CYLINDER UNIT No.GCH15010 REVISED EDITION-A SERVICE MANUAL R744 Cylinder Unit [Model Name] EHPT20Q-VM2EA Note: • This manual describes service data of cylinder unit only. • RoHS compliant products have <G> mark on the spec name plate. • Please void GCH15010.
The discharge pipework from the emergency devices of the cylinder unit should be installed according to local law / regulations. Only use accessories and replacement parts authorised by Mitsubishi Electric. These should only be fitted by a qualified technician. Electrical All electrical work should be performed by a qualified technician according to local regulations and the instructions given in this manual.
— Tundish (Accessory item) — <Note> Isolating valve (Local supply) — Make sure to correctly install the Mitsubishi Electric Accessory Magnetic filter (Local supply) (Recommended) — Parts (e.g. Primary expansion vessel, Tundish and Filling loop) Strainer (Local supply) — in the field.
5-2. Service access diagrams Service access Parameter Dimension (mm) 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. The cylinder unit must be located indoors and in a frost-free environment, for example in a utility room, to minimise heat loss from stored water.
WIRING DIAGRAM <How to use TBO.1> 6-1-1 Cylinder unit WIRING DIAGRAM <EHPT20Q-VM2EA> Connect them using either way as shown below. Tool Tool Power supply to Booster heater CNPWM ~/N 230V 50Hz (WHT) Conductor Conductor CN01 Outline view Top view (WHT)
6-1-2 Electrical Connection CAUTION This product contains ensure you are electrically grounded / earthed in order to discharge any possible static elec- Breaker abbreviation Meaning Earth leakage circuit breaker for booster heater The outdoor unit can only be powered via Cylinder unit. Terminal block 1 terminals as indicated in the figures to the Terminal block 2...
6-2 DIP Switch Functions OFF ON Located on the FTC 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.
23. THW5A (Stored water temp. thermistor (upper)) 11. Automatic air vent 24. THW5B (Stored water temp. thermistor (lower)) Note: unit, national regulations. corrosive reaction ensure clear water Model name EHPT20Q-VM2EA Maximum Booster heater Mass of the unit when full Note: GCH15010...
Local system 1-zone temperature control 1-zone temperature control (2-zone valve ON/OFF control) Zone1 Zone1 Zone2 IMPORTANT<Air discharging of pump A> Filling the System (Primary Circuit) Note: Make sure to turn OFF the booster heater power supply before filling the system on to Always use a new filling loop with double check valve when filling the Note: If the air is not sufficiently discharged, hot water is not supplied and an...
CONTROLS 9-1. Main Controller <Main controller parts> Letter Name Function Screen Screen in which all information is displayed Menu Access to system settings for initial set up and 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 system on.
9-2. Setting the Main Controller After the power has been connected to the outdoor and cylinder units (See chapter 7) the initial system settings can be entered via the main controller . one minute whilst the control menus load. 5. Press button E (Power) (refer to page 9-3.
<Main Controller Menu Tree> Unrestricted access Initial Installer only Main screen Long press Information Option Forced DHW ON ( )/OFF ON ( )/Prohibited ( )/Timer ( ) Heating ON ( )/Prohibited ( )/Timer ( ) Menu Consumed electrical energy Delivered energy Short Press Main menu...
<Main Controller Menu Tree> Unrestricted access Installer only Initial Main screen Long press Menu Short Press Main menu Main menu Manual operation Long Press Function settings Service Thermistor adjustment Password protected ON/OFF <See section> Economy settings for pump Delay Auxiliary settings ON/OFF Electric heater (Heating) Delay...
9-4. 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".
<Thermistor adjustment> This function allows adjustments to be made to the thermistor readings from -10 – 10°C in 0.5°C intervals. THW1: Thermistor (Flow water temp.) THW2: Thermistor (Return water temp.) THW3: Thermistor (Flow water temp.(to tank)) THW4: Thermistor (DHW supply temp.) THW5A: Thermistor (Stored water temp.(upper)) THW5B: Thermistor (Stored water temp.
<Heat source setting> The default heat source setting is heat pump and booster heater present in the system to be operational. This is referred to as Standard operation on the menu. Heat source setting screen <Pump speed> 1. From the Service menu highlight Pump speed. 2.
<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. 1. Heating operation for auto adaptation mode Menu subtitle Function Range...
Default ***(factory fitted pump) EHPT20Q-VM2EA *1 "***" displayed in the energy monitor setting mode means the factory fitted pump is connected as pump 1 so that the input is automatically calculated. When anti-freeze solution (propylene glycol) is used for primary water circuit, set the produced energy adjustment if necessary.
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.
<Summary of settings> This function shows the current installer/user entered settings. Abbreviation Explanation Abbreviation Explanation HWtemp DHW supply max. temp. Hroom 1 Heating target room temperature HWdrop DHW supply max. temp. drop Hroom 2 Heating target room temperature HWtime DHW max operation time Hflow 1 Heating target flow temperature NO HW...
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.
<Table 9-4-1> Request Request content Range Unit code Water circulation pump 1 - Accumulated operating time (after reset) 0 - 9999 10 hours Water circulation pump A - Accumulated operating time (after reset) 0 - 9999 10 hours Indoor unit - DIP SW1 setting information Refer to detail contents described hereinafter.
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...
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...
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...
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...
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 00 xx 40 xx 01 xx 41 xx 02 xx 42 xx 03 xx 43 xx 04 xx...
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 C0 xx 80 xx C1 xx 81 xx C2 xx 82 xx C3 xx 83 xx C4 xx...
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...
Input signal display (Request code: 176/554) 0: OFF (open) 1: ON (short) 0: OFF (open) 1: ON (short) Display Display 00 80 00 C0 00 81 00 C1 00 82 00 C2 00 83 00 C3 00 84 00 C4 00 85 00 C5 00 86...
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>...
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 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 Error Code Action...
10-4. Self diagnosis and action Check if DIP SW is set correctly. (Refer to Section 6-2.) Error code Title and display conditions Possible Cause Diagnosis and action Circulation water temperature overheat Check (See for how protection to check). <DHW/Heating/FS/OS> Open Error code displayed when THW1 detects a Check the strainer for blockages.
Error code Title and display conditions Possible Cause Diagnosis and action P1/L5 Indoor unit temperature thermistor failure Connector/terminal wire has become Visually check the terminals and connec- * The thermistors subject to failure can be checked detached or loose wiring. tions and reattaches appropriate.
Error code Title and display conditions Possible Cause Diagnosis and action Low primary circuit (Heat source side) flow Reduced flow in primary water circuit Check circulation pump (See 10-6. for how rate detected by flow sensor Due to 1 or more of the following; to check).
Error code Title and display conditions Possible Cause Diagnosis and action Indoor unit temperature thermistor (TH1) failure Refer to error codes (P1/L5). Indoor unit temperature thermistor (TH2) failure Refer to error codes (P1/L5). E0/E4 Main remote controller communication failure 1. Contact failure with transmission cable 1.
Error code Title and display conditions Possible Cause Diagnosis and action Indoor unit/wireless receiver communication 1. Connection fault with wireless receiver- 1. Check the connections to the wireless re- failure FTC connection ceiver and FTC have not become loose and Error code J0 is displayed when the FTC can not that the connecting cable is not damaged.
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.
Contact your Mitsubishi Electric dealer. Check plumbing/wiring to 3-way valve. 3-way valve fault (i) Manually override 3-way valve using the main remote controller. (Refer to <Manual operation>...
Contact your Mitsubishi Electric dealer. 7. Incorrectly sized heat emitter. 7. Check the heat emitter surface area is adequate Increase size if necessary.
Fault symptom Possible cause Explanation - Solution After DHW operation At the end of the DHW mode operation the 3-way Normal operation no action necessary. room temperature valve diverts hot water away from the DHW circuit rises slightly. into space heating circuit. This is done to prevent the cylinder unit compo- nents from overheating.
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.
10-6. Checking component parts' function Part Name Check Points Water circulation pump (primary circuit , pump1・A) <Water circulation pump (primary circuit) characteristics> Pump speed BROWN PWM input signal Signal cable Speed 1 Speed 2 Speed 3 Speed 4 Default se ng Speed 5 BLUE Signal ref.
Part Name Check Points Flow sensor (1,A,B) Flow sensor 1 , B Flow signal Yellow White Flow signal Green 5V DC Brown CN1A 0.35V part name symbol Flow sensor 1 CN1A Flow [l/min] Flow sensor A CN2A Flow sensor B CN2B Flow sensor A Flow signal...
Part Name Check Points 3-way valve (1) Check the movement of the red indicator. The red indicator normally points <DHW> <Heating> to A in DHW mode and to B in Heating mode as shown to the left. (2) If each indicator position is correct but the 3-way valve does not work prop- Motor erly, the motor may not fit onto the valve securely, so remove the motor by Indicator (red)
10-7. Test point diagram FTC (Controller board) 6.3A/250V 10A/250V CN01 Power supply CNP1/OUT1 (230V AC) Water circulation CN3C pump1(230V) Transmission (Indoor/Outdoor) CNPA/OUTA (0-24V DC) Water circulation LED1 pumpA(230V) Power supply(FTC) OUT3(TBO1. 1-2) 2-way valve2b (230V AC) OUT3(TBO1. 3-4) 2-way valve2a (230V AC) CN1A Flow sensor1 input...
DISASSEMBLY PROCEDURE DISASSEMBLY PROCEDURE PHOTOS 1. How to remove the front panel Figure 1 < Front Panel > (1) Remove the 5 screws of the front panel. (Figure 1) (2) Pull out the bottom of the front panel. < CAUTION > During regular use, the cylinder unit is connected to the main controller by a lead wire.
DISASSEMBLY PROCEDURE PHOTOS 3. How to remove the controller board Photo 3 < Controller board > controller box (1) Disconnect all lead wires connected to the controller board in the controller box. (2) Remove the resin parts (total 12) connected to the controller box from the controller board, and remove the controller board.
DISASSEMBLY PROCEDURE PHOTOS 5. How to remove the thermistor Photo 5-1 There are three kinds thermistor in total as follows. Each connector of thermistors is correspond to ①〜③ in Photo 5-1. Thermistor - THW1,THW2 Thermistor - THW3,THW4 Thermistor - THW5A,THW5B CNW12 connector (RED) CNW3 connector (BLUE) CNW5 connector (WHITE)
DISASSEMBLY PROCEDURE PHOTOS Photo 5-4 5-2. How to remove the thermistor THW3,THW4 < CAUTION > (1) Remove the front panel. The thermistor is located inside insulation. (2) Remove the copper clamps of the thermistor THW3,THW4 from the pipes.(Photo 5-4） (3) Disconnect the connector (BLUE) of the thermistor THW3,THW4 from the controller board.(Photo 5-5）...
DISASSEMBLY PROCEDURE PHOTOS Photo 5-6 Photo 5-7 5-3. How to remove the thermistor THW5A,THW5B (1) Remove the front, right, left, and rear panels. (Photo 5-6) (Refer to section 6-1 and 6-2) (2) Remove all tapes securing the insulation first, then remove two sheets of insulation around the tank.
From the previous page. DISASSEMBLY PROCEDURE PHOTOS Photo 5-10 (3) Remove the thermistor THW5A,THW5B from the tank, then disconnect the connector (WHITE) for thermistor THW5A,THW5B from the controller boad. Remove cable clamps and cable bands in the lead wire, then remove the thermistor THW5A,THW5B from the tank.
DISASSEMBLY PROCEDURE PHOTOS 6-1. How to remove the Side panels (R,L) Figure 3 top panel (1) Remove the 12 screws of the top panel.(Figure 3) (2) Remove the 10 screws of the rear panel.(Figure 4) side panel (3) Remove the 2 screws of the stay-pipe of the upper side panel.(Figure 3 and 4) 2 screws (4) Remove the 4 screws of the fixing plate.(Figure 3)
DISASSEMBLY PROCEDURE PHOTOS 7. How to remove water pump1 (primary circuit)/pump Photo 7-1 (Larger scale of the A part) valve < Water pump1 > (Water pump lower left in the cylinder unit) (1) Remove the front panel . CNP1 connector (2) Disconnect the CNP1 connector, the earth cable and the CNPWM connector in the controller box.
From the previous page. DISASSEMBLY PROCEDURE PHOTOS Photo 7-7 (6) Close (OFF) the pump valve (Photo 7-7) the handle and turn it carefully. pump valve Nut of the (7) Remove the water pump1 by removing the two G1 pump valve 1/2”...
DISASSEMBLY PROCEDURE PHOTOS 8. How to remove the water pump A (primary circuit) Photo 8-1 (Larger scale of the A part) < Water pump A > (Water pump lower right in the cylinder unit) (1) Remove the front panel. CNPA (2) Disconnect the CNPA connector, the earth cable connector and the CNPWM3 connector in the control box.
DISASSEMBLY PROCEDURE PHOTOS (5) Open the drain cocks of the water pump A top Photo 8-6 and bottom and drain away water in the water pump A.(Photo 8-6) drain cock (6) Remove the two G1 1/2" nut stays by removing the 4 screws.(Photo 8-7 and 8-8) ・...
DISASSEMBLY PROCEDURE PHOTOS Photo 9-1 9. How to remove the strainer valve < Strainer valve > (1) Remove the front panel. cable (2) Release the band on the strainer valve.Release the clamps lead wire from the cable clamps. (Photos 9-1) transportation.
From the previous page. DISASSEMBLY PROCEDURE PHOTOS (6) Remove the strainer valve by detaching the quick connection. O-ring. Take it off upper the strainer valve earlier and drain valve. < Strainer cover (debris recovery) > the strainer valve and the other to turn the cover. (Photo 9-7) Photo 9-7 strainer valve...
DISASSEMBLY PROCEDURE PHOTOS Photo 10-1 10. How to remove the 3-WAY VALVE / 3-WAY VALVE MOTOR < 3-WAY VALVE / 3-WAY VALVE MOTOR > (1) Remove the front panel. (2) Disconnect the CNV1 connector on the controller board. (Photo 10-1 and 10-2) (3) Release the 3-way valve motor lead wire from the cable clamps, the quick connection and the cable strap in the controller box and the cable band below the...
From the previous page. DISASSEMBLY PROCEDURE PHOTOS (4) Remove the 3-way valve motor from the 3-way 3-way valve valve by pressing the button on the 3-way valve motor motor (viewed from the front of the cylinder unit). Photo 10-5 (Photos 10-5) valve motor.
From the previous page. DISASSEMBLY PROCEDURE PHOTOS drain cock the booster heater inlet (lower right), and drain Photo 10-9 water. (photo 10-9) (bottom, left and right) connected to the 3-way valve, and drain water in the 3-way valve from the booster heater inlet.
DISASSEMBLY PROCEDURE PHOTOS 11. How to remove the pressure relief valve / air vent / manometer Photo 11-1 < Pressure relief valve > pressure relief valve cap (1) Remove the front panel. (2) Open the pressure relief valve cap and lower the tank internal pressure.(Photo 11-1) quick connection...
From the previous page. DISASSEMBLY PROCEDURE PHOTOS Photo 11-7 < Manometer > pump valve (1) Remove the front panel. (2) Open the pressure relief valve cap and lower the tank internal pressure.(Photo 11-3) (3) Close(OFF) the pump valve and strainer valve.(Photo 11-7 and 11-8) When the pump valve/strainer valve handle is stiff, pump valve...
From the previous page. DISASSEMBLY PROCEDURE PHOTOS (5) Remove the three screws securing the fixing support for the manometer, remove the quick connection at the rear of the manometer, and remove the manometer together with the fixing support.(Photo 11-10 and 11-11) (6) Remove the two screws securing the manometer, and then remove the manometer and nipple.(Photo 11-12 and 11-13)
DISASSEMBLY PROCEDURE PHOTOS 12. How to remove the flow sensor1(primary circuit) Flow sensor 1 Photo 12-1 < Flow Sensor 1 > (1) Remove the front panel. (2) Disconnect the CN1A connector in the controller box. (Photo 12-2 and 12-3) (3) Release the flow sensor lead wire from the cable clamps and the bands below the control box.
DISASSEMBLY PROCEDURE PHOTOS (5) Close(OFF) the pump valve and strainer Photo 12-6 valve.(Photo 12-6 and 12-7) When the pump valve/strainer valve handle is stiff, use a tool to grip the handle and turn it carefully. pump valve When opening or closing the pump valve/strainer valve, ensure to do so fully, not halfway.
DISASSEMBLY PROCEDURE PHOTOS CN2B 13. How to remove the flow sensor B (primary circuit) Photo 13-1 connector < Flow Sensor B > (1) Remove the front panel. (2) Disconnect the CN2B connector in the controller box. (Photo 13-1) cable (3) Release the flow sensor lead wire from the cable bands clamps and the bands below the controller box.
From the previous page. DISASSEMBLY PROCEDURE PHOTOS 14. How to remove the flow sensor A (Sanitary circuit) CN2A < Flow Sensor A > Photo 14-1 connector (1) Remove the front panel. (2) Disconnect the CN2A connector in the controller box. (Photo 14-1) (3) Release the flow sensor lead wire from the cable clamps and the bands below the controller box.
From the previous page. DISASSEMBLY PROCEDURE PHOTOS 15. How to remove the HEX(Primary and Sanitary circuit) < HEX > (1) Remove the front panel. Photo 15-1 (2) Stop water flow at the water source. (3) Open the pressure relief valve cap and lower the tank internal pressure.(Photo 12-5) (4) Drain water inside the HEX using the drain cock (Primary circuit) and the drain cock (Sanitary...
DISASSEMBLY PROCEDURE PHOTOS Photo 16-1 16. How to remove the booster heater < booster heater > (1) Remove the front panel. (2) Disconnect the CNBHT connector on the controller board , and the booster heater lead wires wired to the BHC2 contactor respectively and release the lead wires from the quick connection, the cable clamp , the cable strap , the coated clamp and the band.(Photo 16-1,16-...
DISASSEMBLY PROCEDURE PHOTOS (4) Close(OFF) the pump valve and strainer Photo 16-7 valve.(Photo 16-7 and 16-8) When the pump valve/strainer valve handle is stiff, use a tool to grip the handle and turn it carefully. pump valve When opening or closing the pump valve/strainer valve, ensure to do so fully, not halfway.
DISASSEMBLY PROCEDURE PHOTOS screw(B) (7) Remove all screws attached to the fixing plate, Photo 16-12 and then remove the fixing plate.(Photo 16-12) front frame(L) (8) Remove the 2 screws(A) that hold the heater stay onto the front frame(L). Lift the booster heater fixing plate slightly and remove the booster heater with the heater stay from the front frame(L).
Notes on replacing the parts When installing the parts that are not listed above, observe the tightening torques in accordance with Table 11-1. Always use a new O-ring or gasket. Table 11-1 Size Recommended tightening torque [inch] [Nm] G1 1/2 30 ±...
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 Default Field...
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 potable circuit, remove mesh from strainer clean and replace in strainer. *1 Drop the primary/heating system pressure to zero check and if necessary top up the expansion vessel (1 bar).
HEAD OFFICE : TOKYO BLDG., 2-7-3, MARUNOUCHI, CHIYODA-KU, TOKYO 100-8310, JAPAN Copyright 2015 MITSUBISHI ELECTRIC CORPORATION Distributed in Jul. 2021 No. GCH15010 REVISED EDITION-A New publication, effective Dec. 2015 Specifications are subject to change without notice. Distributed in Dec. 2015 No. GCH15010...