Rinnai Sensei RU199i User manual

PVC/CPVC Common Venng Installaon Instrucons 1
Copyright © 2018 Rinnai America Corporaon. All Rights Reserved.
For U.S. and Canadian Installaons
CUS
—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 licensed professional.
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.
WARNING
100000625(01) 12/18
RU199i (REU-N3237FF-US)
RU180i (REU-N2934FF-US)
RU160i (REU-N2530FF-US)
RU130i (REU-N2024FF-US)
CU199i (REU-N3237FFC-US)
CU160i (REU-N2530FFC-US)
RUR199i (REU-NP3237FF-US)
RUR160i (REU-NP2530FF-US)
MODELS
CERTIFIED TO ANSI Z21.10.3 - CSA 4.3

PVC/CPVC Common Venng Installaon Instrucons 2
Copyright © 2018 Rinnai America Corporaon. All Rights Reserved.
READ AND SAVE THESE INSTRUCTIONS
Contents
Welcome...........................................................................................................................................3
Safety................................................................................................................................................4
About the Common Venng System ..................................................................................................5
Venng Guidelines............................................................................................................................... 5
Schedule 40 PVC/CPVC Common Vent Guidelines.............................................................................. 7
High Altude Installaons ................................................................................................................... 8
Common Vent Maximum Equivalent Lengths..................................................................................... 9
3 in. Common Venng.....................................................................................................................10
3 in. Direct Vent and Room Air.......................................................................................................... 10
4 in. Common Venng.....................................................................................................................11
4 in. Direct Vent and Room Air.......................................................................................................... 11
6 in. Common Venng.....................................................................................................................12
6 in. Direct Vent and Room Air.......................................................................................................... 12
Common Vent Terminaons............................................................................................................13
Sample Horizontal Terminaon Assembly........................................................................................14
Sample Vercal Terminaon Assembly-Room Air ............................................................................15
Maintenance Clearances .................................................................................................................16
Water Heater Clearances................................................................................................................... 16
Vercal Terminaon Clearances........................................................................................................ 16
Horizontal Terminaon Clearances ................................................................................................... 17
Combuson Air Requirements.........................................................................................................18
Exhaust Vent Terminaon Clearances..............................................................................................21
Addional Clearances......................................................................................................................23
Installaon Instrucons (Condensate Trap and Drain Pipe) ..............................................................24
Final Checklist .................................................................................................................................24

PVC/CPVC Common Venng Installaon Instrucons 3
Copyright © 2018 Rinnai America Corporaon. All Rights Reserved.
This manual provides installaon instrucons for PVC/CPVC common venng and is a supplement to the Installaon
and Operaons Manual supplied with the Rinnai Tankless Water Heater.
Common venng must sasfy all the requirements of the Installaon and Operaons Manual, as well as the
requirements in this manual.
For detailed informaon on the Rinnai Tankless Water Heater, including installaon instrucons, refer to the Tankless
Water Heater Installaon and Operaon Manual or view an online version at rinnai.us.
Welcome
To The Installer
• This manual is intended for the trained and qualied professional and is designed for licensed installers who
should have skills such as:
− Gas sizing
− Connecng gas lines, water lines, valves, and electricity
− Knowledge of applicable naonal, state, and local codes
− Installing venng through a wall or roof
− Training in installaon of tankless water heaters. Training on Rinnai Tankless Water Heaters is
accessible at www.trainingevents.rinnai.us
• A trained and qualied professional must test the Common Venng System for leaks before use.
• The installaon must conform to the Rinnai Tankless Water Heater Installaon and Operaon Manual that is
shipped with the unit, local codes, or in the absence of local codes, with the Naonal Fuel Gas Code,
ANSI Z223.1/NFPA 54.
• Read all instrucons contained in this manual before installing the Common Venng System.
• Proper installaon is the responsibility of the installer.
• When installaon is complete, give all manuals related to the common venng installaon (including this
manual and the Rinnai Tankless Water Heater Installaon and Operaon Manual) directly to the
consumer. The manuals should be stored in a readily accessible locaon for future reference.
To The Consumer
• Keep this manual for future reference.
• Be sure your Common Venng System is installed by a trained and qualied professional.

PVC/CPVC Common Venng Installaon Instrucons 4
Copyright © 2018 Rinnai America Corporaon. All Rights Reserved.
• 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 qualied installer, service agency or the gas supplier.
• The warning signs in this manual are here to prevent injury to you and others. Please follow them explicitly.
• Installaons must comply with local requirements and with the Naonal Fuel Gas Code, ANSI Z223.1/NFPA 54 for
U.S. installaons.
• Use only the materials listed in this manual for vent, air intake pipe, and ngs. Failure to comply with this
warning could result in property damage.
• DO NOT slope the combuson air pipe toward unit. Failure to comply with this warning could result in property
damage, personal injury, or death.
• DO NOT apply PVC/CPVC glues, solvents, or cleaners to the tankless water heater’s intake or exhaust gasket
connecons. Failure to correctly assemble the components according to these instrucons and the Rinnai water
heater installaon and operaon manual may result in property damage, personal injury, or death.
READ ALL INSTRUCTIONS BEFORE INSTALLATION
WARNING
Safety Symbols
Indicates an imminently
hazardous situaon which, if
not avoided, will result in
personal injury or death.
Indicates a potenally hazardous
situaon which, if not avoided, could
result in personal injury or death.
Indicates a potenally hazardous
situaon which, if not avoided, could
result in minor or moderate injury. It
may also be used to alert against
unsafe pracces.
Safety alert symbol. Alerts you to potenal
hazards that can kill or hurt you and others.
DANGER CAUTION
WARNING
This manual contains the following important safety symbols. Always read and obey all safety messages.
Safety
Topics in this secon
• Safety Symbols

PVC/CPVC Common Venng Installaon Instrucons 5
Copyright © 2018 Rinnai America Corporaon. All Rights Reserved.
Venng Guidelines
About the Common Venng System
Common venng allows mulple Rinnai Tankless Water Heaters to share the same vent system.
Rinnai Tankless Water Heaters can only be common vented with Schedule 40 PVC/CPVC or with a Rinnai cered
common vent system.
Example: Rinnai Common Venting Example: Schedule 40 PVC/CPVC
Common Venting
• Use only the materials listed in this manual for vent, air intake pipe, and ngs. Failure to comply with this
warning could result in property damage, personal injury, or death.
• When cung vent components, ensure that the cuts are straight.
• Chamfer and deburr all edges before installing the components.
• Vent joints must not leak. Conrm gas ght connecons of every vent joint.
• Before operang the water heater(s), ensure vent system is clean and free of debris.
• Vent system must be supported according to the vent manufacturer’s installaon instrucons.
• Venng should be as direct as possible with a minimum number of ngs.
• The common vent system must only be installed by a trained and qualied professional.
Common Vent Terminaon Clearances
• Vent terminaon per ANSI Z223.1/NFPA 54. For clearances not specied in ANSI Z223.1/NFPA 54,
clearances are in accordance with local installaon codes and the requirements of the gas supplier.
Topics in this secon
• Venng Guidelines
• Schedule 40 PVC/CPVC Common Vent
Guidelines
• High Altude Installaons
• Common Vent Maximum Equivalent
Vent Lengths

PVC/CPVC Common Venng Installaon Instrucons 6
Copyright © 2018 Rinnai America Corporaon. All Rights Reserved.
Do Not
• Do not exceed the maximum number of units indicated in the Rinnai Tankless Water Heater Installaon and
Operaon Manual.
• Do not use cellular core PVC/CPVC, Radel, ABS or galvanized material for the exhaust vent.
• Do not combine vent components from dierent manufacturers.
• Do not connect the venng system with an exisng vent or chimney.
• Do not cover vent components with thermal insulaon.
• Do not common vent with the vent pipe of any other type of water heater or appliance.
• Do not reduce vent diameter to less than 2 in. (51 mm).
• Do not install the water heater in an area of negave pressure.
• Do not install the water heater, venng, and vent terminaon(s) in any areas where the air may contain
corrosive compounds.
Must Do
• You must use vent components that are cered and listed with the water heater model.
• The vent system must vent directly to the outside of the building and use outside air or room air for
combuson.
• Avoid dips or sags in horizontal vent runs by installing supports per the vent manufacturer’s instrucons.
• Support horizontal vent runs a minimum of every four feet and all vercal vent runs a minimum of every six
feet.
• Venng should be as direct as possible with a minimum number of pipe ngs.
• Vent components connected to the water heater must be secured with one self-tapping screw. Do not use
any glues or solvents to connect vent components to the water heater.
• Set the temperature seng on all water heaters being common vented to the same temperature.
WARNING
DO NOT slope the combustion air pipe toward unit. Failure to comply with this warning could result in property
damage, personal injury, or death.
DO NOT apply PVC/CPVC glues, solvents, or cleaners to the tankless water heater’s intake or exhaust gasket
connections. Failure to correctly assemble the components according to these instructions may result in property
damage, personal injury, or death.

PVC/CPVC Common Venng Installaon Instrucons 7
Copyright © 2018 Rinnai America Corporaon. All Rights Reserved.
PVC solvents (primer and glue) can be extremely flammable. Vapors may cause a flash fire or
explosion resulting in property damage, personal injury or death.
• Keep solvents away from heat, sparks, flames and all other sources of ignition.
• Do not solder, cut or weld until all vapors have dissipated.
• PVC solvents are heavier than air causing them to settle at low points of the system.
• Before using PVC solvent:
− Disconnect power to the water heater.
− Remove the front cover of the water heater.
− Ensure areas around the water heater and PVC venting are well ventilated.
− Allow all vapors to dissipate before applying power to the system or introducing any other source of ignition.
When installing PVC/CPVC Common Vent, follow these guidelines:
•Avoid sharp bends or tees in the vent system.
These vent components create addional
restricons that could reduce performance of
the water heaters.
•PVC combuson air and exhaust should
terminate with elbow or tee poinng down.
This will stop unwanted moisture from
entering the vent system.
•Fire rated penetraons shall be restopped.
Contact your vent supplier or local restop
manufacturer for appropriate restop
methods.
•Examine all vent components for damage prior to
installaon.
•PVC/CPVC vent systems must be free to expand and
contract. Refer to the vent manufacturer’s
installaon instrucons for appropriate support
methods.
•PVC/CPVC venng must include unrestricted vent
movement through walls, ceilings, and roof
penetraons.
•Use only PVC/CPVC primer and cement approved
for use by the vent manufacturer.
•Refer to vent manufacturer’s installaon
instrucons for proper joint assembly procedures
and products.
•PVC/CPVC common venng should include a
condensate drain and trap between the header and
vent length. Condensate trap must include a loop
that can hold 6 in. (15 cm) of water. See “PVC/CPVC
Common Vent Installaon” illustraon on this page.
WARNING
DO NOT mix vent pipe, ngs or joining methods
from dierent vent manufacturers.
DO NOT aempt to repair damaged vent. Damaged
vent components must be replaced.
DO NOT use short radius elbows in the common
vent system.
DO NOT
ACCEPTABLE ACCEPTABLE NOT ACCEPTABLE
90° Elbows,
Long Sweep
90° Elbows,
Short Sweep
90° Elbows,
Close Turn
HEADER VENT
PVC/CPVC Common Vent Installation
Schedule 40 PVC/CPVC Common Vent Guidelines

PVC/CPVC Common Venng Installaon Instrucons 8
Copyright © 2018 Rinnai America Corporaon. All Rights Reserved.
High Altude Installaons
Tankless water heaters using common venng at altudes over 2,000  (610 m) will automacally derate according to
the tables below. Use the tables below for calculang your total BTU for mulple tankless water heaters.
• High altude installaons are cered up to 10,200  (3,109 m).
• Reference the respecve Rinnai Tankless Water Heater Installaon and Operaon Manual to set the water
heater up for the altude at which they will be operang.
High Altude Derate
PROPANE (LP GAS)
Number
of Water
Heaters
2,001 -
5,200 
5,201 -
7,700 
7,701 -
10,200 
1168,000 151,000 120,000
2332,640 298,980 237,600
3493,920 443,940 352,800
4651,840 585,880 465,600
5806,400 724,800 576,000
6957,600 860,700 684,000
71,105,440 993,580 789,600
81,249,920 1,123,440 892,800
NATURAL GAS
Number
of Water
Heaters
2,001 -
5,200 
5,201 -
7,700 
7,701 -
10,200 
1170,000 153,000 139,000
2336,600 302,940 275,220
3499,800 449,820 408,660
4659,600 593,640 539,320
5816,000 734,400 667,200
6969,000 872,100 792,300
71,118,600 1,006,740 914,620
81,264,800 1,138,320 1,034,160
NOTE
Unless recovering a tank, Rinnai recommends electronically connecng with common
venng and where water heaters are in a manifold system. Refer to the Rinnai
Tankless Water Heater Installaon and Operaon Manual for addional details on
electronically connecng mulple water heaters.

PVC/CPVC Common Venng Installaon Instrucons 9
Copyright © 2018 Rinnai America Corporaon. All Rights Reserved.
For the table below:
• Header is the main vent pipe into which several vents
connect.
• Vent Length is the distance from the end of the header to the
vent terminaon.
• Maximum vent length starts at the end of the header
system.
• Use 10  (3 m) as equivalent vent length for 90° elbows.
• For use with SENSEI™ internal (indoor) tankless
water heaters.
Header Vent Length
Common Vent Maximum Equivalent Vent Lengths
Common Vent Maximum Equivalent Vent Length
Rinnai Common Vent System or Schedule 40 PVC/CPVC
Water Heater
Model # Water Heaters
Max
System
BTU/HR
HEADER DIAMETER
3 in. 4 in. 6 in.
3 in.
Vent Diameter 4 in. Vent Diameter 6 in. Vent Diameter 6 in. Vent Diameter
RU199i
(REU-N3237FF-US)
CU199i
(REU-N3237FFC-US)
RUR199i
(REU-NP3237FF-US)
2398,000 65  150 
150 
150 
3597,000
4796,000 65 
5995,000
61,194,000
71,393,000 70 
81,592,000
91,791,000 90 
10 1,990,000
11 2,189,000 41 
12 2,388,000
RU160i
(REU-N2530FF-US)
CU160i
(REU-N2530FFC-US)
RUR160i
(REU-NP2530FF-US)
2320,000 90  150 
150 
150 
3480,000 100 
4640,000 65 
5800,000
6960,000
RU180i
(REU-N2934FF-US)
2360,000 65 
150 
150 
150 
3540,000
4720,000 65 
5900,000
61,080,000
71,260,000 70 
81,440,000
91,620,000 90 
10 1,800,000
11 1,980,000 41 
12 2,160,000
RU130i
(REU-N2024FF-US)
2260,000 90  150 
150 
150 
3390,000 100 
4520,000 65 
5650,000
6780,000

PVC/CPVC Common Venng Installaon Instrucons 10
Copyright © 2018 Rinnai America Corporaon. All Rights Reserved.
3 in. Common Venng
EXHAUST
AIR
INTAKE
Direct Vent
Room Air
Inline
• Refer to the “Combuson Air Requirements” secon of this manual for room
air requirements.
EXHAUST
Inline
AIR
INTAKE
AIR
INTAKE

PVC/CPVC Common Venng Installaon Instrucons 11
Copyright © 2018 Rinnai America Corporaon. All Rights Reserved.
4 in. Common Venng
Inline
Direct Vent
• Maximum 4 Units
Room Air
• Maximum 4 Units
• Refer to the “Combuson Air Requirements” secon of this manual for room air
requirements.
Back-to-Back
Back-to-Back
Inline
AIR
INTAKE AIR
INTAKE

PVC/CPVC Common Venng Installaon Instrucons 12
Copyright © 2018 Rinnai America Corporaon. All Rights Reserved.
Inline
Direct Vent
• Maximum 12 Units
Room Air
• Maximum 12 Units
• Refer to the “Combuson Air Requirements” secon of this manual for room air requirements.
Back-to-Back
6 in. Common Venng
Inline Back-to-Back

PVC/CPVC Common Venng Installaon Instrucons 13
Copyright © 2018 Rinnai America Corporaon. All Rights Reserved.
Common Vent Terminaons
Tee 10
90° Elbow 10
45° Elbow 5
Product
Descripon
Horizontal
Vercal
Equivalent
Length ()
Diagram
Various 3 in., 4 in., and 6 in. Schedule 40 PVC/CPVC Terminaons:

PVC/CPVC Common Venng Installaon Instrucons 14
Copyright © 2018 Rinnai America Corporaon. All Rights Reserved.
Support Brackets Required
3 . (0.91 m)
Minimum
Between Brackets
Header Tees Should be Schedule 40 Drain Tees.
Do Not Use Sharp Turn Tee’s or Elbows
Vent terminaon per ANSI Z223.1/NFPA 54. For
clearances not specied in ANSI Z223.1/NFPA 54,
clearances are in accordance with local installaon
codes and the requirements of the gas supplier.
Sample Horizontal Terminaon Assembly
NOTE
3 . (0.91 m)
Minimum
Between Brackets
Exhaust
Terminaon:
Tee or Elbow
Combuson Air
Terminaon:
Tee or Elbow
Condensate Trap
6 in (152 mm)
Minimum

PVC/CPVC Common Venng Installaon Instrucons 15
Copyright © 2018 Rinnai America Corporaon. All Rights Reserved.
Support Brackets Required
Room Air applicaons should
include an elbow and vent
screen or room air lter.
Sample Vercal Terminaon Assembly-Room Air
Vent terminaon per ANSI Z223.1/NFPA 54. For
clearances not specied in ANSI Z223.1/NFPA 54,
clearances are in accordance with local installaon
codes and the requirements of the gas supplier.
NOTE
3 . (0.91 m)
Minimum
Between Brackets
3 . (0.91 m)
Minimum
Between Brackets
Condensate Trap
6 in (152 mm)
Minimum
Exhaust
Terminaon:
Elbow
Header Tees Should be Schedule 40 Drain Tees.
Do Not Use Sharp Turn Tee’s or Elbows

PVC/CPVC Common Venng Installaon Instrucons 16
Copyright © 2018 Rinnai America Corporaon. All Rights Reserved.
There should be a minimum of 12 in. (305 mm) between exhaust and intake terminaons.
Clearances of Brackets:
All supports, such as wall brackets or spacer blocks, must be installed with a maximum distance of 78 in. (2 m) between
each support. Addional supports can be installed before and aer an elbow if needed.
Freestanding Components:
Components which are installed freestanding for vercal terminaon with a length of over 59 in. (1.5 m), must be
addionally secured to the building with guys or braces.
Vercal Terminaon Clearances (All System Sizes)
Water Heater Clearances
If the vent system is to be enclosed, it is suggested that the design of the enclosure shall permit inspecon of the vent
system. The design of such an enclosure shall be deemed acceptable by the installer or the local inspector.
Refer to the Rinnai Tankless Water Heater Installaon and Operaon Manual for minimum clearance requirements
around the water heater.
Maintenance Clearances
Pitched Roof Terminaon Clearances:
12 in. (305 mm)
above roof or
ancipated snow
level
12 in. (305 mm) min
12 in.
(305 mm)
min
Exhaust Vent
Combuson Air
Topics in this secon
• Water Heater Clearances
• Vercal Terminaon Clearances
• Horizontal Terminaon Clearances
Vent terminaon per ANSI Z223.1/NFPA 54. For
clearances not specied in ANSI Z223.1/NFPA 54,
clearances are in accordance with local installaon
codes and the requirements of the gas supplier.
NOTE

PVC/CPVC Common Venng Installaon Instrucons 17
Copyright © 2018 Rinnai America Corporaon. All Rights Reserved.
Horizontal Terminaon Clearances
This appliance, along with the Common Vent System, is cered with the 3 in., 4 in., 6 in. wall terminaon mounted in
the orientaon shown below.
The exhaust and combuson air terminaons must follow these clearances:
• 12 in. minimum vercally from boom of combuson air terminaon to ground or ancipated snow line.
• 12 in. minimum from edge of exhaust terminaon to edge of combuson air terminaon.
There should be a minimum of 36 in. (91 cm) between exhaust terminaons in mulple common vent installaons.
Refer to the Rinnai Tankless Water Heater Installaon and Operaon Manual for maximum vent lengths based on the
vent diameter installed.
During colder weather when the exhaust
temperature is much hoer than the outside
air, the exhaust fumes will condense, producing
water vapor. As a result, a plume of water
vapor may be seen leaving the exhaust.
Exhaust
Vent
Combuson
Air Vent
Vent Size Separaon Distance
3 in., 4 in., 6 in. 12 in. Minimum
MINIMUM 12 in. (305 mm)
COMBUSTION AIR IS NOT ALLOWED
IN THE SHADED AREA
Combuson
Air Vent
Combuson
Air Vent
Combuson
Air Vent
Combuson
Air Vent
Combuson
Air Vent
Min 12 in. (305 mm) above grade or
ancipated snow level
Exhaust
Vent
From Exhaust Vent to Combuson Air Vent:
• Minimum 12 in. (305 mm)
NOTE

PVC/CPVC Common Venng Installaon Instrucons 18
Copyright © 2018 Rinnai America Corporaon. All Rights Reserved.
Combuson Air Requirements
Common Vent Applicaons Ulizing Room Air
This rack system requires adequate combuson air for venlaon and diluon of ue gases. Failure to provide
adequate combuson air can result in unit failure, re, explosion, serious bodily injury or death. Use the following
methods to ensure adequate combuson air is available for correct and safe operaon of this rack system.
Important: Combuson air must be free of corrosive chemicals. Do not provide combuson air from corrosive
environments. System failure due to corrosive air is not covered by warranty.
Combuson air must be free of acid forming chemicals such as sulfur, uorine and chlorine. These chemicals have been
found to cause rapid damage and decay and can become toxic when used as combuson air in gas appliances. Such
chemicals can be found in, but not limited to bleach, ammonia, cat lier, aerosol sprays, cleaning solvents, varnish,
paint, and air fresheners. Do not store these products or similar products in the vicinity of the water heater system.
Unconned Space:
An unconned space is dened in Naonal Fuel Gas Code, ANSI Z223.1/NFPA 54 as “a space whose volume is not less
than 50 cubic feet per 1,000 Btu/hr (4.8 m 3 per kW per hour) of the aggregate input rang of all appliances installed in
that space. Rooms communicang directly with the space in which the appliances are installed, through openings not
furnished with doors, are considered a part of the unconned space.” If the “unconned space” containing the system
is in a building with ght construcon, addional outside air may be required for proper operaon. Outside air
openings should be sized the same as for a conned space.
Conned Space:
(Small Room, Closet, Alcove, Ulity Room, Etc.)
A conned space is dened in the Naonal Fuel Gas Code, ANSI Z223.1/NFPA 54 as "a space whose volume is less than
50 cubic feet per 1,000 Btu/hr (4.8 m3 per kW per hour) of the aggregate input rang of the combined appliances
installed in that space." A conned space must have two combuson air openings. Size the combuson air openings
based on the BTU input for all gas ulizaon equipment in the space and the method by which combuson air is
supplied.
Condensate Trap
6 in (152 mm)
Minimum

PVC/CPVC Common Venng Installaon Instrucons 19
Copyright © 2018 Rinnai America Corporaon. All Rights Reserved.
Vent terminaon per ANSI Z223.1/NFPA 54. For
clearances not specied in ANSI Z223.1/NFPA 54,
clearances are in accordance with local installaon
codes and the requirements of the gas supplier.
(Be sure to maintain 12 in. (305 mm) above grade or
ancipated snow level)
Exhaust
Locaon
To maintain proper circulaon of combuson air, two
permanent openings (one upper, one lower) must be
posioned in conned spaces. The upper shall be within
12 in. (305 mm) of the top of the conned space and the
lower opening shall be within 12 in. (305 mm) of the
boom of the conned space. Openings must be
posioned as to never be obstructed.
Using Outdoor Air For Combuson
Outdoor air can be provided to a conned space through
two permanent openings, one commencing within 12 in.
(305 mm) of the top and one commencing within 12 in.
(305 mm) of the boom of the conned space. The
openings shall communicate to the outside by one of two
ways.
Louvers and Grills
When sizing the permanent opening, consideraon must
be taken for the design of the louvers or grills to maintain
the free area required for all gas ulizing equipment in
the space. If the free area of the louver or grill design is
not available, assume wood louvers will have 25% free
area and metal louvers or grills will have 75% free area.
Under no circumstance should the louver, grill or screen
have openings smaller than 1/4 in.
Example:
Wood: 10 in x 12 in x 0.25 = 30 in2
Metal: 10 in x 12 in x 0.75 = 90 in2
12 in. (305 mm)
10 in.
(254 mm)

PVC/CPVC Common Venng Installaon Instrucons 20
Copyright © 2018 Rinnai America Corporaon. All Rights Reserved.
Using Indoor Air For Combuson
When using air from other room(s) in the building, the
total volume of the room(s) must be of adequate volume
(greater than 50 cubic feet per 1,000 Btu/hr). Each
combuson air opening must have at least one square inch
of free area for each 1,000 Btu/hr, but not less than 100
square inches each.
When communicang directly with the outdoors through
horizontal ducts, each opening shall have a minimum free
area of 1 in2/2,000 Btu/hr (1,100 mm2/kW) of total input
rang of all appliances in the conned space.
Note: If ducts are used, the cross seconal area of the duct
must be greater than or equal to the required free area of
the openings to which they are connected.
When communicang indirectly with the outdoors
through vercal ducts, each opening shall have a
minimum free area of 1 in2/4,000 Btu/hr (550 mm2/kW)
of total input rang of all appliances in the conned
space. Combuson air to the appliance can be provided
from a well venlated ac or crawl space.
TO PREVENT POSSIBLE
PERSONAL INJURY OR DEATH
DUE TO ASPHYXIATION, COMMON VENTING WITH
OTHER MANUFACTURER’S INDUCED DRAFT APPLIANCES
IS NOT ALLOWED.
WARNING
□Verify proper clearances around the vents.
□Ensure that the “Combuson Air Requirements”
are followed that will provide sucient
combuson air for the appliance.
□Ensure approved venng components have been
used.
□All horizontal vent runs must be sloped up away
from the water heater a minimum of 1/4 in.
(6 mm) per foot.
□Verify that there is adequate combuson air.
□Installaon complies with Naonal Fuel Gas Code,
ANSI Z223.1/NFPA 54, as well as local and state
regulaons therein.
Checklist for Combuson Air and
Venng Requirements
(Be sure to maintain 12 in. (305 mm) above grade or
ancipated snow level)
Vent terminaon per ANSI Z223.1/NFPA 54. For
clearances not specied in ANSI Z223.1/NFPA 54,
clearances are in accordance with local installaon codes
and the requirements of the gas supplier.
Exhaust
Combuson air provided to the system should
not be taken from any area of the structure
that may produce a negave pressure (such as
exhaust fans or powered venlaon fans).
NOTE