Rinnai 308FTR Service Manual

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ENERGYSAVER

RHFE-308FTR

SERVICE MANUAL

High Efficiency Power Flued Gas Space Heater

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.

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.

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.

WARNING

Failure to comply with these instructions may result in serious personal injury or damage to the appliance.

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

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

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

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

mmH

O - millimetres of water (gauge pressure)

- 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 -3 08FTR in co rpo ra te s an impr ov e d modulating control syste m t o provide comfo r table 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.

• Incl u d es a 24 ho u r d ig ital cl ock and dual timer, a n d an economy mode functi on. This reduces gas con-

sumptio n w i thout af fect ing comfort.

• Temperature control is monitored by “fuzzy logic” t ec h n ology - relevanc e 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 prob lem occur s or ser v ic e is requir ed, an error coded mes sa ge appears o n th e digital display to

direct the service technician to the cause of the problem.

• Info rmation about any previous f a u l t s is sto r e d in the PCB and can be re c a lled 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 exch an gers and bl o wer s a re at ta ch e d . T h is i s th en covered by an outer ca se which is constr ucted 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 e xchanger is com posed of two sub-he at exc hanger se ts . The left hand set, N

1.0 mm alu mi n i s ed s t ee l . T he ri ght ha nd set, N heat exchange r No1 is c onne cte d to the outlet of t he combus tion c hamb er, the outlet is co nnect ed to subheat exchanger No2. 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 combusti on air fan d ra ws combus ti on a ir from the ou t s ide atmosphere through the flue manifold pipe. Air is then blown into th e c o mb u sti on chambe r via a rubber tube. Com b u stio n pr o ducts in the combus tion chamber are pushed out into sub-heat exchanger N 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 combus tion gas outlet, and is connect ed to the outlet of sub-he at exchanger N diameter ) is the co m b usti o n a i r i nlet and is connected to t h e inlet o f t h e com busti on fan a i r p ipe. Various flue lengths are avail abl e.

Ignition is continuous spa rk i n conju nct ion with an electrically operate d solenoid a n d cont rol is monitored by the PCB. Ga s pa ss es th r ou gh the R½ 15 (BSP) inlet fitt ing , then via a flan g e connec ti o n to the solenoid valves N

1, No2, a regulator modulating valve, aluminium injector manifold, before entering the burner.

2 is co nstr ucted of 0.8 m m st ainless steel. The inlet of sub-

1, to sub-heat exchanger No2, and then into the 34 mm

1 is constructed of

2. The outer pipe (70 mm

2. Dimensions

Note: All dimensions are in millimetres

3. Specification

Type of applia nce Fan forced flued g as s pace 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

High: 39 W Low: 30 W Consumption

Output 10.5 MJ/h Combustion system Stainless steel bunsen burne Ignition system Continuous electrical spark, direct to main burner Operati on Fi ng e r touch cont rol buttons Temperature control Electronic thermostat, modulating HI-LOW/OFF Temperature range LOW (10

C), 16 ~ 26oC (1oC incre ment s), HIG H (co ntin uous) 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 - 26

C 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 (130

C, 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 40

C after 10 mins

4. Cut-Away Diagram

5. Installation

NOTE:

refer to the installation instru ctions in the custome r’s operating instructions.

The informa tion provided he re is on ly a guide. F or full det ails on installa tion proc edures, please

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.

Flue fittings must be kept clear of flammabl materials.

The flue terminal should be positioned away from flammable materials.

In areas subject to heavy snowfall, keep snow clear of flue termin al at all times.

Recomme nded mi nimu m cle ara nce s an d dist anc es from obs truc tions.

6. Performance Characteristics

1. Basic Combustion Specification

Item Specification

Rinnai model number RHFE-308 FTR Gas typ NG Propane/LPG Gas consumption MJ/h

Injector size (∅ mm) 1.30 0.90 Injector quantity 2 2 Regulator pressure (kPa)

Burner marking P P Combustion method Bunsen burner Burner type Stainless slit style Solenoid valve Direct s i n g le seated valve type Modulating solenoid valve Direct single seated valve type

HI LO

13 13

0.60 1.04

0.12 0.19

2. Combustion Fan Speeds (rpm)

Natural Propane/LPG

Ignition 1710 1560 Re-ignition 1800 1680 Normal - High 3000 3090 Normal - Low 1440 1440

3. Warm Ai r Discha rge Temperature Di stribution

Condition: < High Combustion >

Test gas: Natural Measured input: 12.55 MJ/h Nominal input: 13 MJ/h Room temperature: 25oC

(Unit

24 24 55 9 45 72 64 18 56 81 83 36 62 66 77 42 68 43 70 45 42 39 57 45

Condition: < Low Combustion >

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Test gas: Natural Measured input: 5.27 MJ/h Nominal input: 5 MJ/h Room temperature: 25oC

10 17 30 9 23 39 38 13 29 48 42 28 35 44 46 37 37 28 43 34 22 26 31 28

4. Measurement Points

(Unit

∆

5. Warm Air Discharge Velocity

Convection Fan rpm HIGH: 740

LOW: 550

Room Temperature: 22oC

(Unit: m/sec)

1.62

1.46

1.99

1.78

3.20

2.61

3.35

2.66

3.27

2.47

3.13

2.37

2.57

1.32

2.57

1.92

3.54

2.53

3.44

2.60

3.37

2.52

2.11

1.23

1.70

1.34

2.89

2.15

3.12

2.44

3.14

2.28

3.33

2.62

3.33

2.54

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 m

6. Noise Level

1.08

0.84

2.12

1.58

2.51

1.91

2.75

2.08

3.32

2.46

3.42

2.58

Unit: dB(A).

High 36.5

Low 31.5

7. Th ermal Eff iciency

Conditions: Horizontal mushroom flue with unit installed with back spacers.

Gas Type Combustion Thermal Efficiency (%)

Natural

High 81.3

Low 84.8

High 83.5

Propane

Low 88.1

8. Humidifier Capacity

Method Tray Capacity Evaporation

Evaporation 0.8 Litres 0.1 Litres/hour

Note: Evaporation rate varies depending on conditions of use.

Conditions: Standard setting: High combustion Measurement Method: According to JIS (Japanese Industrial Standard)

7. Schematic Diagram

8. Control Panel Layout

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

9. Operating Principles

1. Normal Operation

Push the ON/O FF Button to operate the a ppliance. T h e Po wer ON/Combustio n Ind i c a t or will glow green. The comb ust ion fan will run o n high until p re-purge is completed.

Pre-purge is completed after approximately 15 seconds, following which, the c ombustion fan will decrease revolutions to enable ignition to occur. After the combustion fan reaches a pre-determined speed, (depend ing on gas type) the electrode pr od u c e s the sp a r k to begin t he i gnition cycle.

After the spark i s sen sed as having crosse d the spark gap by t he PCB, the solenoids (SV as the modulati ng valve will open and allow ga s to flow to the burner.

The flame rod senses the flame on the main burner. After the flame is sensed, the Power ON/Combustion Indica tor chang es to red and the spark stops. After an additional 15 secon ds the convect ion fan begins to operate.

The room temperature is se nsed by the temperature thermistor located at the rear of the appliance. The printed c ircuit b oard cont rols th e air/gas ratio to the optimu m level according t o the select ed 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.

& SV2) as well

2. Thermostat Control

The selected and room tem peratures are display ed on th e Time/Temp Display. T ime 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. Turnin g Off

Simply press the ON/OFF Button. The solenoids, together with the modulating valve will close. The combus tion f an will also sto p, and all indi cat ors will go out. After the burner ex t i n gu is h es, the convection fan will c ontinue to run for up to 210 seconds, ensur in g the appliance is cool.

4. Economy Mode

To enga ge t he economy funct io n press the Economy b u tt on 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. Aft er 3 0 min u te s t he tem p eratu re 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 th e heatin g effect ivene ss , and is an e nergy s avi ng feat ure. Y ou may press the Economy button again at any time, to cancel the economy function.

5. Child Lock

To act iv ate th e chi ld lock press the Child Lock b ut t on. The Lock Indic a tor 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 loc k is activated whi lst the appliance is OFF, then the complete range of functions will be locked.

6. Fi lter Indicator

When the air filter becomes covered in dust and the temperature inside the appliance rises, the Filter Indicator will glow.

7. Fu zzy 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 the warm air coming from the heater. This increases heating efficiency as well as improving control over the flow of warm air being disch ar ged by th e app liance.

In order to achie ve comfortable heating, it is preferable to avoid cold d ra fts o r draughts from the appliance. Also, for incre as ed efficien c y i t is import ant to redu ce ove r h e ati ng i n the room an d concen trate heating in the area where people are most oft en situated.

Fuzzy Logic is us ed i n order to ac h ie ve the followi ng impro ve d h eati ng pattern.

Standard Control

'Room temper ature' and 'the time elapsed since the start of combustion’ are the basis for fuzzy logic. Th means of contro l is t he s pe ed of the convection fan and modulation of gas combustion.

Fuzzy Co ntrol

b. Fuzzy Logic Summarised

In the case of a conventional fan heater, the convection fan operates normally from the time of ignition, and a cold draught may accompa ny the flow of air from the appliance. To solve thi s problem, fuzzy logic controls the speed of the convection fan after taking into consideration the room t emperature at the time of ignition. For example, in the case of t he room temperature being low, the fan is made to rotate at a low speed, raising the dis charge air temper ature. As the room temperature rises, the speed of the convection fan is g radua lly incre as ed. In this way i t is possible to e nsure a comforta ble volume of warmed a ir whilst decreas ing the possibility o f cold draughts immedi ate ly after ignition.

The fan s p eed incre as es proportiona l ly as time passes and the room gradu a lly he a t s u p. 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 t o t he conditions at the time.

8. Clock and Timer Setting and Operation

Refer to “Appendix” on pa ge59 of this manual.

9. Intelli gent Timer [Pre Heat]

This func tion en a bl e s th e room to be heate d t o the pr e- se t temper a tur e pr ior t o the time pro grammed in the On Timer. See Intelligent Timer [Pre-heat]” on pa ge14 for more information.

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.

11. Safety Devices

Flame rod sensor

Senses main burner ignition an d s huts off the solenoid v al ves when the flame cu r r ent drops below 0.1 µA.

Spark sensing circuit

Senses the location of spark a nd opens the solenoid v alve s only whe n the spark locat ion is confirmed as correct.

Pre-purge circuit

Purges heat exchanger and flue prior to spark commencing.

Combustion fan rpm s ensing circuit

Senses the operation of the combustion fan and maintains a pre-determined rotation speed.

Overheat protecti on switches

Shuts of f th e so len o i d 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 o u t at 21 6 ± 2°C (one shot)

iv) Thermistor

Operates at 130 ~ 90

C (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 uni t 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 p ower failure occurs. The unit will relight afte r the power is restored , and t he c lo c k t i m e will be slow by the amount of tim e the p o we r was off.

Thermistor Type Temperature Control

Controls r oom temperatur e wit h i n the ran ge of 16~26oC in 1oC steps.

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