Rinnai REU-16 User manual

2
The Rinnai Infinity 16i water
heater, when correctly installed,
complies with the requirements
of the United Kingdom Water
Regulations / Byelaws
(Scotland). These Products can
be found listed in the Water Fit-
tings and Materials Directory.
The Rinnai Infinity 16i water heater
is CE Marked as allowed by
Technigas.
Certificate number E0940/5399
ID number 0461BQ0836
Date of Issue 23 Dec 2005
Quality System Standard
ISO 9001 - 1994
The Design, Development, and Manufacture of Gas Water Heating Appliances
done under Rinnai’s Quality Management System is certified under the Quality
Management System Standard ISO 9001.
Registration Number JQ0003D
Registered since: February 1994
Certified by Japan Gas Appliances Inspection Association.

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This appliance may only be serviced or repaired by someone certified competent to
do so. At the time of printing the only people deemed competent to install this
appliance are those that are CORGI registered for this type of appliance in this type
of location who have a current ACS certificate.
1. Gas safety (Installation & Use) regulations 1998 are the ‘Rules in force’. In your own
interest and that of safety, it is law that all gas appliances are installed and serviced by
competent persons in accordance with the above regulations. Failure to install appliances
correctly could lead to prosecution. Other persons should NOT attempt to install this
equipment.
2. Installation must be in accordance with the current issue of the following:
Building Regulations issued by the Department of the Environment
Building Standards (Scotland) Regulations.
I.E.E. Wiring regulations for electrical installations.
Gas safety (Installation and Use) Regulations current issue.
BS 5546
BS 5440
BS 6891
BS 5482
BS 6700
BS 6644
Institute of Gas Engineers Publications
Local byelaws
Water regulations
Health and safety at work etc. Act 1974
IGE/UP/10 Part1 Edition 2.
Building Regulation J
Please be sure that you are fully aware of your obligations and responsibilities under
these regulations.
UK INSTRUCTIONS
Such other specifications
and regulations that may
supersede or complement
the above documents.

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Contents………………………………………………………………..…………………4
Glossary of Terms and Symbols.............................................................................5
Introduction.............................................................................................................6
Specification of 16i..................................................................................................7
Sensors and Safety Devices..................................................................................8
Combustion Specifications.....................................................................................8
Dimensions.............................................................................................................9
Schematic Diagram..............................................................................................10
Structure Diagram.................................................................................................11
Main Components.................................................................................................12
Water Flow............................................................................................................14
Water Pressure vs. Flow.......................................................................................16
Gas Conversion Procedure..................................................................................17
Testing..................................................................................................................19
Gas Pressure Setting............................................................................................20
Dip Switch Setting.................................................................................................22
Troubleshooting the Infinity 16i.............................................................................23
Remotes...............................................................................................................24
Operational Flow Chart.........................................................................................25
Time Charts..…………………………………………………………………......…….26
Error Codes.........................…………………………………………………….....….27
Diagnostic Checks………............……………………………………………............29
Fault Finding Chart…………………………...........................………………………39
Wiring Diagram..……………………………………............………………...............46
Diagnostic Points….………………………………………………......………..……...47
Servicing Procedure…….……………………………………………………………..48
Dismantling for Service……………………………………………………………......49
Exploded Diagram................................................................................................56
Parts List...............................................................................................................61
Letter of Compliance……………………………………………………....….............65
CE Certificate……………………………..……………………………………............66
Service Contact……………………………….…………………………….........……67
Contents

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Glossary of Terms and Symbols

6
Introduction
The Rinnai Infinity hot water units represents the latest
technology in continuous flow, temperature controlled hot water.
Features
• The Rinnai Infinity 16i will NEVER RUN OUT of hot water. As long as electricity,
water, and gas supplies are connected, hot water is available when hot water taps
are open.
• Built into the main micro-processor is the facility to LIMIT THE MAXIMUM TEM-
PERATURE of the hot water supplied. The water temperature may be set to vari-
ous temperatures. This is particularly useful when the hot water unit is installed
where young children or the infirm may be using the hot water. If required, the tem-
perature can be changed via the control pad on the front of the unit or with a local-
ised controller. For further information, please contact Rinnai.
• Rinnai Infinity internal units are powered flue appliances. This makes them COM-
PACT, saving both floor and wall space.
• The temperature of outgoing hot water is CONSTANTLY MONITORED by a
BUILT-IN SENSOR. If the temperature of the outgoing hot water rises to more than
55°C the burner is shut OFF and only turned ON again when the temperature falls
to below the selected temperature.
• The burner lights automatically when the hot water tap is opened, and extinguishes
when the tap is closed. IGNITION IS ELECTRONIC, so there is no pilot light. When
the hot water tap is off, no gas is used.
• The 16i has a built in controller on the front of the unit for easy control. Two addi-
tional external temperature controllers can be mounted remotely from the heater.
This offers the following additional features:
Localised temperature setting.
Diagnostic message.
Error Codes.
• Temperatures selected at the controllers are retained in the SYSTEM MEMORY
when the controller gives up priority or the system is turned off. Temperatures over
550C will revert to 550C when power and/or priority is regained.
• Operating NOISE LEVEL IS VERY LOW.
• ERROR MESSAGES ARE DISPLAYED on the Temperature Controllers, assisting
with service.
• FROST PROTECTION device built in as standard.

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Specification of 16i
Type of Appliance Temp Controlled Continuous Flow Gas Water Heater
Operation With / Without remotes (Kitchen, Bathroom, etc.)
Flue System Room Sealed, Forced Draught Flue
Installation Internally Mounted only
Available Temps 37C - 48C (1 deg Increments) 50, 55, 60
Width 370 mm
Dimensions Height 675 mm
Depth 130 + 45 mm
Weight 15 kg
Gas 1/2 in bsp
Connections Cold Water 1/2 in bsp
Hot Water 1/2 in bsp
Ignition System Direct Electronic Ignition
Noise Level 49 dB(A)
Nox 55 ppm Max
Water Temp Control Simulation feed forward and feedback
Flame Failure Flame Rod
Boil Dry Water Flow Sensor
Remaining Flame 97 C bimetal switch
Safety Devices Over current Glass Fuse 3 Amp
Over pressure Pressure Relief Valve 15 bar open, 12 bar close
Combustion Fan Integrated circuit system
Fusible Link 150 C Thermal Fuse
Over temperature Lockout Thermistor 95 C
Heater Mounted MC-45-SR-EU
Remote Controls Kitchen BC-45-SR-EU or BSC-45-SR-EU
Bathroom BC-45-SR-EU or BSC-45-SR-EU
Remote Cable Two core sheathed (double insulated) flex with min 0.55 mm2
G20 Nat Gas Press Low 1.8 mbar
G20 Nat Gas Press High 9.0 mbar
G25 Nat Gas Press Low 1.8 mbar
G25 Nat Gas Press High 9.0 mbar
G30 LPG (Butane) Press Low 2.2 mbar
G30 LPG (Butane) Press High 11.4 mbar
G31 LPG (Propane) Press Low 2.2 mbar
G31 LPG Propane) Press High 14.2 mbar
Gas Consumption Low (Gross)
G20 Nat Gas 4.7 kW 0.4 m3/hr
G25 Nat Gas 4.0 kW 0.4 m3/hr
G30 LPG (Butane) 4.9 kW 0.35 kg/hr
G31 LPG (Propane) 4.9 kW 0.35 kg/hr
Gas Consumption High (Gross)
G20 Nat Gas 34.9 kW 3.26 m3/hr
G25 Nat Gas 29.6 kW 3.26 m3/hr
G30 LPG (Butane) 36.8 kW 2.6 kg/hr
G31 LPG (Propane) 36.5 kW 2.6 kg/hr
Max Flow raised 25C 15.2 L/min
Min Operation Flow 2.4* L/min
Water Pressure Nom. 1.1 - 7.0 bar
Power Supply 230 V / 50 Hz
Electric Consumption 68 Watts

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• Heat Exchanger Thermistor: Measures hot water temperature at heat exchanger outlet. If
water temperature reaches a predetermined limit, gas supply is stopped.
• Hot Water Delivery Thermistor: Measures hot water temperature at the outlet valve (i.e. the
‘mixed’ temperature).
• Flame Rod: Monitors combustion characteristics inside the combustion chamber. If the flame
fails, gas supply is stopped.
• Overheat Switch: Situated on the heat exchanger, gas supply is stopped when water
temperature reaches 97ºC for a number of seconds.
• Fusible Link: Situated on the heat exchanger, electrical power supply is stopped if the
temperature exceeds 150ºC.
• Water Pressure Relief Valve: Safeguards the water circuit against excessive inlet pressure.
Opens at 15 bar, closes at 12 bar.
• Electrical Fuse: (3A glass fuse) prevents against over-current. Surge Protector: prevents
against over-current.
• Boil Dry Prevention: If water flow sensor detects no flow, gas supply is stopped.
• Combustion Fan Speed Sensor: In case of combustion fan defect (no rotation of fan) gas
supply is stopped.
• Temperature Cutout: If the delivered hot water temperature rises above the required delivery
temperature for a number of seconds, the gas supply is stopped.
Sensors and Safety Devices
Combustion Specifications
The secondary gas pressure is set with the cover off the unit and a manometer measuring
the pressure from the gas valve (regulator) test point
Gas Type
Injector
size
(mm)
Primary
Pressure (mbar)
Secondary Pressure
(mbar)
Gas Input [Gross]
(kW)
Low High Low High
Natural Gas
(G20) 1.3 20 1.8 9.0 4.7 34.9
Propane (G31) 37 2.2 14.2 4.9 36.5
Damper
Nat Gas
LPG

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Dimensions

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HOT WATER SUPPLY OPERATION
Ignition
Press ON/OFF Button of Optional Remote Control to turn on unit . The remote control display
and priority LED will light up. When a hot water tap is opened the Water Flow Sensor revolves
and sends a pulse signal to the Printed Circuit Board (PCB.) When the PCB detects a water
flow over 2.4 L/min it compares the temperature at the Hot Water Thermistor to the set point
and begins the ignition process; the Combustion Fan starts first. Once the chamber has been
purged and the air proving has made the Electrode begins to spark to Earth. The Main
Solenoid Valve and Changeover Solenoid Valve 2 are opened and the Burner lights. The
Flame Rod will ensure proper burning before Changeover Solenoid Valve 1 will open.
Temperature Setting
With the Temperature Control Buttons on the controller the outlet temperature can be set from
37 - 60℃. When the temperature set point is above 50℃the High Temperature Indicator
glows. Temperature can not be set above 48℃while hot water is in use (flowing.) The unit will
continually monitor the outgoing temperature and can fully modulate the performance with the
Modulating Valve and the Servo Control.
Standby
When the hot water tap is closed the PCB no longer receives a pulse signal from the Water Flow
Sensor. The PCB shuts the Main Solenoid Valve and Change-over Solenoid Valves and the
Burner extinguishes. The combustion fan will run on to post purge the chamber.
Schematic Diagram

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Structure Diagram

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Main Components
1. Gas Control Unit
1.1 Modulating Valve
This device is used by the PCB to adjust the volume of gas to the burner in proportion to the
volumetric flow rate of water in order to maintain a supply of constant temperature hot water
amid changes in water flow rates and incoming temperatures.
1.2 Change-over Solenoid Valves
Additional solenoid valves are included to section the burner and stage the control in 3
steps. This gives the Burner more steady combustion at the required capacity and allows
the water heater to operate at very low flow rates and temperature rises.
2. Flame Rod
Monitors combustion characteristics inside the combustion chamber. If the flame fails, gas
supply is stopped. Works through rectification of the combustion flame. An AC current is
supplied to the flame rod. Electrons can only pass from the rod to the burner, and never
from the burner to the rod, so the resultant DC current is used to prove combustion. When
the DC current is present the burner has normal combustion, if the DC current is not present
(or an AC current is present) the unit shuts the solenoid valve.

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3. Thermal Fuse
The thermal fuse is an electric link which must be intact for the unit to operate. If the
thermal fuse reaches a set temperature it will melt and the unit will shut down. The
thermal fuse must be replaced if it melts. It is to protect against over heating and heat
exchanger splits where water may leak out and be superheated into steam.
4. Overheat Safety (Bi-metal Switch)
This Bi-metal Switch is fixed at the bend of the Heat Exchanger hot water outlet. If the
temperature outlet from the heat exchanger reaches 970C the bi metal switch will open
and the solenoid valve circuit is broken. This will cease combustion in case of overheat.
5. Combustion Fan
The combustion fan supplies primary air into the wing burners and secondary air up
through the Bunsen style burners. The fan is DC low voltage and the speed is controlled
by the PCB depending on the hot water flow and temperature. The fan speed is
compared to the current required to attain that speed for air proving. If the fan current is
over or under the parameters for the given speed the unit will shut down on air proving.
6. Water Volume Servo with Water Flow Sensor
6.1 Water Flow Sensor
Water flow sensing is done with a small turbine that spins when water travels through it
in the correct direction. Each of the four fins on the turbine has a small magnet on it.
Outside of the valve there is a magnetic sensor that detects the speed that the turbine is
revolving. The revolution speed is input to the PCB which relates this speed to the water
flow volume and determines whether it is sufficient for ignition.
6.2 Water Volume Flow Servo
The water volume is adjusted by opening and closing the water flow valve with the servo
motor. This will limit the maximum hot water flow to 20 L/min, and will limit the water
flow further when the burner is at high fire to ensure the temperature setpoint it met.
Main Components

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Water Flow
The figures on the following page show the available water flow rates for different outlet
temperatures based on a range of inlet temperatures. Regardless of the output capacity the maximum
flow rate is limited to 20 litres/minute.
Water Flows can also be calculated by the following formula:
M = 60 x ( Q / C x T )
Where M = Water flow rate in litres/minute. If M is greater than 20, the water must be mixed down at
the point of use as the maximum flow rate of the unit is limited to 20.
Q = Heat energy output in kW = 28 kW for the Infinity 16i (the heat input to the water)
C = Specific heat of water = 4.2KJ/Kg C. Constant for this calculation.
T = Temperature rise required ( C)
Example:
What is the flow rate available with an incoming water temperature of 10 C and a required
temperature of 20 C ?
T = 20 - 10 = 10 C
Q = 28
C = 4.2
M = 60 x ( 28 / (4.2 x 10) ) = 40 l/min. Since 40 is greater than 20 this flow rate must be mixed at the
outlet.
How to read the charts on the following page.
The vertical axis indicates the selected temperature on the remote control and the horizontal axis
indicates the flow of water in litres/ minute. Remote control range is between 370C and 600C under
normal conditions (temperatures up to 750C may be available if set on the dip switches.) The
temperature rise is the difference between the Incoming Water Temp and the Hot Water Outlet Temp
as selected on the controller.
Select the appropriate chart based on incoming water temperature. Draw a horizontal line across the
graph from the selected temperature at the controller until it intersects the curve. From this point
draw a vertical line until it intersects the axis. The value at this point of the axis is the maximum flow
rate available. If the value is over 20 litres/minute a higher temperature will have to be used on the
controller and the water temperature mixed down at the outlet.

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Incoming Water Temp 5C
0
10
20
30
40
50
60
70
80
0 5 10 15
Hot Water Flowrate L/min
Hot Water Outlet Temp C
I
2.4 L/min
min Flow
Incoming Water Temp 10C
0
10
20
30
40
50
60
70
80
0 5 10 15 20
Hot Water Flowrate L/min
Hot Water Outlet Temp C
I
2.4 L/min
min Flow
Incoming Water Temp 20C
0
10
20
30
40
50
60
70
80
0 5 10 15 20 25
Hot Water Flowrate L/min
Hot Water Outlet Temp C
I
2.4 L/min
min Flow
I
20 L/min
max Flow
Water Flow

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The water pressure vs. flow characteristics are as follows:
Regardless of how high the incoming water pressure is it is not possible to obtain more than
20 L/min from the Rinnai Infinity 16i. In order to have this much flow the temperature rise
must be low enough that the unit has the capacity to satisfy the temperature setpoint for this
flow rate. For higher temperature rises the flow rate will be lower, regardless of the incoming
pressure.
The water heater has a water flow regulator that will throttle the flow rate back to make sure
that the unit only supplies water at the required temperature. If demand exceeds the
capacity of the unit, the unit will limit the water flow so the temperature does not alter.
The water heater’s heat exchanger has a much higher pressure drop at high flow rates then
at low flow rates. For low pressure installations use higher temperature set points.
In order to achieve maximum flow rate 1.5 bar pressure is required. The unit will operate on
lower pressures. It is advisable to have at least 1.1 bar pressure.
0
5
10
15
20
25
012345678
WATER PRESSURE（bar）
WATER VOLUME（L/min）
Water Pressure vs. Flow

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Gas Conversion Procedure

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Gas Conversion Procedure

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Testing
1. Purge gas, hot water and cold water supply lines before making the final connection
of the water heater. Swarf in either the gas or water supplies may cause damage.
2. Turn on gas and cold water supplies.
3. Test for water leaks and gas escapes near the unit.
4. Isolate gas and electric supply. Remove test point screw located on the inlet gas
pipework below the heater and attach pressure gauge.
5. Turn the power on at the switch and turn on gas. Warning: There are 230V AC live
supplies inside the heater.
6. If remote controllers are fitted, turn the controller on, select the maximum delivery
temperature and open ALL available hot water outlets. If remote controllers are not
fitted, simply open all available hot water outlets. (CAUTION: Ensure building
occupants do not have access to hot water outlets during this procedure).
7. The gas pressure check must be carried out with all other appliances on the same
main operating at maximum capacity to ensure that there is sufficient gas pressure.
8. With all appliances on the same main operating at high fire check the pressure at the
test point on the inlet to the gas valve. The pressure must be within the local defined
limits for the type of gas that is being used. If the pressure is lower, the gas supply is
inadequate and the water heater will not operate to specification. Check gas meter,
regulator and pipework for correct operation/sizing and rectify as required. Note that
the gas regulator on the appliance is electronically controlled and factory pre-set.
Under normal circumstances it does not need adjustment during installation.
UK the gas pressure must be at least 20 mbar for G20 Natural Gas as used in
UK. For G31 Propane as used in the UK the pressure must be at least 34.5
mbar.
9. Close hot water outlets.
10.Inspect and clean the strainer and the filter located on the cold water inlet pipe. This
procedure may need to be repeated to ensure the strainer remains clear.
11.If temperature controllers are fitted, it is necessary to test their operation through the
complete range of functions.
12.Confirm the hot water delivery temperature using a thermometer. If controllers are
fitted, compare the measured value to the set point.
13.After testing is completed, explain to the user the functions and operation of the
water heater and temperature controllers.

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Gas Pressure Setting
The working gas pressure on the water heater is electronically controlled and factory set.
Under normal circumstances it does not require adjustment during installation. Perform
this procedure only if the unit is not operating correctly and all other possible causes for
incorrect operation have been eliminated. Contact Rinnai before attempting
to alter the gas pressure. Failure to do so could void the warranty.
1. Turn 'OFF' the gas supply.
2. Turn 'OFF' 230V power supply.
3. Remove the front cover from the appliance.
4. Check gas type dip switches no.1 and no. 2
are in the correct position for the type of gas
(Nat. or LPG)* you are using. See Fig. 1
On is in the right hand position, Off is in the
left hand position.
5. Attach pressure gauge to burner test point. (Fig. 2)
6. Turn 'ON' the gas supply.
7. Turn 'ON' 230V power supply.
8. If remote controllers are fitted, turn the unit 'ON' at the
controller and select a maximum delivery temperature.
9. Open a hot water tap fully. (CAUTION: Ensure
building occupants do not have access to hot water
outlets during this procedure.) Wait for the unit to
light.
10.Set the Rinnai Infinity to 'Forced Low' combustion by
setting No. 7 dipswitch to 'ON'. (Fig. 3)
off on SW
off on SW
1 -Nat. Gas 1 -LPG
2 -Nat. Gas
2 -LPG
3
3
4
4
5
5
6
6
7
7
8
8
off on SW
1
2
3
4
5
6
7
8
Fig. 3
Fig. 1
Fig. 2
* Note:
Simply changing the position of the dip switches will not convert the unit from
one gas type to the other. The conversion procedure requires a change of
injector manifold. Contact Rinnai or your supplier.