Rheem Australia Pty Ltd ABN

Transcription

1 Rheem Australia Pty Ltd ABN SERVICE INSTRUCTIONS Lazer 441, 451, 741, 751, 761, 771, 781 & 791 Series TM001 Revision: AD Issued: Jan 14 Lazer 1 & 2 Silhouette (Designer Series) Classic (Modular Series) Silhouette (Modular Series) 441 Series 761 Series 771 Series 791 Series 451 Series 781 Series 741 Series 751 Series First Issued: May 1987

2 CONTENTS INTRODUCTION... 3 SAFETY WARNING... 3 MODEL IDENTIFICATION... 3 SPECIFICATIONS... 4 PREVENTATIVE MAINTENANCE... 5 OPERATION... 6 Electronic Controller Operating Modes... 6 COMPONENTS AND THEIR FUNCTIONS... 7 INSTALLATION TES... 8 WIRING DIAGRAMS /751 (2.5L - 40L) , 791 & 771/781 (2.5L 40L) FAULT FINDING General Fault Finding Chart Mode 1 Fault Finding Component Tests Mode 2 Fault Finding Component Tests Mode 3 & 4 Fault Finding LAZER BOILING WATER UNITS AT HIGH ALTITUDES How to Adjust the Temperature Setting of the Controller (ECB) ELECTRICAL IN-SERVICE TESTING ACCESSING COMPONENTS COMPONENT REPLACEMENT Water Temperature Sensor (Thermistor) DOCUMENT REVISION HISTORY

3 INTRODUCTION The information provided in these instructions is based on the Rheem Lazer Boiling Water Unit being installed in accordance with the installation instructions provided with each unit. Should you require further technical advice on the Rheem Lazer Boiling Water Unit, contact your nearest Rheem Australia Service Office where all genuine replacement parts are also available. SAFETY WARNING The purpose of this Service Manual is to provide sufficient information to allow a person with the skills as required by the controlling Regulatory Authorities to carry out effective repairs in the minimum of time. Safety precautions or areas where extra care should be observed when conducting tests outlined in this service manual are printed in bold italics. Take care to observe the recommended procedure. Certain diagnostic procedures outlined in these Service Instructions require live testing of certain components. An RCD should be installed between the power point and 3-pin cord of the water heater whilst conducting the tests. MODEL IDENTIFICATION The identification (model) number is designed to convey detailed information about the heater to which it is attached. Lazer Boiling Water Units are interpreted thus: 7 - Automatic Operation 4 & 7 - White enamel jacket 5 & 8 - S/Steel jacket 6 & 9 - Plastic Jacket, Silhouette 1 - Single heating unit 2 - Double heating unit 025 = 2.5 litre capacity 045 = 4.5 litre capacity 050 = 5.0 litre capacity 075 = 7.5 litre capacity 150 = 15 litre capacity 250 = 25 litre capacity 400 = 40 litre capacity SERIAL NUMBER 741/751 Series The serial number incorporates the date of manufacture as thus: Month of Manufacture Year of Manufacture Serial Number SERIAL NUMBER 771/781, 761 & 791 Series The serial number indicates the country code AU for Australia and a sequential build number. The date of manufacture is listed on the rating plate inside the jacket by the month and year i.e. SEP

4 Capacity Litres Model Heating Element Input (kw) Load & Wiring Type Electrical Supply Inlet & Outlet Connection SPECIFICATIONS Inlet Water Pressure (kpa) amp 230/240 VAC 50 1 x pin plug 50Hz R½/ x amp 230/240 VAC 3-pin plug 50Hz R½/ amp 230/240 VAC x pin plug 50Hz R½/ amp 230/240 VAC x pin plug 50Hz R½/ x x x amp 3-pin plug 15 amp circuit 20 amp circuit 230/240 VAC 50Hz 230/240 VAC 50Hz 230/240 VAC 50Hz Min Max 1000 R½/ R½/ R½/15 4

5 PREVENTATIVE MAINTENANCE It is suggested for peak performance that the Boiling Water Unit be serviced every six months. Servicing must be performed by suitably qualified persons. Hot surface or liquid. Personal Protective Clothing (PPE) shall be worn to reduce the risk of burns or scalding. 1. Check the inlet strainer located inside the water inlet connection to ensure it is clean and not blocked with foreign matter. If an additional auxiliary filter is fitted, such as in areas of poor water quality check to ensure it is also clean and not blocked with foreign matter. 2. Check for signs of excessive corrosion on jacket and internal panels. Corrosion can be indicative that a leak is present. 3. Check for leaks at all BWU fittings. 4. Check the vent line to ensure it is not blocked with foreign matter. It is imperative that the vent line does not become blocked as the BWU is not designed to be pressurised. 5. Isolate power and check all electrical connections for signs of overheating due to poor connection. 6. Conduct an electrical in-service test. (Refer to page 18). 7. Check tap for signs of leaking & excessive dripping after operation (clean or replace if required. 5

6 OPERATION IMPORTANT: High altitude will affect the Lazer Boiling Water Unit operation. Refer to page 17 for more details To commission water heater from empty: Turn on water supply first Turn on 240V supply, solenoid will open and filling will commence. Filling will continue until the water reaches the WLS low-level probe. Filling will stop and heating will commence until water reaches 97ºC. Heating continues and filling re-commences and continues until water temperature drops to 93ºC. Each time the solenoid valve closes the WLS high level is checked. This process repeats itself until the water level reaches the WLS high-level probe, at which time the solenoid closes and the heating unit is switched off when water temperature reaches 97ºC. From there on the heating unit will cycle to maintain water temperature between 93 and 97ºC. The drawing off of boiling water will cause the solenoid to open and deliver cold water on to the WTS which will in turn cause heating to commence. The continuous drawing of water will cause the solenoid to close after 25 seconds; ensuring water temperature is not continually reduced. Electronic Controller Operating Modes Mode 1. Empty When water level is below the WLS low-level probe the heating unit will turn OFF, and the solenoid valve will open to allow water to enter. When water level reaches the WLS low-level probe, a delay of 2 seconds will elapse before the solenoid closes and heating commences. Mode 2. Not Full Continuing from Mode 1, the heating unit will have power on throughout Mode 2. While it is heating, small quantities of water (approx. 100mL per cycle) are admitted through the solenoid each time the water temperature is sensed at 97ºC. The solenoid will: Open to fill at 97ºC Close at 93ºC The solenoid cycle time will depend on the delay between cold-water entry and the sensing of 93ºC, which is directly related to: Temperature of inlet water. Pressure of inlet water. Capacity of the Lazer Boiling Water Unit. Water level in the Lazer Boiling Water Unit Water temperature should not drop below 93ºC throughout the fill cycle. Each time the solenoid closes, the WLS high- level probe is activated and, if found to be covered with water the ECB will change to Mode 3. 6

7 Mode 3. Full When water has covered the WLS high-level probe the solenoid will close and heating will continue until a temperature of 97ºC is attained. The solenoid will open again for a split second at this time. Thereafter the solenoid opens only when the water level falls below the WLS high- level probe. Heating will continue to cycle ON and OFF between 93 and 97ºC. The drawing of water from the tap will return the ECB to Mode 2. During continuous drawing of water the solenoid will close after being open for 25 seconds. Draining of all water will return the ECB to Mode 1. Mode 4. Over temperature Cut Out (OTC) The OTC mode will activate when the solenoid remains open for longer than 25 seconds in Mode 2. Once activated the OTC will switch OFF power to the solenoid and heating unit and remain in this state until the water temperature drops below 93ºC. At this temperature the ECB will switch back to Mode 2. The OTC mode is not temperature activated and will not prevent continuous boiling of the Lazer. COMPONENTS AND THEIR FUNCTIONS ELECTRONIC CONTROL BOX (ECB): A box containing a transformer, relay and electronic PC board which provides the logic to monitor and control water level and temperature. An over temperature function is incorporated to prevent the unit boiling dry. The wiring terminals are 240 volt and 0 to 24 volt; therefore it is essential to connect all wires to the correct positions. WATER LEVEL SENSOR (WLS): An insulated stainless steel probe that monitors: Low water level to ensure the heating element cannot operate unless covered by water High water level to ensure the maximum water level is not exceeded. Damage to the probe insulation will cause the heater to malfunction. SOLEID VALVE / INLET FILTER: A 12-volt solenoid for 741/751 series with an inline filter attached is located in front of the inner tank at the top of the water heater. A 24-volt solenoid for 761,771/781, 791 series with an inline filter attached is located on the lower left hand side of the water heater. The operation is ON or OFF, but because of its small orifice size water hammer is not a problem. HEATING UNIT / SENSOR PROBE: A square flanged heating unit, bent at 90º on some units to suit the width of the tank, incorporating a sensor probe centrally located between the element loop. 7

8 TEMPERATURE SENSOR (WTS): A thermistor is inserted inside the probe of the heating unit and monitors water temperature to maintain water at near boiling point. OVERFLOW / VENT: The outlet of this pipe must be to atmosphere for the following reasons: To allow air to escape while filling To allow excess water to escape To allow steam to escape while heating To prevent inner tank collapse when draining INSTALLATION TES The Lazer boiling water unit is not weatherproof. External locations must be protected from the weather and freezing conditions. MOUNTING POSITION: Minimum clearances required for servicing are 350mm clear above the top and to the right for 741/751 series and 150mm clear above the top and to the right for 761, 771/781 and 791 series. Refer to installer to correct if clearances are less than required. OVERFLOW/VENT: A drain line discharging to the atmosphere with a continuous fall, not exceeding 1 metre and with not more than 3 bends is required. The point of discharge should be where the user can see it, but not cause annoyance or injury if water or steam is discharged. A drain line not meeting these requirements must be installed with an air-break (tundish). WATER SUPPLY: The Lazer Boiling Water Unit is not a pressurized appliance. An AIR- BREAK is incorporated into the internal filler pipe. Connect only to a cold water supply with a constant pressure above the minimum supply pressure as specified in the SPECIFICATION TABLE on page 4. The maximum supply pressure shall not exceed 1000kPa for all models. An approved stopcock is required for servicing purposes in the cold water supply line before the Lazer Boiling Water Unit. IMPORTANT: Non-return valves or stopcocks incorporating a non-return valve MUST T BE INSTALLED in the water supply connection for 741, 751and 761 series. 771, 781 and 791 series have a non-return valve fitted within the water heater. DO T CONNECT TO A HOT WATER SUPPLY. HOT WATER TAP: The tap is supplied with a chrome plated brass extension piece on 741/751 and 771/781 series. A 29mm A/F nut allows the tap to be aligned to a vertical position. On 761 and 791 series the tap is a Rocker type and is already installed for use. The tap will drain all the contents of the Lazer Boiling Water Unit on some 741/751 series, and therefore expose the heating unit to the air. DO T: Over-tighten tap into tank. Remove the tap to service heating unit. 8

9 ELECTRICAL CONNECTION: All Lazer Boiling Water Units are designed for 220/240 volt 50 Hertz electrical supply. Installations that cannot achieve the specified supply current, i.e. private generators should be avoided. The internal wiring is designed to suit the load rating of the heating unit stated on the RATING LABEL found inside the jacket. DO T FIT A HEATING UNIT OF HIGHER RATING THAN SPECIFIED ON THE RATING LABEL. Lazer Boiling Water Units with 10amp load are supplied with a 3-pin plug. A licensed electrician must wire units of 15amp capacity to a suitable supply. WIRING DIAGRAMS 741/751 (2.5L - 40L) 2.5L -15L 25L - 40L 9

10 Ready Ground Ready Ground Vp Vp Element Element Neutral Neutral Earth Earth Low Low High High Solenoid- Solenoid- Solenoid+ Solenoid+ 761, 791 & 771/781 (2.5L 40L) /781 Series 2.5L - 15L ECB Solenoid WLS Phase Sensor- Sensor+ W BL R R W B/W R 2.4kW Element R B G BL R Note: ECO not fitted on 15L models BL BR G BL P E N Terminal Block LED Board 761 & 791 models only B=Black BL=Blue BR=Brown G=Green W=White R=Red B/W=Black/White 771/781 Series 25-40L ECB Solenoid WLS Phase Sensor- Sensor+ W BL R R W B/W Relay BR 3.6kW - 25L 4.6kW - 40L Element G BL R BR BL BR G BL P E N Terminal Block 10

11 FAULT FINDING It is possible to independently test individual components of the Lazer Boiling Water Unit, however it is strongly recommended that this Test Procedure be followed irrespective of a suspected malfunctioning component. A failed or malfunctioning component may be the result of incorrect installation, faulty or intermittent services, i.e. large voltage or water pressure fluctuations, water filtration units or non-return valves in the water supply line or, incorrectly installed overflow/vent pipes. Prior to commencing this Procedure ensure that the water pressure and electrical supply meet the required specification for the Lazer boiling water unit outlined on page 4. General Fault Finding Chart Disconnect power and isolate water supply Remove the jacket front or access covers Drain tank completely via drain plug or tap Water at elevated temperatures may be present when draining, care should be taken to prevent scalding Refit drain plug, reconnect power and restore water supply Is the water solenoid open? Mode 1 diagnosis 1 Water solenoid closes after a period? Element commences heating? Mode 2 diagnosis 2 Solenoid alternates operation until upper water level reached, element remains on continuously? Was the solenoid open for longer than 25 seconds? Over temperature mode diagnosis 4 Element de-energized after a period? Mode 2 diagnosis 2 Element cycles to maintain water temperature? Mode 3 diagnosis 3 Normal Operation 11

12 Mode 1 Fault Finding 1 Is the solenoid open? Does the solenoid close? Mode 2 Diagnosis 2 Is there continuity of the earth strap from the tank to the ECB? TEST 1 Repair broken strap or wiring Disconnect the plug from the water level probe 2.1 Does the solenoid open? Is the connection to the water level probe clean and tight? Clean connection or replace wiring. Retest operation Isolate power before checking the water level probe connection Is scale built up on probe wires or body? TEST 2 Replace ECB Retest operation Clean or replace water level probe Restest operation Is the supply voltage from the ECB correct? TEST 3 Is the resistance of the solenoid valve correct? TEST 4 Replace solenoid valve Retest operation 2 Mode 2 Diagnosis Is the resistance of the solenoid valve correct? TEST 4 Replace ECB Retest operation Replace ECB and solenoid valve Retest operation 12

13 Component Tests 1-4 Test 1 Test 2 Normal resistance between the tank and the earth point on the ECB is 0 ohms (dead short) when measured with a multimeter on the x1 resistance scale. Normal resistance between the high level probe wire and low level probe wire should be infinity (open circuit) when measured with a multimeter on the x10m resistance scale. Test 3 Test 4 Install RCD and exercise caution when conducting live tests 741/751 series Normal voltage at the solenoid under load should be between 6 and 12 volts when measured with a multimeter on the DC voltage scale. 761, 771/781 and 791 series Normal voltage at the solenoid under load should be between 8 and 24 volts when measured with a multimeter on the DC voltage scale. 741/751 series Normal resistance of the solenoid coil should be 23 ohms +/- 5% when measured with a multimeter on the x1 resistance scale. 761, 771/781 and 791 series Normal resistance of the solenoid coil should be 55 ohms +/- 5% when measured with a multimeter on the x1 resistance scale. 13

14 Mode 2 Fault Finding 2 Is voltage present at the element? TEST 5 Capacity of Lazer? 2.5, 5 & 7.5 litre models Replace ECB Retest operation 15, 25 & 40 litre models Is voltage present at relay? TEST 6 Replace relay Retest operation Has the Solenoid closed? Replace solenoid Retest operation Is the resistance of the element correct? TEST 7 Replace element Retest operation 2.2 Does the unit boil continuously? Is the resistance of the thermistor correct? TEST 8 Replace thermistor Retest operation Is the thermistor fully inserted into the well? Refit the thermistor in the correct position Retest operation Does the solenoid close when upper water level reached? Adjust the temperature setting by following the potentiometer procedure in this manual. Retest operation if fault persists replace the ECB

15 Component Tests 5-8 Test 5 Test 6 Install RCD and exercise caution when conducting live tests Normal voltage at the element is 240v when measured with a multimeter on the AC voltage scale Install RCD and exercise caution when conducting live tests Normal voltage to the relay coil is 240v when measured with a multimeter on the AC voltage scale. Test 7 Test 8 Normal resistance of the element and ECO when measured with a multimeter on the x1 resistance scale is: 2.4kW ohms +/- 5% 3.6kW ohms +/- 5% 4.6kW ohms +/- 5% Normal resistance of the water temperature sensor (Thermistor) is 950 ohms ohms at 20ºC. The Thermistor should be replaced if the reading is less than 850 ohms or greater then 1250 ohms. When measured with a multimeter on the x1k scale a normal reading will be between.95 and

16 Mode 3 & 4 Fault Finding 3 Are large quantities of hot water being discharged from the vent pipe? Is the vent pipe longer than 3 metres? Siphoning may be occurring. Advise user to have a tundish installed as per the installation instructions. Unit may enter over temperature (OTC) mode during this condition if the solenoid opens for periods exceeding 25 seconds Check the water level probe sensor wires for correct length Does the unit discharge large quantities of hot water intermittently? Replace solenoid Retest operation Does the unit maintain water temperature during periods of non use? Draw a quantity of water from the unit through the tap Did the unit Refill and heat? Normal Operation OTC MODE Are large amounts of hot water being drawn through the tap? Any time the solenoid is open for a period exceeding 25 seconds before a shift in temperature is detected the unit will enter the over temperature mode (OTC) Check for low supply flow due to water filters etc Advise customer to draw smaller quantities of water at one time 16

17 LAZER BOILING WATER UNITS AT HIGH ALTITUDES An increase in altitude will reduce the boiling temperature of water. Therefore it is necessary to provide an adjustment on the Lazer Control System for installations over 300 metres above sea level. All controllers supplied as a component of the finished product are factory adjusted to deliver water at a temperature of 92ºC. Why should temperature adjustment be necessary? Replacement of the Electronic Controller Replacement of the Thermistor or a Heating Unit and Thermistor. Altitude compensation Where is the Adjustment Potentiometer and what does it look like? Relative to the controller terminals, the Potentiometer (Trim Pot) for temperature adjustment is located at the right rear of the control box. Access is provided by means of a 10mm diameter hole in the controller cover (refer to figure below). Some controllers have no covers fitted, so the Trim Pot is visible on the PCB at the described location. The Trim Pot can be identified as being a white or blue disc, approximately 6mm in diameter and having a screw driver slot in its top face. The dotted lines of the TRIM POT arc represent HOURS. Each hour represents approx 1ºC How to Adjust the Temperature Setting of the Controller (ECB) Components adjacent to the trim pot will be live, take care while making adjustments not to touch other components. 1. Isolate the electrical supply and drain the Lazer Boiling Water Unit to a low level. 2. Using a 3mm wide screw driver, rotate the Trim Pot ANTICLOCKWISE to its MINIMUM SETTING. 3. Switch the power back ON and allow it to operate automatically for 5 MINUTES (the element should switch on and the solenoid valve should operate at least once). 4. Using a 3mm wide screw driver, rotate the Trim Pot CLOCKWISE to its MAXIMUM SETTNG. The unit will now boil and not take water. 5. Allow the unit to boil for approx. 1 minute before rotating the Trim Pot ANTICLOCKWISE until such time as the solenoid opens, allowing water to flow into the tank. 6. Rotate the Trim Pot ANTICLOCKWISE a further turn (approx. 45 degrees). This will prevent the unit from boiling should atmospheric pressure decrease. 7. Before re-fitting the jacket cover wait at least one solenoid operation to ensure that the unit has been correctly adjusted. 17

18 ELECTRICAL IN-SERVICE TESTING Wear Personal Protective Equipment when conducting step 1 of these procedures to reduce the risk of electric shock. Refer to Rheem safety procedure on electrical testing. 1. For 3 15L models: Isolate power by switching off at power point and unplugging BWU 3 pin plug from power point. For 25 & 40L models: Isolate power by turning isolation switch off and then removing fuse (or switching off circuit breaker). Disconnect Active, Neutral and Earth wires from BWU terminal block. Procedure 1: To check insulation resistance of the BWU Neutral Circuit (reading not to be below 1 mega-ohm). 2. For 3 15L models: Connect megger leads to the neutral and earth pins on the 3-pin plug. For 25 & 40L models: Connect megger leads to the Neutral conductor and the Earth terminal of the BWU terminal block. 3. Operate insulation resistance tester. A reading above 1 mega ohm should be obtained. 4. If a reading below 1 mega ohm is indicated, all component parts will need to be individually tested to locate the fault. Procedure 2: To check insulation resistance of the BWU Active Circuit (reading not to be below 1 mega-ohm). 5. For 3 15L models: Connect megger leads to the active and earth pins on the 3-pin plug. For 25 & 40L models: Connect megger leads to the active conductor and the earth terminal of the BWU terminal block. 6. Operate insulation resistance tester. A reading above 1 mega ohm should be obtained. 7. If a reading below 1 mega ohm is indicated, all component parts will need to be individually tested to locate the fault. Procedure 3: To check Earth Continuity of the water heater. 8. Set the multimeter to x1 Ω (ohms) resistance scale. 9. (3 15L Models) Measure between the earth pin on the 3 pin plug and the water heater jacket. The reading should be less than 0.5Ω. (25-40L models) Measure between the earth terminal and the water heater jacket. The reading should be less than 0.5Ω. 10. If a reading greater than this value is obtained the earthing connection should be checked for corrosion/tightness and the power lead earth wire tested, if necessary replace the power lead. 18

19 ACCESSING COMPONENTS Ensure that the unit is unplugged or isolated from the electrical supply. Removing & Replacing Jacket Lid and Name Plate (741/751 Series) Removing the Lid (Figure 1) 1. Remove the four retaining screws. 2. Remove the LID by lifting from the jacket. Removing the Nameplate (Figure 2) 1. Remove the two retaining screws. 2. Slide the Nameplate forward on the Tap Stem and rotate through 90 degrees to obtain access to components. Note: The Tap does not need to be removed to service or replace components housed behind the Nameplate. Removing & Replacing Jacket Front (761 and 791 Series) Figure 1 Figure 2 Removing the Jacket Front (Figures 3&4) 1. Remove the two retaining screws. (Figure 3) 2. Remove the spout by pulling down and gently pushing toward the back. Figure 3 3. Insert fingertips between the Jacket Front and Jacket Back in the vicinity of the Jacket Retaining Clips and gently pull the Jacket Front forward until free of tap. (Figure 4) 4. Lift the Jacket Front until free of the Retaining Clips. Warning: The LED Display lead (item 1, figure 4) must now be disconnected from the ECB. The Jacket Front is then free to be removed. Figure 4 19

20 COMPONENT REPLACEMENT Water Temperature Sensor (Thermistor) Ensure that the unit is unplugged or isolated from the electrical supply. 741/751 Series 1. Remove the nameplate. (Refer to page 19) 2. Disconnect the wiring to the water temperature sensor. 3. Withdraw the water temperature sensor from the element. 4. Coat the thermistor with heat sink compound 5. Slide the replacement water level sensor into the element ensuring it seats at the end of the tube. 6. Reconnect the wiring and refit the nameplate. 7. Restore power and test operation of boiling water unit. Figure 5 761, 771/781 & 791 series 2.5L 7.5L 1. Remove the jacket front. 2. Disconnect the wiring to the water temperature sensor. 3. Withdraw the water temperature sensor from the element. 4. Coat the thermistor with heat sink compound 5. Slide the replacement water level sensor into the element ensuring it seats at the end of the tube. 6. Reconnect the wiring and refit the nameplate. 7. Restore power and test operation of boiling water unit. 771/781 series 15L 40L 1. Remove the left hand side panel. (Refer to figure 9 page 22) 2. Disconnect the wiring to the water temperature sensor. 3. Withdraw the water temperature sensor from the element. 4. Coat the thermistor with heat sink compound 5. Slide the replacement water level sensor into the element ensuring it seats at the end of the tube. 6. Reconnect the wiring and refit the nameplate. 7. Restore power and test operation of boiling water unit. Figure 6 20

21 Electronic Control Box Ensure that the unit is unplugged or isolated from the electrical supply. 741/751 Series 1. Remove the Jacket Top (Refer to page 19) 2. Gently disconnect the push-on spade terminals 3. Slide the ECB upwards to disengage from the metal tabs in the back panel and lift the ECB clear. 4. Replace the ECB repeating the above steps in the reverse. Ensure that the wiring loom terminals are correctly replaced. Check the terminal block connector to ensure that no wires were accidentally dislodged during the service repair. 5. Restore the power supply and test the unit for normal operation. 6. Refit the Jacket Top. 761, 771/781 and 791 Series 1. Remove the Jacket Front, 2.5L 7.5L (Refer to page 19) or Left hand side panel, 15L 40L (Refer to figure 9 page 22). 2. Gently disconnect the push-on spade terminals and the multi-pin connector from the ECB. 3. With the aid of fingertips, gently unclip the ECB Mounting Clips (3) clear of the controller board and lift the ECB (4) through 40 degrees as shown in figure Remove the ECB from the rear Mounting Clips by pulling forward. 5. Replace the ECB repeating the above steps in the reverse. Ensure that the wiring loom terminals are correctly replaced. Check the terminal block connector to ensure that no wires were accidentally dislodged during the service repair. 6. Restore the power supply and test the unit for normal operation. 7. Refit the Jacket Front or Top. Figure 7 Figure 8 TE: ALWAYS check product EARTHING before replacing the Jacket Front or Top 21

22 Solenoid Valve Ensure that the unit is unplugged or isolated from the electrical supply and the stopcock is closed. 761, 771/781 and 791 Series 1. Remove the Jacket Front (2.5L - 7.5L models, refer to page 19) or Side Panel (15-40L models, refer to figure 9) 2. Disconnect the push-on spade terminals from the solenoid 3. Disconnect the inlet supply pipe to the unit. 4. Disconnect the silicone tube 5. Hold the inlet fitting with the aid of a 24mm AF spanner and, using a 27mm AF spanner remove the retaining nut. 6. Remove the Nylon Washer 7. Remove the valve and inlet assembly from the tank. 8. Unscrew the valve assembly from the inlet fitting. 9. Reassemble the inlet fitting, nylon washer and replacement valve assembly. 10. Refit the assembly in reverse order of above. 11. Restore water supply and check for water leaks. 12. Refit panels, restore power supply and test unit for normal operation. Figure 9 741/751 Series 1. Remove the jacket top (Refer to page 19) 2. Disconnect the solenoid lead spade connectors from the ECB. 3. Place absorbent cloth below and around solenoid to protect ECB and wiring from water spillage. 4. Hold the solenoid securely and undo the compression nuts on either side of the valve assembly. 5. Remove the solenoid valve assembly. 6. Fit the replacement solenoid valve assembly ensuring the water flow is in the direction of the arrow on the brass body. 7. Complete assembly in reverse order of above. 8. Restore water supply and check for water leaks. 9. Refit panels, restore power supply and test unit for normal operation. Figure 10 22

23 Water Level Probe Ensure that the unit is unplugged or isolated from the electrical supply and the stopcock is closed. A common Water Level Probe is supplied as a replacement part. Prior to fitting the probe it may be necessary to cut the long and short sensor wires to suit the model. Refer to the table on page 24 for correct cutting lengths. 741/751 and 771/781 Series Removing the Water Level Probe 1. Remove the jacket top, all 741/751series and 771/781 series 15l 40L, or jacket front, 771/781 series 2.5L 7.5L. (Refer to page 12) 2. Disconnect the wiring connector from the Water Level Probe. 3. Remove the Water Level Probe by pulling vertically out of the tank (Exercise care not to distort the tank top). Replacing the Water Level Probe 1. Bend the high level probe wire (item 3, figure 11) away from the low level probe wire (item 4, figure 11) to an angle of 15º, or such that slight pressure is needed to squeeze the probe wires together when inserting the Water Level Probe into the tank sleeve. 2. Insert the replacement Water Level Probe into the tank sleeve and press until seated. (Exercise care not to distort the tank top.) 3. Refit the wiring connector to the Water Level Probe 4. Restore water and power supplies, check for water leaks and test boiling water unit for correct operation. 5. Refit the jacket top or front. 761 and 791 Series Removing the Water Level Probe 1. Remove the jacket front. (Refer to page 19) 2. Disconnect the wiring connector from the Water Level Probe 3. Remove the Water Level Probe by pulling vertically out of the tank. (Exercise care not to distort the tank top.) Figure Bend the high level probe wire (item 3, figure 12) away from the low level probe wire (item 4, figure 12) to an angle of 15º, or such that slight pressure is needed to squeeze the probe wires together when inserting the Water Level Probe into the tank sleeve. 6. Insert the replacement Water Level Probe into the tank sleeve and press until seated. (Exercise care not to distort the tank top.) 7. Refit the wiring connector to the Water Level Probe 8. Restore water and power supplies, check for water leaks and test boiling water unit for correct operation. 9. Refit the jacket front. Figure 12 23

24 Water Level Probe Lengths Cut each leg of the Water Level Probe to the length shown in the table below Model Short Probe Length in mm Long Probe Length in mm (Length X) (Length Y) / / / / / / / /

25 Element Ensure that the unit is unplugged or isolated from the electrical supply and the stopcock is closed. Water at elevated temperatures may be present when draining, care should be taken to prevent scalding. 1. Drain the Lazer boiling water unit 741/751 Series 2. Remove the Nameplate. (Refer to page 19) 3. Disconnect the 2 wires from the element terminals. 4. Disconnect the wiring to the water temperature sensor. 5. Undo the 2 retaining nuts from the element flange and remove the element. 6. Replace element gasket if required. 7. Reassemble in the reverse order of above. 8. Restore water and power supplies and allow unit to fill and heat. 9. Check for water leaks 10. Refit nameplate. Disconnect power during this step. 761, 771/781 and 791 series 2.5L 7.5L 1. Drain the Lazer boiling water unit. 2. Remove the Jacket Front. (Refer to page 19) 3. Disconnect wire from element terminal and ECO. 4. Disconnect the wiring to the water temperature sensor. 5. Undo the 2 retaining nuts from the element flange and remove the element. 6. Replace element gasket if required. 7. Reassemble in reverse order of above. 8. Restore water and power supplies and allow unit to fill and heat. 9. Check for water leaks. 10. Refit the Jacket Front. Disconnect power during this step. 15L 40L Follow the procedure outlined above, removing the left hand side panel (Refer to figure 9 page 22) not the jacket front at step 2. 25

26 Tap Ensure that the unit is unplugged or isolated from the electrical supply and the stopcock is closed. Water at elevated temperatures may be present when draining, care should be taken to prevent scalding. 741/751 & 771/781 Series 1. Drain the Lazer boiling water unit. Tap head only 2. Using a spanner undo the lock nut at the tap head. 3. Remove the tap head. 4. Fit the replacement tap, ensuring it is vertical when retightening the lock nut 5. Restore water and power supplies and test boiling water unit operation Complete Tap Assembly 2. Grip the tap extension with multigrips (or similar) and unscrew the tap assembly from the tank. Care should be taken not to damage or distort the tank. 3. Apply Teflon thread tape to the replacement tap extension and screw into the tank. Care should be taken not to damage or distort the tank. (A barrier such as a piece of cloth should be wrapped around the replacement tap extension to prevent damage to the finish of the shaft by tools) 4. Ensure the tap head is vertical; loosening the tap head lock nut will allow adjustment of the tap head position. 5. Restore water and power supplies and boiling water unit operation. Figure /791Series 1. Drain the Lazer boiling water unit 2. Remove the jacket front. (Refer to page 19) 3. Unscrew the lock nut (anti-clockwise) and gently pull the tap assembly from the tap body. 4. Carefully insert the replacement tap assembly into the tap body and tighten the lock nut (clockwise). Note: Do not over tighten, as this will cause the tap to drip. To replace the spring, lightly compress the spring by pressing on the front of the diaphragm. This will facilitate the removal of the tap cap pin to allow the tap to be disassembled. Figure 14 Note: The tap seal and spring are replaceable as separate items. Refer to Spare Parts Manual SPM-BW for part numbers. 26

27 DOCUMENT REVISION HISTORY Title: Lazer 441, 451, 741, 751, 761, 771, 781 & 791 Series Service Instructions Document N o : TM001 Rev Details of change D.O.I. A Service Instructions issued for 441/451 series Lazer 05/87 B Service Instructions updated to cover 741, 751, 771, 781, 761 & 791 series Lazer 27/04/01 C Reference to Southcorp replaced by Rheem Australia 28/03/03 AD Format updated; Warranty Statement removed; Exploded views & Replacement Parts Lists removed, now form part of Boiling Water Spare Parts Manual SPM-BW 02/01/14 TE: Every care has been taken to ensure accuracy in preparation of this publication. No liability can be accepted for any consequences which may arise as a result of its application. 27