Rinnai RLX94i User manual

Direct Vent Tankless Water
Heater Installaon and
Operaon Manual
—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.
This enre manual must be le for the consumer. The consumer must read and
refer to this manual for proper operaon and to maintain the water heater.
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
READ ALL OF THE INSTRUCTIONS THOROUGHLY BEFORE INSTALLING OR OPERATING THIS WATER HEATER.
This manual provides informaon on the installaon, operaon, and maintenance of the water heater. For proper
operaon and safety, it is important to follow the instrucons and adhere to the safety precauons.
A licensed professional must install the water heater according to the exact instrucons on pages 4-30.
The consumer must read the enre manual to properly operate the water heater and to have regular maintenance
performed.
ANS Z21.10.3 ● CSA 4.3
FOR INDOOR APPLICATIONS ONLY
RL75i..................... REU-VC2528FFUD-US
REU-VC2528FFUD-US(A)
RLX94i................... REU-VC2737FFUD-US
RL94i..................... REU-VC2837FFUD-US
FOR OUTDOOR APPLICATIONS ONLY
RL75e.................... REU-VC2528WD-US
REU-VC2528FFUD-US(A)
RL94e.................... REU-VC2837WD-US
SANITATION
Low Lead Content
NSF/ANSI 372
CUS
U307-0710X03
060 00012 31315 4

2VC Series Manual
Table of Contents
This is the safety alert symbol. This symbol alerts you to potenal hazards that can kill or hurt you
and others.
Indicates an imminently hazardous situaon which, if not avoided, will result in death or
serious injury.
Indicates a potenally hazardous situaon which, if not avoided, could result in death or
serious injury.
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.
DANGER
CAUTION
WARNING
Table of Contents ..................................................... 2
Safety Behaviors and Pracces for the
Consumer and Installer ............................................ 3
Installaon Instrucons
(for the licensed professional) ............................. 4
Prepare for Installaon......................................5
Determine Installaon Locaon ........................6
Freeze Protecon.............................................11
Checklist to Determine Installaon Locaon...12
Mount to Wall..................................................12
Remove the Front Panel .................................. 12
Installaon of Venng (indoor models only) ...13
Condensate (indoor models only)....................15
Checklist for Venng and Condensate
(indoor models only)........................................15
Installaon of Plumbing...................................16
Checklist for Plumbing .....................................19
Installaon of Gas Supply ................................19
Connect Electricity ...........................................21
Adjust for High Altude ...................................21
Adjust for Vent Length (indoor models only) .. 21
Checklist for Gas and Electricity.......................21
Installaon of Temperature Controller............22
Final Checklist...................................................24
Technical Data ........................................................25
Specicaons ...................................................25
Dimensions.......................................................26
Pressure Drop and Water Flow Curves............27
Ladder Diagram................................................28
Recirculaon Mode..........................................29
Operaon Instrucons .......................................31
Consumer Operaon Guidelines for the
Safe Operaon of your Water Heater..............32
How to Use the Temperature Controller .........33
How to Set the Temperature ...........................34
Diagnosc Codes..............................................36
Required Maintenance.....................................39
Freeze Protecon and Winterizaon ........40
Flushing the Heat Exchanger.....................41
Manual Draining of the Water Heater ......42
State Regulaons....................................................43
Replacement Parts .................................................44
Consumer Warranty ...............................................45
French Version........................................................48
Important Safety Informaon
Safety Denions
NOTICE: Rinnai somemes shares customer contact informaon with businesses that we believe provide
products or services that may be useful to you. By providing this informaon, you agree that we can
share your contact informaon for this purpose. If you prefer not to have your informaon shared with
these businesses, please contact customer service and ask not to have your informaon shared. We
will however, connue to contact you with informaon relevant to the product(s) you registered and/
or your account with us.
If you have any quesons or feel that the manual is incomplete contact Rinnai at 1-800-621-9419.

VC Series Manual 3
CAUTION
BURN HAZARD. Hot exhaust and vent may cause
serious burns. Keep away from water heater unit.
Keep small children and animals away from the
unit.
Hot water outlet pipes leaving the unit can be hot
to touch. In residenal applicaons, insulaon
must be used for hot water pipes below 36” due to
burn risk to children.
Safety Behaviors and Pracces for the Consumer and Installer
Before operang, smell all around the appliance
area for gas. Be sure to smell next to the oor
because some gas is heavier than air and will sele
on the oor.
Keep the area around the appliance clear and free
from combusble materials, gasoline, and other
ammable vapors and liquids.
Combusble construcon refers to adjacent walls
and ceiling and should not be confused with
combusble or ammable products and materials.
Combusble and/or ammable 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 o the electrical power supply by
unplugging the power cord or by turning o the
electricity at the circuit breaker. (The
temperature controller does not control the
electrical power.)
 Turn o the gas at the manual gas valve, usually
located immediately below the water heater.
 Turn o the incoming water supply. This can be
done at the isolaon valve immediately below
the water heater or by turning o the water
supply to the building.
WARNING
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 aempted repair
may result in a re or explosion.
Do not use this appliance if any part has been under
water. Immediately call a licensed 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 substute materials. Use only parts
cered for the appliance.
Should overheang occur or the gas supply fail to
shut o, turn o the manual gas control valve to the
appliance.
Do not adjust the DIP switch unless specically
instructed to do so.
Do not use an extension cord or an adapter plug
with this appliance.
Any alteraon to the appliance or its controls can be
dangerous and will void the warranty.
California law requires this noce to be provided:
California Proposion 65:
This product contains chemicals known to the state of California to cause cancer, birth defects, or other
reproducve harm.
WARNING

4VC Series Manual
A licensed professional must install the appliance,
inspect it, and leak test it before use. The warranty
will be voided due to any improper installaon.
The installer 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 can be accessed on-line at
www.trainingevents.rinnai.us)
Installaon Instrucons
Installaon Steps
Prepare for Installaon ......................................5
Determine Installaon Locaon.........................6
Checklist to Determine Installaon Locaon...12
Mount to Wall..................................................12
Remove the Front Panel ..................................12
Installaon of Venng (indoor models only) ...13
Condensate (indoor models only)....................15
Checklist for Venng and Condensate
(Indoor models only)........................................15
Installaon of Plumbing ...................................16
Checklist for Plumbing .....................................19
Installaon of Gas Supply.................................19
Connect Electricity ...........................................21
Adjust for High Altude ...................................21
Adjust for Vent Length (indoor models only) ..21
Checklist for Gas and Electricity.......................21
Installaon of Temperature Controller............22
Final Checklist...................................................24
General InstruconsInstaller Qualicaons
DO NOT
Do not install the RL75i, RL94i, or the RLX94i
outdoors.
Do not install the RL75e or the RL94e indoors.
Do not install the appliance in an area where water
leakage of the unit or connecons will result in
damage to the area adjacent to the appliance or to
lower oors of the structure. When such locaons
cannot be avoided, it is recommended that a
suitable drain pan, adequately drained, be installed
under the appliance. The pan must not restrict
combuson air ow.
Do not obstruct the ow of combuson and
venlaon air. Combuson air shall not be
supplied from occupied spaces.
Do not use this appliance in an applicaon such as
a pool or spa heater that uses chemically treated
water . (This appliance is suitable for lling large or
whirlpool spa tubs with potable water.)
Do not use substute parts that are not authorized
for this appliance.
MUST DO
The installaon must conform with local codes or,
in the absence of local codes, with the Naonal
Fuel Gas Code, ANSI Z223.1/NFPA 54, or the
Natural Gas and Propane Installaon Code, CSA
B149.1. If installed in a manufactured home, the
installaon must conform with the Manufactured
Home Construcon and Safety Standard, Title 24
CFR, Part 3280 and/or CAN/SCA Z240 MH Series,
Mobile Homes.
The appliance, when installed, must be electrically
grounded in accordance with local codes or, in the
absence of local codes, with the Naonal Electrical
Code, ANSI/NFPA 70, or the Canadian Electrical
Code, CSA C22.1.
The appliance and its appliance main gas valve
must be disconnected from the gas supply piping
system during any pressure tesng of that system
at test pressures in excess of 1/2 psi (3.5 kPa)
(13.84 in W.C.).
Type of installaon
For installaon in residenal and commercial
applicaons.
Cered for installaon in manufactured (mobile)
homes.

VC Series Manual 5
Prepare for installaon
Parts included
Tools needed
Materials needed
 The appliance must be isolated from the gas supply
piping system by closing its individual manual
shuto valve during any pressure tesng of the gas
supply piping system at test pressures equal to or
less than 1/2 psi (3.5 kPa) (13.84 in W.C.).
 You must follow the installaon instrucons and
those in Care and Maintenance for adequate
combuson air intake and exhaust.
INFORMATION
 If a water heater is installed in a closed water
supply system, such as one having a backow
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 overheang occur or the gas supply fail to
shut o, turn o the manual gas control valve to
the appliance.
 Keep the air intake locaon free of chemicals such
as chlorine or bleach that produce fumes. These
fumes can damage components and reduce the life
of your appliance.
 Tankless water heater
 Color coded cold (blue) and hot (red) isolaon
valves
 Pressure relief valve
 MC-91-2 temperature controller (integrated into
indoor models; provided with outdoor models)
 Pipe wrenches (2)
 Adjustable pliers
 Screwdrivers (2)
 Wire cuers
 Gloves
 Safety glasses
 Level
Tools that might be needed
 Hammer drill with
concrete bits
 Saw
 Threading machine with
heads and oiler
 Core drill with diamond
head
 Torch set
 Copper tubing cuer
 Steel pipe cuer
Materials that may be needed
 Soap or gas leak
detector soluon
 Approved venng
 Teon tape
(recommended) or pipe
compound
 Heat tape
 Pipe insulaon
 Electrical wire and
conduit per local code
 Concrete wall anchors
 Oponal pipe cover
 Oponal temperature
controller
 5/8” ID PVC exible
tubing
 2 conductor 22 AWG
wire for controller
 Single gang electrical
box
 Wire nuts
 Unions and drain valves
General Instrucons (connued)

6VC Series Manual
Environment
Air surrounding the water heater, venng, and vent
terminaon(s) is used for combuson 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 oen contains these compounds. Therefore it
is recommended that outdoor models be used for these
locaons where possible.
The water heater, venng, and vent terminaon(s)
should not be installed in any areas where the air may
contain these corrosive compounds. If it is necessary for
a water heater to be located in areas which may contain
corrosive compounds, the following instrucons are
strongly recommended.
IMPORTANT CONSIDERATIONS FOR:
Indoor/Internal Water Heaters
 DO NOT Install in areas where air for combuson
can be contaminated with chemicals.
 Before installaon, consider where air has the
ability to travel within the building to the water
heater.
 Where possible, install the water heater in a sealed
closet so that it is protected from the potenal of
contaminated indoor air.
 Chemicals that are corrosive in nature should not
be stored or used near the water heater.
Outdoor/External Water Heaters and Vent
Terminaons of Indoor/Internal Water Heaters
 Install the water heater as far away as possible
from exhaust vent hoods.
 Install as far away as possible from air inlet vents.
Corrosive fumes may be released through these
vents when air is not being brought in through
them.
 Chemicals that are corrosive in nature should not
be stored or used near the water heater or vent
terminaon.
Damage and repair due to corrosive compounds in the
air is not covered by warranty.
Consideraon of care for your water heater should
include evaluaon of water quality.
The water must be potable, free of corrosive chemicals,
sand, dirt, or other contaminates. It is up to the
installer to ensure the water does not contain corrosive
chemicals, or elements that can aect or damage the
heat exchanger. Water that contains chemicals
exceeding the levels below aect and damage the heat
exchanger. Replacement of the heat exchanger due to
water quality damage is not covered by the warranty.
Maximum Level
Total Hardness Up to 200 mg / L
Aluminum * Up to 0.2 mg / L
Chlorides * Up to 250 mg / L
Copper * Up to 1.0 mg / L
Dissolved Carbon Dioxide (CO2) Up to 15.0 mg / L or PPM
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
Determine Installaon Locaon
Water Quality
* Source: Part 143 Naonal Secondary Drinking Water
Regulaons
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/or the heat exchanger
ushed regularly.
When scale build-up in the heat exchanger begins to
aect the performance of the water heater, a diagnosc
code “LC#” will display. Flush the heat exchanger to
prevent damage to it. Scale build up is caused by hard
water set at a high temperature.
Rinnai oers Southeastern Filtraon’s “ScaleCuer
Water Condioning System” that oers superior lime
scale prevenon and corrosion control by feeding a
blend of control compounds into the cold water
supply.
You must ensure that clearances will be met and that
the vent length will be within required limits. Consider
the installaon environment, water quality, and need
for freeze protecon. Requirements for the gas line,
water lines, electrical connecon, and condensate
disposal can be found in their respecve installaon
secons of this manual.
Part Number Descripon
103000038 Southeastern Filtratrion
ScaleCuer System 3/4” Feed
103000039 ScaleCuer Rell

VC Series Manual 7
INSIDE
CORNERDETAIL
FIXED
CLOSED
OPERABLE
FIXED
CLOSED
OPERABLE
B
B
B
A
J
BM
C
F
B
B
E
D
L
G
A
H
K
I
[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
minimum of two sides beneath the oor.
 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.
Clearance to opposite wall is 24 inches (60 cm).
X
V
AIR SUPPLY INLET
VENT TERMINAL
AREA WHERE TERMINAL IS
NOT PERMITTTED
For indoor models, you must install a vent terminaon to bring in combuson air and expel exhaust.
SNOW
TERMINATION
Clearance in
Ref. A also
applies to
anticipated
snow line
Direct Vent (Indoor Unit) Other than direct vent (Outdoor unit)
Ref
Descripon
Canadian Installaons
(CSA B149.1)
US Installaons Canadian Installaons
(CSA B149.1)
US Installaons
(ANSI Z223.1 / NFPA 54)
AClearance above grade, veranda, porch, deck, or
balcony 12 inches (30 cm) 12 inches (30 cm) 12 inches (30 cm) 12 inches (30 cm)
BClearance to window or door that may be opened 36 inches (91 cm) 12 inches (30 cm)
6 in (15 cm) for appliances ≤
10,000 Btuh (3 kW), 12 in (30
cm) for appliances > 10,000 Btuh
(3 kW) and ≤ 100,000 Btuh (30
kW), 36 in (91 cm) for appliances
>100,000 Btuh (30 kW)
4  (1.2 m) below or to side
of opening; 1  (300 mm)
above opening
CClearance to permanently closed window ****
D
Vercal clearance to venlated sot, located
above the terminal within a horizontal distance of
2 feet (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
3 feet (91 cm) within a
height 15 feet (4.5 m)
above the meter/
regulator assembly
*
3 feet (91 cm) within a height 15
feet (4.5 m) above the meter/
regulator assembly
*
IClearance to service regulator vent outlet 36 inches (91 cm) *36 inches (91 cm) *
J
Clearance to nonmechanical air supply inlet to
building or the combuson air inlet to any other
appliance
36 inches (91 cm) 12 inches (30 cm)
6 in (15 cm) for appliances ≤
10,000 Btuh (3 kW), 12 in (30
cm) for appliances > 10,000 Btuh
(3 kW) and ≤ 100,000 Btuh (30
kW), 36 in (91 cm) for appliances
>100,000 Btuh (30 kW)
4  (1.2 m) below or to side
of opening; 1  (300 mm)
above opening
KClearance to a mechanical air supply inlet 6 feet (1.83 m)
3 feet (91 cm) above if
within 10 feet (3 m)
horizontally
6 feet (1.83 m)
3 feet (91 cm) above if
within 10 feet (3 m)
horizontally
LClearance above paved sidewalk or paved
driveway located on public property 7 feet (2.13 m) *7 feet (2.13 m) *
MClearance under veranda, porch, deck, or balcony 12 inches (30 cm)  *12 inches (30 cm)  *
Terminal Clearances

8VC Series Manual
24"
V
Check to determine whether local codes supersede
these clearances.
 Avoid terminaon locaons near a dryer vent.
 Avoid terminaon locaons near commercial
cooking exhaust.
 You must install a vent terminaon at least 12
inches above the ground.
60"
V
V
(1.52 m)
between
terminals at
dierent levels
(0.61 m) to wall or parapet
(0.30 m) between
terminals at same
level
12"
V V
(1.52 m) vercally
between terminals
V
60"
V
Addional clearances - RL75i, RL94i, RLX94i
12"
12"
36"
INSIDE
CORNER
V V
(0.30 m ) to
an inside
corner (0.30 m) between
terminals at same
level
Important consideraons for locang vent
terminaon under a sot (venlated or unvenlated
or eave vent; or to a deck or porch)
 Do not install vent terminaon under a sot vent
such that exhaust can enter the sot vent
 Install vent terminaon such that exhaust and
rising moisture will not collect under
eaves. Discoloraon to the exterior of the
building could occur if installed too close.
 Do not install the vent terminaon too close
under the sot where it could present
recirculaon of exhaust gases back into the
combuson air intake part of the terminaon.

VC Series Manual 9
2"
12"
60"
36"
Local codes supersede these clearances.
 Avoid terminaon locaons near a dryer vent.
 Avoid terminaon locaons near commercial
cooking exhaust.
 Avoid terminaon locaons near any air inlets.
Addional clearances
RL75e, RL94e
(0.30 m) to an
inside corner
(50 mm) between terminals at same level
(1.52 m) vercally
between terminals
(0.91 m) to venlated or unvenlated
sot or eve vent; or to a deck or porch

10 VC Series Manual
Unit clearances
* 0 inches from vent components and condensate
drain line.
The clearance for servicing is 24 inches in front of the
water heater.
For closet installaon, clearance is 6 inches (152 mm)
from the front of the water heater.
Indoor models: RL75i, RL94i, RLX94i Outdoor models: RL75e, RL94e
The clearance for servicing is 24 inches in front of the
water heater.
to Combusbles
inches (mm)
to Non-
Combusbles
inches (mm)
Top of Heater 12 (305) 2 (51)
Back of Heater 0 (zero) 0 (zero)
Front (Panel) 24 (610) 0 (zero)
Front (Exhaust) 24 (610) 24 (610)
Sides of Heater 6 (152) 1/8 (3.2)
Ground/Boom 12 (305) 2 (51)
to Combusbles
inches (mm)
to Non-
Combusbles
inches (mm)
Top of Heater 6 * (152) 2 *(51)
Back of Heater 0 (zero) 0 (zero)
Front of Heater 6 (152) 6 (152)
Sides of Heater 2 (51) 1/2 (13)
Ground/Boom 12 (305) 12 (305)
Vent 0 (zero) 0 (zero)

VC Series Manual 11
Freeze Protecon
Make sure that in case of freezing weather that the
water heater and its water lines are protected to
prevent freezing. Damage due to freezing is not
covered by the warranty.
With electrical power and gas supplied, the water
heater will not freeze when the outside air
temperature is as cold as –22°F (-30°C) for indoor
models or is as cold as –4°F (-20°C) for outdoor
models, when protected from direct wind exposure.
Because of the “wind-chill” eect, any wind or
circulaon of the air on the unit will reduce its ability
to protect itself from freezing.
In the event of a power failure and/or gas
interrupon at temperatures below freezing the
water heater should be drained of all water to
prevent freezing damage. In addion, drain the
condensate trap and drain line.
Loss of freeze protecon may result in water damage
from a burst heat exchanger or water lines.
The unit may be drained manually. However, it is
highly recommended to:
 drain down solenoid valves be purchased and
installed that will automacally drain the unit if
power is lost. These are available in a kit,
104000059. (The condensate trap is not aected
by the auto drain down solenoid valves and will
have to be manually drained.)
 a surge protector with terminals be purchased
and installed which allows the solenoid valves to
operate if the unit is disabled due to a diagnosc
code. This is available as 104000057.
In addion, the solenoid valves should be connected
electrically to a surge protector with terminals. This
allows the solenoid valves to operate if the water
heater is disabled due to a diagnosc code.
The freeze protecon features will not prevent the
external piping from freezing. It is recommended that
hot and cold water pipes be insulated. Pipe cover
enclosures may be packed with insulaon for added
freeze protecon.
Maximum vent length
(indoor models only)
1. Determine the number of 90 degree elbows in
the vent system. (Two 45 degree elbows count as
one 90 degree elbow.)
2. Refer to the table to nd the maximum vent
length based on the number of elbows.
3. Adjust switch No. 1 in the SW1 DIP switch (tan
switches) if required by the applicable note.
 If the length is greater than 21  (6.4 m) then
move switch No. 1 (SW1) to OFF.
 If the length is greater than 15  (4.6 m) then
move switch No. 1 (SW1) to OFF.
 If the length is greater than 9  (2.7 m) then move
switch No. 1 (SW1) to OFF.
Move switch No. 1 (SW1) to OFF.
Example: If you have one elbow then your maximum
vent length is 35 feet (10.7 m). If your
actual length is greater than 15  (4.6 m)
then move switch no. 1 (SW1) to OFF.
Number of
90° Elbows
Maximum vent length
041  (12.5 m) 
135  (10.7 m) 
229  (8.8 m) 
323  (7.0 m) 
417  (5.2 m) 
511  (3.4 m) 
65  (1.5 m) 
If you have a longer vent length (see number 3
regarding max. vent length), switch No. 1 is required
to be in the OFF posion. This ensures the water
heater will run properly. Blocked ue diagnosc
codes and shutdowns may result if switch No. 1 is not
in the correct posion.
NOTICE

12 VC Series Manual
Mount to Wall
wall installaon
brackets
1. Idenfy the installaon locaon and conrm that
the installaon will meet all required clearances.
2. Securely aach the water heater to the wall
using any of the holes in the wall installaon
brackets which are at the top and boom of the
water heater. Ensure that the aachment
strength is sucient to support the weight.
Refer to the weight of the water heater in the
Specicaons secon.
Use a leveling tool to ensure that the water
heater is level. Proper operaon requires that
the water heater be level.
NOTE: The water heater must be installed in an
upright posion. Do not install upside down or on its
side.
Checklist to Determine Installaon
Locaon
□The water heater is not exposed to corrosive
compounds in the air.
□The water heater locaon complies with the
clearances.
□For indoor models, the planned venng will not
exceed the maximum length for the number of
elbows used.
□The planned venng terminaon/air intake
locaon meets the clearances.
□Indoor air is not being used for combuson.
□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 (for indoor models) or other
120 VAC, 60 Hz source is available.
□The installaon must conform with local codes or,
in the absence of local codes, with the Naonal
Fuel Gas Code, ANSI Z223.1/NFPA 54, or the
Natural Gas and Propane Installaon Code, CSA
B149.1. If installed in a manufactured home, the
installaon must conform with the Manufactured
Home Construcon and Safety Standard, Title 24
CFR, Part 3280 and/or CAN/SCA Z240 MH Series,
Mobile Homes.
□Leave the enre manual taped to the water
heater (indoor models), temperature controller
(outdoor models), or give the enre manual
directly to the consumer.
Remove the Front Panel
Slide the plasc trim pieces on each side of the water
heater to expose the screws.
Remove the 4 screws and pull o the front panel.

VC Series Manual 13
Manufacturer Listed and Tested Vent Products
for RL75i, RL94i, and RLX94i Telephone Fax Contact
Ubbink Rolux Vent System 800-621-9419 678-829-1666 www.rinnai.us
Heat-Fab Saf-T Vent SC system 800-772-0739 413-863-4803 [e-mail],
www.heaab.com
Metal-Fab Corr/Guard Vent/Air Intake System 800-835-2830 316-943-2717 [email protected],
www.metal-fabinc.com
Installaon of venng (indoor models only)
Install the correct venng for your model according to the venng manufacturer’s instrucons and the
guidelines below.
Refer to the manufacturer’s technical literature for specic part numbers and instrucons.
Venng Guidelines
DO NOT
 Do not use PVC, CPVC, ABS or galvanized material
to vent this appliance.
 Do not combine vent components from dierent
manufacturers.
 Vent diameter must not be reduced.
 Do not connect the venng system with an
exisng vent or chimney.
 Do not common vent with the vent pipe of any
other water heater or appliance.
MUST DO
 This water heater is a direct vent water heater and
therefore is cered and listed with the vent
system. 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 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 every four feet and
all vercal vent runs every six feet or in
accordance with local codes.
 Venng should be as direct as possible with a
minimum number of pipe ngs.
 Vent connecons must be rmly pressed together
so that the gaskets form an air ght seal.
 The vent piece connected to the water heater
must be secured with one self-tapping screw.
INFORMATION
 Refer to the instrucons of the vent system
manufacturer for component assembly
instrucons.
 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
enclosure shall be deemed acceptable by the
installer or the local inspector.
NOTICE
If it becomes necessary to access an enclosed vent
system for service or repairs, Rinnai is not responsible
for any costs or dicules in accessing the vent
system. The warranty does not cover obtaining
access to a vent system in an enclosed environment.

14 VC Series Manual
Flue Installaon (indoor models only)
Vercal Terminaon
(condensate collector must be used in all installaons)
3 in (75 mm)
minimum
3 in (75 mm)
minimum
Horizontal Terminaon using Condensate Collector
3 in (75 mm)
minimum
Condensate
Trap
To adjust the condensate collector posion or to
replace the female vent top with a male vent top:
1. Loosen the 4 screws at the rear bracket
2. Slide the bracket away from the female vent top.
3. Remove the 4 screws aaching the female vent top
to the water heater.
4. Li up the female vent top and reposion as desired
(or replace with a male vent top).
5. Install the 4 screws at the vent top and ghten the 4
screws at the bracket.
Secure the rst vent component to the water heater
with one self-tapping screw at the hole located above
the condensate collector.
Bracket
Condensate Collector
Securing Screw
Horizontal Terminaon without using the Condensate Collector
Maximum Height *
5 feet (1.52 m)
Regions of cold climate will create more
condensate in the vent system. The
condensate collector should be used in
cold climates.
If more than one elbow is used in the
vercal secon the condensate collector
must be used.
* The condensate collector must be used in
horizontal terminaons if a vercal rise in
the vent system exceeds 5.
If the condensate collector is not used, the drain pipe must
be capped to prevent exhaust gases and condensate from
entering the building. The cap is supplied on the appliance.
In such an instance slope the venng 1/4” per foot away
from appliance according to vent manufacturer’s
installaon instrucons.
WARNING
Install the venng terminaon according to the diagrams and instrucons below.
Slope the venting 1/4” per foot toward
the appliance according to the vent
manufacturers installation instructions.
Dispose of condensate per local codes.

VC Series Manual 15
Condensate
(indoor models only)
Condensate can form in the vent of high eciency
direct vent appliances. Without proper drainage,
condensate will damage the heat exchanger.
To prevent condensate damage, follow these
instrucons.
DO NOT
 Do not allow condensate to enter the water
heater.
 Do not connect the condensate drain pipe directly
to the rain sewer.
 Do not connect the condensate drain line with an
air condioning evaporator coil drain or.
 Do not connect the condensate drain line to the
pressure relief valve/line of the appliance.
MUST DO
 Use only venng that is approved and idened as
acceptable for your parcular model.
 For vercal terminaons, install a condensate drain
and trap as close as possible to the appliance.
 Slope the venng toward the appliance according
to the vent manufacturer’s installaon
instrucons.
 All condensate must drain and be disposed of
according to local codes.
 Use only corrosion resistant materials for the
condensate drain lines such as PVC pipe or plasc
hose.
 The condensate drain pipe (along its enre length)
must be at least the same diameter as the drain
line, (5/8 inch NPT).
 The end of the condensate drain pipe should be
open to the atmosphere. The end should not be
under water or other substances.
 To minimize freezing of the condensate, run the
condensate drain line through an interior wall or
between insulaon and an interior wall.
 The condensate collector should be used for all
combinaon domesc/hydronic heang
applicaons.
Checklist for Venng and
Condensate (indoor models only)
□Verify proper clearances around the vent
terminaons and air intakes.
□Ensure you have used the correct venng
products for the model installed and that you
have completely followed the venng
manufacturer’s installaon instrucons and these
installaon instrucons.
□Verify that the vent pipe has a downward slope or
grade to the outside of 1/4 inch per foot (1.2° )
OR if the vent pipe is sloped toward the water
heater (as some local codes require), that a
condensate collector is installed to allow
condensaon to drain away from the water
heater to a proper drain source.
□Verify that condensate will not be allowed to
drain back into the water heater.
□Verify that the vent system does not exceed the
maximum length for the number of elbows used.
INFORMATION
 A condensate trap is available, P/N 222053.
 Regions of cold climate will create more
condensate in the vent system. The condensate
collector should be used in cold climates.
 The condensate drain pipe should be as short as
possible and have a downward pitch.

16 VC Series Manual
Installaon of Plumbing
A manual water control valve must be placed in the
water inlet connecon to the water heater before it is
connected to the water line. Unions may be used on
both the hot and cold water lines for future servicing
and disconnecon of the unit.
DO NOT
 Do not introduce toxic chemicals such as those
used for boiler water treatment to the potable
water used for space heang.
MUST DO
 The piping (including soldering materials) and
components connected to this appliance must be
approved for use in potable water systems.
 Purge the water line to remove all debris and air.
Debris will damage the water heater.
 If the appliance will be used as a potable water
source, it must not be connected to a system that
was previously used with a nonpotable water
heang appliance.
 Ensure that the water lter on the water heater is
clean and installed.
Piping Requirements
Pressure Relief Valve Requirements
Install the pressure relief valve according to these
instrucons.
An approved pressure relief valve is required by the
American Naonal Standard (ANSI Z21.10.3) for all
water heang systems and shall be accessible for
servicing.
DO NOT
 Do not plug the relief valve and do not install any
reducing ngs or other restricons in the relief
line. The relief line should allow for complete
drainage of the valve and the line.
 Do not place any other type valve or shuto device
between the relief valve and the water heater.
MUST DO
 The relief valve must comply with the standard for
Relief Valves and Automac Gas Shuto Devices for
Hot Water Supply Systems ANSI Z21.22 and /or the
standard Temperature, Pressure, Temperature and
Pressure Relief Valves and Vacuum Relief Valves,
CAN1-4.4.
 The relief valve must be rated up to 150 psi and to
at least the maximum BTU/hr of the appliance.
 The discharge from the pressure relief valve should
be piped to the ground or into a drain system per
local codes.
 The pressure relief valve must be manually
operated once a year to check for correct
operaon.
 The relief valve should be added to the hot water
outlet line and near the hot water outlet according
to the manufacturer’s instrucons. DO NOT place
any other type valve or shut o device between
the relief valve and the water heater.
INFORMATION
 If a relief valve discharges periodically, this may be
due to thermal expansion in a closed water supply
system. Contact the water supplier or local
plumbing inspector on how to correct this
situaon. Do not plug the relief valve.
 The American Naonal Standard (ANSI Z21.10.3)
does not require a combinaon temperature and
pressure relief valve for this appliance. However,
local codes may require a combinaon
temperature and pressure relief valve.
Isolaon Valves
Isolaon valves are included with this water heater.
Rinnai strongly recommends the installaon of
isolaon valves on the cold and hot water lines
because they provide the ability to isolate the water
heater from the structure’s plumbing and allow quick
access to ush the heat exchanger. Flushing the heat
exchanger regularly is required as part of the proper
maintenance for this water heater.
Water discharged from the pressure relief valve could
cause severe burns instantly or death from scalds.
WARNING

VC Series Manual 17
Isolaon Valves and Pressure Relief Valve
The isolaon valves provide the ability to isolate the
water heater from the structure’s plumbing and allow
quick access to ush the heat exchanger. Check with
local codes to determine if a pressure and
temperature relief valve is required. The included
valves meet American Naonal Standard (ANSI
Z21.10.3) / Canadian Standard (CSA 4.3) and are
ANSI/NSF 61 approved for potable water.
Isolaon Valves Installaon Instrucons:
1. Wrap the ends of the threaded water inlet and
outlet on the tankless water heater, as well as
the threaded end of the approved pressure relief
valve with a minimum of 5 wraps of Teon®
tape.
2. Install the pressure relief valve to the 3/4”
threaded port on the HOT (RED) water service
valve (will be adjacent to or above the cut o,
never below). See Pressure Relief Valve Secon
for proper installaon requirements.
3. Loosen the 3/4” union nut on the HOT water
valve and connect to the HOT water outlet on
the tankless water heater. If nut is removed,
ensure that you realign the tailpiece accurately
to the valve, and that the black washer and/or
gasket is properly posioned.
4. Align the direcon of the HOT water drain to the
desired posion.
5. Tighten the union assembly to the HOT water
valve. DO NOT over torque.
6. Repeat steps 3-5 for the COLD water valve.
(BLUE valve) for connecon to the COLD water
inlet on the tankless water heater.
7. Connect the INLET on the COLD water valve to
the MAIN SOURCE of the water supply.
8. Connect the OUTLET on the HOT water valve to
the HOT WATER plumbing system.
9. Ensure that both drain valves are in the
closed/“OFF” posion.
Pressure Relief Valve (PRV) Installaon Instrucons:
The PRV must be connected to the 3/4” threaded port
on the HOT (RED) water service valve (will be adjacent
to or above the shut o, never below). Installaon
must maintain a ¾” port size with no shut o valve or
line restricon in-between the appliance and the PRV.
The discharge line from the PRV should pitch
downward and terminate 6” above drains where
discharge will be clearly visible. The discharge end of
the line shall be plain (unthreaded) and a minimum of
¾” in diameter. The discharge line material must be
suitable for water at least 180° Fahrenheit. No valve
of any type may be installed in the discharge line of
the pressure relief valve.
Pressure Relief Valve Maintenance:
For proper care of this approved pressure relief valve,
it is recommended that the valve is manually
operated once a year. In doing so, it will be necessary
to take precauons with regard to the discharge of
potenally scalding hot water under pressure. Ensure
discharge water has a safe place to ow. Contact
with your body or other property may cause damage
or harm.
Please note that only the PRV in this package is
cered by CSA Internaonal as an approved item.
APressure Relief Valve (PRV)
BPRV Discharge Outlet
CHot Drain Valve
DCold Drain Valve
EHot Ball Valve
FCold Ball Valve
When unscrewing the UNION FITTING, Be careful not
to lose any washers and/or gaskets that may be
present.
NOTICE
A
B
C
D
F
E

18 VC Series Manual
Piping Diagram for Basic Installaon
GasSup
ply
3/4"C
oldWate
rSupply
Line
3/4" Hot Water Supply Line
Rinnai
Water Heater
Rinnai
Equipment List
Rinnai
Water Heaters
RIK-KIT (Optional)
(3/4" Fittings Include:
2 Unions, 2 Ball Valves,
2 Drain Valves and
1 Pressure Relief Valve.)
QTY
1
1
3/4"G
asConne
ction
For Building Fixtures
Pressure Relief Valve
3/4" Ball Valve
3/4" Union
Check Valve
S
Pressure Regulator
Circulating Pump
Solenoid Valve
Boiler Drain Valve
KEY This is not an engineered drawing. It is intended only as a guide and not
as a replacement for professionally engineered project drawings. This
drawing is not intended to describe a complete system. It is up to the
contractor/engineer to determine the necessary components and
configuration of the particular system being installed. This drawing does
not imply compliance with local building code requirements. It is the
responsibility of the contractor/engineer to ensure installation is in
accordance with all local building codes. Confer with local building
officials before installation.

VC Series Manual 19
Connect Water Heater to Water Supply
Water connecons to the tankless water heater
should follow all state and local plumbing codes.
If this is a standard installaon, refer to the Piping
Diagram for Basic Installaon.
1. Plumb water supply to the tankless water heater
on the 3/4” MNPT connecon at the boom of
the unit marked “Water Inlet”, which is the cold
water supply.
2. Plumb the building hot water supply to the 3/4”
MSPT connecon marked “Water Outlet”, which
is the hot water supply.
If a pipe cover will be installed, make sure water lines
to the water heater t.
Checklist for Plumbing
□Purge the water line of all debris and air by
closing the hot isolaon valve and opening the
cold isolaon valve and its drain. Debris will
damage the water heater. Use a bucket or hose
if necessary.
□Ensure that hot and cold water lines are not
crossed to the unit and are leak free.
□Ensure that a pressure relief valve is installed with
a rang that exceeds the BTU input of the water
heater model. Refer to the rang plate on the
side of the water heater for BTU input.
□Clean the inlet water lter by closing the cold and
hot water inlet isolaon (shut-o) valves. Put a
bucket under the lter at the boom of the water
heater to catch any water that is contained inside
the unit. Unscrew the water lter. Rinse the
lter to remove any debris. Install the lter and
open the isolaon valves.
□Check for proper water pressure to the water
heater. Minimum/Maximum water pressure is
20-150 psi. Rinnai recommends 30-80 psi for
maximum performance.
Installaon of Gas Supply
MUST DO
 A manual gas control valve must be placed in the
gas supply line to the water heater. A union can be
used on the connecon above the shut o valve
for the future servicing or disconnecon of the
unit.
 Check the type of gas and the gas inlet pressure
before connecng the water heater. If the water
heater is not of the gas type that the building is
supplied with, DO NOT connect the water heater.
Contact the dealer for the proper unit to match the
gas type.
 Check the gas supply pressure immediately
upstream at a locaon provided by the gas
company. Supplied gas pressure must be within
the limits shown in the Specicaons secon of
this manual with all gas appliances operang.
 Before placing the appliance in operaon, all joints
including the heater must be checked for gas
ghtness by means of leak detector soluon, soap
and water, or an equivalent nonammable
soluon, as applicable. (Since some leak test
soluons, including soap and water, may cause
corrosion or stress cracking, the piping shall be
rinsed with water aer tesng, unless it has been
determined that the leak test soluon is non-
corrosive.)
 Use approved connectors to connect the unit to
the gas line. Purge the gas line of any debris
before connecon to the water heater.
General Instrucons
WARNING
1. A licensed professional must install the gas
supply.
2. Turn o 120v power supply.
3. Turn o the gas.
4. Gas is ammable. Do not smoke or provide other
ignion sources while working with gas.
5. Do not turn on the water heater or gas unl all
fumes are gone.

20 VC Series Manual
Size the gas pipe
The gas supply must be capable of handling the enre
gas load required at the locaon. Gas line sizing is
based on gas type, the pressure drop in the system,
the gas pressure supplied, and gas line type. For gas
pipe sizing in the United States, refer to the Naonal
Fuel Gas Code, NFPA 54. The below informaon is
provided as an example. The appropriate table from
the applicable code must be used.
1. For some tables, you will need to determine the
cubic feet per hour of gas required by dividing the
gas input by the heang value of the gas
(available from the local gas company). The gas
input needs to include all gas products at the lo-
caon and the maximum BTU usage at full load
when all gas products are in use.
2. Use the table for your gas type and pipe type to
nd the pipe size required. The pipe size must be
able to provide the required cubic feet per hour
of gas or the required BTU/hour.
Example:
The heang value of natural gas for your locaon is
1000 BTU/FT3. The gas input of the RL94i is 199,000
BTU/HR. Addional appliances at the locaon require
65,000 BTU/hr. Therefore the cubic feet per hour =
(199,000 + 65,000) / 1000 = 264 FT3/HR. If the pipe
length is 10 feet then the 3/4 inch pipe size is capable
of supplying 264 FT3/HR of natural gas.
Gas Input of all gas products (BTU / HR)
Heang Value of Gas (BTU / FT 3 )
Cubic Feet
per Hour =
(CFH)
 Any compound used on the threaded joint of the
gas piping shall be a type that resists the acon of
liqueed petroleum gas (propane / LPG).
 The gas supply line shall be gas ght, sized, and so
installed as to provide a supply of gas sucient to
meet the maximum demand of the heater and all
other gas consuming appliances at the locaon
without loss of pressure.
INFORMATION
 Refer to an approved pipe sizing chart if in doubt
about the size of the gas line.
Length Pipe Size (inches)
3/4 11 1/4 1 1/2
10 273 514 1060 1580
20 188 353 726 1090
30 151 284 583 873
40 129 243 499 747
50 114 215 442 662
60 104 195 400 600
70 95 179 368 552
80 89 167 343 514
90 83 157 322 482
100 79 148 304 455
Pipe Sizing Table - Natural Gas
Inlet Pressure: less than 2 psi (55 inches W.C.)
Pressure Drop: 0.3 inches W.C.
Specic Gravity: 0.60
Schedule 40 Metallic Pipe
cubic feet per hour
Length Pipe Size (inches)
1/2 3/4 11 1/4
10 291 608 1150 2350
20 200 418 787 1620
30 160 336 632 1300
40 137 287 541 1110
50 122 255 480 985
60 110 231 434 892
80 101 212 400 821
100 94 197 372 763
Pipe Sizing Table - Propane Gas
Inlet Pressure: 11.0 inches W.C.
Pressure Drop: 0.5 inches W.C.
Specic Gravity: 1.50
Schedule 40 Metallic Pipe
Capacity in Thousands of BTU per Hour