Mitsubishi Electric EHST20C-VM6HA Service Manual

Mitsubishi Electric EHST20C-VM6HA Service Manual

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CYLINDER UNIT
SERVICE MANUAL
R410A
[Model name]
EHST20C-VM6HA
EHST20C-YM9HA
EHST20C-VM6A
EHST20C-YM9A
EHST20C-VM6SA
EHPT20X-VM2HA
EHPT20X-VM6HA
EHPT20X-YM9HA
EHPT20X-VM6A
EHPT20X-YM9A
CYLINDER UNIT
[Service Ref.]
EHST20C-VM6HA.UK
EHST20C-YM9HA.UK
EHST20C-VM6A.UK
EHST20C-YM9A.UK
EHST20C-VM6SA.UK
EHPT20X-VM2HA.UK
EHPT20X-VM6HA.UK
EHPT20X-YM9HA.UK
EHPT20X-VM6A.UK
EHPT20X-YM9A.UK
MAIN CONTROLLER
Note:
• This manual describes only
service data of cylinder unit.
• RoHS compliant products have
<G> mark on the spec name
plate.
CONTENTS
1. REFERENCE MANUAL ................................... 2
2. SAFETY PRECAUTION ................................... 3
3. SPECIFICATIONS ............................................ 7
4. PART NAMES AND FUNCTIONS .................. 8
5. OUTLINES AND DIMENSIONS ..................... 10
6. WIRING DIAGRAM ......................................... 11
7. FIELD WIRING ............................................... 21
8. WATER SYSTEM DIAGRAM ......................... 25
9. CONTROLS ................................................... 28
10. TROUBLESHOOTING ................................... 43
11. DISASSEMBLY PROCEDURE ...................... 56
13. SERVICE AND MAINTENANCE ................... 73
PARTS CATALOG (OCB507)
July 2011
No. OCH507

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Summary of Contents for Mitsubishi Electric EHST20C-VM6HA

  • Page 1: Table Of Contents

    CYLINDER UNIT July 2011 No. OCH507 SERVICE MANUAL R410A [Model name] [Service Ref.] Note: • This manual describes only EHST20C-VM6HA.UK EHST20C-VM6HA service data of cylinder unit. • RoHS compliant products have EHST20C-YM9HA.UK EHST20C-YM9HA <G> mark on the spec name plate. EHST20C-VM6A.UK EHST20C-VM6A EHST20C-YM9A.UK...
  • Page 2: Reference Manual

    REFERENCE MANUAL OUTDOOR UNIT'S SERVICE MANUAL Service Ref. Service Manual No. PUHZ-RP35/50/60/71VHA4 PUHZ-RP100/15/140VKA OCH451 PUHZ-RP100/15/140YKA PUHZ-HRP71/100VHA PUHZ-HRP71/100VHA PUHZ-HRP71/100VHAR1 PUHZ-HRP100VHAR OCH45 PUHZ-HRP100/15YHA PUHZ-HRP100/15YHA PUHZ-HRP100/15YHAR1 PUHZ-W50/85VHA PUHZ-W50/85VHA-BS OCH439 PUHZ-W85VHAR1 PUHZ-W85VHAR1-BS PUHZ-W85VHA.UK OCH465 PUHZ-W85VHA-BS.UK PUHZ-HW11/140YHA PUHZ-HW11/140YHA-BS PUHZ-HW11/140YHA PUHZ-HW11/140YHA-BS PUHZ-HW140VHA OCH439 PUHZ-HW140VHA-BS PUHZ-HW140VHA PUHZ-HW140VHA-BS PUHZ-HW140VHAR1-BS...
  • Page 3: Safety Precaution

    Do not position furniture or electrical appliances below the outdoor unit or cylinder unit. The discharge pipework from the emergency/safety devices of the cylinder unit should be installed according to local law. Only use accessories and replacement parts authorised by Mitsubishi Electric and employ a qualified technician to fit the parts. Electrical All electrical work should be performed by a qualified technician according to local regulations and the instructions given in this manual.
  • Page 4 WARNING (SPLIT MODELS ONLY) Do not discharge refrigerant into the atmosphere. If refrigerant leaks during installation, ventilate the room. Use appropriate tools for high pressure refrigerant. When pumping down refrigerant , stop the compressor before disconnecting the refrigerant pipes. During installation securely fasten the refrigerant pipes before starting the compressor. Check that refrigerant gas does not leak after the completion of installation.
  • Page 5 CAUTIONS RELATED TO NEW REFRIGERANT Cautions for units utilizing refrigerant R410A Use a vacuum pump with a reverse flow check Use new refrigerant pipes. valve. If using the existing R22, be careful of the followings. Vacuum pump oil may flow back into refrigerant cycle and ·...
  • Page 6 [1] Cautions for service (1) Perform service after recovering the refrigerant left in unit completely. (2) Do not release refrigerant in the air. (3) After completing service, charge the cycle with specified amount of refrigerant. (4) When performing service, install a filter drier simultaneously. Be sure to use a filter drier for new refrigerant.
  • Page 7: Specifications

    SPECIFICATIONS Product specification...
  • Page 8: Part Names And Functions

    PART NAMES AND FUNCTIONS <EHST20C-*M*HA/*M*A> (Split model system) Number Component Automatic air vent Pressure relief valve Expansion vessel Main controller Control and electrical box Immersion heater (Only for EHST20C-*M*HA) DHW tank 3-way valve Water circulation pump Manual air vent Booster heater Drain cock (Booster heater) Strainer valve Flow switch...
  • Page 9 <EHPT20X-VM2HA> (UK Packaged model system) Number Component Automatic air vent Pressure relief valve Expansion vessel Main controller Control and electrical box Temperature and pressure relief valve (not visible) Immersion heater DHW tank 3-way valve Water circulation pump Manual air vent Booster heater Drain cock (Booster heater) Strainer valve...
  • Page 10: Outlines And Dimensions

    OUTLINES AND DIMENSIONS (Unit: mm) 5-1. Technical Drawings Air vent Pressure relief valve G1/2 Main controller Temperature and pressure relief valve and its access plate (EXPT20X-VM2HA only) Terminal block <Right side> <Left side> <Front> Letter Pipe description Connection size/type DHW outlet connection  mm/Compression Cold water inlet connection  mm/Compression...
  • Page 11: Wiring Diagram

    WIRING DIAGRAM 6-1. EHST20C-VM6HA * See Chapter 6-10.
  • Page 12 6-2. EHST20C-YM9HA * See Chapter 6-10.
  • Page 13 6-3. EHST20C-VM6A EHST20C-VM6SA * See Chapter 6-10.
  • Page 14 6-4. EHST20C-YM9A * See Chapter 6-10.
  • Page 15 6-5. EHPT20X-VM2HA * See Chapter 6-10.
  • Page 16 6-6. EHPT20X-VM6HA * See Chapter 6-10.
  • Page 17 6-7. EHPT20X-YM9HA * See Chapter 6-10.
  • Page 18 6-8. EHPT20X-VM6A * See Chapter 6-10.
  • Page 19 6-9. EHPT20X-YM9A * See Chapter 6-10.
  • Page 20 6-10. Dip switch setting <Dip Switch Functions> Located on the FTC3 printed circuit board are 4 sets of small white switches known as Dip switches. The Dip switch number is printed on the circuit board next to the relevant switches. The word ON is printed on the circuit board and on the Dip switch block itself.
  • Page 21: Field Wiring

    FIELD WIRING Option 1: Cylinder unit powered via outdoor unit <1 phase> Cylinder unit Outdoor unit To control Wiring Power board Earth circuit supply breaker leakage breaker 230V Isolating 50Hz switch ECB1 ELB for Wiring Power booster circuit supply heater breaker (Primary circuit) 230V...
  • Page 22 <3 phase> Cylinder unit Outdoor unit To control board Power Wiring supply Earth circuit leakage breaker 400V breaker Isolating 50Hz switch ECB1 ELB for Wiring booster Power circuit heater Supply breaker (Primary circuit) 400V Isolating switch 50Hz ECB2 ELB for Wiring Power immersion...
  • Page 23 Option2: Cylinder unit powered by independent source. If the cylinder and outdoor units have separate power supplies, the following requirements MUST be carried out: Black Initial settings CNO1 (Power supplied • Cylinder unit electrical box connector connections changed (see Figure 7-3) Cylinder unit by outdoor unit) control board...
  • Page 24 <3 phase> Cylinder unit Power Wiring supply Earth circuit leakage breaker breaker 230V Isolating 50Hz switch Outdoor unit To control board Power Wiring supply circuit Earth breaker leakage 400V breaker Isolating 50Hz switch ECB1 ELB for Wiring booster Power circuit heater supply breaker...
  • Page 25: Water System Diagram

    WATER SYSTEM DIAGRAM EHST20C-*M*HA / *M*A EHST20C-VM6SA...
  • Page 26 EHPT20X-VM2HA EHPT20X-*M*HA / *M*A...
  • Page 27 Filling the cylinder unit 1. Check all connections including factory fitted ones are tight. 2. Insulate pipe work between cylinder and outdoor unit. 3. Thoroughly clean and flush, system of all debris. (see section 4.2 of Installation Manual for detailed instructions.) 4.
  • Page 28: Controls

    CONTROLS 9-1. Main Controller <Main controller parts> Letter Name Function Screen in which all information is displayed Screen Access to system settings for initial set up and Menu modifications. Back Return to previous menu. Confirm Used to select or save. (Enter key) Power/Holiday If system is switched off pressing once will turn sys- tem on.
  • Page 29 <Main Controller Menu Tree> Initial Unrestricted access Main screen Installer only Information Option Forced DHW ON/OFF ON/OFF/Timer Heating ON/OFF/Timer Holiday Active/Non active Set time Main menu Normal Edit DHW max. temp DHW max. temperature drop DHW max. operation time DHW mode restriction Legionella Active/Non active Edit...
  • Page 30 9-2. Service Menu The service menu provides functions for use by installer or service engineer. It is NOT intended the home owner alters settings within this menu. It is for this reason password protection is required to prevent unauthorised access to the service settings.
  • Page 31 Auxiliary Setting This function is used to set the parameters for any auxiliary parts used in the sys- tem. From the service menu use F1 and F2 buttons to highlight Auxiliary setting then press CONFIRM. Auxiliary setting menu screen <Economy settings for pump> From the Auxiliary setting menu highlight Economy Settings for pump.
  • Page 32 <Manual operation> During the filling of the system the pump and 3-way valve can be manually over- ridden using manual operation mode. When manual operation is selected a small timer icon appears in the screen. The function selected will only remain in manual operation for a maximum of 2 hours. This is to prevent accidental permanent override of the FTC3.
  • Page 33 <Heat source setting> The default heat source setting is heat pump and all electric heaters present in the system to be operational. This is referred to as Standard operation on the menu. From the service menu use F1 and F2 buttons to scroll through list until is highlighted.
  • Page 34 <Room Temp Control (Heating)> This function allows operational setting of flow temperature range from the Eco- dan and also the time interval at which the FTC3 collects and processes data for the auto adaptation mode. From the Operation setting menu use F1 and F2 buttons to scroll through the list until Room temp.
  • Page 35 Indoor unit switch setting display (Request code: 162 to 165) 0: OFF 1: ON 0: OFF 1: ON SW1, SW, SW3, SW4 SW1, SW, SW3, SW4 Display Display 00 00 00 40 00 01 00 41 00 0 00 4 00 03 00 43 00 04...
  • Page 36 Indoor unit switch setting display (Request code: 162 to 165) 0: OFF 1: ON 0: OFF 1: ON SW1, SW, SW3, SW4 SW1, SW, SW3, SW4 Display Display 00 80 00 C0 00 81 00 C1 00 8 00 C 00 83 00 C3 00 84...
  • Page 37 Output signal display (Request code: 175) Please refer to Table 2 on relevant wiring diagram whilst using the following. 0: OFF 1: ON 0: OFF 1: ON Display Display xx 00 xx 40 xx 01 xx 41 xx 02 xx 42 xx 03 xx 43 xx 04...
  • Page 38 Indoor unit switch setting display (Request code: 175) Please refer to Table 2 on relevant wiring diagram whilst using the following. 0: OFF 1: ON 0: OFF 1: ON Display Display xx 80 xx C0 xx 81 xx C1 xx 82 xx C2 xx 83 xx C3...
  • Page 39 Input signal display (Request code: 176) Output signal display (Request code: 175) Please refer to Table 1 on relevant wiring diagram whilst using the following. Please refer to Table 2 on relevant wiring diagram whilst using the following. 0: OFF (open) 1: ON (short) 0: OFF 1: ON...
  • Page 40 <Thermistor Reading> This function shows the current readings of thermistors located on the water and refrigerant circuit Thermistor Description Room temperature Refrigerant return temperature Water flow temperature THW1 THW Water return temperature TH5A — TH5B Tank temperature TH5C — Ambient (outdoor) temperature <Summary of Settings>...
  • Page 41 <Password protection> Password protection is available to prevent unauthorised access to the service menu by untrained persons. From the service menu use F1 and F2 buttons to scroll through list until is highlighted. Press CONFIRM. When password input screen is displayed use buttons F1 and F2 to move left and right between the four digits, F3 to lower the selected digit by 1, and F4 to increase the selected digit by 1.
  • Page 42 <Emergency operation> In Emergency operation mode the outdoor heat pump unit will not operate. Heat- ing for DHW and space heating is provided by the booster heater and the tank immersion heater (if installed). Space heating flow temp is restricted 40°C if an immersion heater is not present on the DHW tank then the booster heater will also indirectly heat the DHW.
  • Page 43: Troubleshooting

    TROUBLESHOOTING 10-1. Troubleshooting <Summary of self diagnosis based on Error Codes and Service Procedures> Present and past Error codes are logged and displayed on the main controller or control board of the outdoor unit. Please refer to the table below and subsequent explanations to diagnose and remedy typical problems that may occur in the field. Unit Condition Error Code Action...
  • Page 44 10-4. Self diagnosis and action Check if Dip SW is set correctly. (Refer to Chapter 6-10.) Error code Title and display conditions Possible Cause Diagnosis and action Insufficient system head Booster heater overheat detection Refer to table in section 10-6. to determine <DHW/Heating/LP/FS/OS>...
  • Page 45 Error code Title and display conditions Possible Cause Diagnosis and action Insufficient system head Circulation water temperature overheat Refer to table in section 10-6. to determine if protection system pump meets requirements. <DHW/Heating/LP/FS/OS> If more head required either add an pump of Error code displayed when THW1 detects the same size or replace existing pump with a temp.
  • Page 46 Error code Title and display conditions Possible Cause Diagnosis and action Insufficient system head Circulation water freeze protection Refer to table in section 10-6. to determine if <DHW/Heating/LP/FS/OS> system pump meets requirements. Error code displayed when THW1 detects If more head required either add an pump of a temp.
  • Page 47 Error code Title and display conditions Possible Cause Diagnosis and action Low primary circuit flow rate detected by Insufficient system head Refer to table in section 10-6. to determine flow switch if system pump meets requirements. <DHW/Heating/LP/FS> If more head required either add an pump of the same size or replace existing pump Error code displayed when flow switch with capacity model.
  • Page 48 Error code Title and display conditions Possible Cause Diagnosis and action Fault with FTC3 transmission/receiving Indoor/outdoor communication failure (Transmission error) circuit board Turn the power to the indoor unit OFF and Electrical noise causes interference with Error code E7 is displayed if despite the then ON.
  • Page 49 10-5. Troubleshooting by inferior phenomena Fault symptom Possible cause Explanation - Solution 1. There is no power supply to main controller. Main controller display Check LED on FTC3. does not work. (i) When LED2 is lit. Check the main controller wiring for damage or contact failure. (ii) When LED2 is blinking.
  • Page 50 Please contact your Mitsubishi Electric dealer. 7. Immersion heater cut out has triggered. Check immersion heater thermostat and press reset button, located on immersion heater boss, if safe.
  • Page 51 Please contact your Mitsubishi Electric dealer. 8. Incorrectly sized heat emitter. 8. Check the heat emitter surface area is adequate Increase size if necessary.
  • Page 52 Fault symptom Possible cause Explanation - Solution Duration is set to excessively short time at “Economy setting for Set “Economy setting for pump” longer. 3 Heating mode has been pump”. (Go to “Service menu” → “Auxiliary setting” → “Economy on standby for a long setting for pump”).
  • Page 53 Part Name Check Points Measure the resistance between the terminals with a tester. Booster heater Thermostat (90 °C) and thermal cut out (121 °C) Terminal Normal Abnormal 121 °C 90 °C 110(±35)mΩ Manual reset Thermal 9-10 Open or Short water cut-out thermostat 2kW heater (230V, 1 phase)
  • Page 54 <Thermistor Characteristics Charts> • Room temperature thermistor (TH1) • Liquid refrigerant temperature thermistor (TH2) • Flow water temperature thermistor (THW1) • Return water temperature thermistor (THW2) • DHW tank temperature thermistor (THW5B) Thermistor R0 = 15kΩ ± 3% B constant = 3480 ± 2% Rt = 15exp {3480 ( 73+t –...
  • Page 55 10-7. Test point diagram FTC3 (Controller board) 6.3A/50V 6.3A/50V 6.3A/50V CNP/OUT1 (TBO.1 1-2) Water circulation pump1 (230V AC) CN01 Power supply OUT2 (TBO.1 3-4) (230V AC) Water circulation pump (field supply) (230V AC) 6.3A/50V CNV1/OUT4 (TBO.1 7-9) 3-way valve (7-8:230V AC) CN3C CNBHT/BHT (TBO.2 1-2) Transmission...
  • Page 56: Disassembly Procedure

    ● Do not expose the electric parts to water. ● When replacing or servicing water circuit parts, drain system first. EHST20C-VM6HA, EHST20C-YM9HA, EHST20C-VM6A, EHST20C-YM9A, EHST20C-VM6SA, EHPT20X-VM2HA, EHPT20X-VM6HA, EHPT20X-YM9HA, EHPT20X-VM6A, EHPT20X-YM9A Check individual illustrations and positions of the parts by referring to the parts catalog included in this manual.
  • Page 57 THW3 connector Terminal block (TB1) Contactors w The photos shown are of the EHST20C-VM6HA model. Photo 3-3 <Controller board> (Photo 3-3) (4) Disconnect all the lead wires from the controller board. (5) Remove the controller board from the 7 board supports.
  • Page 58 (Photo 4-3) frame frame CNF connector Cable straps (under the control box) Note: Disconnect the field wiring as necessary. w The photos shown are of the EHST20C-VM6HA model. Photo 4-2 Photo 4-3 Control box Swing...
  • Page 59 DISASSEMBLY PROCEDURE PHOTOS 5. How to remove water pump/ pump valve Photo 5-1 <Water pump> (1) Remove the front panel. (Refer to Procedure 1.) Nut (1") Gasket(1") (2) Remove the control box cover. (Refer to Procedure 3.) (3) Disconnect the CNP1 connector on the controller board Pump valve and release the lead wire from the 3 cable clamps and handle (upper)
  • Page 60 DISASSEMBLY PROCEDURE PHOTOS 6. How to remove the 3-WAY VALVE / 3-WAY VALVE MOTOR Photo 6-1 (1) Remove the front panel. (Refer to Procedure 1.) (2) Remove the control box. (Refer to Procedure 4.) (3) Remove the 3-way valve motor from the 3-way valve while pressing the button on the back of the motor (viewed Nut (1") from the front of the cylinder unit).
  • Page 61 DISASSEMBLY PROCEDURE PHOTOS 7. How to remove the flow switch Photo 7-1 (1) Remove the front panel. (Refer to Procedure 1.) (2) Remove the control box cover. (Refer to Procedure 3.) Lead wire Flow switch (3) Disconnect the CN2F connector on the controller board. (Photo 4-1) (4) Release the lead wire from the 5 bands and 2 cable straps.
  • Page 62 (7) Remove the two screws on the heater stay. Lift the Terminal block (TB1) Contactors booster heater slightly and remove the booster heater w The photos shown are of the EHST20C-VM6HA model. from the heater stay. (Photo 8-4) (8) Remove the flare joint from the booster heater. Photo 8-2 (Photo 8-3) w When reinstalling the flare joint, use a new 3/8"...
  • Page 63 DISASSEMBLY PROCEDURE PHOTOS 9. How to remove the thermostat/immersion heater Photo 9-1 <Thermostat> (1) Remove the front panel. (Refer to Procedure 1.) (2) Peel off the water-proof tapes on the plastic head of the thermostat in order to reveal the thermostat terminals, and disconnect the lead wires from the terminals.
  • Page 64 DISASSEMBLY PROCEDURE PHOTOS 10. How to remove the plate heat exchanger Photo 10-1 (1) Remove the front panel. (Refer to Procedure 1.) Pump frame (2) Pump down the refrigerant circuit and close the Bands stop valve at the outdoor unit side. (Refer to 12. SUPPLEMENTARY INFORMATION.) (3) Remove the control box.
  • Page 65 DISASSEMBLY PROCEDURE PHOTOS 10. How to remove the plate heat exchanger Photo 10-4 (10) Displace the plate heat exchanger together with the refrigerant pipes, the water pipe and the flexible hose to the front of the cylinder unit while feeding the top ends of the 2 refrigerant pipes though the openings in the top panel and remove the heat exchanger unit from the cylinder unit.
  • Page 66 DISASSEMBLY PROCEDURE PHOTOS 12. How to remove the pressure relief valve / manometer / air Photo 12-1 Manometer vent (automatic) (1) Remove the front panel. (Refer to Procedure 1.) (2) Swing the control box to the front. (Refer to Procedure 4.) <Manometer>...
  • Page 67 DISASSEMBLY PROCEDURE PHOTOS 13. How to remove the expansion vessel Photo 13-1 (1) Remove the front panel. (Refer to Procedure 1.) Expansion vessel Flare joint Flare nut (2) Swing the control box to the front. (Refer to Procedure 4.) (3) Remove the flare nut using two spanners: one to hold the flare joint and the other to turn the flare nut.
  • Page 68 DISASSEMBLY PROCEDURE PHOTOS Photo 16-1 Drain cock 16. How to remove the drain cock (primary circuit) (booster heater side) (1) Remove the front panel. (Refer to Procedure 1.) Booster heater side (2) Remove the drain cock from the booster heater by turning the drain cock.
  • Page 69 DISASSEMBLY PROCEDURE PHOTOS 19. Remove the liquid refrigerant temp. thermistor (TH2) Photo 19-1 Thermistor <THW1> / flow water temp. & return water temp. thermistor (THW1,THW2) / tank water temp. thermistor (THW5B) (1) Remove the front panel. (Refer to Procedure 1.) (2) Remove the control box cover.
  • Page 70 DISASSEMBLY PROCEDURE PHOTOS 20. How to remove the booster heater temp. thermistor Photo 20-1 Booster heater (THW3) (1) Remove the front panel. (Refer to Procedure 1.) (2) Remove the control box cover. (Refer to Procedure 3.) (3) Remove the THW3 connector on the controller board. (Photo 19-2) (4) Cut the band bundling the THW3 cable.
  • Page 71 Notes on replacing the parts Replacement of the parts listed below requires the following procedure. After the parts are removed, eliminate loctite on threads by applying loctite remover, apply new loctite, and then install and tighten the parts to the specified tightening torques below.
  • Page 72: Supplementary Information

    SUPPLEMENTARY INFORMATION Refrigerant recovery (pump down) for split systems only For split system the following procedures should be followed to recover system refrigerant: Note) Pump down operation can not be activated by switching the pump down switch (SWP) or test run switch on the outdoor unit PCB. Ensure both the outdoor unit and the indoor unit are in emergency mode before carrying out the following.
  • Page 73: Service And Maintenance

    SERVICE AND MAINTENANCE Engineers form The main controller settings changed from the default settings are reset by replacing the controller board. To facilitate reselecting settings on the main controller, it is recommended to write down the changes in the sheet below before replacement. Commissioning/Field settings record sheet Default Field...
  • Page 74 Annual Maintenance Log Book Engineer name Contractor name Site name Site number Cylinder maintenance record sheet Warranty number Model number Serial number Mechanical Frequency Notes Turn OFF water supply, drain tank, remove mesh from strainer clean and replace in strainer. *1 Keep water supply OFF, open hot water taps and check the expansion vessel charge pressure.
  • Page 76 HEAD OFFICE : TOKYO BLDG., -7-3, MARUNOUCHI, CHIYODA-KU, TOKYO 100-8310, JAPAN Copyright 2011 MITSUBISHI ELECTRIC ENGINEERING CO., LTD. New publication, effective Jul. 2011 Distributed in Jul. 011 No. OCH507 Specifications subject to change without notice Made in Japan...

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