Rinnai Rice Cooker RL94i ( REU-VB2735FFUD-US), R98LSi ( REU-VA3237FFU-US), R98LSi-ASME Installation Manual
Direct Vent Tankless Water Heater
Operation and Installation Manual
RL75i .................. REU-VB2528FFUD-US
RL94i .................. REU-VB2735FFUD-US
R98LSi ................ REU-VA3237FFU-US
R98LSi-ASME .... REU-VA3237FFU-ASME
FOR INDOOR APPLICATIONS ONLY
Table of Contents ..................... 2
The VB series (RL75i, and RL94i) are certified for
installation in manufactured (mobile) homes.
Register your product at www.rinnairegistration.com or
call 1-866-RINNAI1 (746-6241)
INSTALLER: Leave this manual with the appliance.
CONSUMER: Retain this manual for future reference.
WARNING
result causing property damage, personal injury or death.
— Do not store or use gasoline or other flammable vapors and
liquids in the vicinity of this or any other appliance.
— WHAT TO DO IF YOU SMELL GAS
• Do not try to light any appliance.
• Do not touch any electrical switch; do not use any phone in
your building.
• Immediately call your gas supplier from a neighbor’s phone.
Follow the gas supplier’s instructions.
• If you cannot reach your gas supplier, call the fire
department.
ANS Z21.10.3
●
CSA 4.3
— Installation and service must be performed by a qualified
installer, service agency or the gas supplier.
Consumer Safety Information ... 4
Operating Instructions ............... 6
Maintenance ........................... 11
Error Codes ............................ 12
Installation Instructions ........... 16
Consumer Support .................. 44
French Version ....................... 47
If the information in these instructions is not
followed exactly, a fire or explosion may
California Proposition 65 lists chemical substances known to the state to cause cancer, birth defects, death,
serious illness or other reproductive harm. This product may contain such substances, be their origin from fuel
combustion (gas, oil) or components of the product itself.
R
R98LSi-ASME
This model has been built in accordance with
the requirements of the ASME Boiler and
Pressure Vessel Code and has received the
Certificate of Authorization from the National
Board. The heat exchanger on this unit has
the NB and HLW stamps.
Table of Contents
Specifications ..................................................... 3
Consumer Safety Information
Safety Definitions ............................................. 4
Safety Behaviors and Practices ....................... 4
Safety Features................................................ 4
Description of Operation .................................... 4
Operating Instructions
Temperature Controller .................................... 5
Features Available on Temperature
Controllers ........................................................ 6
How to Set the Temperature ............................ 7
Temperature Controller Settings .................. 7, 8
Temperature Options Without
a Temperature Controller ................................. 8
Setting the Sound Volume (Voice Prompt) ...... 8
Using the Water Smart / Bath Fill Function ..... 9
Overview ..................................................... 9
Setting the Water Volume ........................... 9
Filling the Tub ............................................ 10
Setting Controller to Mute .............................. 10
Setting the Clock ............................................ 10
Maintenance
Cleaning .................................................... 11
Vent System .............................................. 11
Motors ....................................................... 11
Temperature Controller ............................. 11
Lime / Scale Build-up ................................ 11
Snow Accumulation ................................... 11
Visual Inspection of Flame ........................ 11
Error Codes
Error Code Table ...................................... 12,13
Trouble Shooting for Common Issues ........... 14
Accessing Operating Information................... 14
Water Quality ................................................. 14
Flushing the Heat Exchanger
(Error Code: LC or 00) ................................... 15
Installation Instructions ................................... 16
General Instructions ....................................... 16
Clearances from Appliance ............................ 17
Attachment of the Water Heater .................... 17
Electrical Connection ..................................... 18
Error Indication or Air Handler Control Switch ...
(RL75i, RL94i only) ........................................ 18
Gas Piping
General Instructions ................................ 18
Pipe Sizing Procedure - Example ............ 19
Water Piping
Isolation Valves and
Pressure Relief Valves ............................ 20
Piping Requirements ............................... 21
Pressure Relief Valve Requirements ...... 21
Freeze Protection .............................. 21, 22
Freeze Protection Piping ............................... 23
Recommended Piping for Basic Installation ..
Recommended Piping for
Circulation Systems ....................................... 25
Venting Instructions
Intake / Exhaust Guidelines ..................... 26
Condensate ............................................. 26
Maximum Vent Length ............................ 27
Vent Products .......................................... 28
Flue Terminal Clearances
(ANS Z21.10.3, CSA 4.3
Additional Clearances - Vent Terminal .......... 30
Flue Installation - Concentric Venting
(RL75i, RL94i) ................................................ 31
Flue Installation
(R98LSi, R98LSi-ASME).......................... 32, 33
Connecting Multiple Water Heaters ............... 34
High Altitude Installations ........................ 34, 35
Temperature Controller Installation
Location ................................................... 36
Configurations.......................................... 36
Cable Lengths and Size .......................... 36
Mounting the Controller ........................... 37
Operating Instructions ................................... 38
Technical Data
Pressure Drop Curve ..................................... 39
Outlet Flow Data ............................................ 39
Space Heating ............................................... 40
Dimensions .................................................... 41
Ladder Diagrams ..................................... 42, 43
Consumer Support
Warranty Information ..................................... 44
Limited Warranty ...................................... 44, 45
State Regulations .............................................. 46
French Version ............................................ 47-68
) .............................. 29
24
2 VB Series Indoor LS Manual
Specifications
Model
Minimum Gas Consumption Btu/h
Maximum Gas Consumption Btu/h 180,000
Hot water capacity (Min - Max) *
Hot water capacity (45°F rise)
Default Temperature Setting (no controller) 120º F (49º C)
Temperature Controller Default Setting 104º F (40º C)
Maximum Temp Setting (commercial **) 160º F (71º C) 185º F (85º C)
Maximum Temp Setting (residential)
see Temperature Ranges for more information
Minimum Temperature Setting 98º F (37º C)
Weight 51 lb (23 kg) 53 lb (24 kg) 55 lb (25 kg)
Efficiency Thermal Efficiency: 84.0%
Noise level 49 dB
Normal 76 W 83 W 99 W
Electrical Consumption
By-Pass Control Fixed Electronic
Minimum Gas Supply
Pressure
Maximum Gas Supply
Pressure
Type of Appliance Direct Vent, Temperature controlled continuous flow gas hot water system.
Operation With or without remote controls, mounted in kitchen, bathroom, etc.
Approved Gas Type Natural Gas or Propane - Ensure unit matches gas type supplied at the installation
Connections Gas Supply: 3/4" MNPT, Cold Water Inlet: 3/4" MNPT, Hot Water Outlet: 3/4" MNPT
Ignition System Direct Electronic Ignition
Electric Connections Appliance: AC 120 Volts, 60Hz. Remote Control: DC 12 Volts (Digital)
Water Temperature Control Simulation Feedforward and Feedback.
Water Supply Pressure Minimum Water Pressure: 20 PSI (Recommended 30-80 PSI for maximum
Maximum Water Supply Pressure 150 PSI
Remote Control Cable Non-Polarized Two Core Cable (Minimum 22 AWG)
Energy Star Qualified Yes Yes No (not applicable)
Certified for installation in manufactured (mobile)
homes
Standby 2 W
Anti-frost Protection
Natural Gas 5.0 inch W.C.
Propane 8.0 inch W.C.
Natural Gas 10.5 inch W.C.
Propane 13.5 inch W.C.
RL75i
9,900 (NG)
10,300 (LPG)
0.4 - 7.5 GPM
(1.5 - 28.5 L/min)
6.6 GPM
(25.0 L/min)
Selectable at 120º F (49º C) or at 140º F
(60º C)
Energy Factor: 0.82
184 W 116 W
Yes Yes No No
RL94i
199,000 (NG)
190,000 (LP)
0.4 - 9.4 GPM
(1.5 - 35.5 L/min)
7.1 GPM
(27.0 L/min)
R98LSi
237,000
0.6 - 9.8 GPM
(2.4 - 37 L/min)
8.5 GPM
(32.2 L/min)
140º F (60º C)
R98LSi-ASME
19,000
* Minimum flow may vary slightly depending on the temperature setting and the inlet water temperature.
** for commercial and hydronic applications requiring higher temperatures
Rinnai is continually updating and improving products. Therefore, specifications are subject to change without
prior notice.
The maximum inlet gas pressure must not exceed the value specified by the manufacturer. The minimum value
listed is for the purpose of input adjustment.
VB Series Indoor LS Manual 3
Consumer Safety Information
Safety Definitions
This is the safety alert symbol. This symbol alerts you to potential hazards that can kill or hurt you and
others.
DANGER
WARNING
CAUTION
Indicates an imminently hazardous situation which, if not avoided, will result in death or
serious injury.
Indicates a potentially hazardous situation which, if not avoided, could result in death or
serious injury.
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.
Safety Behaviors and Practices
WARNING
• Keep the area around the appliance clear and free
from combustible materials, gasoline, and other
flammable vapors and liquids.
• Any alteration to the appliance or its controls can be
dangerous and will void the warranty.
• Always check the water temperature before entering
a shower or bath.
Safety Features
• Overheat: The appliance will automatically shut
down when the appliance exceeds a predetermined
temperature.
• Do not use this appliance if any part has been under
water. Immediately call a qualified service
technician to inspect the appliance and to replace
any part of the control system and any gas control
which has been under water.
• Power Surge Fuse: A glass fuse protects against
overcurrent. If the fuse blows then all indicator
lamps will be off.
• Flame Failure: The appliance will automatically
shut down if the burner flame is not adequate.
• Power Failure: The appliance will cut off the gas if
it loses electrical power.
• Fusible Link: In case the overheat feature does
not prevent the temperature from rising then the
fusible link will break shutting off the appliance.
Description of Operation
The Rinnai water heater is one of the most advanced
water heaters available. It provides a continuous
supply of hot water at a preset temperature. This
appliance is direct vent where air is brought in from the
outside and combustion gases are exhausted to the
outside.
While electricity, water, and gas supplies are
connected, the Rinnai water heater produces hot water
whenever a hot water tap is open.
Ignition is electronic. There is no pilot light consuming
gas while the water heater is not being used. The gas
burner lights automatically when the hot water tap is
opened and goes out when the tap is closed.
4 VB Series Indoor LS Manual
Installation of the temperature controller is highly
recommended. The temperature controller can set the
temperature within a specific range and can provide
error codes to diagnose any problems.
The temperature of the outgoing hot water is constantly
monitored. The Rinnai water heater may adjust the
water flow in order to maintain the temperature setting.
The water flow may vary from summer to winter due to
the difference in ground water temperature.
Temperature Controller
MC-91-1US & MCC-91-1US
Dimensions (inches): 3.5 W x 4.75 H x 0.75 D
The MC-91 controller is the standard temperature controller that is supplied with the water heater. On indoor
models it is integrated into the front panel. The MCC-91 controller is for commercial and hydronic applications
requiring higher temperatures. When the MCC-91 controller is connected, these higher temperatures are
available on all controller models in the system. Refer to the section on temperature ranges.
In Use
Indicator
Priority
Indicator
Temperature
Display
Priority
Temperature
Selection
Button
ON/OFF
Button
VB Series Indoor LS Manual 5
Operating Instructions
The MC-91 temperature controller is supplied with the RL75, RL94, and R98LS models. Additional functions are
available through the use of optional controllers.
There are several models of temperature controllers that can be purchased separately. Their description,
operation, and installation is provided in this manual in case additional temperature controllers are purchased and
installed.
Features Available on Temperature Controllers
MC-91
MC-100
MCC-91
BC-100
Features
Sends a short series of beeps to all controllers in the system. It is
Call
Clock
Error Codes
Function
In Use Indicator
ON/OFF Button
Power Save
Priority Button /
Indicator
12 hour AM/PM clock. (The MC-100 must be installed for clock
When a fault is detected an error code flashes at the temperature
Used on this model to set the clock or sound volume.
Indicates that hot water is being supplied (i.e. a hot water tap is
Used to turn the water heater ON or OFF.
Indicates that this controller is setting the temperature . Priority
Allows the temperature controller to be in an energy saving
MC-502
Description
not an intercom.
to work on the BC-100.)
display on models MC-91, MCC-91, and MC-502; and flashes at
the clock display on models MC-100 and BC-100.
open).
mode.
can be switched to another controller by pressing its Priority
Button when no hot water is running.
Used to adjust the voice prompt volume.
Sound Volume
Temperature Display
Thermostat
Water Smart / Bath Fill
Button / Indicator
Water Volume
6 VB Series Indoor LS Manual
Shows the temperature setting.
Increases or decreases the temperature setting.
Used to select the Water Smart / Bath Fill Function to fill a bath
with a predetermined volume of water.
Used to select the water volume for the Water Smart / Bath Fill
Function.
How to Set the Temperature
DANGER
1. If the water heater is off, press
the ON/OFF button to turn on.
2. Press the “Priority button” on the
temperature controller. The
green Priority light will glow
indicating that this controller is
controlling the temperature and
that the Rinnai water heater is
ready to supply hot water.
The priority can only be changed
while no hot water is running.
3. Press the ▲ or ▼ buttons to
obtain the desired temperature
setting.
All hot water sources are able to
provide water at this temperature
setting until it is changed again at
this or another temperature
controller.
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 125º F (52º C) 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 140º F (60º C)
20 seconds at 130º F (54º C)
8 minutes at 120º F (49º C)
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.
NOTICE
NOTICE
NOTICE
NOTICE
While any hot water is being provided,
the temperature setting can only be
adjusted between 98º F and 110º F.
Check local codes for the maximum
water temperature setting allowed
when used in nursing homes, schools,
day care centers, and all other public
applications.
If a newly installed unit with a
controller has not been powered for at
least 6 hours then the temperature will
return to the default setting of 104º F
(40º C) if power is interrupted.
There may be a variation between the
temperature displayed on the
temperature controller and the
temperature at the tap due to weather
conditions or the length of pipe to the
water heater.
Temperature Controller Settings
This water heater will attempt to provide hot water at the temperature setting even when the water flow is varied
or when more than 1 tap is in use. The water heater can deliver water at only one temperature setting at a time.
The available temperatures for a given model are provided below.
Model
RL75i
RL94i
R98LSi
R98LSi-ASME
Temp in Celsius ºC 37 38 39 40 41 42 43 46 49
An older controller, MC-45, can be installed with the RL75i and RL94i by moving switch No. 6 in the bank of 6
switches to ON. Some of the temperature settings will be slightly different from the above table.
VB Series Indoor LS Manual 7
98 100 102 104 106 108 110 115 120
98 100 102 104 106 108 110 115 120
98 100 102 104 106 108 110 115 120 125 130 135 140
Temperature Settings Available (ºF)
125 * 130* 135* 140* 150
125* 130* 135* 140* 150
52 54 57 60 66 71 85
**
**
150
**
160
**
160
**
160
**
185
**
185
**
Temperature Controller Settings
* Re-setting the Maximum Temperature (RL75 and RL94 only)
Models RL75 and RL94 have a default maximum temperature of 120º F
(49º C) and an option to increase the maximum temperature to 140 ºF
(60 ºC). Temperature settings from 125-140 ºF (52-60 ºC) are available
by setting switch 6 to ON in the SW1 bank of 8 switches.
** MCC-91 Temperature Controller
These settings require the MCC-91 controller. When the MCC-91
controller is connected, these higher temperatures are available on all
controller models in the system. Use of an MCC-91 controller in a
residential dwelling will reduce the warranty coverage to that of a
commercial warranty application.
The MCC-91 controller is intended for commercial and hydronic
applications only. If an MCC-91 controller is used in a residential
dwelling for a hydronics application, a mixing valve must also be
installed to limit the potable hot water temperature to a safe
temperature. Water temperatures over 125º F (52º C) can cause severe
burns or scalding. Refer to the Danger Alert on water temperatures.
Rinnai shall not, in any event, be liable for damages resulting from such
misuse or misapplication.
Suggested temperatures are
• Kitchen 120 ºF (49º C)
• Shower 98 - 110 ºF (37 - 43 ºC)
• Bath Fill 102 - 110 ºF (39 - 43 ºC)
A temperature lower than 98º F (37º C) can be
obtained at the tap by mixing with cold water.
To change the temperature scale from Celsius to
Fahrenheit or vice versa, press and hold the “On/Off”
button for 5 seconds while the water heater is OFF.
These temperatures are suggestions only.
Maximum Temperature
120º F (49º C) 140 ºF (60 ºC)
Switch No.
ON
O
F
F
1
2
3
4
5
6
7
8
Switch No.
ON
O
F
F
1
2
3
4
5
6
7
8
WARNING
DO NOT adjust the other switches
unless specifically instructed to do
so.
Temperature Options Without a Temperature Controller
The default temperature setting for this appliance installed without a temperature controller is 120º F (49º C). If
desired, the temperature setting can be changed to 140º F (60º C) by adjustment of a switch.
In the SW1 bank of 8 switches, set switch 5 to ON to obtain 140º F water temperature setting. Set switch 5 to
OFF (default) to obtain 120º F water temperature setting.
If a temperature controller is installed, then switch 5 has no effect on temperature settings.
Setting the Sound Volume (Voice Prompt)
MC-100V Press the “Function” button to
adjust the voice prompt
volume. The default sound
volume is set to Medium.
Each subsequent press of the
▲ or ▼ button cycles through
the volume levels in the order
below.
Medium Volume
(default)
High Volume
Off Volume
(beep)
BC-100V Press the “Sound Vol.” button to
adjust the voice prompt volume.
The default sound volume is set
to Medium. Each subsequent
press of the button cycles
through the volume levels in the
order below.
Off Sound
(no beep)
Low Volume
8 VB Series Indoor LS Manual
Using the Water Smart / Bath Fill Function
Overview
This function is exclusive to the BC-100V temperature
controller. The bath fill function allows the consumer
to fill a tub with a preset volume of water at a preset
temperature. This is done by pressing the bath fill
button on the BC-100V controller while no hot water is
flowing and then opening only the hot water tap. The
water heater will stop the hot water flow when the
preset volume has been reached. The hot water tap
should then be closed and the bath fill button pressed.
The temperature settings for the bath fill function are
limited to those in the table below.
Bath Fill Temperature Settings
Available
ºF 98 100 102 104 106 108
ºC 37 38 39 40 41 42
ºF 110 112 114 116 118 120
ºC 43 44 46 47 48 49
NOTICE
Multiple
Water
Heaters
NOTICE
Power
Loss
NOTICE
Anti-scald
Fixtures
The bath fill function will not work
properly if it is connected to multiple
water heaters. The tub will overfill
because the bath fill function is not
able to measure the water volume
when connected to multiple water
heaters.
If power is lost during the bath fill
function, the water heater will shut
down but the water will continue to
flow. When power returns, the water
shuts off and Error Code 03 appears
on the controller.
If power is lost after the bath has filled
but before the bath fill function button
is de-selected, then the water will not
flow during the power loss or after the
power is returned. Once power
returns, close the hot water tap and
de-select the bath fill function. No
error code appears.
Do not use with single handle fixtures
that have anti-scald features built into
them. These fixtures allow a
predetermined amount of cold water
which is not taken into account by the
bath fill function.
Setting the Water Volume
The default volume is set to 25 gallons. The volume
can be set between 10 and 120 gallons.
1. Press the “Priority” button on the
temperature controller. The green
Priority light will glow indicating
that this controller is controlling
the temperature and that the
Rinnai water heater is ready to
supply hot water.
2. Press the “Water Smart Bath Fill”
button to set the water volume
and temperature.
3. Press the “Temp” ▲ or ▼ buttons
to obtain the desired temperature
setting.
NOTICE
To Prevent
Over Filling
4. Press the “Water Vol.”▲ or ▼
buttons to obtain the desired
water volume in gallons.
5. Press the “Water Smart Bath Fill”
button.
Be careful not to overfill the bath. An
average bath volume is 60 gallons.
When filling the bath using this
function for the first time:
•Monitor and remain by the bath while
the water is running.
•Use a low bath fill volume less than
25 gallons
VB Series Indoor LS Manual 9
Using the Water Smart / Bath Fill Function
Filling the Tub
ON!
HOT
ON!
HOT
COLD
COLD
1. Press the “Water Smart / Bath Fill”
button once. The button will
illuminate, and a tone will sound.
2. The voice prompt will announce
“The hot water system is ready.
Open the hot water tap.”
Make sure the water volume is set.
Refer to “Setting the Water
Volume” on the previous page.
Open the hot water tap. The “In
Use” indicator will illuminate on
MC-100V and BC-100V controllers.
The hot water will begin to flow.
3. When the preset volume of water
has been produced then
•the water flow will cease
•the “Water Smart / Bath Fill”
button will flash
•a tone will sound
•the voice prompt will announce,
“Bath fill is complete. Turn
off the bath hot water tap and
push the Bath Fill button.”
4. Turn off the bath hot water tap and
push the Bath Fill button. The
water heater will not allow hot
water to flow from any source until
the “Water Smart / Bath Fill” button
is pushed.
The button light will go out.
NOTICE
To Stop the
Bath Fill
Before it
Finishes
NOTICE
When
Other Taps
Are Open
NOTICE
To stop the water flow during the Bath
Fill function, press the “Water Smart /
Bath Fill” button. The button will flash
and the voice prompt will announce,
“Hot water is not available. Turn off
all hot water taps and push the Bath
Fill button.” Follow the voice prompt
instructions.
During the bath fill function, any hot
water flowing at other locations,
subtracts from the total amount of
water for the bath. For example if the
bath fill function is set for 50 gallons
and 5 gallons of hot water are used at
other locations during the fill period
then the bath will only fill with 45
gallons.
During the operation of the bath fill
function, the MC-91 “In Use” indicator
does not light up.
Setting Controller to Mute
Models MC-91 and MCC-91
To eliminate the beeps when keys are pressed or to turn the beeps back on, press and hold both the ▲and ▼
buttons until a beep is heard (approximately 5 seconds).
Setting the Clock
MC-100V Press the “Function” button twice within 10 seconds to set the clock. Press the ▲ or
▼ button to reach the desired time. The clock on the BC-100V automatically shows
the time which has been set on the MC-100V.
10 VB Series Indoor LS Manual
Maintenance
WARNING
Turn off the electrical power supply, the manual gas
valve and the manual water control valve whenever
servicing the unit.
Repairs and maintenance should be performed by a
qualified service technician. The appliance should be
inspected annually by a qualified service technician.
Verify proper operation after servicing.
Cleaning
It is imperative that control compartments, burners,
and circulating air passageways of the appliance be
kept clean.
Clean as follows:
1. Turn off and disconnect electrical power. Allow to
cool.
2. Close the water shut off valves. Remove and clean
the water inlet filter.
3. Remove the front panel by removing 4 screws.
4. Use pressurized air to remove dust from the main
burner, heat exchanger, and fan blades. Do not
use a wet cloth or spray cleaners on the burner.
Do not use volatile substances such as benzene
and thinners. They may ignite or fade the paint.
Snow Accumulation
Keep the area around flue terminal free of snow and
ice. The appliance will not function properly if the
intake air or exhaust is impeded (blocked or partially
blocked) by obstructions.
Visual Inspection of Flame
The burner must flame evenly over the entire surface
when operating correctly. The flame must burn with a
clear, blue, stable flame. See the parts breakdown of
the burner for the location of the view ports.
The flame pattern should be as shown in the figures
below.
5. Use soft dry cloth to wipe cabinet.
Vent System
The vent system should be inspected at least annually
for blockages or damage.
Motors
Motors are permanently lubricated and do not need
periodic lubrication. Keep fan and motor free of dust
and dirt by cleaning annually.
Temperature Controller
Use a soft damp cloth to clean the temperature
controller. Do not use solvents.
Lime / Scale Build-up
If you receive Error Code “LC”, refer to the procedure,
Flushing the Heat Exchanger. Refer to the section on
Water Quality to see if your water needs to be treated
or conditioned. (When checking maintenance code
history, “00” is substituted for “LC”.)
VB Series Indoor LS Manual 11
Error Codes
The Rinnai water heater has the ability to check its own operation continuously. If a fault occurs, an error code
will flash on the display of the temperature controller. This assists with diagnosing the fault and may enable you
to overcome a problem without a service call. Please identify the code displayed when inquiring about service.
WARNING
Some of the checks below may need to be done by a qualified service technician. Call a
service technician for any remedy that involves gas or electricity. Call a service
technician if you have any doubt or reservation about performing the remedy yourself.
Code Fault Remedy
02
03
10
11
12
No burner operation during
freeze protection mode
Power interruption during
Bath Fill (Water will not flow
when power returns).
Air Supply or Exhaust
Blockage
No Ignition Check that the gas is turned on at the water heater, gas meter, or cylinder.
Flame Failure Check that the gas is turned on at the water heater and gas meter. Check for
Service Call
Turn off all hot water taps. Press ON/OFF twice.
Ensure Rinnai approved venting materials are being used.
Check that nothing is blocking the flue inlet or exhaust.
Check all vent components for proper connections.
Ensure vent length is within limits.
Ensure condensation collar was installed correctly.
Verify dip switches are set properly.
Check fan for blockage.
Ensure gas type and pressure is correct.
Ensure gas line, meter, and/or regulator is sized properly.
Bleed all air from gas lines.
Verify dip switches are set properly.
Ensure appliance is properly grounded.
Disconnect EZConnect™ or MSA controls to isolate the problem.
Ensure igniter is operational.
Check igniter wiring harness for damage.
Check gas solenoid valves for open or short circuits.
Remove burner cover and ensure all burners are properly seated.
Remove burner plate and inspect burner surface for condensation or debris.
obstructions in the flue outlet.
Ensure gas line, meter, and/or regulator is sized properly.
Ensure gas type and pressure is correct.
Bleed all air from gas lines.
Ensure proper Rinnai venting material was installed.
Ensure condensation collar was installed properly.
Ensure vent length is within limits.
Verify dip switches are set properly.
Ensure appliance is properly grounded.
Disconnect keypad.
Disconnect EZConnect™ or MSA controls to isolate the problem.
Check power supply for loose connections.
Check power supply for proper voltage and voltage drops.
Ensure flame rod wire is connected.
Check flame rod for carbon build-up.
Disconnect and reconnect all wiring harnesses on unit and PC board.
Check for DC shorts at components.
Check gas solenoid valves for open or short circuits.
Remove burner plate and inspect burner surface for condensation or debris.
Check the ground wire for the PC board.
12 VB Series Indoor LS Manual
Code Fault Remedy
Error Codes
14
16
31
32
33
34
52
61
65
71
72
73
LC
No
code
Thermal Fuse Check gas type of unit and ensure it matches gas type being used.
Over Temperature
Warning
Burner Sensor Error Measure resistance of sensor.
Outgoing Water
Temperature Sensor
Fault
Heat Exchanger
Outgoing Temperature
Sensor Fault
Combustion Air
Temperature Sensor
Fault
Modulating Solenoid
Valve Signal Abnormal
Combustion Fan Failure Ensure fan will turn freely.
Water Flow Control Fault The water flow control valve has failed to close during the bath fill function. Immediately turn
Solenoid Valve Circuit
Fault
Flame Sensing Device
Fault
Burner Sensor Circuit
Error
Scale Build-up in Heat
Exchanger (when
checking maintenance
code history, “00” is
substituted for “LC”)
Nothing happens when
water flow is activated.
Check for restrictions in air flow around unit and vent terminal.
Check for low water flow in a circulating system causing short-cycling.
Ensure dip switches are set to the proper position.
Check for foreign materials in combustion chamber and/or exhaust piping.
Check heat exchanger for cracks and/or separations.
Check heat exchanger surface for hot spots which indicate blockage due to scale build-up.
Refer to instructions in manual for flushing heat exchanger.
Measure resistance of safety circuit.
Ensure high fire and low fire manifold pressure is correct.
Check for improper conversion of product.
Check for restrictions in air flow around unit and vent terminal.
Check for low water flow in a circulating system causing short-cycling.
Check for foreign materials in combustion chamber and/or exhaust piping.
Check for clogged heat exchanger.
Replace sensor.
Check sensor wiring for damage.
Measure resistance of sensor.
Clean sensor of scale build-up.
Replace sensor.
Check sensor wiring for damage.
Measure resistance of sensor.
Clean sensor of scale build-up.
Replace sensor.
Check for restrictions in air flow around unit and vent terminal.
Check sensor wiring for damage.
Measure resistance of sensor.
Clean sensor of scale build-up.
Ensure fan blade is tight on motor shaft and is in good condition.
Replace sensor.
Check modulating gas solenoid valve wiring harness for loose or damaged terminals.
Measure resistance of valve coil.
Check wiring harness to motor for damaged and/or loose connections.
Measure resistance of motor winding.
off the water and discontinue the bath fill function. Contact a state qualified or licensed
contractor to service the appliance.
Replace the PC Board.
Ensure flame rod is touching flame when unit fires.
Check all wiring to flame rod for damage.
Remove flame rod and check for carbon build-up; clean with sand paper.
Check inside burner chamber for any foreign material blocking flame at flame rod.
Measure micro amp output of sensor circuit with flame present.
Replace flame rod.
Check sensor wiring and PC board for damage.
Replace sensor.
Flush heat exchanger. Refer to instructions in manual.
Replace heat exchanger.
NOTE: The LC code is the only error code that will allow the unit to keep running. The
display will alternate between the LC code and the temperature setting. The controller will
continue to beep. The LC code will reset if power is turned off and then on.
Clean inlet water supply filter.
On new installations ensure hot and cold water lines are not reversed.
Check for bleed over. Isolate unit from building by turning off cold water line to building.
Isolate the circulating system if present. Open your pressure relief valve; if water is
flowing, there is bleed over in your plumbing.
Ensure you have at least the minimum flow rate required to fire unit.
Ensure turbine spins freely.
Measure the resistance of the water flow control sensor.
Check for DC shorts at components.
VB Series Indoor LS Manual 13
Trouble Shooting for Common Issues
I don’t have any hot water when I open the tap.
Make sure there is gas, water, and electricity to the
Rinnai water heater (power is turned on and the gas is
turned on).
When I was using the hot water, the water got cold.
If you adjusted the flow from the tap to lessen it, you
may have gone below the minimum flow required. The
Rinnai water heater requires a minimum flow rate to
operate. (See the specification page for the flow rate
of your model.)
If you are experiencing issues with higher temperature
settings, then Rinnai recommends reducing the
temperature setting. Selecting a temperature closer to
that which is actually used at the faucet will increase
the amount of hot water being delivered to the faucet,
due to less cold water mixing at the fixture.
White smoke comes out of the exhaust.
During colder weather when the exhaust temperature
is much hotter than the outside air, the exhaust fumes
condense producing water vapor.
When I open a hot tap, I do not immediately get hot
water.
Hot water must travel through your plumbing from the
Rinnai water heater to the faucet. The time period for
hot water to reach your fixture is determined by the
amount of water in the plumbing system between the
water heater and the fixture, water pressure, and the
flow rate of the fixture.
After I turn off the hot water tap, the fan on the
Rinnai water heater continues to run.
The fan is designed to continue running for a short time
after the flow of water stops. This is to ensure constant
water temperatures during rapid starting and stopping,
as well as exhausting any residual gas flue products
from the unit.
Accessing Operating Information
Models MC-91 and MCC-91
To display the most recent error codes press and hold the “On/Off” button for 2 seconds. While holding the “On/
Off” button press the ▲ button. The last 9 error codes will flash one after the other. To exit this mode press the
“On/Off” and ▲ button as before.
To display the water flow through the water heater press and hold the ▲ button for 2 seconds and without
releasing the ▲ button press the “On/Off” button.
To display the outlet water temperature press and hold the ▼ button for 2 seconds and without releasing the ▼
button press the “On/Off” button.
Water Quality
Consideration of care for your water heater should
include evaluation of water quality. If the water quality
exceeds the target levels provided in the table, you
may want to treat or condition the water.
* Source: Part 143 National Secondary Drinking Water
Regulations
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
Iron * Up to 0.3 mg / L
Manganese * Up to 0.05 mg / L
Maximum Level
pH * 6.5 to 8.5
TDS (Total Dissolved
Solids) *
Zinc * Up to 5 mg / L
14 VB Series Indoor LS Manual
Up to 500 mg / L
Flushing the Heat Exchanger (Error Code: LC or 00)
An “LC” or “00” error code indicates the unit is beginning to lime up and must be flushed. Failure to flush the
appliance will cause damage to the heat exchanger. Damage caused by lime build-up is not covered by the unit’s
warranty. After flushing, reset the LC fault code by turning off the power to the unit and turning the power back
on.
1. Disconnect electrical power to the water heater.
2. Close the shutoff valves on both the hot water and
cold water lines (V3 and V4).
3. Connect pump outlet hose (H1) to the cold water
line at service valve (V2).
4. Connect drain hose (H3) to service valve (V1).
5. Pour 4 gallons of undiluted virgin, food grade,
white vinegar into pail.
6. Place the drain hose (H3) and the hose (H2) to
the pump inlet into the cleaning solution.
7. Open both service valves (V1 and V2) on the hot
water and cold water lines.
8. Operate the pump and allow the cleaning solution
to circulate through the water heater for 1 hour at
a rate of 4 gallons per minute (15.1 liters per
minute).
9. Turn off the pump.
10. Rinse the cleaning solution from the water heater
as follows:
a. Remove the free end of the drain hose (H3)
from the pail.
b. Close service valve, (V2), and open shutoff
valve, (V4). Do not open shutoff valve, (V3).
c. Allow water to flow through the water heater for
5 minutes
d. Close service valve, (V1), and open shutoff
valve, (V3).
11. Disconnect all hoses.
12. With (V4) closed, remove the in-line filter at the
cold water inlet and clean out any residue. Place
filter back into unit and open (V4).
13. Restore electrical power to the water heater.
KEY
3/4" Ball Valve
3/4" Union
Check Valve
Pressure Relief Valve
Water Heater
V1
S
Rinnai
n
I
F
V2
Pressure Regulator
Circulating Pump
Boiler Drain Valve
Solenoid Valve
n
i
e
l
e
t
r
l
i
CLEAN THERMISTORS
Remove and clean thermistors
H3
V4
V3
with a soft cloth or sponge after
removing O-rings.
W
H
o
t
a
e
t
r
n
i
L
e
W
C
o
a
t
L
n
i
G
a
d
l
e
r
e
s
S
u
p
p
y
l
H2
Cleaning solution is 4 gallons of
undiluted virgin, food grade,
white vinegar.
Circulating Pump
VB Series Indoor LS Manual 15
H1
Installation Instructions
Only properly trained and qualified installers
should install this appliance. The warranty may
be voided due to improper installation or
installation by a non-qualified installer.
Rinnai highly recommends all installers attend a
product knowledge class.
For information on a Rinnai Training Course or
for questions on installation call 1-800-621-
9419.
RL75i .................. REU-VB2528FFUD-US
RL94i .................. REU-VB2735FFUD-US
R98LSi ................ REU-VA3237FFU-US
R98LSi-ASME .... REU-VA3237FFU-ASME
The VB series (RL75i, and RL94i) are certified for installation in
manufactured (mobile) homes.
General Instructions
WARNING
Do not use substitute materials.
Use only parts certified with the appliance.
• This appliance must be installed by a state qualified
or licensed contractor. It is the responsibility of the
person having the water heater installed to ensure
the installing contractor has proper licenses and
permits for installing water heaters in your location.
Rinnai highly recommends that installers attend a
product knowledge class to ensure customer
satisfaction and warranty coverage. Failure to
comply with state and local codes pertaining to
water heater installations may void the warranty.
• This appliance is not to be installed outdoors.
• A qualified installer or service technician should
install the appliance, inspect it, and leak test it
before use.
• 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. If
installed in a manufactured home, the installation
must conform with the Manufactured Home
Construction 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 National 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 testing of that system at
test pressures in excess of 1/2 psi (3.5 kPa) (13.84
in W.C.).
• The appliance must be isolated from the gas supply
piping system by closing its individual manual
shutoff valve during any pressure testing 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.).
• Follow the installation instructions and those in Care
and Maintenance for adequate combustion and
ventilation air.
• The appliance should be located in an area where
water leakage of the unit or connections will not
result in damage to the area adjacent to the
appliance or to lower floors of the structure. When
such locations cannot be avoided, it is
recommended that a suitable drain pan, adequately
drained, be installed under the appliance. The pan
must not restrict combustion air flow.
• The flow of combustion and ventilation air shall not
be obstructed. Combustion air shall not be supplied
from occupied spaces.
• This appliance is not suitable for use in an
application such as a pool or spa heater that uses
chemically treated water . (This appliance is
suitable for filling large or whirlpool bath tubs with
potable water.)
• 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.
• Should overheating occur or the gas supply fail to
shut off, turn off the manual gas control valve to the
appliance.
• 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.
• For gas type conversion, contact Rinnai.
16 VB Series Indoor LS Manual
Clearances from Appliance
Top of
Heater
Back of
Heater
Front of
Heater
Sides of
Heater
Ground/
Bottom
Vent
to Combustibles
RL75i
RL94i
6 inches **
(152 mm)
0 (zero) 0 (zero) 0 (zero) 0 (zero)
6 inches
(152 mm)
2 inches
(51 mm)
12 inches
(305 mm)
0 (zero) 4 inches * 0 (zero) 0 (zero)
R98LSi
12 inches
(305 mm)
6 inches
(152 mm)
2 inches
(51 mm)
12 inches
(305 mm)
2 inches **
(51 mm)
6 inches
(152 mm)
1/2 inch
(13 mm)
12 inches
(305 mm)
to Non-
Combustibles
RL75i
RL94i
R98LSi
2 inches
(51 mm)
6 inches
(152 mm)
1/2 inch
(13 mm)
2 inches
(51 mm)
to top
to side
to front
to ground/bottom
* 4 inches (102 mm) for enclosed area; 1 inch (26 mm) for unenclosed area.
** 0 inches from vent components and condensate drain line.
The clearance for servicing is 24 inches in front of the water heater.
For closet installation: clearance is 6 inches (152 mm) from the front.
Attachment of the Water Heater
1. Identify the installation location and confirm that
the installation will meet all required clearances.
2. Securely attach the water heater to the wall using
any of the holes in the wall installation brackets
which are at the top and bottom of the water
heater. Ensure that the attachment strength is
sufficient to support the weight. Refer to the
weight of the water heater in the Specifications
section.
NOTE: Rinnai water heaters should be installed in an
upright position. Do not install upside down or on its
side.
wall installation
brackets
VB Series Indoor LS Manual 17
Electrical Connection
The water heater requires 120 VAC, 60 Hz power from a properly grounded circuit.
If using the 6 foot long power cord, plug it into a standard 3 prong 120 VAC, 60 Hz properly grounded wall outlet.
The wiring diagram is located on the Technical Sheet attached to the inside of the front cover.
The water heater must be electrically grounded in accordance with local codes, or in the absence of local codes
with the National Electrical Code, ANSI/NFPA 70 and/or the CSA C22.1, Canadian Electrical Code.
Error Indication or Air Handler Control Switch (RL75i, and RL94i only)
When using the Rinnai water heater with an Error Indication Switch, switch No. 4 in the bank of 8 switches should
be in the off position. This is the default position.
To connect the water heater to the Rinnai Air Handler, the Control Switch is necessary to function as the electrical
connection. When the Control Switch is functioning as the electrical connection between the water heater and air
handler, switch No. 4 in the bank of 8 switches should be in the on position.
The Error Indication Switch and the Rinnai Air Handler Control Switch are optional products available from Rinnai.
Installation instructions are included with these products.
Gas Piping
General Instructions
• A manual gas control valve must be placed in the
gas supply line to the Rinnai water heater. A union
can be used on the connection above the shut off
valve for the future servicing or disconnection of the
unit.
• Check the type of gas and the gas inlet pressure
before connecting the Rinnai water heater. If the
Rinnai 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 location provided by the gas
company. Supplied gas pressure must be within the
limits shown in the Specifications section.
• Before placing the appliance in operation all joints
including the heater must be checked for gas
tightness by means of leak detector solution, soap
and water, or an equivalent nonflammable solution,
as applicable. (Since some leak test solutions,
including soap and water, may cause corrosion or
stress cracking, the piping shall be rinsed with water
after testing, unless it has been determined that the
leak test solution is non-corrosive.)
• Always use approved connectors to connect the unit
to the gas line. Always purge the gas line of any
debris before connection to the water heater.
• The gas supply line shall be gas tight, sized, and so
installed as to provide a supply of gas sufficient to
meet the maximum demand of the heater and all
other gas consuming appliances at the location
without loss of pressure.
• Any compound used on the threaded joint of the gas
piping shall be a type which resists the action of
liquefied petroleum gas (propane / LPG).
• Refer to an approved pipe sizing chart if in doubt
about the size of the gas line.
18 VB Series Indoor LS Manual
Gas Piping
Pipe Sizing Procedure - Example
The gas supply must be capable of handling the entire gas load at the location. 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 National Fuel Gas Code, NFPA 54. For Canadian gas pipe sizing, refer to the Natural
Gas and Propane Installation Code CAN/CSA B149.1. The below information 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 heating value of the gas (available from the local gas company). The gas input needs to include all gas
products at the location and the maximum BTU usage at full load when all gas products are in use.
Gas Input of all gas products (BTU / HR)
Cubic Feet per Hour (CFH) =
Heating Value of Gas (BTU / FT 3 )
2. Use the table for your gas type and pipe type to find 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 heating value of natural gas for your location is 1000 BTU/FT
199,000 BTU/HR. Additional appliances at the location require 65,000 BTU/hr. Therefore the cubic
feet per hour = (199,000 + 65,000) / 1000 = 264 FT
pipe size is capable of supplying 264 FT
3
/HR of natural gas.
3
/HR. If the pipe length is 10 feet then the 3/4 inch
3
. The gas input of the RL94i is
Pipe Sizing Table - Natural Gas
Schedule 40 Metallic Pipe
Inlet Pressure: less than 2 psi (55 inches W.C.)
Pressure Drop: 0.3 inches W.C.
Specific Gravity: 0.60
Capacity in cubic feet per hour
Length
10
20
30
40
50
60
70
80
90
3/4 1 1 1/4 1 1/2
273 514 1060 1580
188 353 726 1090
151 284 583 873
129 243 499 747
114 215 442 662
104 195 400 600
95 179 368 552
89 167 343 514
83 157 322 482
Pipe Size (inches)
Pipe Sizing Table - Propane Gas
Schedule 40 Metallic Pipe
Inlet Pressure: 11.0 inches W.C.
Pressure Drop: 0.5 inches W.C.
Specific Gravity: 1.50
Capacity in Thousands of BTU per Hour
Length
10
20
30
40
50
60
80
100
125
1/2 3/4 1 1 1/4
291 608 1150 2350
200 418 787 1620
160 336 632 1300
137 287 541 1110
122 255 480 985
110 231 434 892
101 212 400 821
94 197 372 763
89 185 349 716
Pipe Size (inches)
100
125
150
175
200
VB Series Indoor LS Manual 19
79 148 304 455
70 131 269 403
63 119 244 366
58 109 224 336
54 102 209 313
150
175
200
84 175 330 677
74 155 292 600
67 140 265 543
Water Piping
Isolation Valves and Pressure Relief Valve (RL75i and RL94i)
The isolation valves provide the ability to isolate the
water heater from the structure’s plumbing and allow
quick access to flush the heat exchanger. Check with
local codes to determine if a pressure and temperature
relief valve is required. The included valves meet
American National Standard (ANSI Z21.10.3) /
Canadian Standard (CSA 4.3) and are ANSI/NSF 61
approved for potable water.
A
C
D
Isolation Valve (Cold)
Isolation Valve (Hot)
Pressure Relief Valve (PRV)
Isolation Valves Installation Instructions:
1. Wrap the ends of the threaded water inlet & 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 Teflon® tape.
2. Screw the pressure relief valve into the 3/4”
threads opposite the wing handle on the HOT
water service valve. (RED drain handle) (see
Pressure Relief Valve Section for proper
installation 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 is positioned such
that the raised metal edge of the valve is inside
the washer.
4. Align the direction of the HOT water drain to the
desired position.
5. Tighten the union assembly to the HOT water
valve using approximately 15 foot lbs of torque.
6. Repeat steps 3-5 for the COLD water valve.
(BLUE drain handle) for connection 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 valve lever handles are in
the closed position (perpendicular to the drain
portion of the body).
107000081
107000083
107000085
B
A Pressure Relief Valve (PRV)
B PRV Discharge Outlet
C Hot Ball Valve Drain Handle
D Cold Ball Valve Drain Handle
Pressure Relief Valve Installation Instructions:
The PRV must be connected by the threaded
connection opposite the wing handle on the hot water
valve (designated by the RED drain handle) or the
threaded connection on the side of the relocation
fitting above the hot water valve. Installation must
maintain a ¾” port size with no shut off valve or line
restriction 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 180º Fahrenheit and can be no more than 30
feet in length and contain no more than 4 elbows or
bends. 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 precautions with regard to the discharge of
potentially scalding hot water under pressure. Ensure
discharge has a place to flow. Contact with your body
or other property may cause damage or harm.
Please note that only the PRV in this package is
certified by CSA International as an approved item.
20 VB Series Indoor LS Manual
Piping Requirements
• A manual water control valve must be placed in the
water inlet connection to the Rinnai 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 disconnection of the unit.
• 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 Rinnai water heater.
Pressure Relief Valve Requirements
• An approved pressure relief valve is required by the
American National Standard (ANSI Z21.10.3) /
Canadian Standard (CSA 4.3) for all water heating
systems, and shall be accessible for servicing.
• The relief valve must comply with the standard for
Relief Valves and Automatic Gas Shutoff 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 to
prevent exposure or possible burn hazards to
humans or other plant or animal life. Follow local
codes. Water discharged from the relief valve could
cause severe burns instantly, scalds, or death.
• The pressure relief valve must be manually
operated once a year to check for correct operation.
• Toxic chemicals such as those used for boiler water
treatment are not to be introduced to the potable
water used for space heating.
• 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
heating appliance.
• Ensure that the water filter on the Rinnai water
heater is clean and installed.
• The relief valve should be added to the hot water
outlet line and near the hot water outlet according to
the manufacturer’s instructions. DO NOT place any
other type valve or shut off device between the relief
valve and the water heater.
• Do not plug the relief valve and do not install any
reducing fittings or other restrictions in the relief line.
The relief line should allow for complete drainage of
the valve and the line.
• 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 situation.
Do not plug the relief valve.
• Neither Rinnai nor the American National Standard
(ANSI Z21.10.3) / Canadian Standard (CSA 4.3)
requires a combination temperature and pressure
relief valve for this appliance. However, local codes
may require a combination temperature and
pressure relief valve.
Freeze Protection
The freeze protection features include electrical
heating elements. Freeze protection may be disabled
if electricity is not supplied, or if there is an error
preventing the water heater from functioning. Loss of
freeze protection may result in water damage from a
burst heat exchanger or water lines.
The installation of auto drain down solenoid valves is
optional. However, Rinnai strongly recommends that
these valves be installed to prevent damage from
freezing in case the normal freeze protection should
become disabled. Any product damage due to
freezing will not be covered by the warranty.
In addition, 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 an error code.
VB Series Indoor LS Manual 21
The solenoid valves and surge protector with terminals
are available for purchase at Rinnai.
The freeze protection features will not prevent the
external piping from freezing. Rinnai recommends
heat tracing and insulating hot and cold water pipes
connecting units. Pipe cover enclosures may be
packed with insulation for added freeze protection.
With electrical power supplied, Rinnai water heaters
will not freeze when the outside air temperature is as
cold as –22ºF (-30ºC) for indoor models or is as cold
as –4ºF (-20ºC) for outdoor models, when protected
from direct wind exposure. Because of the “wind-chill”
effect, any wind or circulation of the air on the unit will
reduce its ability to freeze protect.
Freeze Protection
Manual draining of the water heater
WARNING
If the water heater is not going to be used during a period of possible freezing weather, it is recommended that the
water inside the water heater be drained.
To manually drain the water:
1. Shut off cold water supply and gas supply.
2. Turn off the temperature controller.
3. Disconnect the power to the water heater.
4. Open hot water drain plug at the hot water outlet.
5. Remove water filter to drain the cold water.
If an isolation kit is installed, remove the drain caps on
both isolation valves and open both valves above the
caps (blue and red valve handles).
To resume normal operation:
1. Confirm that all water drain plugs are removed, that
the gas supply is turned off, and that all taps are
closed.
2. Screw in the hot water drain plug.
3. Screw in the water filter in the cold water inlet.
If the isolation kit was used to drain the unit, replace the drain caps
and close both isolation valves (blue and red valve handles).
To avoid burns, wait until the equipment cools down before draining the water. The
water in the appliance will remain hot after it is turned off.
Hot water
outlet
Hot water
drain plug *
Cold water
inlet
Water
filter
4. Open the cold water supply.
5. Open a tap and confirm that water flows, and then close.
6. Turn on the power.
7. After confirming that the temperature controller is off, turn on
the gas supply.
8. Turn on the temperature controller.
* Use a wrench or other
tool to unscrew the hot
water drain plug.
Running a low volume of water through the water heater to prevent freezing
If the temperature exceeds the ability of the water heater to freeze
protect itself, or if power is lost, the following steps may prevent the
water heater and external piping from freezing. (Units connected with
MSA or EZConnect should be drained to prevent freezing if not in use.)
1. Turn the water heater off.
2. Close the gas supply valve.
3. Reduce the flow to about 0.1 gal/min or to where the stream is about
0.2 inches thick.
ON!
HOT
COLD
0.1 gal/min or
about 0.2 inch
thick
When the water heater or external piping has frozen
1. Do not operate the water heater if it or the external piping is frozen.
2. Close the gas and water valves and turn off the power.
3. Wait until the water thaws. Check by opening the water supply valve.
4. Check the water heater and the piping for leaks.
22 VB Series Indoor LS Manual
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