground up that would outperform and outlast all others.
Quickly, our goal grew from not just making a better water heater, but creating an intelligent
water heating and delivery system. Innovation is our hallmark, and simplicity, eciency, and
durability are at the core of every lntellihot product.
Our products are proudly engineered and built in Galesburg, Illinois. lntellihot has helped
commercial customers throughout the nation save thousands of dollars while eliminating
downtime. Our talented team of dedicated professionals is ready to assist you and help your
business succeed.
I thank you for purchasing our lntellihot products.
Sincerely,
Sri Deivasigamani
CEO, lntellihot Inc.

Table of Contents
1. General Information
1.1 Items Shipped With Water Heater ..............2
1.2 Serial Number Locations .....................2
2. Safety
2.1 Safety Signal Words.........................3
2.2 Installation Warnings ........................3
3. TechnicalSpecications
3.1 SpecicationsChart.........................5
3.2 Nomenclature..............................6
3.3 High Elevation Installations ...................6
3.4 ConnectionSpecications ....................7
3.5 Exhaust Gas Standards ......................7
3.6 Overall Dimensions ..........................8
3.7 CongurationOptions .......................9
4. Quick Reference Installation Guide
4.1 Install the Water Heater......................11
4.2 Pre-Startup Instructions .....................11
5. Preparation Before Installation
5.1 Selecting an Indoor Installation Site ............13
6. Gas Connection
6.1 Quick Reference Installation Instructions ........14
6.2 Fuel Source ...............................14
6.3 Gas Pressure Requirements...................14
6.4 Gas Pressure Regulator ......................14
6.4.1 Venting of Gas Supply Regulators .......15
6.5 Length of Gas Supply Line ....................15
6.6 Gas Piping Material .........................15
6.7 DetermineCorrectGasPipeDiameter ..........15
6.8 GasPipeDripLegandShut-oValve . . . . . . . . . . . 15
6.9 ConnectingGasLinetoUnit ..................16
6.10 Gas Pipe Sizing Tables . . . . . . . . . . . . . . . . . . . . . . . 17
7. Air Intake Inlet and Exhaust Gas Outlet Pipe
Connections
7.1 Quick Reference Installation Guide .............19
7.2 TypicalSingleUnitAirIntakeInletandExhaustGas
Outlet Pipe Installation ............................19
7.3 Two Pipe Vent System (Direct Vent)............20
7.3.1 SingleUnitCongurations .............20
7.3.2 MultipleUnitsCongurations...........21
7.3.3 SideWallAirIntakeInletandExhaustGas
Outlet Pipe Termination......................21
7.3.4 RoofAirIntakeInletandExhaustGasOutlet
Pipe Termination ...........................22
7.4 Single Pipe Venting System...................22
7.4.1 SingleUnit..........................22
7.4.2 MultipleUnits .......................23
7.5 CombustionAirRequirements .................24
7.6 IntakeAirInletandExhaustGasOutletPipeDiameter
and Length .....................................24
7.7 VentingClearanceSpecications ..............25
7.8 Exhaust Gas Outlet Pipe Materials .............26
7.9 AirIntakeInletPipeVentMaterials .............26
7.10 Recommended Exhaust-Gas Outlet Pipe Transitions
27
8. Water Connections
8.1 Quick Reference Installation Instructions ........28
8.2 HotWaterConnection .......................28
8.3 ColdWaterConnection ......................29
8.4 CondensateDrainLine .......................29
9. Electrical Power
9.1 Electrical Recommendations ..................30
9.2 ConnectionInstructions......................30
10. Adjusting CO2Level
10.1 General Information .........................31
10.2 AdjustmentProcedure .......................31
11. Natural Gas to Propane Conversion
11.1 General Information .........................34
11.2 ConversionProcedure.......................34
12. Operation
12.1 ControlPanel ..............................36
12.2 Turning Water Heater ON and OFF .............36
12.3 Setting the Time............................37
12.4 AdjustingtheWaterTemperature ..............37
12.5 Security ..................................38
12.5.1 Setting Passcode Protection ...........38
12.5.2 ChangingPasscode ..................39
12.5.3 Forgot Passcode .....................40
12.6 UnitOverview..............................40
12.7 Life Screen ................................41
12.8 UnitInformation ............................42
12.9 More Screens ..............................43
12.9.1 Cellular ............................43
12.9.2 Error History ........................44
12.9.3 telliCareService(SubscribeatStartup) ..44
13. Connecting Multiple Units
13.1 General Information .........................47
13.2 Installation Procedure .......................47
13.3 VentingforMultipleUnits ....................48
14. Maintenance
14.1 Maintenance-FreeCirculationPump ............49
14.2 AirFilter ..................................49
14.2.1 Inspection ..........................49
15. Wiring Diagrams and Troubleshooting
15.1 OperationalFlowChart ......................51
15.2 CompleteWiringDiagram(allmodels)...........52
15.3 Troubleshooting Guide .......................53
16. Serviceable Parts
16.1 Display ...................................59
16.2 ControlBoard ..............................60
16.3 WaterCircuit(topside) ......................61
16.4 WaterCircuit(bottomside) ...................62
16.5 Exhaust...................................63
16.6 Heat Exchanger ............................64
16.7 Heat Exchanger (top side) ....................65
16.8 Miscellaneous ..............................66
17. Requirements for State of Massachusetts
17.1 Notice Before Installation ................. 67
18. Warranty
18.1 Warranty..................................68
19. Product Warranty Registration
19.1 Warranty..................................71

1 iN199
November 2021 - Revision 00
WARNING
If the information in these instructions is not followed
exactly, a re or explosion could result causing
property damage, personal injury, or death.
— 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
neighbor’s 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 the gas
supplier.
This product complies with ANSIZ21.10.3 (2011) / CSA 4.3 Gas Water Heater. For use as potable water heating.
DANGER
To avoid product damage, personal injury, or
even possible death, carefully read, understand,
and follow all the instructions in this Installation
& Operation Manual before installing this
product. Improper installation, adjustment, alteration,
or maintenance can cause injury, loss of life, and/or
property damage. This water heater should be installed
and serviced by a qualified technician. The lack of
proper service can result in a dangerous condition.
Due to Intellihot’s policy of continuous product improvement
and technology, the design, technical specifications, or both in
this manual are subject to change without notice.
This manual contains safety information, installation
instructions, and maintenance procedures. It must be left
with the homeowner or placed near the water heater in a
noncombustible location. The customer should retain this
manual for future reference.
— Ne pas entreposer ni utiliser d’essence ou
ni d’autres vapeurs ou liquides inammables
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’appareil.
• Ne touchez à aucun interrupteur; ne pas vous
servir des téléphones se trouvant dans
le bâtiment.
• Appelez immédiatement votre fournisseur de gaz
depuis un voisin. Suivez les instructions
du fournisseur.
• Si vous ne pouvez rejoindre le fournisseur,
appelez le service 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.
AVERTISSEMENT
Assurez-vous de bien suivre 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.
Contact Information
Call us, your dealer, first if you have any questions about this
product. We can help answer questions about installation,
operation, or if there are damaged or missing parts when
unpacking this unit from the shipping box.
Dealer Contact Information
Certified to
NSF/ANSI 372

iN199 General Information 2
November 2021 - Revision 00
1. General Information
1.1 Items Shipped With Water Heater
The items shown in the illustration are shipped loose with the
water heater.
Pressure Relief Valve
(must be installed)
Strainer
(must be installed)
Communication
Cable
Keys
Installation &
Operation Manual
3/4" Gas Nipple
(not pictured)
Installation & Operation Manual
1.2 Serial Number Locations
The unit’s serial number is located on the left side of the unit.
Provide this serial number when inquiring about service or
warranty solutions.
Unit Serial Number: ______________________________
Date of Installation: ___ / ___ / ______

3 iN199 Safety
November 2021 - Revision 00
2. Safety
2.1 Safety Signal Words
DANGER
Indicates an imminently hazardous situation which, if
not avoided, results 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, might result in minor or moderate injury.
NOTICE
Indicates that equipment or property damage can result if
instructions are not followed.
SAFETY
INSTRUCTIONS
Safety instructions (or equivalent) signs indicate
specific safety-related instructions or procedures.
Note: Contains additional information important to a
procedure.
2.2 Installation Warnings
WARNING
DO NOT use this water heater for any purpose other
than heating water.
Read, understand, and follow the Installation & Operation
Manual, including all warnings and precautions, before
operating this water heater. If you do not follow these
instructions exactly, a fire or explosion can result, causing
property damage, personal injury, or loss of life.
Follow all local codes and the most recent edition of the
National Fuel Gas Code (ANSI Z223.1/NFPA 54) in the USA or
the Natural Gas and Propane Installation Code in Canada (CSA
B149.1).
This water heater must be installed by a licensed plumber,
gas fitter, or professional service technician. Installation by
unqualified person(s) voids the warranty.
This water heater is designed for operations at outlet
temperature(s) not in excess of 190°F (88°C).
DANGER
A. This water heater does not have a pilot light. It is
equipped with an ignition device which automatically
lights the burner. Do not try to light the burner
manually.
B. BEFORE OPERATING, smell all around the water
heater area for gas. Be sure to smell near the floor
because some gas is heavier than air and settles on
the floor.
WHAT TO DO IF YOU SMELL GAS:
• Do not try to light any appliance.
• Do not touch any electric switch; do not use any phone in
your building.
• 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 or
police department.
C. Use only your hand to turn the manual gas shut-off
valve. Never use tools. If the manual gas shut-off
valve does not turn by hand, don’t try to repair it.
Call a qualified service technician. Force or attempted
repair can result in a fire or explosion.
WARNING
DO NOT use or store flammable liquids around the water
heater, including gasoline, oils, spray paints, etc.
DO NOT operate this water heater unless it is properly
vented to the outside (the exhaust vent piping must be
connected from the unit directly to the outside). Improper
venting can cause a build-up of carbon monoxide, which
can result in brain damage or death. Exhaust gases must
be completely expelled out of the building.
This water heater is factory preset for NATURAL
GAS but can be field-converted for use with propane.
For propane conversion, refer to the Propane (LPG)
Conversion section of this manual. Connecting the
water heater to any other gas supply can result in
property damage, serious injury, or even death.
This water heater is suitable for use in potable water
heating applications. The cold and hot water fittings on
the top of the water heater MUST NOT be connected to
any heating system.
The water heater temperature is factory set to 120°F
(49°C). Hot water temperatures above 125°F can cause
severe burns instantly or death from scalds. If the
proposed water heater outlet temperature is to be set
above 125°F, installation of a thermostatically controlled
(or temperature-limiting) mixing valve is recommended
for all hot water going to faucets to avoid the risk
of scalding. Examples include commercial applications
where 140°F (60°C) is often needed or if the space
heating temperature required is higher than the domestic
hot water. Always check the temperature of the hot
water before bathing, showering, washing, etc.
Protect against snow and debris accumulation around
the vent terminations. Regularly inspect the exhaust
vent pipe and the air intake pipe to ensure they remain
clear from obstructions at all times.

iN199 Safety 4
November 2021 - Revision 00
CAUTION
Make sure you know the location of the gas shut-off
valve and how to operate it. Immediately close the
gas shut-off valve if the water heater is subjected to
fire, overheating, flood, physical damage, or any other
damaging condition that might affect the operation of
the unit. Have the water heater checked by a qualified
technician before resuming operation.
If the water quality is known to have high acidity, high
hardness, or both, water treatment is recommended.
Consult the local water authority.
SAFETY
INSTRUCTIONS
DO NOT use this appliance if any part has been under
water.
DO NOT reverse the cold water and gas connections as
this damages the gas valve.
DO NOT overtighten fittings as damage might occur,
causing internal leakage.
Locate the appliance in an area where leakage within
the unit or at its connections does not result in damage
to the surrounding area. The manufacturer is not
responsible for any damage resulting from leaking if
adequate drainage is not provided.

5 iN199 Technical Specifications
Jul 2023 - Revision 02
3. Technical Specifications
3.1 Specifications Chart
Technical Data iN199 Specification iN199A Specification
Type Indoor, Floor-Mounted
Fuel Preset for natural gas but convertible to propane
MinimumInput(BTUs/hour) 30,000
MaximumInput(BTUs/hour) 199,950
MaximumOutput(BTUs/hour) 195,950
Thermal Efficiency 98%
Turn Down Ratio (TDR) 6.7:1
WaterInlet/OutletConnection 1-1/2"NPT
GasInletConnection 1-1/2"NPT(3/4"w/nipple)
CondensateDrainConnection 3/4"PVC
MaximumCondensateFlowRate(GPM) 1.4
UnitdimensionsHXWXD(inches) 67.5X20X20(15.6cu.ft)
ServiceClearances 4"ontheback,6"onthetop,12"onthefront,and6"onthesides
Unitweight(lbs) 273
ShippingCrateDimensionsHXWXD/Weight 27X29.5X85(Inches)/373(LBS)
Venting Type Direct Vent (2 pipe – air intake and exhaust gas outlet), Power Vent (1 pipe – exhaust gas only)
VentingMaterials(USA) Sch.40PVC,Sch.80CPVC,Polypropylene,StainlessSteel(AL29-4C)
VentingMaterials(Canada) TypeBHGasVentClasses:IIA(PVC),IIB(CPVC),IIC(Polypropylene),I(AL294CSS)
Venting Size (Diameter) 3"
Max8"VentLength–SinglePipe/PowerVent 195' *
Max8"VentLength–TwoPipe/DirectVent 95' *
* Venting Note: From the maximum length above, deduct 5 ft. per 90° elbow and 2 ft. per 45° elbow.
Ignition Electronic Spark Ignition
Temperature Range 100°F – 190°F
Temperature Stability +/-4°F(whenondemand)
InstallationLocationAmbientTemperature 40°F – 130°F
Safety FlameRod,ThermalFuse,OverheatPreventionDevice,FanSpeedMonitor,FlueTemperatureMonitor,BlockedVentDetector,
Dual Flame Sensing
WaterPressureMin/Max(PSI) 30/150 30/160
NG/LP-Min.StaticGasPressure(FullFire) 2.5"WC(setregulatorsto8"NCforNGor11"forLP)
NG/LP-MaximumStaticGasPressure 14"WC
GasPressureforAdjustments 8"WCforNaturalGas,11"WCforPropane
Electrical 120VAC,60Hz
PowerConsumption Max9.5Amps,16W(Standby)
Internal Water Volume (gallons) 1
Features and Approvals iN199
Cascading Masterless,4-Unit,AutomaticRotation
CommonVenting Yes,Upto4Units
Heat Exchanger Expandable, Stainless 316L
ApplianceCerticationtoANSIZ21.10.3 ETL(Z21.10.3/CSA4.3) ETL(Z21.10.3/CSA4.3),ASMEHLW
SCAQMD(Pending) UltraLowNox(under20PPM)
Performance Specification
Hot Water Output (45°F Rise) 8.7
Hot Water Output (70°F Rise) 5.6
Hot Water Output (90°F Rise) 4.4
Hot Water Output (100°F Rise) 3.9
Hot Water Output (140°F Rise) 2.8
Warranty Heat Engine Coil - 6 years, All Other Parts - 1 year
Note:Duetocontinuousproductimprovements,thedesignandtechnicalspecificationsaresubjecttochangewithoutnotice.

iN199 Technical Specifications 6
November 2021 - Revision 00
3.2 Nomenclature
Gas Inlet
Air Intake
Exhaust Port
Pressure
Relief Valve
Hot Water Outlet
Recirculation Inlet
Cold Water Inlet
3.3 High Elevation Installations
For operation at elevations above 2,000 feet, the hot water
delivery capacity should be reduced by 4% for each 1,000 feet
above sea level.
Clearance Requirements
For the water heater to operate properly and efficiently, the
clearances specified in the table below are recommended.
21"
6"
6"
6"
6"
(top)
Service Clearances: If multiple units are installed, complete the electrical
connections first before making all other connections (gas, water, supply air,
exhaust, and condensate). This enables the 1" side to side clearances mentioned
in 3.1 Specifications Chart.
Location Required Recommended
From
Combustibles
From Non-
Combustibles
Service
Clearance1
Top 6" (15 cm) 2" (51 cm) 6" (15 cm)
Back 5/8" (16 mm) 5/8" (16 mm) 4" (10 cm)
Sides 1" (25 mm) 1/2" (13 mm) 6" (15 mm)
Front 2" (5 cm) 2" (5 cm) 21" (53 cm)
Bottom 0" (0 mm) 0" (0 mm) 0" (0 mm)
1Service clearances are recommended dimensions to allow for normal service
of the unit.

7 iN199 Technical Specifications
November 2021 - Revision 00
3.4 Connection Specifications
Connections
Description Specification
Gas Supply Inlet Connection 3/4" NPT
Water Supply Inlet Connection 1-1/2" NPT
Heated Water Outlet Connection 1-1/2" NPT
Air Intake Inlet 3" Polypropylene
Condensate Drain Connection 3/4"
Power Supply 120V AC Power
3.5 Exhaust Gas Standards
CO2and CO Standards
Description CO2Range (%) Max. CO Level
Particles Per Million
(ppm)
Natural Gas
High Fire 9.1% to 9.3% < 200 ppm
Low Fire 9.1% to 9.3% < 60 ppm
Propane Gas
High Fire 10.1% to 10.5% < 200 ppm
Low Fire 10.1% to 10.5% < 60 ppm

iN199 Technical Specifications 8
November 2021 - Revision 00
3.6 Overall Dimensions
3" PVC OR PP FRESH
AIR INTAKE
3" PVC OR PP EXHAUST
POWER CORD
LOW VOLTAGE PORTS 1-1/2" NPT WATER OUTLET
TEMPERATURE AND PRESSURE
RELIEF VALVE (FIELD INSTALLED)
PRESSURE RELIEF
VALVE (FIELD INSTALLED)
1-1/2" NPT GAS INLET
(3/4" W/NIPPLE)
POWER CORD
FRONT DISPLAY
3/4" RECIRCULATION
RETURN
CONDENSATE DRAIN
1-1/2" WATER INLET
BOTTOM PANEL
ELECTRICAL ACCESS PANEL
FRONT TOP PANEL
BOTTOM PANEL
SIDE FRONT REAR
TOPBOTTOM
2.1"
[54.47]
2.6"
[65.98]
1.1"
[26.95]
.16"
[26.95]
1"
[25.02]
5.4"
[136.89]
3.6"
[91.81]
3.5"
[89.98]
3.6"
[91.23]
16"
[405.46] Ø 0.6"
[16] 13.9"
[352.67]
15.6"
[395.81]
10.2"
[258.96]
67.3"
[1709.71]
20.4"
[517.91]
10.2"
[259.02]
6.3"
[161.17]
14"
[356.77]
8.5"
[215.97]
7.6"
[192.19]
17.2"
[437.43]
6.3"
[159.97]
18.3"
[464.11]

9 iN199 Technical Specifications
November 2021 - Revision 00
3.7 Configuration Options
Hot Water
Supply
Gas Supply
Cold Water Supply
Isolation Valve
Check Valve
Pipe Coupling
Pipe Cap
Recirculation Pump
LEGEND
Neuron (1 UNIT) Pressure Relief Valve
Expansion
Tank
HOT WATER FIXTURES
DRAWING NUMBER:
JOB NAME:
This document/drawing contains confidential and proprietary information and is the property of Intellihot Inc. This
document/drawing was prepared for the sole purpose of soliciting quotes, producing samples, or propose services. It is submitted
in confidence on the condition that you and your representatives have, by receiving it, agreed not to reproduce or copy it, in whole
or in part, or to furnish such information to others, or to make an other use of it except for the purposes stated above.
Recirculation Line
Hot Water Return
NOTES:
1. This schematic is a suggested piping configuration.
2. Any additional requirements from local codes and ordinances shall supercede this diagram.
3. For pipe sizes and gas pressure requirements, please refer to Installation & Operation Manual.
4. Gas pressure regulators to be installed on each unit. (Follow manufacturer's installation instructions)
See Note #4
System with no storage tank and without mixing valve.
Hot Water
Supply
Gas Supply
Cold Water Supply
Isolation Valve
Check Valve
Pipe Coupling
Pipe Cap
Recirculation Pump
LEGEND
Neuron (1 UNIT)
w/ tank-type heater Pressure Relief Valve
Expansion
Tank
HOT WATER FIXTURES
DRAWING NUMBER:
JOB NAME:
This document/drawing contains confidential and proprietary information and is the property of Intellihot Inc. This
document/drawing was prepared for the sole purpose of soliciting quotes, producing samples, or propose services. It is submitted
in confidence on the condition that you and your representatives have, by receiving it, agreed not to reproduce or copy it, in whole
or in part, or to furnish such information to others, or to make an other use of it except for the purposes stated above.
Recirculation Line
Hot Water Return
Traditional
Tank-Type Heater
NOTES:
1. This schematic is a suggested piping configuration.
2. Any additional requirements from local codes and ordinances shall supercede this diagram.
3. For pipe sizes and gas pressure requirements, please refer to Installation & Operation Manual.
4. Gas pressure regulators to be installed on each unit. (Follow manufacturer's installation instructions)
See Note #4
System with mixing valve but no storage tank.

iN199 Technical Specifications 10
November 2021 - Revision 00
Hot Water
Supply
Gas Supply
Cold Water Supply
Isolation Valve
Check Valve
Pipe Coupling
Pipe Cap
Recirculation Pump
LEGEND
Neuron (3 UNIT) Pressure Relief Valve
Expansion
Tank
HOT WATER FIXTURES
DRAWING NUMBER:
JOB NAME:
This document/drawing contains confidential and proprietary information and is the property of Intellihot Inc. This
document/drawing was prepared for the sole purpose of soliciting quotes, producing samples, or propose services. It is submitted
in confidence on the condition that you and your representatives have, by receiving it, agreed not to reproduce or copy it, in whole
or in part, or to furnish such information to others, or to make an other use of it except for the purposes stated above.
Recirculation Line
Hot Water Return
NOTES:
1. This schematic is a suggested piping configuration.
2. Any additional requirements from local codes and ordinances shall supercede this diagram.
3. For pipe sizes and gas pressure requirements, please refer to Installation & Operation Manual.
4. Gas pressure regulators to be installed on each unit. (Follow manufacturer's installation instructions)
See Note #4
Multiple unit system with mixing valve but no storage tank.

11 iN199 Quick Reference Installation Guide
November 2021 - Revision 00
4. Quick Reference Installation Guide
4.1 Install the Water Heater
When installing the water heater, follow all local building codes
and the current edition of the National Fuel Gas Code (ANSI
Z223.1/NFPA 54) in the USA, or National Gas and Propane
Installation Code (CAN/CGA B149.1) in Canada.
Note: For water heater installations in Massachusetts, refer to
section “16. Serviceable Parts” on page 59.
1. Select an installation location.
For an interior or exterior location, refer to section “5.
Preparation Before Installation” on page 13.
2. Check the quality of the water to determine if additional
treatment is beneficial to the function and efficiency of the
water heater. For additional information, refer to section “5.
Preparation Before Installation” on page 13.
3. Make all necessary gas connections.
For additional information, refer to section “6. Gas
Connection” on page 14.
4. Make all necessary venting connections.
For additional information, refer to section “7. Air Intake
Inlet and Exhaust Gas Outlet Pipe Connections” on page
19.
5. Make all necessary water connections.
For additional information, refer to section “8. Water
Connections” on page 28.
6. Make all necessary electrical connections. For additional
information, refer to “9. Electrical Power” on page 30.
Note: For additional electrical protection, a surge protector
is recommended. Damage caused by power surges is not
covered by the warranty.
7. If necessary, convert the water heater from the factory preset
of using natural gas to using propane. Refer to section “11.
Natural Gas to Propane Conversion” on page 34 for the
instructions.
8. As part of the propane conversion process, the CO2and
CO values must be adjusted. This process is also required
when installing the water heater at altitudes over 8,000 feet.
This procedure should be completed only by a qualified
technician. To check, adjust, or both the CO2and CO levels,
refer to “10. Adjusting CO2 Level” on page 31.
9. If connecting multiple units together, refer to “13.
Connecting Multiple Units” on page 47.
10. Fill out the Warranty Card and return it to Intellihot. For a
copy of the card, go to “19. Product Warranty Registration”
on page 71.
4.2 Pre-Startup Instructions
1. Recheck the hot and cold water lines, the gas line,
condensate drain line, the fresh air inlet, and exhaust vent to
make sure they are properly connected.
Gas Inlet
Air Intake
Exhaust Port
Pressure
Relief Valve
Hot Water Outlet
Recirculation Inlet
Cold Water Inlet

iN199 Quick Reference Installation Guide 12
November 2021 - Revision 00
2. Open the gas supply valve, cold water valve, and hot water
valve.
Hot
Water
Valve
Gas
Valve
Cold
Water
Valve
Note: Individual regulators not shown for clarity.
3. With the unit OFF, open a nearby hot water faucet and
allow the water to run through the unit until all the air is
removed from the water lines and from the water heater.
4. If multiple units are being installed, follow these instructions
for each unit.
5. Turn ON the power switch at the electrical junction box and
turn ON the ON/OFF switch inside the front cabinet door.
The water heater’s display panel should turn ON.
ON/OFF SWITCH
(LOCATED INSIDE)
6. Follow the instructions in this manual and on the unit’s
display screen. For additional information, refer to section
“12. Operation” on page 36.

13 iN199 Preparation Before Installation
November 2021 - Revision 00
5. Preparation Before Installation
5.1 Selecting an Indoor Installation Site
NOTE:
a. When installing the water heater, follow all local building
codes and the current edition of the National Fuel Gas
Code (ANSI Z223.1/NFPA 54) in the USA, or National
Gas and Propane Installation Code (CAN/CGA B149.1)
in Canada when installing this product.
b. For water heater installations in Massachusetts, refer to
section “16. Serviceable Parts” on page 59.
1. Select an interior location for the installation. Each
installation is unique; therefore, take the time to find the
best location for the water heater.
a. Install the water heater near locations that use hot water,
such as bathroom, kitchen, or laundry room faucets.
b. Select a location that minimizes the length of the water
pipe.
c. If the distances are long or if the faucet or appliance
requires “instant” hot water, we recommend running
a recirculation line back to the water heater from the
farthest fixture.
d. Insulate the hot water supply and recirculation lines.
e. Select a location away from foot traffic and away from
areas where dust, debris, chemical agents, or other
combustible materials could accumulate.
f. Allow sufficient space for service and maintenance access
to all gas, water, and drain connections.
g. Make sure the location meets all building code
requirements.
2. Minimize the distance that the exhaust gas outlet and air
intake inlet must travel to an exterior wall.
a. The exhaust vent outlet must not be located next to a
walkway, near soffit vents, crawl space vents, or other
areas where condensate (water vapor) could cause
damage or create a hazard. Refer to section “7.7 Venting
Clearance Specications” on page 25 for additional
information.
b. The fresh air inlet vent must be separated from the
exhaust vent per guidelines in section “7. Air Intake Inlet
and Exhaust Gas Outlet Pipe Connections” on page 19.
c. Contaminated or dirty air drawn into the intake pipe can
damage the water heater. The warranty does not cover
damage caused by airborne contaminants.
3. Locate the unit close to a drain and near gas and water
connections.
The water heater produces a significant amount of
condensate during normal operation and should be located
near a suitable drain where damage from a possible leak is
minimal. Installing the water heater in a location without
a drain voids the warranty and the manufacturer is not
responsible for any resulting water damages that might
occur. For additional information, refer to section “8.4
Condensate Drain Line” on page 29.
4. Locate the water heater and all the water pipes in an area
where the ambient temperature always remains above
freezing.
a. When the water heater is connected to an electrical
power supply, it automatically prevents the water from
freezing inside the unit.
b. The unit’s freeze protection system does not prevent the
water in the external piping from freezing.
NOTICE
In cold climates, if there is a power failure, the unit’s freeze
protection system does not operate and can result in water
freezing inside the heat engine. To prevent damage to
the water heater, turn OFF the gas supply and inlet water
valve. Drain the unit completely. Damage caused by
freezing water is not covered by the warranty.
5. Select an appropriate location for the combustion air and
exhaust pipes to exit the building, as shown in section “7.7
Venting Clearance Specications”.
6. Check the water quality.
a. Proper maintenance of the water heater is required
to ensure that the water meets EPA quality standards.
Refer to section “18. Warranty” on page 68 for quality
standard requirements and additional information.
b. If you suspect that your water is contaminated in any
way, discontinue use of the water heater and contact an
authorized technician or licensed professional.
c. If the incoming water is known to have a high mineral
content or “hardness” (see warranty section), treatment
is recommended upstream from the water heater.

iN199 Gas Connection 14
November 2021 - Revision 00
6. Gas Connection
WARNING
FIRE AND EXPLOSION HAZARD
To avoid serious injury or even death, the gas line
installation and the gas line inlet pressure test must be
done by a licensed professional.
Always match the water heater with the type of gas
supplied to the unit (natural gas or propane). The water
heater is factory preset for natural gas.
Make sure the gas line pressures are within normal
limits. Pressures outside normal limits can result in
poor performance and hazardous operating conditions.
6.1 Quick Reference Installation Instructions
1. Determine fuel source; natural gas or propane as shown in
“6.2 Fuel Source” on page 14.
2. Measure gas pressure as shown in “6.3 Gas Pressure
Requirements” on page 14.
3. Install a gas pressure regulator and vent line if gas pressure
is above maximum recommendations as shown in “6.4 Gas
Pressure Regulator” on page 14.
4. Measure the length of the supply line as shown in “6.5
Length of Gas Supply Line” on page 15.
5. Select the proper gas piping material as shown in “6.6 Gas
Piping Material” on page 15.
6. Select the proper gas piping diameter as shown in “6.7
Determine Correct Gas Pipe Diameter” on page 15.
7. Install a drip leg on the gas piping as shown in “6.8 Gas Pipe
Drip Leg and Shut-off Valve” on page 15.
8. Install a manual shut-off valve as shown in “6.8 Gas Pipe
Drip Leg and Shut-off Valve” on page 15.
9. Test all gas line connections for leaks.
NOTICE
Do not fire (operate) the water heater until all connections
have been completed and the heat exchanger is filled with
water.
6.2 Fuel Source
1. Natural gas is the factory preset.
2. To convert the unit to propane, refer to section “11. Natural
Gas to Propane Conversion” on page 34.
6.3 Gas Pressure Requirements
iN series water heaters are designed to operate at gas pressures
as low as 2.5” Water Column (WC) (at maximum firing rate).
Gas inlet pressures to each unit should not exceed 14” WC
under any condition (whether the unit is firing or not firing).
Natural Gas Static Gas Pressure
Parameters Specifications
Minimum Static Gas Pressure 2.5" WC (non-corrugated, black
iron)
Recommended Gas Pressure 8" WC
Maximum Static Gas Pressure 14" WC
6.4 Gas Pressure Regulator
1. If the gas inlet pressure is higher than recommended,
install a gas pressure regulator to lower gas pressure to an
acceptable level.
2. The gas pressure regulator must have the same or higher
minimum to maximum modulation range as the iN model it
is regulating. For example, an iN199 gas pressure regulator
should have a modulation range of 30,000 BTU/h to 199,950
BTU/h.
3. When multiple units are connected, use a dedicated gas
pressure regulator for each unit.

15 iN199 Gas Connection
November 2021 - Revision 00
4. Regulators should be mounted with a minimum of 12" of
straight length pipe on either side.
5. To convert the unit to propane, refer to “11. Natural Gas to
Propane Conversion” on page 34.
6.4.1 Venting of Gas Supply Regulators
Make sure the gas supply regulator is properly vented by
following all local codes and the gas regulator manufacturer’s
recommendations.
1. The vent pipe must be at least the same size as the regulator
vent.
2. When multiple units are connected, each regulator must
have a separate vent line.
3. Vent lines must not be connected together or connected
with any other appliance requiring external venting.
4. When selecting the size, the pipe diameter must be increased
by one size for every 20 feet of pipe.
ŐEach 90° elbow is equivalent to approximately:
4.5 feet for nominal pipe sizes of up to 1-1/2"
10.5 feet for nominal pipe sizes of up to 4".
ŐEach 45° elbow is equivalent to approximately:
2 feet for nominal pipe sizes of up to 1-1/2"
5 feet for nominal pipe sizes of up to 4".
6.5 Length of Gas Supply Line
1. Make sure the length supply line is correctly sized.
a. Measure the length of the gas supply line from the gas
meter to the water heater or other appliances requiring
gas. The diameter of the pipe must be in relation to the
length.
b. The total length of gas piping, as well as fitting pressure
drop, must be considered when sizing the gas piping.
Total equivalent length should be calculated from the
meter or source location to the last heater connected.
c. Gas pipe size should be selected on the total equivalent
length. The gas volume for cfh (cubic foot per hour)
flow is the input divided by the calorific value of the fuel
to be supplied.
d. Use the “6.10 Gas Pipe Sizing Tables” on page 17 or
refer to the gas line manufacturers sizing information to
determine the correct diameter for the supply pipe.
e. The diameter of the gas lines vary according to the
specific installation requirements.
6.6 Gas Piping Material
1. All gas piping and components must comply with NFPA
local codes, and utility requirements minimum. Only gas
approved fittings, valves, or pipe should be utilized.
2. Standard industry practice for gas piping is Schedule 40
iron pipe and fittings. All high and low gas pressure piping
systems must comply with local utility and building codes.
3. Assembled piping should be clean of all scale, debris, metal
particles, or foreign material.
4. The piping must be supported from the floor, ceiling, or
walls and by the water heater itself.
6.7 Determine Correct Gas Pipe Diameter
Note: The water heater should be the first appliance to be
connected to the gas supply line.
1. Determine the gas requirement of the water heater(s) and
other appliances requiring gas.
2. Size the pipe diameter according to the COMBINED total
maximum BTUH volume for all the appliances as if they
were all operating at the same time. Use the “6.10 Gas Pipe
Sizing Tables” on page 17.
3. Select the proper header pipe according to the number of
units being connected together, as shown in the chart.
Header Sizing for Multiple iN Units
Number of
Heaters 1 2 3 4
Sch 40 Iron
Pipe 1" 1" 1.5" 1.5"
4. The maximum pressure drop from the source to the final
water heater must not exceed 0.3” WC.
5. The maximum gas flow rate required is the sum of
the maximum inputs of each unit divided by the heat
of combustion of the fuel supplied at the location
(approximately 1,030 BTU per cubic foot for natural gas or
2,520 BTU per cubic foot for propane).
Note: Consult the fuel supplier or utility to confirm that
sufficient volume and normal pressure is provided to the
building at the discharge side of the gas meter or supply
pipe.
6.8 Gas Pipe Drip Leg and Shut-off Valve
1. Install a gas pipe drip leg on each water heater to prevent
dirt, condensation, or debris from entering the gas inlet.
Drip Leg
2. Local codes might require multiple units to have a full size
drip leg on the main gas supply line and one on each unit.
3. The drip leg should have a removable clean-out cap.
4. The gas pipe must not be supported by the drip leg.
5. Follow local building codes when selecting and installing a
shut-off valve.
6. Local codes might require multiple units to have a shut-off
valve on the main gas supply line and one on each unit.
6.9 Connecting Gas Line to Unit
Note: Always clean the inside of the gas line of any dirt or
debris before connecting the piping to the unit.

iN199 Gas Connection 16
November 2021 - Revision 00
Main Supply
Line
Drip
Leg
Manual
Shut-off
Valve
Note: Individual gas regulators not shown for clarity.
Main Supply
Line
Drip
Leg
Drip
Leg
Drip
Leg
Drip
Leg
Manual
Shut-off
Valve
Manual
Shut-off
Valve
Manual
Shut-off
Valve
Manual
Shut-off
Valve
Note: Individual gas regulators not shown for clarity.
1. Install a flanged steel coupling and gasket with a short piece
of 3/4" NPT black pipe.
Note: Individual gas regulators not shown for clarity.
2. Install a manual shut-off valve as described in “6.8 Gas Pipe
Drip Leg and Shut-off Valve” on page 15.
Union
Shut-off
Valve
Note: Wye-Strainer not shown for clarity.
3. Install a drip leg as described in “6.8 Gas Pipe Drip Leg and
Shut-off Valve” on page 15.
4. Continue installing pipe to reach the main gas supply
connection.
5. Test all gas pipe connections.
a. All the gas pipe connections should be tested as
prescribed in NFPA 54.
b. In multiple unit applications, each unit should be isolated
before testing any piping system as pressure might
exceed the allowable pressure of 14.0” WC.
NOTICE
Do not fire (operate) the water heater until all connections
have been completed and the heat exchanger is filled with
water.