Rinnai ENERGYSAVER RHFE-308FTR User manual

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ENERGYSAVER
RHFE-308FTR
High Efficiency Power Flued Gas Space Heater
SERVICE MANUAL

ISO 9001 Model for Quality Assurance in design/development, production, installation and servicing,
aimed primarily at achieving customer satisfaction by preventing nonconformity at all stages
from design through to servicing.
ISO 9002 Same as ISO 9001 but excluding design.
AS 3498 Authorisation requirements for plumbing products - water heaters and hot-water storage tanks,
aimed at ensuring safe, quality products.
AG 102 Approval requirements for gas water heaters as set by The Australian Gas Association and
Australian Liquefied Petroleum Gas Association Ltd, to ensure proper safety performance and
quality levels are achieved.
Proudly a member of The Australian Gas Association.
All of our products are AGA tested and approved.
Distributed and serviced in Australia under a
Quality System certified as complying with ISO
9002 by Quality Assurance Services.
Rinnai New Zealand has been certified to ISO 9001
Quality Assurance by Telarc.
Certified to Australian Standard 3498 by Quality
Assurance Services. Watermark certification is
awarded to products with suitable fittings
complying with safety and water contamination
standards.
Comparative Energy Consumption tested to The
Australian Gas Association requirements of Australian
Gas Code AG 102. An energy rating of 5 stars refers to
an efficiency of approximately 80%, that is, 80% of gas
consumed is converted to useful heat.

© Copyright Rinnai Australia Pty Ltd
A.C.N. 005 138 769 All rights reserved
Produced by Customer Technical Services
July 1998
No portion or part of this manual may be copied without prior permission from Rinnai Australia.
Rinnai Australia takes no responsibility for the accuracy or otherwise of information contained in
this manual, and reserves the right to make modifications and change specifications without notice.
Failure to comply with these instructions may result in serious personal injury or damage to the appliance.
This manual has been compiled by Rinnai Australia Customer Technical Services. While
many individuals have contributed to this publication, it will be successful only if you - the
reader and customer - find it useful. We would like to extend an invitation to users of this
manual to make contact with us, as your feedback and suggestions are valuable resources
for us to include as improvements. Rinnai are constantly working toward supplying
improved appliances as well as information, and specifications may be subject to alteration
at any time.
SRV308
Issue No1
WARNING
ALL WIRING INSIDE THIS APPLIANCE MAY BE AT 240 VOLTS POTENTIAL
ALL SERVICE WORK MUST BE CARRIED OUT BY AN AUTHORISED PERSON.
DO NOT TEST FOR GAS ESCAPES WITH AN OPEN FLAME

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Table of Contents
Glossary of Terms and Symbols .......................................................................... i
1. Introduction .................................................................................................... 1
2. Dimensions ..................................................................................................... 2
3. Specification .................................................................................................... 3
4. Cut-Away Diagram ........................................................................................ 4
5. Installatio ...................................................................................................... 5
6. Performance Characteristics ......................................................................... 7
7. Schematic Diagram ..................................................................................... 10
8. Control Panel Layout .................................................................................. 11
9. Operating Principles ................................................................................... 12
10. Intelligent Timer [Pre-hea t ...................................................................... 14
11. Safety Devices ........................................................................................... 15
12. Operation Flow Chart .............................................................................. 18
13. Diagnostic Points ....................................................................................... 21
14. Wiring Diagram ........................................................................................ 22
15. Block Diagram ........................................................................................... 23
16. Time Charts ............................................................................................... 24
17. E2 PROM .................................................................................................. 27
18. Error Coded Messag e ............................................................................. 29
19. Fault Finding .............................................................................................. 30
20. Fault Analysis ............................................................................................ 33
21. Electrical Component Analysis ............................................................... 36
22. Testing ........................................................................................................ 40
23. Gas Conversion ......................................................................................... 42
24. Gas Pressure Setting Procedur ............................................................... 43
25. Dismantling for servic ............................................................................. 44
26. Exploded Diagram .................................................................................... 51
27. Parts List ..................................................................................................... 56
Appendix............................................................................................................ 59

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Glossary of Terms and Symbols
This glossary of terms and symbols is provided to assist you in understanding some of the language
used throughout this manual.
dB(A) - sound pressure level in decibels, “A” range
DC - direct current
AC - alternating current
Hz - Hertz
IC - integrated circuit
kcal/h - kilocalorie per hour
kPa - kilopascals
LED - light emitting diode
L/min - Litres per minute
mA - milliamps
MJ/h - megajoule per hour
mm - millimetres
mmH2O - millimetres of water (gauge pressure)
NOX- oxides of nitrogen (NO & NO2)
OHS - overheat switch
PCB - printed circuit board
CPU - central processing unit
POT - potentiometer
rpm - revolutions per minute
SV - solenoid valve
ø - diameter
∆
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POV - modulating valve
TH - thermistor

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1. Introduction
Background
The RHFE-308FTR incorporates an improved modulating control system to provide comfortable heating.
Other features of these appliances are improved safety, operation, installation, and maintenance features.
Characteristics
• Built into the main PCB is the software for connection to a central ON-OFF control.
• Gas flow modulates in 7 steps between High and Low ensuring comfortable and efficient heating.
• Includes a 24 hour digital clock and dual timer, and an economy mode function. This reduces gas con-
sumption without affecting comfort.
• Temperature control is monitored by “fuzzy logic” technology - relevance to each other.
• All operation and temperature control is with user-friendly push buttons.
• Improvements have been made to the rear convex section for clean-cut design.
• If a problem occurs or service is required, an error coded message appears on the digital display to
direct the service technician to the cause of the problem.
• Information about any previous faults is stored in the PCB and can be recalled during servicing.
About the 308FTR
The bodywork is formed from 0.6 mm galvanised steel sheet,which forms a box to which the components,
heat exchangers and blowers are attached. This is then covered by an outer case which is constructed from
0.6 mm galvanised steel sheet, and plastic mouldings.
The combustion chamber is constructed from 1.0 mm hot dip aluminium coated steel sheet, located in the
lower centre of the appliance.
The heat exchanger is composed of two sub-heat exchanger sets. The left hand set, No1 is constructed of
1.0 mm aluminised steel. The right hand set, No2 is constructed of 0.8 mm stainless steel. The inlet of sub-
heat exchanger No1 is connected to the outlet of the combustion chamber, the outlet is connected to sub-
heat exchanger N o2. Sub-heat exchanger No2 consists of 3 “sub” sections, constructed from 0.8 mm
stainless steel. The outlet of sub-heat exchanger No2 is constructed from 0.5 mm stainless steel and
connected to the flue by a concertina stainless steel tube.
The combustion air fan draws combustion air from the outside atmosphere through the flue manifold pipe.
Air is then blown into the combustion chamber via a rubber tube. Combustion products in the combustion
chamber are pushed out into sub-heat exchanger No1, to sub-heat exchanger No2, and then into the 34 mm
flue pipe which is connected through the flue manifold to the outside atmosphere.
The flue system is connected with stainless steel concentric pipe. The inner pipe (34 mm diameter.) is the
combustion gas outlet, and is connected to the outlet of sub-heat exchanger No2. The outer pipe (70 mm
diameter) is the combustion air inlet and is connected to the inlet of the combustion fan air pipe. Various
flue lengths are available.
Ignition is continuous spark in conjunction with an electrically operated solenoid and control is monitored
by the PCB. Gas passes through the R½ 15 (BSP) inlet fitting, then via a flange connection to the solenoid
valves No1, No2, a regulator modulating valve, aluminium injector manifold, before entering the burner.

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2. Dimensions
Note: All dimensions are in millimetres

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3. Specification
Type of appliance Fan forced flued gas space heater
Model RHFE-308FTR
Dimensions Width - 425 mm
Depth - 165 mm (with back spacer 250 mm)
Height - 677 mm
Weight Approx 17 kg
Connections Electrical - AC 240 V 50 Hz / 60 Hz
Gas - R½ 15 BSP male threa
Electrical
Consumption High: 39 W Low: 30 W
Output 10.5 MJ/h
Combustion system Stainless steel bunsen burne
Ignition system Continuous electrical spark, direct to main burner
Operation Finger touch control buttons
Temperature control Electronic thermostat, modulating HI-LOW/OFF
Temperature range LOW (10oC), 16 ~ 26oC (1oC increments), HIGH (continuous)
Warm air outlet Bottom of appliance
Air volume control HI ~ LOW (automatic)/OFF
Timer operation Dual Timer - 24 hour, ON & OFF Timer
Operation - 24 hour
Clock - 24 hour digital display
Temperature control - 26oC limit when using timer program
Indicator Burner ON, child lock, filter, economy, digital display, over-ride, clock
setting, timer setting, timer, temperature display
Operating buttons ON-OFF, up-down, child lock, economy, timer, clock setting, over-ride.
Humidifier tray Capacity - 0.8 Litres
Safety devices Flame failure - flame rod
Over heat - bi-metal switch (130oC, 90oC)
- thermal fuse (216oC)
- thermistor (130~90oC)
Power failure - PCB
Power surge - 3 Amp fuse
Fan delay - micro computer timer (Max 210 secs
Pre-purge - combustion fan, pre-purge timer, spark sensor
Room over heat - automatic cut off at 40oC after 10 mins

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4. Cut-Away Diagram

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5. Installation
NOTE: The information provided here is only a guide. For full details on installation procedures, please
refer to the installation instructions in the customer’s operating instructions.
This heater is not designed to be built in. The flue may be positioned directly under opening
windows, with a minimum clearance of 150 mm.
The flue is not designed to be positioned unde
floors or below the level of the heater. The flue terminal should be positioned away from flammable materials.
Flue fittings must be kept clear of flammabl
materials. In areas subject to heavy snowfall, keep snow clear of flue terminal at all times.

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Recommended minimum clearances and distances from obstructions.

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6. Performance Characteristics
1. Basic Combustion Specification
2. Combustion Fan Speeds (rpm)
Item Specification
Rinnai model number RHFE-308 FTR
Gas typ NG Propane/LPG
Gas consumption MJ/h HI 13 13
LO 55
Injector size (∅mm) 1.30 0.90
Injector quantity 2 2
Regulator pressure (kPa) HI 0.60 1.04
LO 0.12 0.19
Burner marking P P
Combustion method Bunsen burner
Burner type Stainless slit style
Solenoid valve Direct single seated valve type
Modulating solenoid valve Direct single seated valve type
Natural Propane/LPG
Ignition 1710 1560
Re-ignition 1800 1680
Normal - High 3000 3090
Normal - Low 1440 1440

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3. Warm Air Discharge Temperature Distribution
Condition: < High Combustion >
Test gas: Natural
Measured input: 12.55 MJ/h
Nominal input: 13 MJ/h
Room temperature: 25oC(Unit ∆oC)
Condition: < Low Combustion >
Test gas: Natural
Measured input: 5.27 MJ/h
Nominal input: 5 MJ/h
Room temperature: 25oC(Unit ∆oC)
4. Measurement Points
24 24 55 9
45 72 64 18
56 81 83 36
62 66 77 42
68 43 70 45
42 39 57 45
10 17 30 9
23 39 38 13
29 48 42 28
35 44 46 37
37 28 43 34
22 26 31 28

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5. Warm Air Discharge Velocity
Convection Fan rpm HIGH: 740
LOW: 550
Room Temperature: 22oC(Unit: m/sec)
Air Flow: Average air velocity on High: 2.784 m/sec
Average air velocity on Low: 2.10 m/sec
Air flow rate on High: 3.82 m3/min
Air flow rate on Low: 2.89 m3/min
Air flow outlet area: 0.0229 m2
6. Noise Level
Unit: dB(A).
7. Thermal Efficiency
Conditions: Horizontal mushroom flue with unit installed with back spacers.
8. Humidifier Capacity
Note: Evaporation rate varies depending on conditions of use.
Conditions: Standard setting: High combustion
Measurement Method: According to JIS (Japanese Industrial Standard)
1.62
1.46 2.57 1.32 1.70 1.34 1.08 0.84
1.99
1.78 2.57 1.92 2.89 2.15 2.12 1.58
3.20
2.61 3.54 2.53 3.12 2.44 2.51 1.91
3.35
2.66 3.44 2.60 3.14 2.28 2.75 2.08
3.27
2.47 3.37 2.52 3.33 2.62 3.32 2.46
3.13
2.37 2.11 1.23 3.33 2.54 3.42 2.58
High 36.5
Low 31.5
Gas Type Combustion Thermal Efficiency (%)
Natural High 81.3
Low 84.8
Propane High 83.5
Low 88.1
Method Tray Capacity Evaporation
Evaporation 0.8 Litres 0.1 Litres/hour

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7. Schematic Diagram

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8. Control Panel Layout
* Refer to “Appendix” on page 59 for explanation on setting clock and programming timers.

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9. Operating Principles
1. Normal Operation
Push the ON/OFF Button to operate the appliance. The Power ON/Combustion Indicator will glow green.
The combustion fan will run on high until pre-purge is completed.
Pre-purge is completed after approximately 15 seconds, following which, thecombustion fan will decrease
revolutions to enable ignition to occur. After the combustion fan reaches a pre-determined speed,
(depending on gas type) the electrode produces the spark to begin the ignition cycle.
After the spark is sensed as having crossed the spark gap by the PCB, the solenoids (SV1& SV2) as well
as the modulating valve will open and allow gas to flow to the burner.
The flame rod senses the flame on the main burner. After the flame is sensed, the Power ON/Combustion
Indicator changes to red and the spark stops. After an additional 15 seconds the convection fan begins to
operate.
The room temperature is sensed by the temperature thermistor located at the rear of the appliance. The
printed circuit board controls the air/gas ratio to the optimum level according to the selected temperature.
The combustion fan is adjusted in conjunction with the opening degree of the modulating valve. The
convection fan is adjusted in the same manner.
2. Thermostat Control
The selected and room temperatures are displayed on the Time/Temp Display. Time and temperature are
displayed alternately depending whether the heater is running or not. The selected temperature is altered by
pressing the Time/Temperature Adjustment buttons.
3. Turning Off
Simply press the ON/OFF Button. The solenoids, together with the modulating valve will close. The
combustion fan will also stop, and all indicators will go out. After the burner extinguishes, the convection
fan will continue to run for up to 210 seconds, ensuring the appliance is cool.
4. Economy Mode
To engage the economy function press the Economy button while the heater is operational. The Economy
Indicator will glow. Once the selected temperature has been reached, the economy function is designed to
drop this temperature by a total of 2oC over a period of one hour. After 30 minutes the temperature will be
reduced by 1oC. After a further 30 minutes the temperature will be reduced by another 1oC. This does not
result in a loss to the heating effectiveness, and is an energy saving feature. You may press the Economy
button again at any time, to cancel the economy function.
5. Child Lock
To activate the child lock press the Child Lock button. The Lock Indicator will glow.
If the child lock is activated during normal operation, then no functions other than the ON/OFF Button will
be operable until the lock is released.
If the child lock is activated whilst the appliance is OFF, then the complete range of functions will be
locked.

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6. Filter Indicator
When the air filter becomes covered in dust and the temperature inside the appliance rises, the Filter
Indicator will glow.
7. Fuzzy Logic
a. The Purpose of Auto Comfort [Fuzzy Logic]
The main aim of the Auto Comfort function is to heat a room by controlling the flow of thewarm air coming
from the heater. This increases heating efficiency as well as improving control over the flow of warm air
being discharged by the appliance.
In order to achieve comfortable heating, it is preferable to avoid cold drafts or draughts from the appliance.
Also, for increased efficiency it is important to reduce overheating in the room and concentrate heating in
the area where people are most often situated.
Fuzzy Logic is used in order to achieve the following improved heating pattern.
Standard Control Fuzzy Control
'Room temperature' and 'the time elapsed since the start of combustion’ are the basis for fuzzy logic. Th
means of control is the speed of the convection fan and modulation of gas combustion.
b. Fuzzy Logic Summarised
In the case of a conventional fan heater, the convection fan operates normally from the time ofignition, and
a cold draught may accompany the flow of air from the appliance. To solve this problem, fuzzy logic
controls the speed of the convection fan after taking into consideration the room temperature at the time of
ignition. For example, in the case of the room temperature being low, the fan is made to rotate at a low
speed, raising the discharge air temperature. As the room temperature rises, the speed of the convection
fan is gradually increased. In this way it is possible to ensure a comfortable volume of warmed air whilst
decreasing the possibility of cold draughts immediately after ignition.
The fan speed increases proportionally as time passes and the room gradually heats up. This improves the
warm air distribution, assisting in a reduction of stratification throughout the room and resulting in more
effective heating conditions. The PCB then continually monitors the room temperature, and adjusts the fan
speed according to the conditions at the time.
8. Clock and Timer Setting and Operation
Refer to “Appendix” on pa ge59 of this manual.
9. Intelligent Timer [Pre Heat]
This function enables the room to be heated to the pre-set temperature prior to the time programmed in the
On Timer. See Intelligent Timer [Pre-heat]” on pa ge14 for more information.

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10. Intelligent Timer [Pre-heat]
The Intelligent 2-way 24-hour programmed dual digital Timer [Pre-Heat] function operates in
conjunction with either “On-Timer”. It enables the pre-set temperature to be reached by the time
programmed by starting ignition up to an hour before the time programmed to start heating.
The actual ignition time is calculated using the difference between the room temperature and set
temperature and the warming-up time which elapsed the last time the appliance was used. The
maximum time ignition will precede the pre-set time is 1 hour. The following chart illustrates how
the intelligent timer operates.
The two timers can be programmed and used individually, or sequentially. Timer operation, once
set, will remain on stand-by for the next day after the final OFF sequence, unless ON/OFF switch is
pressed.

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11. Safety Devices
Flame rod sensor
Senses main burner ignition and shuts off the solenoid valves when the flame current drops below 0.1
µA.
Spark sensing circuit
Senses the location of spark and opens the solenoid valves only when the spark location is confirmed as
correct.
Pre-purge circuit
Purges heat exchanger and flue prior to spark commencing.
Combustion fan rpm sensing circuit
Senses the operation of the combustion fan and maintains a pre-determined rotation speed.
Overheat protection switches
Shuts off the solenoid valves and cut off gas supply in the case of over heating.
i) Bimetal OHS1
Operates at 130 ± 5°C
Recovery at 115 ± 7°C
ii) Bimetal OHS2
Operates at 90 ± 5°C
Recovery at 75 ± 7°C
iii) Thermal Fuse
Cuts out at 216 ± 2°C (one shot)
iv) Thermistor
Operates at 130 ~ 90oC (High ~ Low).
Fan delay
The convection fan starts after a short delay to avoid cold draughts, and keeps running after burner
extinction to allow the unit to cool down.
ON AT 15 sec, after ignition commences
OFF AT max. 210 sec, after combustion
Power failure circuit
Shuts off the solenoid valves if a power power failure occurs. The unit will relight after the power is
restored, and the clock time will be slow by the amount of time the power was off.
ThermistorTypeTemperature Control
Controls room temperature within the range of 16~26oC in 1oC steps.