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Rinnai REU-24 W-A Service Manual

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Summary of Contents for Rinnai REU-24 W-A

  • Page 3: Table Of Contents

    CONTENTS DEVELOPMENT BACKGROUND ........CHARACTERISTICS .

  • Page 4: Development Background

    DEVELOPMENT BACKGROUND The REU-24 W-A is one of a range of continuous flow water heaters produced by Rinnai. The main features of this unit are: compact size, low NO, combustion, high efficiency, and remote temperature control. exchanger to be reduced by 75% compared with conventional instantaneous water heaters.

  • Page 5: Introduction

    See page 9 for further explaination about how this control function operates. The aim of this manual is to provide an operational reference specifically concerning the Infinity REU-24 W-A water heater. A glossary of abbreviations is provided on page 4, to understanding some of the language used throughout this manual. Further assist you in information about this product is contained in the customers operation information booklet.

  • Page 6: Safety Devices

    SAFETY DEVICES Flame Failure Situated on both sides of the burner, the flame rods monitor normal combustion, preventing any discharge of gas to the burner if there is no flame and in conjunction with the P.C.B., isolate the gas. Remaining Flame Safety Device If the flame remains on the burner after the tap is closed, and the water temperature inside the heat exchanger reaches 2OO“C, a DC 90 volt bi-metal cut-off switch isolates the gas to the solenoids.

  • Page 7: Glossary Of Abbreviations

    GLOSSARY of ABBREVIATIONS This glossary of terms is provided to assist you in understanding some of the language used throughout this manual. sound pressure level in decibels, “A” range. dB(A) direct current. DECS direct exchange combustion system. electronic water flow control device. EWFCD - feedback information.

  • Page 8: Specification

    SPECIFICATION Temperature controlled continuous gas hot water system. Type of appliance Forced combustion. Exhaust system R E U - 2 4 W - A Rinnai Australia model N“ Installation Externally mounted. Remote control, mounted in kitchen and/or bathroom. Operation Width 370 mm.

  • Page 9: Combustion Specification

    COMBUSTION SPECIFICATION The FUXJ-24 W-A is only approved for use on Natural gas. Consumption Input Orifice A Orifice B Gas type selection switch positions * 0 5.0 0 5.2 O F F O N O F F O F F O F F * Down position = ON, Up position = OFF.

  • Page 12: Feedforward And Feedback

    FEEDFORWARD AND FEEDBACK Feedforward Information This is the information which the water heater uses to calculate the required parameters to give the temperature selected on the remote control. a) Incoming water temperature The data used is b) Water flow c) Selected temperature at the remote control This data is continually monitored by the P.C.B.

  • Page 13: Water Flows

    WATER FLOWS With the Infinity 24, the maximum water flow possible without mixing at the tap is 21 litres a minute. A simple calculation of the water flow rate in litres per minute can be made using the following charts. The charts indicate the water flow from the Infinity 24 at various combinations of incoming water temperatures, and the selected temperature at the remote control.
  • Page 14 The chart opposite indicates that the water flow rate of the Infinity 24 will, at a preset temperature of 50°C and an incoming water temperature of X, be 13 litres a minute. Water flow (L/min) The chart opposite indicates that the water flow rate of the Infinity 24 will, at a preset temperature of 50°C and an incoming water...
  • Page 15 Calculating The Water Flow The following information is an outline of the formula required to measure accurately the flow rate in litres per minute, as well as being the base for the charts on the preceding page. The most useful way in which this formula can be utilised, is to calculate the water flow rate where there is maximum gas input of 185MI/h.

  • Page 16: Gas Rate

    GAS RATE The most common unit used to calculate the energy required to heat water is the kilocalorie. If the full gas rate is not required to provide the required water temperature rise, ie - when the temperature selected at the remote controls is lower, or the incoming water temperature is higher 1; the amount of gas that the water heater is going to use to carry out a specific heating task will change proportionally to these variables.

  • Page 17: Default Temperature Setting

    This chart is an approximate guide to the gas input according to various temperature rises and water flows. See previous page, last paragraph for the explanation on how to calculate approximate gas consumption in MI/h. Temp Rise DEFAULT TEMPERATURE SETTING On the P.C.B.

  • Page 18: Gas And Water Controls

    GAS AND WATER CONTROLS Mechanical Water Regulator The following graph shows the performance of the water regulator. The top line shows the performance when the electronic water flow control is open, the lower line when it is closed. The bottom line shows that with the electronic water flow control device closed, the maximum flow is 7 L/min.
  • Page 19 Electronic Water Flow Control Device Water pressure to the appliance is controlled by a mechanical diaphragm, spring and valve system. The water flow control consists of a plug and barrel valve which is rotated by a motor to increase or decrease the volume of water passing through the heat exchanger.
  • Page 20 The water flow control device is controlled by a variable resistor (potentiometer). Use the chart on page 16 to determine the approximate resistance of the potentiometer at a given water flow and temperature rise. First determine the water flow from the unit. The tap must be turned on full, the electronic water flow control device does not operate if flow is restricted at the tap.
  • Page 21 This burner technology, called “DECS” (Direct Exchange Combustion System) has been patented by It provides very low levels of NO,, and the very short flame produced allows for a very Rinnai small heat exchanger to be used. Electronic Regulator/Modulating Valve Gas is controlled by a composite regulator/modulating valve, double block safety and changeover valve.

  • Page 22: Operation

    OPERATION The preset temperature is selected at one of the remote controls [where fitted]. Where no remote control is fitted, the temperature can be preset on the P.C.B. see page 14 default temperature setting. When a hot water tap is opened, water begins to flow through the appliance. The turbine in the water flow sensor begins to revolve.
  • Page 28 Overheating has occured. Damage to Repair I Replace. Digital Monitor Thermal fuse, overheat Faulty thermal fuse. combustion is OFF. safety device operated. chamber. Faulty P.C.B. Combustion occumd without Replace rev counter. combustion fan operating. (P.C.B rev counter check circuit faulty). Repair I Replace.
  • Page 29 Delayed Ignition (slow) Spark leak. Explosive Repair / Replace. ignition. Faulty P.C.B. Repair / Replace. Faulty sparker. Repair I Replace. Ventilation duct Replace. blocked. Faulty modulating Faulty P.C.B. Repair / Replace. valve. Repair / Replace. Incorrect orifice. Change to correct specification.

  • Page 30: Chart

    Error Coded Messages One of the following error coded messages will flash on the digital monitor of the romote control when a fault has occured with the applaince. Symptom Remedy Check point Ignition Miss After confirming the gas * Insufficient gas pressure supply, switch system * Modulating valve OFF then ON at the...

  • Page 37: Gas Pressure Setting Procedure

    P.C.B. diagram below. (The REU-24 W-A is only approved to operate on Natural Gas) RATE SWITCHES Do not alter the gas type selection switches unless they are incorrect.

  • Page 38: Comfonent Analysis

    COMPONENT ANALYSIS Note: the letters in brackets,[i.e. @I), (FJ] refer to the corresponding position of the connection on the wiring diagram on page 40. Do not attempt to remove push on connectors from solenoids by pulling on the wires. Pull on the body of the connectors. 1.

  • Page 39: Fan Motor

    7. Modulating valve 4. Fan Motor With the power supply disconnected, DO NOT check by shorting to the release one connector from the solenoid body of the unit. valve then connect the multimeter linked in series to the wiring. Reconnect the Measure with the connector connected to power supply and check the mA the P.C.B.
  • Page 40 11. Electronic Water Flow Control 9. Anti-Frost Heaters Device and Bypass Control Motor Measure with the power and connector Voltage measurement should be done disconnected. with the power connected. Resistance must be checked with the power 2 pin connector. (H-3 disconnected.

  • Page 42: Diagnostic Points

    DIAGNOSTIC POINTS Note: F - refers to the bold numbers at the left of the flow chart on page 20. W - refers to the position of the connections on the wiring diagram. See page 40. Measurement point Values Wire colour AC 90 - 110 Volts Red - Red A C 9 0 - 11OV...

  • Page 44: Dismantling For Service

    DISMANTLING FOR SERVICE CAUTION NOTE: Before proceeding with dismantling, be sure to follow the instructions before each explanation. - Isolate gas supply. - Disconnect electrical supply from wall socket. - Isolate the water supply. - Drain &J water from the appliance. PAGE Front Cover Removal of the...
  • Page 45 1. Removal of the FRONT COVER IMPORTANT CAUTION: 240 Volt exposure. Isolate the For some areas of dismantling you may electrical supply to the appliance and need to isolate any of the following: reconfirm with a neon screwdriver or multimeter. Isolate gas supply.
  • Page 46 P.C.B. TRANSFORMER P.C.B. Unit 3. Removal of the Removal of the CAUTION: 240 Volt exposure. Isolate the CAUTION: 240 Volt exposure. Isolate the electrical supply to the appliance and electrical supply to the appliance and reconfirm with a neon screwdriver or reconfirm with a neon screwdriver or multimeter.
  • Page 47 SOLENOID ASSEMBLY 5. Removal of the b. Remove two (2) sparker securing screws. 2 securina CAUTION: 240 Volt exposure. Isolate the electrical and gas supplies to the appliance, reconfirm with a neon screwdriver or multimeter. Follow section 1 first. Disconnect incoming gas supply union. Remove three (3) gas inlet connection securing screws.
  • Page 48 Remove two (2) water bypass distributor Solenoid assembly can be removed by securing screws. manoeuvring forward. Once it has been removed from the appliance, release the connectors. Release water bypass distributor 5 pin connector and water flow sensor 3 pin connector.
  • Page 49 Water Bypass Distributor Remove P.C.B. Transformer. Follow section 3 step b. Remove Solenoid Assembly. Follow section 5. Disconnect incoming water supply union. Remove two (2) water inlet connection securing screws. Pull down to release from electronic water flow control device. Water Flow Sensor water supply union Remove two (2) electronic water flow control...
  • Page 50 Manoeuvre the electronic water flow control Remove the hot water supply connection device out of the water heater, with the anti-frost tube, as well as removing the anti-frost protection heater assembly and incoming water protection heater from hot water supply supply tube attached.
  • Page 51 Follow section Remove P.C.B. Unit. Follow section 2. Remove hot water supply connection tube and water bypass distributor. Follow section 6 steps a + c. Remove harness B assembly. Release the heat exchanger outlet thermistor connector, outgoing water temperature thermistor, flame rod connector, sparker festoon terminal connectors, water flow sensor connector.
  • Page 52 This must be re-positioned upon reassembly. The flue terminal, heat exchanger, combustion fan, manifold cover, gas connection tube A and NOTE: For advice on replacing the fan motor B can now be removed as one complete or fan blades contact Rinnai directly. assembly.
  • Page 53 11. Removal of the OVER HEAT SWITCH 10. Removal of the MAIN TRANSFORMER CAUTION: 24 0 Volt exposure. Isolate the CAUTION: 24 0 Volt exposure. Isolate electrical, gas, and water supplies to the the electrical, gas, and water supplies to appliance reconfirm with a neon the appliance, reconfirm with a neon screwdriver or multimeter.
  • Page 54 Removal of the ELECTRODE Remove two (2) heat exchanger bracket LEFT/RIGHT left securing screws. CAUTION: 240 Volt exposure. Isolate the electrical, gas, and water supplies to the appliance, reconfirm with a neon screwdriver or multimeter. Drain appliance - see page 42. Follow section 1 first.
  • Page 55 Drain appliance - see page 42. Follow section 1 first. For additional advice on replacing the burner, Follow section 9 steps a 4 j. contact Rinnai directly. Remove flame rod. Follow section 11 steps b + d. Remove thermocouple. Follow section step b.
  • Page 56 17. Removal of the COMBUSTION Remove four (4) flue terminal to heat exchanger CHAMBER securing screws. CAUTION: 240 Volt exposure. Isolate the electrical, gas, and water supplies to the appliance, reconfirm with a neon screwdriver or multimeter. Drain appliance - see page 42. Follow section 1 first.
  • Page 57 Removal of the HEAT EXCHANGER Removal of the INCOMING WATER (OHS) TEMPERATURE THERMISTOR OUTLET THERMISTOR CAUTION: 240 Volt exposure. Isolate the CAUTION: 240 Volt exposure. Isolate the electrical, gas, and water supplies to the electrical, gas, and water supplies to the appliance, reconfirm with a neon screwdriver appliance, reconfirm with a neon screwdriver or or multimeter.

  • Page 58: Showering Tempeibitures

    SHOWERING TEMPERATURES An examination of preferred showering temperatures: by David Fishman and Bronwen Jenne. Reprinted here in part from the article ‘Some like it Hotter’ which appeared in Watson House Bulletin Variations in water flow rate are less of a tests by thermistors taped to the skin.
  • Page 59 temperature to the maximum tolerable level Females prefer shower temperatures 1°C whilst still standing under the water. higher than males, up to maximum tolerable setting. During the course of the tests all water and skin temperatures were recorded every The typical temperature initially set for twenty seconds by the use of a data logging showering was 39°C.

  • Page 60: Parts List

    PARTS LIST Part Name Front panel assembly 92071539 3862 Front panel packing 3760 102 1 Mainbody packing A 3762 Main body packing side AU1 15-163 92063361 3768 Outer case A 3861 Wall mounting bracket top 92071547 Wall mounting bkt bottom BU115-108 9207 1554 Warning label...
  • Page 61 connection ater...
  • Page 62 Part Name Water flow sensor “0” ring 92062199 Water bypass distribution (assy) 92071612 3880 Bypass motor bracket M7C-1-4 Heat exchanger outlet MlOB-2-14 92062207 3826 bypass “0” ring Heat exchanger inlet 92067073 1098 /outlet “0” ring Heat exchanger assembly 92059004 3863 324 1 Hlexc outlet thermistor BU124-621 92066968...
  • Page 63 Part Name RJ Part No High tension cord No. 1 AU1 15-641-1x01 3925 423 1 High tension cord No. 2 AU1 15-641-2 Earth harness AU1 15-623x01 3927 Electrode BU115-613 92066992 3928 Electrode seal packing R1444352 92062223 3828 427 1 Electrode clip 428 1 Heat exchanger bracket left Heat exchanger bracket right...
  • Page 64 Part Name Soun dbuffe rclip front 3949 Soun dbuffe rmaterial side 3950 513 1 Flueterminalpackingtop 3951 514 1 Flue termina I Dackin e side 3952 Flue termina lpackin glowe rA 3953 Flue krmina l packin glowe rB 3954 Flue termi & damper AU1 15-125 Flue termina lmesh 3955...

  • Page 69: Adjusting Temperature

    REMOTE CONTROL LAYOUT TURNING THE INFINITY 24 ON n TO TURN YOUR INFINITY 24 ON. Master Control Simply press the -Ibutton on either Control. The ON indicator will glow on the Control which you have operated. This indicates that the Infinity 24 is ready to supply hot water as soon as a tap is opened.
  • Page 70 TURNING THE INFINITY 24 OFF TRANSFERRING PRIORITY OF TEMPERATURE SELECTION n TO TURN YOUR INFINITY 24 OFF. Simply press the loN/OFFI button on either Remote Control. temperature selection to the This will shut the Infinity 24 down Master Control, simply press the completely Master Control.

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