Mitsubishi Electric EHST17D-YM9D Service Manual

Mitsubishi Electric EHST17D-YM9D Service Manual

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CYLINDER UNIT
SERVICE MANUAL
[Model Name]
EHST17D-VM2D
EHST17D-YM9D
ERST17D-VM2D
ERST17D-VM6D
EHST20D-MED
EHST20D-VM2D
EHST20D-VM6D
EHST20D-YM9D
EHST20D-YM9ED
EHST20D-TM9D
ERST20D-VM2D
ERST20D-VM6D
ERST20D-YM9D
EHST30D-MED
EHST30D-VM6ED
EHST30D-YM9ED
EHST30D-TM9ED
ERST30D-VM2ED
[Service Ref.]
Refer to page 2.
CYLINDER UNIT
ERST30D-VM6ED
ERST30D-YM9ED
EHST20C-MED
EHST20C-VM2D
EHST20C-VM6D
EHST20C-YM9D
EHST20C-YM9ED
EHST20C-TM9D
ERST20C-VM2D
ERST20C-VM6D
ERST20C-YM9D
EHST30C-MED
EHST30C-VM6ED
EHST30C-YM9ED
EHST30C-TM9ED
ERST30C-VM2ED
ERST30C-VM6ED
ERST30C-YM9ED
MAIN REMOTE
CONTROLLER
EHPT17X-VM2D
EHPT17X-VM6D
EHPT17X-YM9D
ERPT17X-VM2D
EHPT20X-MED
EHPT20X-VM6D
EHPT20X-YM9D
EHPT20X-YM9ED
EHPT20X-TM9D
EHPT20X-MHEDW
ERPT20X-MD
ERPT20X-VM2D
ERPT20X-VM6D
EHPT30X-MED
EHPT30X-YM9ED
ERPT30X-VM2ED
ERPT30X-VM6ED
CONTENTS
TECHNICAL CHANGES ....................................... 3
1. REFERENCE MANUAL ................................... 4
2. SAFETY PRECAUTION ................................... 5
3. SPECIFICATIONS ............................................ 7
4. PART NAMES AND FUNCTIONS ................. 11
5. OUTLINES AND DIMENSIONS ..................... 13
6. WIRING DIAGRAM ........................................ 15
7. FIELD WIRING ............................................... 21
8. WATER SYSTEM DIAGRAM ......................... 25
9. CONTROLS ................................................... 29
10. TROUBLESHOOTING ................................... 50
11. DISASSEMBLY PROCEDURE ...................... 67
12. SUPPLEMENTARY INFORMATION ............. 88
13. SERVICE AND MAINTENANCE ................... 89
PARTS CATALOG (OCB714)
October 2020
No. OCH714
REVISED EDITION-B
Revision:
• EHST17D-VM2DR1.UK, EHST17D-
YM9DR1.UK, ERST17D-VM2/6DR1.
UK, EHST20D-MEDR1.UK, EHST20D-
VM2/6DR1.UK, EHST20D-YM9DR1.
UK, EHST20D-YM9EDR1.UK,
EHST20D-TM9DR1.UK, ERST20D-
VM2/6DR1.UK, ERST20D-YM9DR1.
UK, EHST30D-MEDR1.UK, EHST30D-
VM6EDR1.UK, EHST30D-YM9EDR1.
UK, EHST30D-TM9EDR1.UK,
ERST30D-VM2/6EDR1.UK, ERST30D-
YM9EDR1.UK, EHST20C-MEDR1.UK,
EHST20C-VM2/6DR1.UK, EHST20C-
YM9DR1.UK, EHST20C-YM9EDR1.UK,
EHST20C-TM9DR1.UK, ERST20C-
VM2/6DR1.UK, ERST20C-YM9DR1.
UK, EHST30C-MEDR1.UK, EHST30C-
VM6EDR1.UK, EHST30C-YM9EDR1.
UK, EHST30C-TM9EDR1.UK,
ERST30C-VM2/6EDR1.UK, ERST30C-
YM9EDR1.UK, EHPT17X-VM2/6DR1.
UK, EHPT17X-YM9DR1.UK, ERPT17X-
VM2DR1.UK, EHPT20X-MEDR1.UK,
EHPT20X-VM6DR1.UK, EHPT20X-
YM9DR1.UK, EHPT20X-YM9EDR1.
UK, EHPT20X-TM9DR1.UK, EHPT20X-
MHEDWR1.UK, ERPT20X-MDR1.UK,
ERPT20X-VM2/6DR1.UK, EHPT30X-
MEDR1.UK, EHPT30X-YM9EDR1.UK
and ERPT30X-VM2/6EDR1.UK have
been added
• Some descriptions have been modified
in REVISED EDITION-B.
OCH714A is void.
Note:
• This manual describes service data of
cylinder unit only.

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Summary of Contents for Mitsubishi Electric EHST17D-YM9D

  • Page 1 CYLINDER UNIT October 2020 No. OCH714 SERVICE MANUAL REVISED EDITION-B [Model Name] EHST17D-VM2D ERST30D-VM6ED EHPT17X-VM2D Revision: • EHST17D-VM2DR1.UK, EHST17D- EHST17D-YM9D ERST30D-YM9ED EHPT17X-VM6D YM9DR1.UK, ERST17D-VM2/6DR1. UK, EHST20D-MEDR1.UK, EHST20D- ERST17D-VM2D EHST20C-MED EHPT17X-YM9D VM2/6DR1.UK, EHST20D-YM9DR1. UK, EHST20D-YM9EDR1.UK, ERST17D-VM6D EHST20C-VM2D ERPT17X-VM2D EHST20D-TM9DR1.UK, ERST20D- VM2/6DR1.UK, ERST20D-YM9DR1.
  • Page 2 [Service Ref.] EHST17D-VM2D.UK EHST17D-VM2DR1.UK EHPT20X-MEDR1.UK ERST17D-VM2D.UK EHST17D-YM9DR1.UK EHPT20X-VM6DR1.UK EHST20D-MED.UK ERST17D-VM2DR1.UK EHPT20X-YM9DR1.UK EHPT20X-YM9EDR1.UK EHST20D-VM2D.UK ERST17D-VM6DR1.UK EHPT20X-TM9DR1.UK EHST20D-VM6D.UK EHST20D-MEDR1.UK EHPT20X-MHEDWR1.UK EHST20D-YM9D.UK EHST20D-VM2DR1.UK ERPT20X-MDR1.UK EHST20D-YM9ED.UK EHST20D-VM6DR1.UK ERPT20X-VM2DR1.UK EHST20D-TM9D.UK EHST20D-YM9DR1.UK ERST20D-VM2D.UK EHST20D-YM9EDR1.UK ERPT20X-VM6DR1.UK EHST30D-MED.UK EHST20D-TM9DR1.UK EHPT30X-MEDR1.UK EHST30D-VM6ED.UK ERST20D-VM2DR1.UK EHPT30X-YM9EDR1.UK EHST30D-YM9ED.UK ERST20D-VM6DR1.UK ERPT30X-VM2EDR1.UK EHST30D-TM9ED.UK ERST20D-YM9DR1.UK ERPT30X-VM6EDR1.UK ERST30D-VM2ED.UK EHST30D-MEDR1.UK...
  • Page 3: Technical Changes

    TECHNICAL CHANGES Service ref. have been changed as follows. EHST17D-VM2DR1.UK EHST17D-VM2D.UK ERST17D-VM2DR1.UK ERST17D-VM2D.UK EHST20D-MEDR1.UK EHST20D-MED.UK EHST20D-VM2DR1.UK EHST20D-VM2D.UK EHST20D-VM6DR1.UK EHST20D-VM6D.UK EHST20D-YM9DR1.UK EHST20D-YM9D.UK EHST20D-YM9EDR1.UK EHST20D-YM9ED.UK EHST20D-TM9DR1.UK EHST20D-TM9D.UK ERST20D-VM2DR1.UK ERST20D-VM2D.UK EHST30D-MEDR1.UK EHST30D-MED.UK EHST30D-VM6EDR1.UK EHST30D-VM6ED.UK EHST30D-YM9EDR1.UK EHST30D-YM9ED.UK EHST30D-TM9EDR1.UK EHST30D-TM9ED.UK ERST30D-VM2EDR1.UK ERST30D-VM2ED.UK EHST20C-MEDR1.UK EHST20C-MED.UK EHST20C-VM2DR1.UK EHST20C-VM2D.UK EHST20C-VM6DR1.UK EHST20C-VM6D.UK...
  • Page 4 REFERENCE MANUAL OUTDOOR UNIT'S SERVICE MANUAL Service Ref. Service Manual No. SUZ-SWM40VA.TH OCH718 SUZ-SWM60VA.TH OCB718 SUZ-SWM80VA.TH PUHZ-FRP71VHA2 OCH665 PUHZ-FRP71VHA2R1 OCB665 PUHZ-SW120VHAR5(-BS).UK OCH533 PUHZ-SW120YHAR5(-BS).UK OCB533 OCH526 PUHZ-SHW140YHAR5(-BS).UK OCB526 PUHZ-SHW80VAA(-BS).UK PUHZ-SHW80YAA(-BS).UK PUHZ-SHW112VAA(-BS).UK PUHZ-SHW112YAA(-BS).UK PUHZ-SW75VAA(-BS).UK OCH651 PUHZ-SW75YAA(-BS).UK OCB651 PUHZ-SW75VAA-SC.UK PUHZ-SW75YAA-SC.UK PUHZ-SW100VAA(-BS).UK PUHZ-SW100YAA(-BS).UK PUMY-P112VKM4R4(-BS).UK Split model PUMY-P125VKM4R4(-BS).UK PUMY-P140VKM4R4(-BS).UK...
  • Page 5: Safety Precaution

    Do not position furniture or electrical appliances below the outdoor unit or cylinder unit. The discharge pipework from the emergency devices of the cylinder unit should be installed according to local law. Only use accessories and replacement parts authorised by Mitsubishi Electric ask 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 6: Cautions For Service

    CAUTION Use clean water that meets local quality standards on the primary circuit. The outdoor unit should be installed in an area with sufficient airflow according to the diagrams in the outdoor unit installation manual. The cylinder unit should be located inside to minimise heat loss. Water pipe-runs on the primary circuit between outdoor and indoor unit should be kept to a minimum to reduce heat loss.
  • Page 7: Specifications

    SPECIFICATIONS OCH714B...
  • Page 8 OCH714B...
  • Page 9 OCH714B...
  • Page 10 OCH714B...
  • Page 11: Part Names And Functions

    PART NAMES AND FUNCTIONS <E**T***-*M**D> (Split model system) (Packaged model system) Note: For installation of all E**T***-*M*ED* models, make sure to install a suitably sized primary- side expansion vessel. (See figure 8.1 - 8.5 and 10.6.1 for further guidance) <Figure 4.1> EHST17/20D- EHST20/30D- EHST20/30D-...
  • Page 12 ERST20C- ERST30C- EHPT17/20X- EHPT20/30X- EHPT20/30X- ERPT17/20X- ERPT20X- ERPT30X- EHPT20X- Part name *M*D *M*ED *M*D *M*ED *M*D VM*ED MHEDW DHW outlet pipe Cold water inlet pipe Water pipe (Space heating/cooling return connection) Water pipe (Space heating/cooling flow connection) Water pipe (Flow from heat pump connection) —...
  • Page 13: Outlines And Dimensions

    OUTLINES AND DIMENSIONS 5-1. Technical Drawings <E**T***-*M**D> <Unit: mm> (Packaged model system) 67.8 DHW tank <E*PT30X-*M*ED> <EHPT20X-MHEDW> 170L 200L 300L 442.3 capacity 515.7 542.3 1400 1600 2050 PRESSURE TEMPERATURE & RELIEF VALVE HANDLE PRESSURE (SANITARY CIRCUIT) AIR VENT RELIEF VALVE G1/2 MANOMETER MAIN...
  • Page 14: Service Access Diagrams

    5-2. Service access diagrams Service access * An additional 300 mm of space (total Parameter Dimension (mm) 600 mm) is required , when installing 300* the optional 2-zone kit (PAC-TZ02-E) on top of the cylinder unit. c (distance behind unit not visible in the right figure) Sufficient space MUST be left for the provision of discharge pipework as detailed in National and Local Building Regulations.
  • Page 15: Wiring Diagram

    WIRING DIAGRAM 6-1. E**T***-VM2(E)D OCH714B...
  • Page 16 6-2. E**T***-VM6(E)D OCH714B...
  • Page 17 6-3. E**T***-YM9(E)D OCH714B...
  • Page 18 6-4. E**T***-M(E)D OCH714B...
  • Page 19 6-5. EH*T***-TM9(E)D OCH714B...
  • Page 20: Dip Switch Functions

    6-6. DIP Switch Functions The DIP switch number is printed on the circuit board next to the relevant switch- es. The word ON is printed on the circuit board and on the DIP switch block itself. To move the switch you need to use a pin or the corner of a thin metal ruler or similar.
  • Page 21: Field Wiring

    FIELD WIRING Breaker abbreviation Meaning ECB1 Earth leakage circuit breaker for booster heater ECB2 Earth leakage circuit breaker for immersion heater Terminal block 1 Option 1: Cylinder unit powered via outdoor unit (If you want to use independent source, go to the Mitsubishi website.) <1 phase>...
  • Page 22: Electrical Connections 3 Phase

    <3 phase> Affix label A that is included with the manuals near each wiring diagram for cylinder unit and outdoor units. Cylinder unit Outdoor unit To control board Wiring Earth circuit leakage Power supply breaker circuit 3N~ 400 V 50 Hz breaker Isolating *1, *2...
  • Page 23 Option 2: Cylinder unit powered by independent source. If the cylinder unit and outdoor unit have separate power supplies, the following requirements MUST be carried out: Initial settings White (Power supplied by CN01 outdoor unit) • Change the interconnected wiring in the control and electrical box of the Cylinder unit cylinder unit (see Figure 7-3).
  • Page 24 <3 phase> Affix label B that is included with the manuals near each wiring diagram for cylinder unit and outdoor units. Cylinder unit Wiring Earth circuit leakage breaker circuit To control Power supply breaker board Isolating ~/N 230 V 50 Hz *1, *2 switch Outdoor unit...
  • Page 25: Water System Diagram

    WATER SYSTEM DIAGRAM <E*PT17X-*M*D> (Packaged model system) Water flow Cold water *a. Refer to the following section [Local system]. *b. If the outdoor unit is higher than the indoor  unit, or if there is a location where air gets  Drain trapped in the upper part of the water pipe, ...
  • Page 26 *a. Refer to the following section ‘Local sys- <EHPT20X-MHEDW> (UK model system) <Example> Water flow tem’ on the ‘Paper-based manual’. Note Cold water • To enable draining of the cylinder unit, an iso- lating valve should be positioned on both the inlet and outlet pipework.
  • Page 27 Local system 1-zone temperature control Zone1 Zone1 2-zone temperature control 1-zone temperature control with boiler Zone1 Zone1 Zone2 2-zone temperature control & Buffer tank control 1-zone temperature control (2-zone valve ON/OFF control) Zone1 Zone1 Zone2 Zone2 1. Zone1 heat emitters (e.g. radiator, fan coil unit) (local supply) 10.
  • Page 28 Filling the cylinder unit (Primary circuit) 1. Check and charge expansion vessel. 2. Check all connections including factory fitted ones are tight. 3. Insulate pipework between cylinder unit and outdoor unit. 4. Thoroughly clean and flush system of all debris. (Refer to 4.2 in the installation manual.) 5.
  • Page 29: Main Screen

    Menu Access to system settings for initial set up and The following is a guide to viewing the main settings. Should you require modifications. more information please contact your installer or local Mitsubishi Electric Back Return to previous menu. dealer.
  • Page 30: General Operation

    9-2. Setting the Main remote controller After the power has been connected to the outdoor and cylinder units (See "7. FIELD WIRING"), the initial system settings can be entered via the main remote con- troller. 1. Check all breakers and other safety devices are correctly installed and turn on power to the system. 2.
  • Page 31: Long Press

    <Main Remote Controller Menu Tree> Initial Unrestricted access Installer only Main screen * Short press for 1 Zone system. Long press Information Option Forced DHW ON ( )/OFF ON ( )/Prohibited ( )/Timer ( ) Heating/Cooling ON ( )/Prohibited ( )/Timer ( ) Energy monitor Consumed electrical energy Menu...
  • Page 32 <Continued from the previous page.> <Main Controller Menu Tree> Unrestricted access Initial Installer only Main screen Main Long press menu Manual operation Menu Function settings Service Thermistor adjustment Password ON/OFF protected Economy settings for pump Delay ON/OFF Electric heater (Heating) Delay ON/OFF (Booster heater/Immersion heater) Auxiliary settings...
  • Page 33 <Continued from the previous page.> <Main Controller Menu Tree> Unrestricted access Initial Installer only Main screen Main menu Long press Menu Booster heater 1 capacity Electric heater Booster heater 2 capacity capacity Immersion heater Analog output Pump 1 Water pump input Energy monitor Pump 2 settings...
  • Page 34: Service Menu

    9-5. 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. The factory default password is "0000".
  • Page 35: Function Description

    <Thermistor adjustment> This function allows adjustments to be made to the thermistor readings from −10 to 10°C in 0.5°C intervals. THW1: Thermistor (Flow water temp.) THW2: Thermistor (Return water temp.) THW5: Thermistor (DHW tank water temp.) THW6: Thermistor (Zone1 flow temp.)(Option) THW7: Thermistor (Zone1 return temp.)(Option) THW8: Thermistor (Zone2 flow temp.)(Option) THW9: Thermistor (Zone2 return temp.)(Option)
  • Page 36 Mixing valve control 1. From the Auxiliary settings menu highlight Mixing valve control. 2. Press CONFIRM. 3. The Mixing valve control screen is displayed. 4. Use F1 and F2 buttons to set Running time between 10 to 240 seconds. The Running time equals to a period from full open of the valve (at a hot water mixing ratio of 100%) to full close (at a cold water mixing ratio of 100%).
  • Page 37: Heating Operation

    <Operation settings> Heating operation This function allows operational setting of flow temperature range from the Ecodan and also the time interval at which the FTC collects and processes data for the auto adaptation mode. Menu subtitle Function Range Unit Default Flow temp.
  • Page 38 4 kW 0 kW fitted pump) EHST17D-VM2D 2 kW 0 kW 0 kW ERST20C-YM9D 3 kW 6 kW 0 kW EHST17D-YM9D 3 kW 6 kW 0 kW EHST30C-MED 0 kW 0 kW 0 kW ERST17D-VM2D 2 kW 0 kW 0 kW...
  • Page 39 2. Settings using the main remote controller In this menu, all parameters required to record the consumed electrical energy and the delivered heat energy which is displayed on the main remote controller can be set. The parameters are an electric heater capacity, supply power of water pump and heat meter pulse.
  • Page 40: Password Input Screen

    <Summary of settings> This function shows the current installer/user entered settings. Abbreviation Explanation Abbreviation Explanation HWtemp DHW max. temperature Z2 mode Operation mode HWdrop DHW temperature drop - HER (Heating room temperature) HWtime DHW max. operation time - HE (Heating flow temperature) NO HW DHW mode restriction - HCC (Heating compensation curve)
  • Page 41: Completion Screen

    Resetting the password If you forget the password you entered, or have to service a unit somebody else installed, you can reset the password to the factory default of 0000. 1. From the main settings menu scroll down the functions until Service Menu is highlighted.
  • Page 42 <Table 9.5.3> Request Request content Range Unit code Error history 1 (latest) Displays error history. ("– –" is displays if no history is present.) Code Error history 2 (second to last) Displays error history. ("– –" is displays if no history is present.) —...
  • Page 43 Indoor unit switch setting display (Request code: 162 to 166) 0: OFF 1: ON 0: OFF 1: ON SW1, SW2, SW3, SW4, SW5 SW1, SW2, SW3, SW4, SW5 Display Display 00 00 00 40 00 01 00 41 00 02 00 42 00 03 00 43...
  • Page 44 Indoor unit switch setting display (Request code: 162 to 166) 0: OFF 1: ON 0: OFF 1: ON SW1, SW2, SW3, SW4, SW5 SW1, SW2, SW3, SW4, SW5 Display Display 00 80 00 C0 00 81 00 C1 00 82 00 C2 00 83 00 C3...
  • Page 45 Output signal display (Request code: 175/553) Please refer to Table 2 on relevant wiring diagram whilst using the following. 0: OFF 1: ON 0: OFF 1: ON Display Display xx 40 xx 00 xx 01 xx 41 xx 02 xx 42 xx 43 xx 03 xx 04...
  • Page 46 Output signal display (Request code: 175/553) Please refer to Table 2 on relevant wiring diagram whilst using the following. 0: OFF 1: ON 0: OFF 1: ON Display Display xx C0 xx 80 xx C1 xx 81 xx C2 xx 82 xx C3 xx 83 xx C4...
  • Page 47 0: OFF 1: ON Output signal display (Request code: 175/553) Display Please refer to Table 2 on relevant wiring diagram whilst using the following. 40 xx 41 xx 0: OFF 1: ON 42 xx 43 xx Display 44 xx 00 xx 45 xx 01 xx 46 xx...
  • Page 48 Input signal display (Request code: 176/554) Please refer to Table 1 on relevant wiring diagram whilst using the following. 0: OFF (open) 1: ON (short) 0: OFF (open) 1: ON (short) Display Display 00 00 00 40 00 01 00 41 00 02 00 42 00 03...
  • Page 49: Emergency Operation

    Indoor unit only operation Indoor unit only operation In indoor unit only operation, an operation without connecting outdoor unit is possible. Indoor unit When in Indoor unit only operation, the main control has control functions. Necessary Heat pump Not necessary <Heater>...
  • Page 50: Troubleshooting

    TROUBLESHOOTING 10-1. Troubleshooting <Summary of self-diagnosis based on Check codes and Service Procedures> Present and past Check codes are logged, and they can be displayed on the main remote 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 Check code Action...
  • Page 51 10-4. Self-diagnosis and action Check if DIP SW is set correctly. (Refer to "6-6. DIP switch functions".) Check code Title and display conditions Possible Cause Diagnosis and action Circulation water temperature overheat 1. Insufficient system head 1 Refer to table in "10-6. Checking Compo- protection nent Parts' Function"...
  • Page 52 Check code Title and display conditions Possible Cause Diagnosis and action P1/P2/L5/LD Indoor unit temperature thermistor failure 1. Connector/terminal wire has become 1. Visually check the terminals and connec- Note: The thermistors subject to failure can be detached or loose wiring. tions and reattaches appropriate.
  • Page 53 Check code Title and display conditions Possible Cause Diagnosis and action Heating operation error 1. THW1 has become detached from its 1. Visually inspect location and reattach as Note: “3” is displayed in “Request code: 567” in holder. necessary. “Running information”. 2.
  • Page 54 Check code Title and display conditions Possible Cause Diagnosis and action Low primary circuit (Zone2 side) flow rate 1. Insufficient system head 1. If more head required either add a pump of the same size or replace existing pump. detected by flow switch 2.
  • Page 55 Check code Title and display conditions Possible Cause Diagnosis and action <Defrosting> <Defrosting> THW2 detects a temperature ≤15ºC and TH2 1. Reduced water flow 1., 2. Check water piping. detects a temperature ≤−16ºC for consecutive 10 • Clogged filter seconds. •...
  • Page 56 Check code Title and display conditions Possible Cause Diagnosis and action E1/E2 1. Fault with the main remote controller 1. Replace main remote controller circuit Main remote controller control board failure circuit board board. Check code E1 displayed if main remote control- ler cannot access it is non volatile (non power dependent) memory.
  • Page 57: Fault Symptom

    10-5. Troubleshooting by inferior phenomena Fault symptom Possible cause Explanation - Solution Main remote controller 1. There is no power supply to main remote 1. Check LED2 on FTC. (See "6. WIRING DIAGRAM".) display is blank. controller. (i) When LED2 is lit. Check for damage or contact failure of the main remote controller wiring.
  • Page 58 Contact your Mitsubishi Electric dealer. 7. Immersion heater cut-out tripped. 7. Check immersion heater thermostat and press reset button, located on im- mersion heater boss, if safe.
  • Page 59 Contact your Mitsubishi Electric dealer. 5. Immersion heater cut-out has been triggered. 5. Check immersion heater thermostat and press reset button located on immer- sion heater boss, if safe.
  • Page 60 Fault symptom Possible cause Explanation - Solution Heating system does Heating system operates depending on the heating Normal operation, no action necessary. not reach the set load to prevent low-load heating system from the lower temperature. frequent switching (ON/OFF) of the compressor. In 2-zone tempera- 1.
  • Page 61: Cooling Operation

    Fault symptom Possible cause Explanation - Solution Water discharges from 1. If continual – field supplied pressure reducing 1. Check function of pressure reducing valve and replace if necessary. expansion relief valve valve not working. - part of Inlet Control 2.
  • Page 62: Annual Maintenance

    Annual Maintenance It is essential that the cylinder unit is serviced at least once a year by a qualified individual. Any spare parts required should be purchased from Mitsubishi Electric. NEVER bypass safety devices or operate the unit without them being fully operational.
  • Page 63 10-6. Checking Component Parts' Function Part Name Checkpoints Water circulation pump (primary circuit) <Water circulation pump (primary circuit) characteristics> BROWN E*ST30D series PWM input signal Signal cable 80.0 BLUE Signal ref. Speed 5 (Default setting) 70.0 BLACK Speed 4 Feedback signal 60.0 Speed 3 BROWN...
  • Page 64 Part Name Checkpoints Booster heater Measure the resistance between the terminals with a multimeter. Thermostat (90°C) and thermal cut out (121°C) Terminal Normal Abnormal 121 °C 90 °C 9–10 110(±35) mΩ Open or Short Manual reset Thermal cut-out water thermostat 2 kW heater (230 V, 1 phase) 2 kW Terminal...
  • Page 65 Part Name Checkpoints FTC CO Pressure sensor FTC CONTROLLER BOARD CN401 WH Vout (V) CN401 WH 5 VDC Vout (V) MICRO Vout Vout PROCESSOR PRESSURE (MPa) PRESSURE 1-3 : 5 V (DC) (MPa) 3-4 : Output Vout (DC) 1-3 : 5 V (DC) 3-4 : Output Vout (DC) Thermistors Disconnect the connector then measure the resistance with a multimeter.
  • Page 66: Test Point Diagram

    10-7. Test point diagram FTC (Controller board) CNP1/OUT1 (TBO.1 1-2) Water circulation pump1 (230 VAC) OUT2 (TBO.1 3-4) Water circulation pump2 (Local supply) (230 VAC) CN01 OUT3 (TBO.1 5-6) Power supply Water circulation pump3 (230 VAC) (Local supply) (230 VAC) CNP4/OUT14 Water circulation pump4 (230 VAC)
  • Page 67: Disassembly Procedure

    DISASSEMBLY PROCEDURE <Preparation for the repair service> ● Prepare the proper tools. ● Prepare the proper protectors. ● Provide adequate ventilation. ● After stopping the operation of the cylinder and outdoor unit, turn off all the power-supply breaker. ● Discharge the condenser before the work involving the electric parts. ●...
  • Page 68 PHOTOS/ FIGURES DISASSEMBLY PROCEDURE 3. How to remove the electrical parts Photo 3-1 Earth leakage circuit (Step (1) is applied to all the following parts.) Control box breaker (ECB1) Controller board (1) Remove the front panel. (Refer to Procedure 1.) <Earth leakage circuit breaker>...
  • Page 69 PHOTOS/ FIGURES DISASSEMBLY PROCEDURE 4. How to remove the control box Photo 4-1 (1) Remove the front panel. (Refer to Procedure 1.) Screw Bracket (L) Cable clamp Bracket (R) (2) Disconnect only the lead wires in the control box that Screw connect to the components in the cylinder unit.
  • Page 70 DISASSEMBLY PROCEDURE PHOTOS/ FIGURES 5. How to remove water pump (primary circuit)/pump valve/ Photo 5-1 strainer valve <Water pump> Strainer Quick connection Close the pump valve (OFF) before removing the water pump, valve O-ring and open the valves (ON) after reinstalling the water pump. Strainer (1) Remove the front panel.
  • Page 71 From the previous page. DISASSEMBLY PROCEDURE PHOTOS/ FIGURES Photo 5-5 Cover Strainer mesh (inside) <Strainer valve> (6) Remove the 2 screws on the strainer valve stay. (Photo 5-1) (7) Remove the strainer valve by detaching the quick con- nection. • When reinstalling the quick connection, use a new O-ring.
  • Page 72 No.2 BHC1-V ERST20D-VM6D EHPT17X-VM6D No.4 BHC2-U EHST30D-VM6ED EHPT20X-VM6D ERST30D-VM6ED ERPT20X-VM6D Photo 8-1 No.5 BHC2-V EHST20C-VM6D ERPT30X-VM6ED EHST30C-VM6ED Control box Controller board EHST17D-YM9D EHST30C-YM9ED No.1 BHC1-U EHST20D-YM9D EHST30C-TM9ED No.2 BHC1-V EHST20D-YM9ED ERST30C-YM9ED No.3 BHC1-W EHST20D-TM9D EHPT17X-YM9D No.4 BHC2-U ERST20D-YM9D EHPT20X-YM9D No.5...
  • Page 73 From the previous page. DISASSEMBLY PROCEDURE PHOTOS/ FIGURES Photo 8-3 (3) Remove the DIV frame by removing the 2 screws on it. Booster heater O-ring (Photo 8-2) (Only E**T20/30* series) (4) Close (OFF) the pump valve. (Photo 8-2) • When the pump valve handle is stiff, use a tool to grip the handle and turn it carefully.
  • Page 74 From the previous page. DISASSEMBLY PROCEDURE PHOTOS/ FIGURES Photo 8-4 (9) Remove the 2 screws that hold the heater stay onto the front frame (L). Lift the booster heater slightly and remove the booster heater with the heater stay from the front frame (L).
  • Page 75 DISASSEMBLY PROCEDURE PHOTOS/ FIGURES 10. How to remove the plate heat exchanger (P-HEX) (Refrigerant - Water) <E*ST**C/D series> Photo 10-1 (1) Pump down the refrigerant circuit and close the stop valve at the outdoor unit side. DIV frame (Refer to 12. SUPPLEMENTARY INFORMATION.) (2) Remove the front panel.
  • Page 76 From the previous page. DISASSEMBLY PROCEDURE PHOTOS/ FIGURES 10. How to remove the plate heat exchanger (P-HEX) Photo 10-4 (Refrigerant - Water) Expansion vessel (7) Remove the thermistor (TH2) from the thermistor holder. (Refer to Procedure 21.) (8) Remove the manometer with the manometer cover. (Refer to Procedure 12.) (9) Loosen the flare nuts for Air vent (automatic) and pressure relief valve (3 bar), and remove the Air vent...
  • Page 77 DISASSEMBLY PROCEDURE PHOTOS/ FIGURES 12. How to remove the pressure relief valve/manometer/air Photo 12-1 vent (automatic) Manometer (1) Remove the front panel. (Refer to Procedure 1.) Manometer connection (G1/4") Manometer stay (2) Swing the control box to the front. (Refer to Procedure 4.) <Manometer>...
  • Page 78 From the previous page. DISASSEMBLY PROCEDURE PHOTOS/ FIGURES 12. How to remove the pressure relief valve/manometer/air Photo 12-4 Air vent vent (automatic) (automatic) Pressure relief valve (3 bar) <Pressure relief valve (3 bar)> (3) Remove the field piping from the pressure relief valve (3 bar).
  • Page 79 DISASSEMBLY PROCEDURE PHOTOS/ FIGURES Photo 13-1 13. How to remove the expansion vessel (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 2 tapes.
  • Page 80 DISASSEMBLY PROCEDURE PHOTOS/ FIGURES 16. How to remove the drain cock (primary circuit) Photo 16-1 (1) Remove the front panel. (Refer to Procedure 1.) <Pump valve side> (2) Remove the drain cock from the pump valve by turning the drain cock. (Photo 16-1) <Pipe side (for P-HEX)>...
  • Page 81 DISASSEMBLY PROCEDURE PHOTOS/ FIGURES Photo 18-1 18. How to remove the plate heat exchanger (P-HEX) <Water - Water> Gasket (G3/4") Nut (G3/4") (1) Remove the front panel. (Refer to Procedure 1.) (2) Drain water in the P-HEX (Water-Water) using the drain Screw cock (Primary circuit) and the drain cock (Sanitary circuit).
  • Page 82 PHOTOS/ FIGURES DISASSEMBLY PROCEDURE 20. How to remove the scale trap (sanitary circuit) Photo 20-1 (1) Remove the front panel. (Refer to Procedure 1.) (2) Disconnect the CNP4 connector and the earth cable in the control box. (Photo 4-1) Screw fixing the (3) Release the water pump lead wire from the cable clamp S.T.-W.P.
  • Page 83 DISASSEMBLY PROCEDURE PHOTOS/ FIGURES 21. How to remove the liquid refrigerant temp. thermistor Photo 21-1 (TH2)/flow water temp. & return water temp. thermistors Thermistor Thermistor <THW5A> (THW1,THW2)/tank water temp. thermistor (THW5) <THW5B> (1) Remove the front panel. (Refer to Procedure 1.) (2) Disconnect the following thermistor connectors on the controller board and release the lead wires from cable clamps and bands.
  • Page 84 DISASSEMBLY PROCEDURE PHOTOS/ FIGURES 22. How to remove the side panels Photo 22-1 (1) Remove the front panel. (Refer to Procedure 1.) Side panel (Right) (2) Remove the 4 screws on the top panel, and remove the 2 screws that hold the top panel onto the back panel. (Photos 22-2 and 24-1) (3) Remove the side panel (right) by removing the screw fix- ing the side panel (right).
  • Page 85 DISASSEMBLY PROCEDURE PHOTOS/ FIGURES Photo 24-1 24. How to remove the back panel (1) Remove the front panel. (Refer to Procedure 1.) (2) Remove the side panels. (Refer to Procedure 22.) (3) Remove the 4 screws on the back panel, and remove the Top panel Screws (Top panel) 2 screws that hold the back panel onto the frame.
  • Page 86 DISASSEMBLY PROCEDURE PHOTOS/ FIGURES Photo 25-1 25. How to detach and attach the quick connection Refer to the following steps when detaching and attaching the quick connection. (1) Remove the clip. (Photos 25-1 and 25-2) (2) Separate the connected parts to remove the O-ring. (Photo 25-3) Clip •...
  • Page 87 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 tighten- ing torques below.
  • Page 88: Supplementary Information

    SUPPLEMENTARY INFORMATION Refrigerant collecting (pumpdown) for split model systems only Refer to “Refrigerant collection” in the outdoor unit installation manual or service manual. Back-up operation of boiler Heating operation is backed up by boiler. For more details, refer to the installation manual of PAC-TH012HT(L)-E. <Installation &...
  • Page 89: Service And Maintenance

    SERVICE AND MAINTENANCE Engineers Forms Should settings be changed from default, please enter and record new setting in ‘Field Setting’ column. This will ease resetting in the future should the system use change or the circuit board need to be replaced. Commissioning/Field settings record sheet Main remote controller screen Parameters...
  • Page 90 Commissioning/Field settings record sheet (continued from the previous page) Default Field Main remote controller screen Parameters Notes setting setting Setting Service Pump speed Pump speed (1 to 5) menu Heating/Cooling Pump speed (1 to 5) Heat source setting Standard/Heater/Boiler/Hybrid *11 Standard Heat pump setting Heat pump flow rate range Minimum(0 to 100L/min)
  • Page 91 Commissioning/Field settings record sheet (continued from the previous page) Default Field Main remote controller screen Parameters Notes setting setting Service Energy Electric heater Booster heater 1 0 to 30 kW 2 kW monitor set- menu capacity capacity tings Booster heater 2 0 to 30 kW 4 kW capacity...
  • Page 92: Annual Maintenance Log Book

    Annual Maintenance Log Book Contractor name Engineer name Site name Site number Cylinder unit maintenance record sheet Warranty number Model number Serial number Mechanical Frequency Notes Turn OFF water supply, drain DHW tank, remove mesh from strainer clean and replace in strainer. *1 Keep water supply OFF, open hot water taps and check the primary-side expansion vessel charge pressure.
  • Page 93 OCH714B...
  • Page 94 HEAD OFFICE: TOKYO BUILDING, 2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO 100-8310, JAPAN Copyright 2019 MITSUBISHI ELECTRIC CORPORATION Issued: Oct. 2020 No. OCH714 REVISED EDITION-B Issued: Mar. 2020 No. OCH714 REVISED EDITION-A Published: Nov. 2019 No. OCH714 Made in Japan Specifications are subject to change without notice.

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