Rinnai Demand Duo H Series User manual

Demand Duo™ H-Series Installation and Operation Manual
CHS13080HiN .........80 Gallon, 130,000 BTU
CHS13080HiP .........80 Gallon, 130,000 BTU
CHS16080HiN .........80 Gallon, 160,000 BTU
CHS16080HiP .........80 Gallon, 160,000 BTU
CHS19980HiN .........80 Gallon, 199,000 BTU
CHS19980HiP .........80 Gallon, 199,000 BTU
CHS160100HiN .......100 Gallon, 160,000 BTU
CHS160100HiP .......100 Gallon, 160,000 BTU
For Indoor Commercial Applications Only:
Single Tankless H-Series Demand Duo™
This product is NOT intended for residential applications.

Demand Duo™ H-Series Installation and Operation Manual 2
If the informaon in these instrucons is not followed exactly, a
re or explosion may 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
instrucons.
− If you cannot reach your gas supplier, call the re department.
• Installaon and service must be performed by a trained and qualied professional, service
agency or the gas supplier.
WARNING WARNING

READ AND SAVE THESE INSTRUCTIONS
1. Welcome.......................................................................................................................4
2. Safety............................................................................................................................5
2.1 Safety Symbols .......................................................................................................5
2.2 Safety Precautions ..................................................................................................5
3. About ............................................................................................................................7
3.1 Components............................................................................................................7
3.2 Specifications ..........................................................................................................8
3.3 Dimensions .............................................................................................................10
4. Installation.....................................................................................................................12
4.1 Installation Guidelines .............................................................................................12
4.2 What You Will Need ................................................................................................13
4.3 Choose an Installation Location...............................................................................13
5. Venting..........................................................................................................................17
5.1 Venting Requirements.............................................................................................17
5.2 Select a Vent Type..................................................................................................19
6. System Plumbing ..........................................................................................................37
6.1 Pressure Relief Valve Requirements .......................................................................37
6.2 Temperature-PRV Requirements ............................................................................37
6.3 Typical Installations.................................................................................................38
6.4 Piping Diagram for Basic Installations .....................................................................40
6.5 Piping Diagram for Multiple Unit Installations...........................................................41
6.6 Connect the Water Heater to the Water Supply.......................................................42
7. Gas and Power Supply..................................................................................................43
7.1 Connect the Gas Supply..........................................................................................43
7.2 Connect Electricity...................................................................................................46
7.3 Pump Controller ......................................................................................................48
8. Post-Installation Checklist..............................................................................................49
9. Maintenance..................................................................................................................50
10.1 Replacement Parts................................................................................................51
10.2 Service/Maintenance Log ......................................................................................53
10. Warranty......................................................................................................................54

Demand Duo™ H-Series Installation and Operation Manual 4
Thank you for purchasing Rinnai’s Demand
Duo™ H-Series Commercial Hybrid Water
Heating System. This manual provides
information on the installation, operation, and
maintenance of Rinnai’s Demand Duo™ H-Series
Commercial Hybrid Water Heating System. Read
this manual completely before installing or
operating the system.
This manual is a supplement to the
Installation and Operation Manual for
Condensing Tankless Water Heaters; refer to
the tankless water heater installation and
operation manual for complete water heater
details, including:
• Parameter Settings (High Altitude
Adjustment, Vent Length Adjustment, and
more)
• Temperature Controller Installation
• Performance Data
• Diagnostic Codes
• A trained and qualified professional must
install the system, inspect it, and leak test it
before use. The warranty may be voided due
to any improper installation.
• The trained and qualified professional should
have skills such as:
− Gas line sizing
− Connecting gas lines, water lines, valves,
and electricity
− Knowledge of applicable national, state,
and local codes
− Installing venting through a wall or roof
− Training in installation of tankless water
heaters. Training on Rinnai Tankless
Water Heaters is accessible at
www.trainingevents.rinnai.us.
• Read all instructions in this manual before
installing the system. The system must be
installed according to the exact instructions in
this manual.
• Proper installation is the responsibility of the
installer.
• When installation is complete, leave this
manual with the system or give the manual
directly to the consumer.
• You must read the entire manual to
properly operate the water heater and to
have regular maintenance performed.
• Keep this manual for future reference.
• As when using any appliance generating
heat, there are certain safety precautions
you should follow. See the Safety
Precautions section for detailed safety
precautions.
• Be sure your water heater is installed by a
trained and qualified professional.
• If installing in the state of Massachusetts,
you must read the Massachusetts State
Gas Regulations section in the tankless
water heater installation and operation
manual (supplied with tankless water
heater).
For Your Records
Dealer Name:
Dealer Phone #:
Purchase Date:
Tank Serial #:
System Serial #:
Tank Serial
Number Label
System Serial
Number Label

Demand Duo™ H-Series Installation and Operation Manual 5
This manual contains the following important
safety symbols. Always read and obey all safety
messages.
This is the safety alert symbol. This
symbol alerts you to potential hazards
that can kill or hurt you and others.
Indicates an imminently
hazardous situation which,
if not avoided, will result in personal injury or
death.
Indicates a potentially
hazardous situation
which, if not avoided, could result in minor or
moderate injury. It may also be used to alert
against unsafe practices.
DANGER
CAUTION
Indicates a potentially
hazardous situation
which, if not avoided, could result in personal
injury or death.
WARNING
WARNING
• Before operating, smell all around the
appliance area for gas. Be sure to smell next
to the floor because some gas is heavier than
air and will settle on the floor.
• Keep the area around the appliance clear and
free from combustible materials, gasoline, and
other flammable vapors and liquids.
• Combustible construction refers to adjacent
walls and ceiling and should not be confused
with combustible or flammable products and
materials. Combustible and/or flammable
products and materials should never be stored
in the vicinity of this or any gas appliance.
• Always check the water temperature before
entering a shower or bath.
• To protect yourself from harm, before
performing maintenance:
− Turn off the electrical power supply by
unplugging the power cord or by turning off
the electricity at the circuit breaker. (The
“On/Off” button on the temperature control-
ler does not control the electrical power.)
− Turn off the gas at the gas valve, usually
located immediately before the water heat-
er.
− Turn off the incoming water supply. This
can be done at the isolation valve
immediately before the water heater or by
turning off the water supply to the building.
• 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, do not try to
repair it; call a licensed professional. Force or
attempted repair may result in a fire or explo-
sion.
• Do not use this appliance if any part has been
under water. Immediately call a
trained and qualified professional to inspect
the appliance and to replace any part of the
control system and any gas control which has
been under water.
• Do not use substitute materials. Use only
parts certified for the appliance.
• Should overheating occur or the gas supply
fail to shut off, turn off the manual gas control
valve to the appliance.
• Do not use an extension cord or an adapter
plug with this appliance.
• Any alteration to the appliance or its controls
can be dangerous and will void the warranty.
• If a water heater is installed in a closed water
supply system, such as one having a
backflow preventer in the cold water supply
line, means shall be provided to control
thermal expansion. Contact the water
supplier or local plumbing inspector on how to
control thermal expansion.
Topics in this section
• Safety Symbols
• Safety Precautions

Demand Duo™ H-Series Installation and Operation Manual 6
• Only trained and qualified professionals are
permitted to adjust parameter settings.
• Proper venting is required for the safe
operation of this appliance.
• Flammable liquids such as cleaning solvents,
aerosols, paint thinners, adhesives, gasoline
and propane must be handled and stored with
extreme care. These flammable liquids emit
flammable vapors and when exposed to an
ignition source can result in a fire hazard or
explosion. Flammable liquids should not be
used or stored in the vicinity of this or any
other gas appliance.
• DO NOT operate the water heater without the
front panel installed. The front panel should
only be removed for service/maintenance or
replacing internal components.
• BURN HAZARD. Hot exhaust and vent may
cause serious burns. Keep away from the
water heater. Keep small children and animals
away from the water heater.
• Hot water outlet pipes leaving the water heater
can be hot to touch.
• Do not store or use gasoline or other
flammable vapors and liquids in the vicinity of
this or any other appliance.
• Install the vent system per local and national
codes.
• Do not install this water heater above 10,200 ft
(3,109 m).
• Do not obstruct combustion air to the water
heater.
• Failure to properly vent this appliance can
result in death, personal injury and/or property
damage.
• Rinnai recommends that every home have a
carbon monoxide (CO) alarm inside or directly
outside each bedroom or sleeping area. Check
batteries monthly and replace them annually.
DO NOT adjust the
internal gas valve. The
design is such that
adjustment is not required. Warranty will be
voided if the internal gas valve is adjusted.
WARNING
• Keep the air intake location free of chemicals
such as chlorine or bleach that produce
fumes. These fumes can damage
components and reduce the life of your
appliance.
• Make sure the water heater and its water
lines are protected from freezing. Damage
due to freezing is not covered by the
warranty.
FLAMMABLE
Flammable Vapors
WARNING
FOR YOUR SAFETY
Do not store or use gasoline or other
flammable vapors and liquids in the vicinity of this
or any other appliance.
Hot water can be
dangerous, especially for
infants or children, the
elderly, or infirm.
There is hot water scald
potential if the thermostat
is set too high.
Water temperatures over
125ºF (51ºC) can cause
severe burns or scalding
resulting in death.
Hot water can cause first degree burns with
exposure for as little as:
3 seconds at 140ºF (60ºC)
20 seconds at 130ºF (54ºC)
8 minutes at 120ºF (48ºC)
Test the temperature of the water before placing
a child in the bath or shower.
Do not leave a child or an infirm person in the
bath unsupervised.
DANGER

Demand Duo™ H-Series Installation and Operation Manual 7
Figure 1: Components
Gas Flex Line
Flare Nut
Adapter
(Supplied but
not installed)
Pump
Electric Conduit
Dirt Leg
Gas Swivel
DuoSmart™
Digital Controller
Front Cover
Topics in this section
• Components
• Specifications
• Dimensions

Demand Duo™ H-Series Installation and Operation Manual 8
Appliance Type Commercial Hybrid Water Heating System Consisting of Condensing Tankless
Water Heater, Insulated Storage Tank, Pump and Controller
Model CHS199100Hi CHS160100Hi CHS19980Hi CHS16080Hi CHS13080Hi
Minimum Gas Consumption Btu/hr (kW/hr) 15,000 (4.3)
Maximum Gas Consumption Btu/hr (kW/hr) 199,000 (58.3) 160,000 (46.9) 199,000 (58.3) 160,000 (46.9) 130,000 (38.1)
Tank Volume 119 Gallons (450 Liters) 80 Gallons (303 Liters)
First Hour Delivery at 100°F Rise1317 Gallons
(1,200 Liters)
271 Gallons
(1,026 Liters)
290 Gallons
(1,098 Liters)
244 Gallons
(924 Liters)
209 Gallons
(791 Liters)
Product Weight 431 lb (195 kg) 429 lb (195kg) 307 lb (139 kg) 305lb (138 kg) 305lb (138 kg)
Sound Level 49 dB 48 dB 49 dB 48 dB 48dB
Installation Type Internal (Indoor) Commercial Applications
Category Category IV
Ignition System Direct Electronic Ignition
Water Supply Pressure 150 PSI (Maximum)
Temperature Setting 98°F (37°C) to 185°F (85°C) 98°F (37°C) to
140°F (60°C)3
Electrical Data
Normal 265 W 223 W 265 W 233 W 219 W
Standby 44 W 44 W 44 W 44 W 44 W
Freeze Protection 148 W 148 W 148 W 148 W 148 W
Max Current 5.5 A 5.5 A 5.5 A 5.5 A 5.5 A
Fuse Tankless Water Heater Engine: 10 Amps, Controller: 10 Amps
Gas Supply Pressure2 Natural 3.5 - 10.5 in. w.c.
Propane 8.0 - 13.5 in. w.c.
By-Pass Flow Control Electronic
Connections Gas Supply Inlet: 3/4 in. MNPT Hot Water Outlet: 1-1/2 in. MNPT
Cold Water Inlet: 1-1/2 in. MNPT
Electric Connections Appliance: AC 120 Volts, 60Hz.
Integrated Temperature Controller: DC 12 Volts (Digital)
Water Temperature Control Simulation Feed Forward and Feedback
ENERGY STAR® Certified (Tankless engine) Yes
Complies with South Coast Air Quality
Management District 14 ng/J or 20 ppm NOx
Emission Levels
Yes
1First Hour Delivery Rating is a theoretical calculation based on 70% usable tank capacity (Tank Capacity x .70 + (recovery) = First Hour Delivery
Rating
2The maximum gas supply pressure must not exceed the value specified by the manufacturer.
3Temperature limit of 185°F can be achieved using optional MCC-91 controller.
Rinnai products are continually being updated and improved; therefore, specifications are subject to change without prior notice.
Table 1: Specifications

Demand Duo™ H-Series Installation and Operation Manual 9
Product
Number
Gas
Type
Input U.S. Gallon / HR Liters / HR at Temperature Rise Indicated
Tank
Capacity
°F 30°F 40°F 50°F 60°F 70°F 80°F 90°F 100°F 110°F 120°F 130°F 140°F
BTU/HR kW °C 17°C 22°C 28°C 33°C 39°C 44°C 50°C 56°C 61°C 67°C 72°C 78°C
CHS199100Hi NG/
LP 199,000 58
119 Gals. GPH 780 585 468 390 334 292 260 234 213 195 180 167
450 Liters LPH 2,953 2,214 1,771 1,476 1,264 1,105 984 886 806 738 681 632
CHS160100Hi NG/
LP 160,000 58
119 Gals. GPH 627 470 376 314 269 235 209 188 171 157 145 134
450 Liters LPH 2,374 1,780 1,424 1,187 1,017 890 791 712 647 593 548 509
CHS19980Hi NG/
LP 199,000 58
80 Gals. GPH 780 585 468 390 334 292 260 234 213 195 180 167
303 Liters LPH 2,953 2,214 1,771 1,476 1,264 1,105 984 886 806 738 681 632
CHS16080Hi NG/
LP 160,000 58
80 Gals. GPH 627 470 376 314 269 235 209 188 171 157 145 134
303 Liters LPH 2,374 1,780 1,424 1,187 1,017 890 791 712 647 593 548 509
CHS13080Hi NG/
LP 130,000 58
80 Gals. GPH 509 382 306 255 218 191 170 153 139 127 118 109
303 Liters LPH 1,929 1446 1,157 964 827 723 643 579 526 482 445 413
Table 2: Recovery Capacity / Input

Demand Duo™ H-Series Installation and Operation Manual 10
RIGHT
TOP
FRONT
LEFT
Measurements below are
shown in inches (mm).
LEFT
RIGHT
Models
CHS199100Hi
CHS160100Hi
Figure 2: Dimensions 34.77 (883)
Ø 28.30 (718)
31.67 (804) Gas
34.84 (885) Vent
40.21 (1,021)
24.94
(633) T&P
30.88 (784) PRV
34.07 (865)
Condensate
3.40 (86)
Drain
4.20 (107)
1-1/2 in.
MNPT Cold
34.24 (869) PRV
56.74 (1,441) T&P
35.31 (897) Gas
69.40 (1,762)
71.10 (1,805) 1-1/2 in. MNPT Hot

Demand Duo™ H-Series Installation and Operation Manual 11
RIGHT
TOP
FRONT
LEFT
Models
CHS19980Hi
CHS16080Hi
CHS13080Hi
Measurements below
are shown in inches
(mm).
Figure 3: Dimensions 31.86 (809)
Ø 24.25 (616)
27.31 (694) Gas
30.59 (777) Vent
36 (914)
29.04 (738)
Condensate
29.04 (704) PRV
16.58
(421)
T&P
31.73 (806) Gas
54.28 (1,379) T&P
30.76 (781)
PRV
62.69 (1,592)
64.71 (1,643)
1-1/2 in. MNPT Hot
4.19 (106)1-1/2 in.
MNPT Cold
3.54 (90)
Drain

Demand Duo™ H-Series Installation and Operation Manual 12
THIS SECTION IS INTENDED FOR THE
INSTALLER
Installer qualifications: A trained and qualified
professional must install the appliance,
inspect it, and leak test the Demand Duo™
before use. The warranty may be voided due
to any improper installation. The trained and
qualified professional should have skills such
as: Gas sizing; Connecting gas lines, water
lines, valves, and electricity; Knowledge of
applicable national, state, and local codes;
Installing venting through a wall or roof; and
training in installation of tankless water
heaters. Training for Rinnai Tankless Water
Heaters is accessible online at
www.trainingevents.rinnai.us.
• This water heater is suitable for combination
water heating and space heating and not
suitable for space heating applications only.
• The installation must conform with local
codes or, in the absence of local codes, with
the National Fuel Gas Code, ANSI Z223.1/
NFPA 54, or the Natural Gas and Propane
Installation Code, CSA B149.1.
• The appliance, when installed, must be
electrically grounded in accordance with local
codes or, in the absence of local codes, with
the National Electrical Code, ANSI/NFPA 70,
or the Canadian Electrical Code, CSA C22.1.
When installing the Demand Duo™, follow these
guidelines:
DO NOT install the Demand Duo™ Com-
mercial Hybrid Water Heating System out-
doors.
DO NOT install the water heater in an area
where water leakage of the unit or connec-
tions will result in damage to the area adja-
cent to the appliance or to lower floors of
the structure. When such locations cannot
be avoided, it is required that a suitable
drain pan, adequately drained, be installed
under the water heater. The pan must not
restrict combustion air flow.
DO NOT install the water heater in an area
with negative air pressure.
DO NOT obstruct the flow of combustion
and ventilation air.
DO NOT use this appliance in an applica-
tion such as a pool or spa heater that uses
chemically treated water. This appliance is
suitable for filling large or whirlpool spa tubs
with potable water.
DO NOT use substitute parts that are not
authorized for this appliance.
Topics in this section
• Installation Guidelines
• What You Will Need
• Choose an Installation Location
• The appliance and its main gas valve must be
disconnected from the gas supply piping sys-
tem during any pressure testing of that sys-
tem at test pressures in excess of 1/2 psi (3.5
kPa) (13.84 in W.C.). For system testing at
pressures less than or equal to 1/2 psi (3.5
kPa) (13.84 in W.C.) the appliance must be
isolated from the gas supply piping by closing
its individual manual shutoff valve.
• You must follow the installation instructions
and those in the venting section for adequate
combustion air and exhaust.
• If a water heater is installed in a closed water
supply system, such as one having a back-
flow preventer in the cold water supply line,
means shall be provided to control thermal
expansion. Contact the water supplier or local
plumbing inspector on how to control thermal
expansion.
• Should overheating occur or the gas supply
fail to shut off, turn off the manual gas control
valve to the appliance.
• Combustion air must be free of chemicals,
such as chlorine or bleach, that produce
fumes. These fumes can damage compo-
nents and reduce the life of your appliance.

Demand Duo™ H-Series Installation and Operation Manual 13
Carefully unpack your system package and verify
the following contents are included.
If any items are damaged or missing, contact
your local dealer/distributor or call Rinnai
Customer Care at 1-800-621-9419. Do not
attempt to use any item that appears damaged.
Items included with system:
• Rinnai Demand Duo™ Commercial Hybrid
Water Heating System
• Temperature and Pressure Relief Valve
(pre-installed on tank)
• Pressure Relief Valve (pre-installed on the
tankless water heater)
• Installation and Operation Manual (this
manual)
• Installation and Operation Manual for
Tankless Water Heater
• 2 in. PVC Vent Screens (x2) and Vent
Screen Screws
• Gas Flex/Union
To avoid danger of
suffocation, keep
plastic bags away from babies, small children
and pets. Do not use these bags in cribs, beds,
carriages, or playpens. The bags are not a toy.
WARNING
• Threading machine with heads and oiler
• Core drill with diamond head
• Torch set
• Copper tubing cutter
• Steel pipe cutter
• Heat tape
• 5/8 in. ID PVC flexible tubing
• Electrical wire
• Concrete wall anchors
• Optional pipe cover
• PVC glue/cement and primer
• 2 conductor 22 AWG wire for controller
• Single gang electrical box
• Wire nuts
• Unions and drain valves
• Drain pan
• Earthquake strap
When selecting an installation location, you must
ensure that clearances will be met and that the
vent length will be within required limits. Consider
the installation environment, water quality, and
need for freeze protection. Requirements for the
gas line, water lines, electrical connection, and
condensate disposal can be found in their
respective installation sections in this manual.
This section provides information on the
importance of water quality to the Rinnai
Tankless Water Heater. The information is
intended to serve as general guidelines only and
is not a complete list of water quality guidelines.
Consideration of care for your water heater
should include evaluation of water quality. The
water must be potable, free of corrosive chemi-
cals, sand, dirt, or other contaminants. It is up to
the installer to ensure the water does not
contain corrosive chemicals or elements that can
affect or damage the Rinnai Commercial Hybrid
Water Heating System. Water that contains
chemicals exceeding the levels below can dam-
age the Rinnai Tankless Water Heater. Replace-
ment of components due to water quality dam-
age is not covered by the warranty.
• Pipe wrenches (x2)
• Phillips Head screwdriver
• Adjustable pliers
• Wire cutters
• Gloves
• Safety glasses
• Level
• Soap or gas leak detector solution
• Approved venting
• Teflon tape (recommended) or pipe com-
pound
• Pipe insulation
• Hammer drill with concrete bits
• Saw

Demand Duo™ H-Series Installation and Operation Manual 14
1. Choose the right hand truck to support the
weight and size of the water heater. Refer to
section “3.2 Specifications” in this manual for
specific weights and dimensions.
2. Use proper lifting techniques to load the
water heater onto the hand truck:
• Position the water heater onto the hand
truck so the weight is evenly balanced
and the tank is touching the rails of the
hand truck.
• Secure the water heater to the hand
truck:
− Position STRAP A around the
tankless unit as illustrated below.
− Position STRAP B around the base
of the tank below the lower
enclosure. Do not add strap around
the exhaust or vent connection.
Contaminant Maximum Level
Total Hardness Up to 200 mg/L
Aluminum * Up to 0.2 mg/L
Chlorides * Up to 250 mg/LL
Copper * Up to 1.0 mg/L
Dissolved Carbon Dioxide
(CO2) Up to 15.0 mg/L
Iron * Up to 0.3 mg/L
Manganese * Up to 0.05 mg/L
pH * 6.5 to 8.5
TDS (Total Dissolved Solids) * Up to 500 mg/L
Zinc * Up to 5 mg/L
* Source: Part 143 National Secondary Drinking
Water Regulations
Air surrounding the water heater, venting, and
vent termination(s) is used for combustion and
must be free of any compounds that cause
corrosion of internal components. These include
corrosive compounds that are found in aerosol
sprays, detergents, bleaches, cleaning solvents,
oil based paints/varnishes, and refrigerants. The
air in beauty shops, dry cleaning stores, photo
processing labs, and storage areas for pool
supplies often contains these compounds.
Therefore, it is recommended to install as a direct
vent (use outside air for combustion). In
applications utilizing room air where there are
high levels of particulates, Rinnai offers a room
air screen.
The water heater, venting, and vent termination
(s) should not be installed in any areas where the
air may contain these corrosive compounds.
If you install this water heater in an area that is
known to have hard water or that causes scale
build-up, the water must be treated and may
require a more frequent flushing schedule.
This water heater includes a service indicator
(Service Soon, SS). When selected in the
parameter settings, an SS code will display on
the controller indicating that it is time to flush and
service the water heater. Scale build-up is
caused by hard water and can be accelerated if
the water heater is set at a temperature above
120°F.
Rinnai offers Southeastern Filtration’s
“ScaleCutter Water Conditioning System” that
offers superior lime scale prevention and
corrosion control by feeding a blend of control
compounds into the cold water supply.
Lower
Enclosure
Strap A
Strap B
Figure 4: Transport
Table 3: Water Quality Guidelines Do not store or use gasoline or other flammable
vapors and liquids in the vicinity of this or ay
other appliance.
Flammable liquids such as cleaning solvents,
aerosols, paint thinners, adhesives, gasoline
and propane must be handled and stored with
extreme care. These flammable liquids emit
flammable vapors and when exposed to an igni-
tion source can result in a fire hazard or explo-
sion. Flammable liquids should not be used or
stored in the vicinity of this or any other gas ap-
pliance.

Demand Duo™ H-Series Installation and Operation Manual 15
Location Clearance
Top 2 in. (51 mm)
(0 in. from vent components)
** Clearance for servicing the
anode rods is 54 in. (137 cm)
from the top of the water
heater.
Bottom
(Ground)
0 in.
Front 6 in. (152 mm)
* Clearance for servicing is 24
in. (610 mm) in front of water
heater.
Back 0 in.
Sides (Left and
Right)
0 in.
0 in. Minimum 0 in. Minimum
0 in. Minimum
*6 in. Minimum
Door
** 12 in. Minimum
IMPORTANT
Product installed in the state of California
must be braced, anchored, or otherwise
secured to avoid motion or falling during an
earthquake. Contact the California Office of
the State Architect located at 1102 Q Street,
Suite 5100, Sacramento, CA 95811 for
instructions.
1. Loosen screws along the perimeter of the
plastic enclosures.
2. Remove plastic enclosures.
3. Position straps around the tank per the re-
quirements of California Office of the State
Architect. DO NOT POSITION THE STRAPS
OVER PIPE, FITTINGS or WIRE.
4. Replace the plastic enclosures. Modification
of the plastic enclosures may be necessary
to fit the enclosures over the earthquake
straps.
5. Replace the screws around the perimeter of
the plastic enclosures.
STRAP
Plastic
Enclosure
(Side)
Plastic
Enclosure
(Bottom)
STRAP
Figure 5: Clearances
Figure 6: Earthquake Strapping
Table 4: Clearances

Demand Duo™ H-Series Installation and Operation Manual 16
□ The water heater is not exposed to
corrosive compounds in the air.
□ The water heater location complies with
the required clearances.
□
The planned combustion air and exhaust
termination locations meet the required
clearances.
□
The water supply does not contain
chemicals or exceed total hardness that
will damage the heat exchanger.
□
A standard 3 prong 120 VAC, 60 Hz
properly grounded wall outlet or other 120
VAC, 60 Hz source is available.
□
The installation must conform with local
codes or, in the absence of local codes,
with the National Fuel Gas Code, ANSI
Z223.1/NFPA 54, or the Natural Gas and
Propane Installation Code, CSA B149.1.
Use this checklist to ensure you have selected
the correct location for the water heater.

Demand Duo™ H-Series Installation and Operation Manual 17
• When installed as direct vent, refer to the
Tankless Water Heater Installation and
Operation Manual for a complete list of
approved vent manufacturers and products.
You must use vent components that are
certified and listed with the water heater
model.
• Avoid dips or sags in horizontal vent runs by
installing supports per the vent
manufacturer’s instructions.
• Support horizontal vent runs every four feet
and all vertical vent runs every six feet or in
accordance with local codes.
• Venting should be as direct as possible with
a minimum number of pipe fittings.
• Engineered vent systems must be firmly
pressed together so that the gaskets form an
air tight seal.
• The vent piece connected to the water heater
must be secured with one self-tapping screw.
• When installed as Non-Direct Vent (Room
Air), the venting must be Category IV and of
a type listed by a national recognized testing
agency or PVC (when allowed by local code).
WARNING
DO NOT use cellular core PVC/CPVC.
DO NOT use Radel or galvanized materi-
al to vent this appliance.
DO NOT cover non-metallic vent pipe
and fittings with thermal insulation.
DO NOT combine vent components from
different manufacturers.
DO NOT reduce the vent diameter.
DO NOT connect the venting system with
an
existing vent or chimney.
DO NOT common vent with the vent pipe
of any other manufacturer’s water heater
or appliance.
IMPORTANT
For venting information not specified in this
section, refer to the Installation and Operation
Manual for Condensing Tankless Water
Heaters (supplied with each tankless water
heater). This manual includes complete
venting information, including approved vent
manufacturers and terminations.
Topics in this section
• Venting Requirements
• Select a Vent Type
IMPORTANT
If it becomes necessary to access an
enclosed vent system for service or
repairs, Rinnai is not responsible for any
costs or difficulties in accessing the vent
system. The warranty does not cover
obtaining access to a vent system in an
enclosed environment.
• If the vent system is to be enclosed, it is
suggested that the design of the enclosure
shall permit inspection of the vent system.
The design of such enclosure shall be
deemed acceptable by the installer or the
local inspector.
• Refer to the instructions of the vent system
manufacturer for component assembly in-
structions.

Demand Duo™ H-Series Installation and Operation Manual 18
1. Install the water heater.
2. Determine the termination method —
horizontal or vertical, concentric, or twin
pipes, etc.
3. Determine proper location for wall or roof
penetration for each termination.
4. Install termination assembly as described in
this manual or in the vent manufacturer’s
installation instructions.
5. Install air and vent piping from water heater
to termination.
6. Slope horizontal exhaust run towards the
water heater 1/4 in per foot. DO NOT slope
combustion air pipe
towards water heater.
7. Install vent supports and brackets allowing
for movement from expansion, or as per
vent manufacturer’s
instructions or local code requirements.
8. Install vent screen (supplied with water heat-
er) on PVC combustion air and exhaust ter-
mination elbows as
illustrated below.
• Press vent screen inside of termination
piece/elbow.
• Secure vent screen to the elbow with
screw provided.
Check to determine whether local codes
supersede the following clearances:
• Avoid termination locations near a dryer
vent.
• Avoid termination locations near
commercial cooking exhaust.
• Avoid termination locations near any air
inlets.
• You must install a vent termination at least
12 in above the ground or anticipated
snow level.
The vent for this appliance shall not terminate:
• Over public walkways.
• Near soffit vents or crawl space vents or
other area where condensate or vapor
could create a nuisance or hazard or
cause property damage.
• Where condensate or vapor could cause
damage or could be detrimental to the
operation of regulators pressure relief
valves, or other equipment.
Listed below are important considerations for
locating vent termination under a soffit
(ventilated or unventilated or eave vent; or to a
deck or porch):
• Do not install vent termination under a
soffit vent such that exhaust can enter the
soffit vent.
• Install vent termination such that exhaust
and rising moisture will not collect under
eaves. Discoloration to the exterior of the
building could occur if installed too close.
• Do not install the vent termination too
close under the soffit where it could
present recirculation of exhaust gases
back into the combustion air part of the
termination.
Figure 7: Vent Screen Assembly

Demand Duo™ H-Series Installation and Operation Manual 19
Three types of venting options are available:
Concentric Pipe
Combustion air and exhaust vent directly through
a single concentric connection. Hot exhaust exits
through the interior tube, while combustion air
enters through the outer layer.
Exhaust
Exhaust
Combustion
air
Combustion
air Combustion
air
Combustion
air
Exhaust
Direct Vent Non-Direct (Room Air) Vent
Multiple water heaters sharing a combustion air
header and a separate exhaust header that vents
directly through separate penetrations to
Combustion Air
Exhaust Exhaust
Room Air
For Combustion
Twin Pipe
Combustion air and exhaust vent directly
through separate penetrations.
Room air is used for combustion while exhaust vents to the outside.
Multiple water heaters using room air for
combustion while sharing an exhaust
header that vents directly to the outside.
Direct Vent (Concentric Pipe and Twin Pipe)
1
Non-Direct Vent (Room Air)
2
Common Vent (Indoor Units Only. Direct Vent and Non-Direct/Room Air Vent)
3
Figure 8
Figure 9
Figure 10
Figure 11 Figure 12

Demand Duo™ H-Series Installation and Operation Manual 20
Canadian Installaons
(CSA B149.1) U.S. Installaons (ANSI Z223.1 /NFPA 54)
Ref Descripon Direct Vent (Indoor Unit) Direct Vent (Indoor Unit)
AClearance above grade, veranda, porch, deck, or balcony 12 in. (30 cm) 12 in. (30 cm)
BClearance to window or door that may be opened 36 in. (91 cm) 12 in. (30 cm)
CClearance to permanently closed window **
DVercal clearance to venlated sot, located above the terminal within a
horizontal distance of 2  (61 cm) from the center line of the terminal **
EClearance to unvenlated sot **
FClearance to outside corner **
GClearance to inside corner **
HClearance to each side of center line extended above meter/regulator
assembly **
IClearance to service regulator vent outlet
Above a regulator within 3 
(91 cm) horizontally of the vercal
center line of the regulator vent
outlet to a maximum vercal
distance of 15  (4 m)
*
JClearance to non-mechanical air supply inlet to building or the
combuson air inlet to any other appliance 36 in. (91 cm) 12 in. (30 cm)
KClearance to a mechanical air supply inlet 6  (1.83 m) 3  (91 cm) above if within
10  (3 m) horizontally
LClearance above paved sidewalk or paved driveway located on public
property 7  (2.13 m) [1] *
MClearance under veranda, porch, deck, or balcony 12 in. (30 cm) [2] *
Figure 13: Direct Vent Termination Clearances (For Concentric and Twin Pipe)
Direct Vent (Concentric Pipe and Twin Pipe)
1
AIR SUPPLY INLET
VENT TERMINAL
AREA WHERE TERMINAL
IS NOT PERMITTTED
X
V
SNOW
TERMINATION
Clearance in
Ref. A also
applies to
anticipated
snow line
Clearance to opposite wall is 24 in. (60 cm).
[1] A vent shall not terminate directly above a sidewalk or paved driveway that
is located between two single family dwellings and serves both dwellings.
[2] Permied only if veranda, porch, deck, or balcony is fully open on a mini-
mum of two sides beneath the oor.
 Clearances are in accordance with local installaon codes and the
requirements of the gas supplier. (Dégagement conforme aux codes
d’installaon locaux et aux exigences du foumisseur de gaz.)