Mitsubishi EHST20C-VM2C, EHST20C-VM6C, EHST20C-YM9C, EHST20C-TM9C, EHST20C-VM2EC Service Manual

SERVICE MANUAL

CONTENTS

1. REFERENCE MANUAL

...................................

2

2. SAFETY PRECAUTION

...................................

3

3. SPECIFICATIONS

............................................

6

4. PART NAMES AND FUNCTIONS

..................

7

5. OUTLINES AND DIMENSIONS

.......................

8

6. WIRING DIAGRAM

........................................

10

7. FIELD WIRING

...............................................

17

8. WATER SYSTEM DIAGRAM

.........................

21

9. CONTROLS

...................................................

25

10. TROUBLESHOOTING

...................................

45

11. DISASSEMBLY PROCEDURE

......................

61

12. SUPPLEMENTARY INFORMATION

.............

84

13. SERVICE AND MAINTENANCE

...................

85

Note:

• This manual describes
only service data of cylin­der unit.

• RoHS compliant products
have <G> mark on the
spec name plate.

R410A

PARTS CATALOG (OCB570)

CYLINDER UNIT

December 2014

CYLINDER UNIT

No. OCH570

[Model name]

EHST20C-VM2C

EHST20C-VM6C

EHST20C-YM9C

EHST20C-TM9C

EHST20C-VM2EC

EHST20C-VM6EC

EHST20C-YM9EC

EHST20C-MHCW

EHST20C-MEC

EHST20D-VM2C

EHST20D-MHCW

EHST20D-MEC

EHST20D-MHC

EHPT20X-VM2C

EHPT20X-VM6C

EHPT20X-YM9C

EHPT20X-TM9C

EHPT20X-MHCW

[Service Ref.]

EHST20C-VM2C.UK
EHST20C-VM6C.UK
EHST20C-YM9C.UK
EHST20C-TM9C.UK
EHST20C-VM2EC.UK
EHST20C-VM6EC.UK
EHST20C-YM9EC.UK
EHST20C-MHCW.UK
EHST20C-MEC.UK
EHST20D-VM2C.UK
EHST20D-MHCW.UK
EHST20D-MEC.UK
EHST20D-MHC.UK
EHPT20X-VM2C.UK
EHPT20X-VM6C.UK
EHPT20X-YM9C.UK
EHPT20X-TM9C.UK
EHPT20X-MHCW.UK

MAIN REMOTE
CONTROLLER

2

REFERENCE MANUAL

1

OUTDOOR UNIT'S SERVICE MANUAL

Service Ref. Service Manual No.

PUHZ-W50/85VHA(-BS)

OCH439

PUHZ-W50/85VHAR1(-BS)

PUHZ-W50VHAR2(-BS)

PUHZ-W50VHAR3(-BS)

PUHZ-W85VHA2-BS.UK

OCH465

PUHZ-W85VHA2(R1)-BS.UK

PUHZ-W112VHA(-BS) OCH562

PUHZ-HW112/140YHA(-BS)

OCH439

PUHZ-HW112/140YHA2(-BS)

PUHZ-HW112/140YHA2R1(-BS)

PUHZ-HW112/140YHA2R3(-BS)

PUHZ-HW112/140YHA2R4(-BS)

PUHZ-HW140VHA(-BS)

PUHZ-HW140VHA2(-BS)

PUHZ-HW140VHA2R1(-BS)

PUHZ-HW140VHA2R2-BS

PUHZ-HW140VHA2R3(-BS)

PUHZ-HW140VHA2R4(-BS)

PUHZ-SW40/50VHA(-BS)

OCH525

PUHZ-SW40/50VHAR1(-BS)

PUHZ-SW75/100/120VHA(-BS)

OCH533PUHZ-SW100/120YHA(-BS)

PUHZ-SW100/120YHAR1(-BS)

PUHZ-SHW80/112VHA

OCH526

PUHZ-SHW80/112VHAR2(-BS).UK

PUHZ-SWH112/140YHA(R1)

PUHZ-SWH112/140YHAR2(-BS).UK

PUHZ-FRP71VHA OCH544

SUHZ-SW45VA(H).TH

OCH557

SUHZ-SW45VA(H)R1.TH

OCH570

3

SAFETY PRECAUTION

2

Please read the following safety precautions carefully.

WARNING:

Precautions that must be observed to prevent injuries or death.

CAUTION:

Precautions that must be observed to prevent damage to unit.

This installation manual along with the user manual should be left with the product after installation for future reference.
Mitsubishi Electric is not responsible for the failure of locally-supplied parts.

• Besuretoperformperiodicalmaintenance.

• Besuretofollowyourlocalregulations.

• Besuretofollowtheinstructionsprovidedinthismanual.

WARNING

Mechanical

The cylinder unit and outdoor unit must not be installed, disassembled, relocated, altered or repaired by the user. Ask an authorised installer or technician. If

the unit is installed improperly or modied after installation by the user water leakage, electric shock or re may result.

The outdoor unit should be securely xed to a hard level surface capable of bearing its weight.

The cylinder unit should be positioned on a hard level surface capable of supporting its lled weight to prevent excessive sound or vibration.

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 qualied technician to t the parts.

Electrical

All electrical work should be performed by a qualied technician according to local regulations and the instructions given in this manual.

The units must be powered by a dedicated power supply and the correct voltage and circuit breakers must be used.

Wiring should be in accordance with national wiring regulations. Connections must be made securely and without tension on the terminals.

Earth unit correctly.

General

Keep children and pets away from both the cylinder unit and outdoor unit.

Do not use the hot water produced by the heat pump directly for drinking or cooking. This could cause illness to the user.

Do not stand on the units.

Do not touch switches with wet hands.

Annual maintenance checks on both the cylinder unit and the outdoor unit should be conducted by a qualied person.

Do not place containers with liquids on top of the cylinder unit. If they leak or spill onto the cylinder unit damage to the unit and/or re could occur.

Do not place any heavy items on top of the cylinder unit.

When installing, relocating, or servicing the cylinder unit, use only the specied refrigerant (R410A) to charge the refrigerant lines. Do not mix it with any other
refrigerant and do not allow air to remain in the lines. If air is mixed with the refrigerant, then it can be the cause of abnormal high pressure in the refrigerant
line, and may result in an explosion and other hazards.
The use of any refrigerant other than that specied for the system will cause mechanical failure or system malfunction or unit breakdown. In the worst case, this
could lead to a serious impediment to securing product safety.

In heating mode, to avoid the heat emitters being damaged by excessively hot water, set the target ow temperature to a minimum of 2ºC below the maximum
allowable temperature of all the heat emitters. For Zone2, set the target ow temperature to a minimum of 5ºC below the maximum allowable ow temperature

of all the heat emitters in Zone2 circuit.

CAUTION

Use clean water that meets local quality standards on the primary circuit.

The outdoor unit should be installed in an area with sufcient airow 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.

Ensure condensate from outdoor unit is piped away from the base to avoid puddles of water.

Remove as much air as possible from the primary and DHW circuits.

Refrigerant leakage may cause suffocation. Provide ventilation in accordance with EN378-1.

Be sure to wrap insulation around the piping. Direct contact with the bare piping may result in burns or frostbite.

Never put batteries in your mouth for any reason to avoid accidental ingestion.

Battery ingestion may cause choking and/or poisoning.

Install the unit on a rigid structure to prevent excessive sound or vibration during operation.

Do not transport the cylinder unit with water inside the DHW tank. This could cause damage to the unit.

If power to the cylinder unit is to be turned off (or system switched off) for a long time, the water should be drained.

If unused for a long period, before operation is resumed, DHW tank should be ushed through with potable water.

Preventative measures should be taken against water hammer, such as installing a Water Hammer Arrestor on the primary water circuit, as directed by the man-

ufacturer.

As for the handling of refrigerant, refer to the outdoor unit installation manual.

OCH570

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.

Use R410A refrigerant only. Do not allow air to enter the lines. Failure to observe these instructions will cause mechanical failure, system failure or, in the worst

case, serious breach of product safety.

CAUTION (SPLIT MODELS ONLY)

<Using R410A refrigerant heat pumps>

Use C1220 copper phosphorus, for copper and copper alloy seamless pipes, to connect the refrigerant pipes. Make sure the insides of the pipes are clean and
do not contain any harmful contaminants such as sulfuric compounds, oxidants, debris, or dust. Use pipes with the specied thickness. (Refer to section 4.4 in
the installation manual.) Note the following if reusing existing pipes that carried R22 refrigerant.

- Replace the existing are nuts and are the ared sections again.

- Do not use thin pipes. (Refer to section 4.4 in the installation manual.)

Store the pipes to be used during installation indoors and keep both ends of the pipes sealed until just before brazing. (Leave elbow joints, etc. in their packag­ing.) If dust, debris, or moisture enters the refrigerant lines, oil deterioration or compressor breakdown may result.

Use ester oil, ether oil, alkylbenzene oil (small amount) as the refrigeration oil applied to the ared sections. If mineral oil is mixed in the refrigeration oil, oil dete-

rioration may result.

Do not use refrigerant other than R410A refrigerant. If another refrigerant is used, the chlorine will cause the oil to deteriorate.

Use the following tools specically designed for use with R410A refrigerant. The following tools are necessary to use R410A refrigerant. Contact your nearest

dealer for any questions.

Tools (for R410A)

Gauge manifold Flare tool

Charge hose Size adjustment gauge

Gas leak detector Vacuum pump adapter

Torque wrench Electronic refrigerant charging scale

Be sure to use the correct tools. If dust, debris, or moisture enters the refrigerant lines, refrigeration oil deterioration may result.

Do not use a charging cylinder, a cylindrical measuring container, when charging R410A refrigerant gas. If the refrigerant gas is transferred to a charging cylinder,
the composition of the refrigerant will change and system efciency will be reduced.

OCH570

Gravimeter

Unit

5

[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.

[2] Additional refrigerant charge

When charging directly from refrigerant cylinder

· Check that cylinder for R410A on the market is syphon type.

· Charging should be performed with the

refrigerant

cylinder of syphon stood vertically. (Refrigerant is charged from liquid

phase.)

[3] Service tools

Use the service tools below as exclusive tools for R410A refrigerant.

No. Tool name Specifications

1

Gauge manifold

· Only for R410A

· Use the existing fitting

specifications

. (UNF1/2)

· Use high-tension side pressure of 5.3 MPa·G or over.

2

Charge hose

· Only for R410A

· Use pressure performance of 5.09 MPa·G or over.

3

Electronic scale

—

4

Gas leak detector · Use the detector for R134a, R407C or R410A

5

Adaptor for reverse flow check · Attach on vacuum pump.

6

Refrigerant charge base

—

7

Refrigerant cylinder

· Only for R410A ·Top of cylinder (Pink)

· Cylinder with syphon

8

Refrigerant recovery equipment

—

OCH570

6

SPECIFICATIONS

3

Model name

EHST20C-

VM2C

EHST20C-

VM6C

EHST20C-

YM9C

EHST20C-

TM9C

EHST20C-

VM2EC

EHST20C-

VM6EC

EHST20C-

YM9EC

EHST20C-

MEC

EHST20D-

VM2C

EHST20D-

MEC

EHST20D-

MHC

EHPT20X-

VM2C

EHPT20X-

VM6C

EHPT20X-

YM9C

EHPT20X-

TM9C

EHPT20X-

MHCW

EHST20C-

MHCW

EHST20D-

MHCW

Nominal domestic hot water volume 200L

Overall unit dimensions 1600 × 595 × 680 mm (Height × Width × Depth)

Weight (empty) 110 kg 111 kg 112 kg 112 kg 104 kg 105 kg 106 kg 103 kg 103 kg 96 kg 103 kg 98 kg 99 kg 100 kg 100 kg 98 kg 110 kg 103 kg

Weight (full) 320 kg 321 kg 322 kg 322 kg 314 kg 315 kg 316 kg 313 kg 312 kg 305 kg 312 kg 307 kg 308 kg 309 kg 309 kg 307 kg 320 kg 312 kg

Plate heat exchanger (MWA2)

— — — — — — — — —

Plate heat exchanger (MWA1) — — — — — — — —

— — — — — —

Unvented expansion

vessel(Primary heating)

Nominal volume 12 L — — -— — 12 L — 12 L

Charge pressure 1 bar — — — — 1 bar — 1 bar

Safety

device

Water

circuit

(Primary)

Control

thermistor

Heating 1 - 80°C

Pressure relief valve 0.3 MPa (3bar)

Flow sensor Min ow 5.0 L/min

Booster

heater

Manual reset thermostat 90°C — 90°C — — 90°C — — —

Thermal Cut-out (for dry run prevention) 121°C — 121°C — — 121°C — — —

DHW

tank

Control thermistor 40 - 70°C

Temperature and pressure relief valve/

Pressure relief valve

1.0 MPa

(10 bar)

1.0 MPa

(10 bar)

1.0 MPa

(10 bar)

1.0 MPa

(10 bar)

1.0 MPa

(10 bar)

1.0 MPa

(10 bar)

1.0 MPa

(10 bar)

1.0 MPa

(10 bar)

1.0 MPa

(10 bar)

1.0 MPa

(10 bar)

1.0 MPa

(10 bar)

1.0 MPa

(10 bar)

1.0 MPa

(10 bar)

1.0 MPa

(10 bar)

1.0 MPa

(10 bar)

90°C/

0.7 MPa

(7 bar)

90°C/

0.7 MPa

(7 bar)

90°C/

0.7 MPa

(7 bar)

Primary circuit circulating Pump Grundfos UPM2 15 70 - 130

Sanitary circuit circulating Pump Grundfos UPSO 15-60 130 CIL2

Connections

Water 28mm compression primary circuit/ 22mm compression DHW circuit

Refrigerant

(R410A)

Liquid 9.52 mm 9.52 mm 9.52 mm 9.52 mm 9.52 mm 9.52 mm 9.52 mm 9.52 mm 6.35 mm 6.35 mm 6.35 mm

— — — — —

9.52 mm 6.35 mm

Gas 15.88 mm 15.88 mm 15.88 mm 15.88 mm 15.88 mm 15.88 mm 15.88 mm 15.88 mm 12.7 mm 12.7 mm 12.7 mm 15.88 mm 12.7 mm

Target tempera-

ture range

Flow tem-

perature

Heating 25 - 60°C

Cooling —

Room tem-

perature

Heating 10 - 30 °C

Cooling —

Guaranteed

operating range

Ambient *1 0 - 35°C (

80 %RH)

Outdoor

temperature

Heating See outdoor unit spec table.

Cooling —

DHW tank

performance

Maximum allowable hot water temperature

70°C *4 70°C *4 70°C

Time to raise DHW tank temp 15 - 65 °C *2

22.75 mins

Time to reheat 70% of DHW tank to 65 °C *2

17.17 mins

Electrical data

Control

board

Power supply

(Phase, voltage, frequency)

~/N, 230 V, 50 Hz

Breaker (*when powered

from independent source)

10A

Booster

heater

Power supply

(Phase, voltage, frequency)

~/N, 230 V,

50 Hz

~/N, 230 V,

50 Hz

3~, 400 V,

50 Hz

3~, 230 V,

50 Hz

~/N, 230 V,

50 Hz

~/N, 230 V,

50 Hz

3~, 400 V,

50 Hz

—

~/N, 230 V,

50 Hz

— —

~/N, 230 V,

50 Hz

~/N, 230 V,

50 Hz

3~, 400 V,

50 Hz

3~, 230 V,

50 Hz

— — —

Capacity 2kW

2kW+

4kW

3kW+

6kW

3kW+

6kW

2kW

2kW+

4kW

3kW+

6kW

— 2kW — — 2kW

2kW+

4kW

3kW+

6kW

3kW+

6kW

—

— —

Current 9 A 26 A 13A 23A 9 A 26 A 13A — 9 A — — 9 A 26 A 13A 23A —

— —

Breaker 16 A 32 A 16A 32A 16 A 32 A 16A — 16 A — — 16 A 32 A 16A 32A —

— —

Immersion

heater*3

Power supply

(Phase, voltage, frequency)

—

~/N, 230 V,

50 Hz

—

~/N, 230 V,

50 Hz

Capacity — 3kW — 3kW

Current — 13A — 13A

Breaker — 16A — 16A

Sound level 28dBA

Optional extras

●

Wireless Remote Controller PAR-WT50R-E

●

Remote Sensor PAC-SE41TS-E *1 The environment must be frost-free.

●

Wireless Receiver PAR-WR51R-E

●

Thermistor PAC-TH011-E *2 Tested under BS7206 conditions.

●

Immersion heater (1Ph 3kW) PAC-IH03V2-E

●

High temperature thermistor PAC-TH011HT-E *3 Do not t immersion heaters without thermal cut-out.

●

EHPT Accessories for UK PAC-WK01UK-E

●

ecodan Wi-Fi Interface PAC-WF010-E *4 For the model without both booster heater and immersion heater, the maximum allowable hot water temperature is [Maximum outlet water of outdoor unit - 3°C]

For the maximum outlet water of outdoor unit, refer to outdoor unit data book.

OCH570

7

PART NAMES AND FUNCTIONS

4

21

B

A

<EH*T20*-MHCW>
(UK split / packaged model system)

7

4

12

<EHPT20X-*M**C*>
(Packaged model system)

<EHST20*-*M**C*>

(Split model system)

<EHST20*-*M**C>
(Split model system)

<Note>

For installation of EHST20*-*M*EC
model, make sure to install a primary ­side expansion vessel in the field. (See
figure 4.3.1 in the installation manual.)

No. Part name

EHST20C-

VM2C

EHST20C-

*M6/9 C

EHST20C-

*M*EC

EHST20*-

MEC

EHST20D-

VM2C

EHST20D-

MHC

EHPT20X-

VM2C

EHPT20X-

*M6/9 C

EHPT20X-

MHCW

EHST20*-

MHCW

A DHW outlet pipe

B Cold water inlet pipe

C Water pipe (Space heating return connection)

D Water pipe (Space heating ow connection)

E Water pipe (Flow from heat pump connection) — — — — — — —

F Water pipe (Return to heat pump connection) — — — — — —

—

G Refrigerant pipe (Gas)

— — —

H Refrigerant pipe (Liquid) — — —

1 Control and electrical box

2 Main controller

3 Plate heat exchanger (Refrigerant - Water) — — —

4 Booster heater 1,2 — — — —

5 3-way valve

6 Manual air vent

7 Drain cock (Primary circuit)

8 Manometer

9 Pressure relief valve (3bar)

10 Automatic air vent

11 Expansion vessel — —

12 Flow sensor

13 Strainer valve

14 Water circulation pump 1 (Primary circuit)

15 Pump valve

16 DHW tank

17 Plate heat exchanger (Water - Water)

18 Scale trap

19 Water circulation pump (Sanitary circuit)

20 Immersion heater — — — — — — —

21 Temperature and pressure relief valve — — — — — — — —

22 Pressure relief valve (10bar) (DHW Tank) — —

23 Drain cock (DHW tank)

24 Drain cock (Sanitary circuit)

25 Flow water temp. thermistor (THW1)

26 Return water temp. thermistor (THW2)

27 DHW tank water temp. thermistor (THW5)

28 Refrigerant liquid temp. thermistor (TH2) — — —

29 Outdoor unit — — — — — — — — — —

30 Drain pipe (Local supply) — — — — — — — — — —

31 Back ow prevention device (Local supply) — — — — — — — — — —

32 Isolating valve (Local supply) — — — — — — — — — —

33 Magnetic lter (Local supply) (Recommended) — — — — — — — — — —

34 Strainer (Local supply) — — — — — — — — — —

35 Inlet control group *1 — — — — — — — — — —

36

Filling loop (Ball valves, check valves and exible hose) *1

— — — — — — — — — —

37 Potable expansion vessel *1 — — — — — — — — — —

*1 Supplied with UK model ONLY. Please refer to PAC-WK01UK-E Installation Manual for more information on accessories.

<EH*T20*-MHCW>
(UK split/packaged model system)

<EHPT20X-*M**C*>
(Packaged model system)

22

A

B

10

9

11

1

5

6

19

18

12

20

23
17

24

7

15

D

8
2

16

4

13

3

14

C

E/H

F/G

<Table 4-1>

<Figure 4-1>

OCH570

8

OUTLINES AND DIMENSIONS

5

<Unit: mm>

J

A

C
D

B

F/G

E/H

470.7

510.7

0

67.8

522.3

462.3

402.3

342.3

88.3

0

46.7

136.7

114.2

91.7

69.2

0

42.1

552.7

470.7

0

G1/2

83 427

30413

118

680

CPF 15mm

595

100 ± 20

449

1600

595

1600

449

J

A

B

D

C

F/G

E/H

46.7

136.7

114.2

91.7

69.2

0

67.8

522.3

462.3

402.3

342.3

127.8

0

552.7

542

0

470.7

510.7

0

680

100 ± 20

120 ± 20

G1/2

G1/2

118

123

Letter Pipe description Connection size/type

A DHW outlet connection 22 mm/Compression
B Cold water inlet connection 22 mm/Compression
C Space heating return connection 28 mm/Compression
D Space heating ow connection 28 mm/Compression
E Flow from heat pump connection (No plate heat exchanger) 28 mm/Compression
F Return to heat pump connection (No plate heat exchanger) 28 mm/Compression

G

Refrigerant (GAS)
(With plate heat exchanger)

12.7 mm/Flare (EHST20D-*)

15.88 mm/Flare (EHST20C-*)

H

Refrigerant (LIQUID)
(With plate heat exchanger)

6.35 mm/Flare (EHST20D-*)

9.52 mm/Flare (EHST20C-*)

J

Electrical cable inlets

For inlets , and , run low-voltage wires including external input wires and ther-

mistor wires. For inlets

and , run high-voltage wires including power cable, indoor-

outdoor cable, and external output wires.

*For a wireless receiver (option) cable and ecodan Wi-Fi interface (option) cable, use inlet .

<Left side> <Front> <Right side>

<Top>

Air vent

Main controller

Pressure relief valve
(Primary circuit)

Terminal block

Front panel

Temperature and
pressure relief valve
and it's access plate

<EH*T20*-*M**C>

<EH*T20*-MHCW>

Pressure relief valve
(Sanitary circuit)

Pressure relief valve
(Primary circuit)

Main controller

Terminal block

<Left side> <Front>

<Right side>

<Top>

Air vent

Front panel

5-1. Technical Drawings

OCH570

9

a

b b

d

Service access

5-2. Service access diagrams

Service access

Parameter Dimension (mm)
a 300
b 150
c

(distance behind unit not visible

in the right gure)

10

d 500

Sufcient 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.

OCH570

1

3

5

7

X6

X7

1

3

1

3

CNBHT

(BLK)
CNBC
(GRY)

CNBH
(WHT)

NL

S3S2S1

NL

S3S2S1

To outdoor

unit

TB1

ORN

ORN

YLW

YLW

GRN/YLW

To outdoor

unit

Power supply
~/N 230V 50Hz

TB1

ORN

BLU

RED

BLU

RED

YLW

GRN/YLW

1

3

CN3C
(BLU)

BLK

BLK

BLK

BLK

1

3

ORN

BRN

CN3C
(BLU)

ORN

ORN

BRN

YLW

Indoor unit powered

by independent source

Indoor unit powered

via outdoor unit

CIRCUIT

BREAKER

1

3

CN3C
(BLU)

1

3

CNPWM

(WHT)

LED1

LED2

LED3

LED4

TBI.1

TBI.2

1310 12 141174 65 932 811310 12 141174 65 932 811310 12 141174 65 932 81

IN6

IN1

IN2

IN3

IN4

IN5

IN7

THW8

THW7

THW6

THW9

THWB1

THWB2

t°t°t°t°t°t

°

Main

controller

1

+

-+-+-

2

1

2

CN20

(RED)

TH1

t

°

1

3

CN21

(YLW)

TH2

t

°

1

4

THW1

THW2

CNW12

(RED)

t°t

°

1

2

THW5

CNW5

(WHT)

t

°

CN108

5

1

Wireless receiver

(Option)

WiFi adapter

(Option)

5

1

5

1

CNRF
(WHT)

CN105
(RED)

CN22
(BLU)

1

5

Close

Open

N

X15

X12

TBO.3

TBO.2

TBO.1

F1

F2

MXV

M

1

~

MP2

MP1

M

1

~

CNV1
(WHT)

X11

X10

X4

X14

X3

X2

X1

X5B

X5A

1
2
3
4
5
6
7
8

1
2
3
4
5
6

1
2
3
4
5
6

1

1

3

3

3

CNP1
(WHT)

CNP4
(RED)

CNPWM

(WHT)

TBO.1

TBO.2

TBO.3

TBO.4

CNP1

(WHT)

CNP4

(RED)

CNV1

(WHT)

CN22
(BLU)

CNIT
(BLU)

TAB1

CN01
(WHT)

F2 F1

6.3A 250V 10A 250V

SW1

SW2

SW3

SW4

SW5

1

8

1

8

1

1

5

1
3

1
3

8

1

8

1

6

CN01
(WHT)

CN01
(WHT)

2

1

4
6

2

1

1
2
4
6

4
6

CNBH
(WHT)

CNBC
(GRY)

1

1

3

1
2

1
2

1
2

CNBHT

(BLK)

1

3

7

1

3

CNIH

(ORN)

1

4

1

3

CNW5
(WHT)

CN21
(YLW)

CNW12

(RED)

CN20
(RED)

TBI.2

MP3

M

1

~

IN8

IN9

IN10

TBI.3

TBI.3

1

4

CN1A
(WHT)

TBI.1

2WV2b

M

1

~

M

1

~

MP4

M

1

~

1

3

L
(1)N(3)

ORN

RED

BLU

BLU

RED

ORN

IHC

IHT

IH

642

531

A1

A2

A B

2

4

Immersion heater (1Ph3kW)(Option)

Power supply

to Immersion heater

~/N 230V 50Hz

1

2

CNIH
(ORN)

3

3WV

M

1

~

Signal output

(Boiler)

Signal output

(Error)

Signal output

(Defrost)

Signal output

(Comp ON)

ECB2

1

2
4

6

CN01
(WHT)

WHT

WHT

2 2

2

ECB1

L

(1)N(3)

BHCP

BLU

BLU

RED

WHT/No.2

WHT/No.1

RED

VLT

VLT

GRY

GRY

BHC1

BHT

642

531

A1

A2

BH1

BHF

2

4

Power supply

to Booster heater

642

531

A1

A2

CNBH
(WHT)

CNBHT
(BLK)

2

2

2

CNBC
(GRY)

1

1

3

3

1

3

~/N 230V 50Hz

1
2
3
4
5
6

TBO.4

M

2WV2a

1

3

X9

X8

X13

CNIH

(ORN)

1
2
3
4
5
6

1
2
3
4
5
6

1
2
3
4
5
6
7
8

1
2
3
4
5
6

12 146 108

137 11945321

12 146 108

137 11945321

12 146 108

137 11945321

Tool

Tool

Conductor

Conductor

Outline view Top view

<How to use TBO.1 to 4>

Connect them using either way as shown below.

10

6 WIRING DIAGRAM

1. Symbols used in wiring diagram are, : connector, : terminal
block.

2. Indoor unit and outdoor unit connecting wires have polarities, make sure
to match terminal numbers (S1, S2, S3) for correct wirings,

3. Since the outdoor unit side electric wiring may change, be sure to check
the outdoor unit electric wiring diagram for service.

Table 1 Signal Inputs

Name

Terminal block

Connector

Item OFF (Open) ON (Short)
IN1 TBI.1 13-14 — Room thermostat 1 input Refer to SW2-1 in <6-7. DIP switch setting>.
IN2 TBI.1 11-12 — Flow switch 1 input Refer to SW2-2 in <6-7. DIP switch setting>.
IN3 TBI.1 9-10 — Flow switch 2 input (Zone1) Refer to SW3-2 in <6-7. DIP switch setting>.
IN4 TBI.1 7-8 — Demand control input Normal

Heat source OFF/ Boiler operation *2

IN5 TBI.1 5-6 —

Outdoor thermostat input *1

Standard operation

Heater operation/ Boiler operation *2
IN6 TBI.1 3-4 — Room thermostat 2 input Refer to SW3-1 in <6-7. DIP switch setting>.
IN7 TBI.1 1-2 — Flow switch 3 input (Zone2) Refer to SW3-3 in <6-7. DIP switch setting>.
IN8 TBI.3 1-2 — Electric energy meter 1

Refer to <6-7. DIP switch setting>.IN9 TBI.3 3-4 — Electric energy meter 2

IN10

TBI.3 5-6 — Heat meter

*1. If using outdoor thermostat for controlling operation of heaters, the lifetime of the heaters and related

parts may be reduced.

*2. To turn on the boiler operation, use the main controller to select “Boiler” in “External input setting“ screen

in the service menu.

Table 2 Outputs

Name

Terminal block

Connector

Item OFF ON

OUT1

TBO.1 1-2 CNP1 Water circulation pump 1 output (Space heating & DHW) OFF ON

OUT2

TBO.1 3-4 — Water circulation pump 2 output (Space heating for Zone1) OFF ON

OUT3

TBO.1 5-6 —

Water circulation pump 3 output (Space heating for Zone2)

*1

OFF ON

2-way valve 2b output *2

OUT4

TBO.2 4-6 CNV1 3-way valve output Heating DHW

OUT5

TBO.2 1-2

— Mixing valve output *1 Stop

Close

TBO.2 2-3 Open

OUT6

—

CNBH 1-3

Booster heater 1 output OFF ON

OUT7

—

CNBH 5-7

Booster heater 2 output OFF ON

OUT9

TBO.4 3-4 CNIH Immersion heater output OFF ON

OUT10

TBO.3 1-2 — Boiler output OFF ON

OUT11

TBO.3 3-4 — Error output Normal Error

OUT12

TBO.3 5-6 — Defrost output Normal Defrost

OUT13

TBO.4 1-2 — 2-way valve 2a output *2 OFF ON

OUT14

— CNP4 Water circulation pump 4 output (DHW) OFF ON

OUT15

TBO.3 7-8 — Comp ON signal OFF ON

Do not connect to the terminals that are indicated as “—” in the “Terminal block” eld.
*1. For 2-zone temperature control.
*2. For 2-zone valve ON/OFF control.

6-1. EHST20C-VM2C, EHST20C-VM2EC, EHST20D-VM2C, EHPT20X-VM2C

Symbol Name
TB1 Terminal block <Power supply, Outdoor unit>
ECB1

Earth leakage circuit breaker for booster heater

ECB2

Earth leakage circuit breaker for immersion heater

MP1

Water circulation pump 1(Space heating & DHW)

MP2

Water circulation pump 2 (Space heating for Zone1)(Local supply)

MP3

Water circulation pump 3 (Space heating for Zone2)(Local supply)

MP4 Water circulation pump 4 (DHW)
3WV 3-way valve
2WV2a 2-way valve (For Zone 1)(Local supply)
2WV2b 2-way valve (For Zone 2)(Local supply)
MXV Mixing valve (Local supply)
BHT Thermostat for booster heater
BHF Thermal fuse for booster heater
BH1 Booster heater 1
BHC1 Contactor for booster heater 1
BHCP Contactor for booster heater protection
IHT Thermostat (xed temp.) for immersion heater
IH Immersion heater
IHC Contactor for immersion heater

Symbol Name
TH1 Thermistor (Room temp.)(Option)
TH2 Thermistor (Ref. liquid temp.)
THW1 Thermistor (Flow water temp.)
THW2 Thermistor (Return water temp.)
THW5 Thermistor (DHW tank water temp.)
THW6 Thermistor (Zone1 ow temp.)(Option)
THW7 Thermistor (Zone1 return temp.)(Option)
THW8 Thermistor (Zone2 ow temp.)(Option)
THW9 Thermistor (Zone2 return temp.)(Option)
THWB1 Thermistor (Boiler ow temp.)(Option)
THWB2 Thermistor (Boiler return temp.)(Option)
IN1 Room thermostat 1 (Local supply)
IN2 Flow switch 1 (Local supply)
IN3 Flow switch 2 (Local supply)
IN4 Demand control (Local supply)
IN5 Outdoor thermostat (Local supply)
IN6 Room thermostat 2 (Local supply)
IN7 Flow switch 3 (Local supply)
IN8 Electric energy meter 1 (Local supply)
IN9 Electric energy meter 2 (Local supply)
IN10 Heat meter (Local supply)
FLOW TEMP. CONTROLLER (FTC5)

TBO.1-4

Terminal block <Outputs>
TBI.1-3 Terminal block <Signal Inputs, Thermistor>
F1 Fuse (T10AL250V)
F2 Fuse (T6.3AL250V)
SW1-5 DIP switch *See 6-7. DIP switch setting.
X1-15 Relay
LED1 Power supply (FTC5)
LED2 Power supply (Main controller)
LED3 Communication (FTC5-Outdoor unit)
LED4 Reading or writing data to SD card
CNPWM

Pump speed control signal for MP1

CN108 SD card connector

OCH570

WHT

WHT

2 2 2

2

ECB1

L

(1)N(3)

BHCP

BLU

BLU

BLU

REDRED

BLU/No.3

WHT/No.2

WHT/No.1

BLU/No.4

RED

VLT

VLT

PNK

PNK

GRY

GRY

BHC2

BHC1

BHT

642

531

A1

A2

642

531

A1

A2

BH1

BHF

BH2

2

4

Power supply

to Booster heater

642

531

A1

A2

CNBH

(WHT)

CNBHT

(BLK)

2

2

2

2

CNBC
(GRY)

1

1

3

5

7

3

1

3

~/N 230V 50Hz

1

3

5

7

X6

X7

1

3

1

3

CNBHT

(BLK)
CNBC
(GRY)

CNBH
(WHT)

NL

S3S2S1

NL

S3S2S1

To outdoor

unit

TB1

ORN

ORN

YLW

YLW

GRN/YLW

To outdoor

unit

Power supply

~/N 230V 50Hz

TB1

ORN

BLU

RED

BLU

RED

YLW

GRN/YLW

1

3

CN3C
(BLU)

BLK

BLK

BLK

BLK

1

3

ORN

BRN

CN3C
(BLU)

ORN

ORN

BRN

YLW

Indoor unit powered

by independent source

Indoor unit powered

via outdoor unit

CIRCUIT

BREAKER

1

3

CN3C
(BLU)

1

3

CNPWM

(WHT)

LED1

LED2

LED3

LED4

TBI.1

TBI.2

1310 12 141174 65 932 811310 12 141174 65 932 811310 12 141174 65 932 81

IN6

IN1

IN2

IN3

IN4

IN5

IN7

THW8

THW7

THW6

THW9

THWB1

THWB2

t°t°t°t°t°t

°

Main

controller

1

+

-+-+-

2

1

2

CN20

(RED)

TH1

t

°

1

3

CN21

(YLW)

TH2

t

°

1

4

THW1

THW2

CNW12

(RED)

t°t

°

1

2

THW5

CNW5

(WHT)

t

°

CN108

5

1

Wireless receiver

(Option)

WiFi adapter

(Option)

5

1

5

1

CNRF
(WHT)

CN105
(RED)

CN22
(BLU)

1
2
3
4
5
6

1

5

Close

Open

N

TBO.4

TBO.2

TBO.1

F1

F2

M

2WV2a

MXV

M

1

~

MP2

MP1

M

1

~

1

3

CNV1
(WHT)

X9

X8

X13

X4

X14

X3

X2

X1

X5B

X5A
1
2
3
4
5
6

1
2
3
4
5
6

1

1

3

3

3

CNP1
(WHT)

CNP4
(RED)

CNPWM

(WHT)

TBO.1

TBO.2

TBO.3

TBO.4

CNP1
(WHT)

CNP4
(RED)

CNV1
(WHT)

CN22
(BLU)

CNIT
(BLU)

TAB1

CN01
(WHT)

F2 F1

6.3A 250V 10A 250V

SW1

SW2

SW3

SW4

SW5

1

8

1

8

1

1

5

1
3

1
3

8

1

8

1

6

CN01
(WHT)

CN01
(WHT)

2

1

4
6

2

1

1
2
4
6

4
6

CNBH
(WHT)

CNBC
(GRY)

1

1

3

1
2

1
2

1
2

CNBHT

(BLK)

1

3

7

1

3

CNIH

(ORN)

1

4

1

3

CNW5
(WHT)

CN21
(YLW)

CNW12

(RED)

CN20

(RED)

TBI.2

CNIH
(ORN)

MP3

M

1

~

IN8

IN9

IN10

TBI.3

TBI.3

1

4

CN1A
(WHT)

TBI.1

2WV2b

M

1

~

M

1

~

MP4

M

1

~

1

3

L
(1)N(3)

ORN

RED

BLU

BLU

RED

ORN

IHC

IHT

IH

642

531

A1

A2

A B

2

4

Immersion heater (1Ph3kW)(Option)

Power supply

to Immersion heater

~/N 230V 50Hz

1

2

CNIH

(ORN)

3

3WV

M

1

~

ECB2

1

2
4

6

CN01

(WHT)

Tool

Tool

Conductor

Conductor

Outline view Top view

<How to use TBO.1 to 4>

Connect them using either way as shown below.

X15

X12

TBO.3

X11

X10

1
2
3
4
5
6
7
8

Signal output

(Boiler)

Signal output

(Error)

Signal output

(Defrost)

Signal output

(Comp ON)

1
2
3
4
5
6

1
2
3
4
5
6

1
2
3
4
5
6
7
8

1
2
3
4
5
6

12 146 108

137 11945321

12 146 108

137 11945321

12 146 108

137 11945321

11

6-2. EHST20C-VM6C, EHST20C-VM6EC, EHPT20X-VM6C

Table 1 Signal Inputs

Name

Terminal block

Connector

Item OFF (Open) ON (Short)
IN1 TBI.1 13-14 — Room thermostat 1 input Refer to SW2-1 in <6-7. DIP switch setting>.
IN2 TBI.1 11-12 — Flow switch 1 input Refer to SW2-2 in <6-7. DIP switch setting>.
IN3 TBI.1 9-10 — Flow switch 2 input (Zone1) Refer to SW3-2 in <6-7. DIP switch setting>.
IN4 TBI.1 7-8 — Demand control input Normal

Heat source OFF/ Boiler operation *2

IN5 TBI.1 5-6 — Outdoor thermostat input *1

Standard operation

Heater operation/ Boiler operation *2
IN6 TBI.1 3-4 — Room thermostat 2 input Refer to SW3-1 in <6-7. DIP switch setting>.
IN7 TBI.1 1-2 — Flow switch 3 input (Zone2) Refer to SW3-3 in <6-7. DIP switch setting>.
IN8 TBI.3 1-2 — Electric energy meter 1

Refer to <6-7. DIP switch setting>.IN9 TBI.3 3-4 — Electric energy meter 2

IN10

TBI.3 5-6 — Heat meter

*1. If using outdoor thermostat for controlling operation of heaters, the lifetime of the heaters and related parts

may be reduced.

*2. To turn on the boiler operation, use the main controller to select “Boiler” in “External input setting“ screen in

the service menu.

Table 2 Outputs

Name

Terminal block

Connector

Item OFF ON

OUT1

TBO.1 1-2 CNP1 Water circulation pump 1 output (Space heating & DHW) OFF ON

OUT2

TBO.1 3-4 — Water circulation pump 2 output (Space heating for Zone1) OFF ON

OUT3

TBO.1 5-6 —

Water circulation pump 3 output (Space heating for Zone2) *1

OFF ON

2-way valve 2b output *2

OUT4

TBO.2 4-6 CNV1 3-way valve output Heating DHW

OUT5

TBO.2 1-2

— Mixing valve output *1 Stop

Close

TBO.2 2-3 Open

OUT6

—

CNBH 1-3

Booster heater 1 output OFF ON

OUT7

—

CNBH 5-7

Booster heater 2 output OFF ON

OUT9

TBO.4 3-4 CNIH Immersion heater output OFF ON

OUT10

TBO.3 1-2 — Boiler output OFF ON

OUT11

TBO.3 3-4 — Error output Normal Error

OUT12

TBO.3 5-6 — Defrost output Normal Defrost

OUT13

TBO.4 1-2 — 2-way valve 2a output *2 OFF ON

OUT14

— CNP4 Water circulation pump 4 output (DHW) OFF ON

OUT15

TBO.3 7-8 — Comp ON signal OFF ON

Do not connect to the terminals that are indicated as “—” in the “Terminal block” eld.
*1. For 2-zone temperature control.
*2. For 2-zone valve ON/OFF control.

1. Symbols used in wiring diagram are, : connector, : terminal

block.

2. Indoor unit and outdoor unit connecting wires have polarities, make sure
to match terminal numbers (S1, S2, S3) for correct wirings,

3. Since the outdoor unit side electric wiring may change, be sure to check
the outdoor unit electric wiring diagram for service.

Symbol Name
TB1 Terminal block <Power supply, Outdoor unit>
ECB1

Earth leakage circuit breaker for booster heater

ECB2

Earth leakage circuit breaker for immersion heater

MP1

Water circulation pump 1(Space heating & DHW)

MP2

Water circulation pump 2 (Space heating for Zone1)(Local supply)

MP3

Water circulation pump 3 (Space heating for Zone2)(Local supply)

MP4 Water circulation pump 4 (DHW)
3WV 3-way valve
2WV2a 2-way valve (For Zone 1)(Local supply)
2WV2b 2-way valve (For Zone 2)(Local supply)
MXV Mixing valve (Local supply)
BHT Thermostat for booster heater
BHF Thermal fuse for booster heater
BH1 Booster heater 1
BH2 Booster heater 2
BHC1 Contactor for booster heater 1
BHC2 Contactor for booster heater 2
BHCP Contactor for booster heater protection
IHT Thermostat (xed temp.) for immersion heater
IH Immersion heater
IHC Contactor for immersion heater

Symbol Name
TH1 Thermistor (Room temp.)(Option)
TH2 Thermistor (Ref. liquid temp.)
THW1 Thermistor (Flow water temp.)
THW2 Thermistor (Return water temp.)
THW5 Thermistor (DHW tank water temp.)
THW6 Thermistor (Zone1 ow temp.)(Option)
THW7 Thermistor (Zone1 return temp.)(Option)
THW8 Thermistor (Zone2 ow temp.)(Option)
THW9 Thermistor (Zone2 return temp.)(Option)
THWB1 Thermistor (Boiler ow temp.)(Option)
THWB2 Thermistor (Boiler return temp.)(Option)
IN1 Room thermostat 1 (Local supply)
IN2 Flow switch 1 (Local supply)
IN3 Flow switch 2 (Local supply)
IN4 Demand control (Local supply)
IN5 Outdoor thermostat (Local supply)
IN6 Room thermostat 2 (Local supply)
IN7 Flow switch 3 (Local supply)
IN8 Electric energy meter 1 (Local supply)
IN9 Electric energy meter 2 (Local supply)
IN10 Heat meter (Local supply)
FLOW TEMP. CONTROLLER (FTC5)

TBO.1-4

Terminal block <Outputs>
TBI.1-3 Terminal block <Signal Inputs, Thermistor>
F1 Fuse (T10AL250V)
F2 Fuse (T6.3AL250V)
SW1-5 DIP switch *See 6-7. DIP switch setting.
X1-15 Relay
LED1 Power supply (FTC5)
LED2 Power supply (Main controller)
LED3 Communication (FTC5-Outdoor unit)
LED4 Reading or writing data to SD card
CNPWM

Pump speed control signal for MP1

CN108 SD card connector

OCH570

NL

S3S2S1

NL

S3S2S1

To outdoor

unit

TB1

ORN

ORN

YLW

YLW

GRN/YLW

To outdoor

unit

Power supply
~/N 230V 50Hz

TB1

ORN

BLU

RED

BLU

RED

YLW

GRN/YLW

1

3

CN3C
(BLU)

BLK

BLK

BLK

BLK

1

3

ORN

BRN

CN3C
(BLU)

ORN

ORN

BRN

YLW

Indoor unit powered

by independent source

Indoor unit powered

via outdoor unit

CIRCUIT

BREAKER

1

3

CN3C
(BLU)

1

3

CNPWM

(WHT)

LED1

LED2

LED3

LED4

CN108

5

1

Wireless receiver

(Option)

WiFi adapter

(Option)

5

1

5

1

CNRF
(WHT)

CN105

(RED)

1
2
3
4
5
6

1

3

5

7

1

5

Close

Open

N

X6

X15

X12

X7

TBO.4

TBO.3

TBO.2

TBO.1

F1

F2

M

2WV2a

MXV

M

1

~

MP2

MP1

M

1

~

1

3

1

3

CNV1

(WHT)

1

3

CNBHT

(BLK)
CNBC
(GRY)

CNBH
(WHT)

X11

X9

X8

X13

X10

X4

X14

X3

X2

X1

X5B

X5A

1
2
3
4
5
6
7
8

1
2
3
4
5
6

1
2
3
4
5
6

1

1

3

3

3

CNP1
(WHT)

CNP4
(RED)

CNPWM

(WHT)

TBO.1

TBO.2

TBO.3

TBO.4

CNP1
(WHT)

CNP4
(RED)

CNV1
(WHT)

CN22
(BLU)

CNIT

(BLU)

CN01
(WHT)

F2 F1

6.3A 250V 10A 250V

SW1

SW2

SW3

SW4

SW5

1

8

1

8

1

1

5

1
3

1
3

8

1

1
2
3
4
5
6

1
2
3
4
5
6

1
2
3
4
5
6
7
8

1
2
3
4
5
6

8

1

6

CN01
(WHT)

CN01
(WHT)

2

1

4
6

2

1

1
2
4
6

4
6

CNBH
(WHT)

CNBC
(GRY)

1

1

3

1
2

1
2

1
2

CNBHT

(BLK)

1

3

7

1

3

CNIH

(ORN)

1

4

1

3

CNW5
(WHT)

CN21
(YLW)

CNW12

(RED)

CN20

(RED)

TBI.2

CNIH

(ORN)

MP3

M

1

~

2 2 2

L2
(3)L1(1)L3(5)

BHCP

BLK

BLK

WHT

WHTWHT

BLK

REDRED

BLU/No.4

WHT/No.2

WHT/No.3

WHT/No.1

BLU/No.5

BLU/No.6

RED

VLT

VLT

PNK

PNK

WHT

WHT

GRY

GRY

BHC2

BHC1

BHT

642

531

A1

A2

642

531

A1

A2

BH1

BHF

BH2

2

4 6

Power supply

to Booster heater

642

531

A1

A2

CNBH
(WHT)

CNBHT

(BLK)

2

2

2

2

2

CNBC
(GRY)

1

1

3

5

7

3

1

3

3~ 400V 50Hz

TBI.3

1

4

CN1A
(WHT)

TBI.1

2WV2b

M

1

~

M

1

~

MP4

M

1

~

1

3

L
(1)N(3)

ORN

RED

BLU

BLU

RED

ORN

IHC

IHT

IH

642

531

A1

A2

A B

2

4

Immersion heater (1Ph3kW)(Option)

Power supply

to Immersion heater

~/N 230V 50Hz

1

2

CNIH
(ORN)

3

Signal output

(Boiler)

Signal output

(Error)

Signal output

(Defrost)

Signal output

(Comp ON)

ECB1

ECB2

1

2
4

6

CN01

(WHT)

3WV

M

1

~

12 146 108

137 11945321

12 146 108

137 11945321

12 146 108

137 11945321

TBI.1

TBI.2

1310 12 141174 65 932 811310 12 141174 65 932 811310 12 141174 65 932 81

IN6

IN1

IN2

IN3

IN4

IN5

IN7

THW8

THW7

THW6

THW9

THWB1

THWB2

t°t°t°t°t°t

°

Main

controller

1

+

-+-+-

2

1

2

CN20

(RED)

TH1

t

°

1

3

CN21

(YLW)

TH2

t

°

1

4

THW1

THW2

CNW12

(RED)

t°t

°

1

2

THW5

CNW5

(WHT)

t

°

CN22
(BLU)

TAB1

IN8

IN9

IN10

TBI.3

Tool

Tool

Conductor

Conductor

Outline view Top view

<How to use TBO.1 to 4>

Connect them using either way as shown below.

12

6-3. EHST20C-YM9C, EHST20C-YM9EC, EHPT20X-YM9C

1. Symbols used in wiring diagram are, : connector, : terminal
block.

2. Indoor unit and outdoor unit connecting wires have polarities, make sure
to match terminal numbers (S1, S2, S3) for correct wirings,

3. Since the outdoor unit side electric wiring may change, be sure to check
the outdoor unit electric wiring diagram for service.

Table 1 Signal Inputs

Name

Terminal block

Connector

Item OFF (Open) ON (Short)
IN1 TBI.1 13-14 — Room thermostat 1 input Refer to SW2-1 in <6-7. DIP switch setting>.
IN2 TBI.1 11-12 — Flow switch 1 input Refer to SW2-2 in <6-7. DIP switch setting>.
IN3 TBI.1 9-10 — Flow switch 2 input (Zone1) Refer to SW3-2 in <6-7. DIP switch setting>.
IN4 TBI.1 7-8 — Demand control input Normal

Heat source OFF/ Boiler operation *2

IN5 TBI.1 5-6 — Outdoor thermostat input *1 Standard operation

Heater operation/ Boiler operation *2
IN6 TBI.1 3-4 — Room thermostat 2 input Refer to SW3-1 in <6-7. DIP switch setting>.
IN7 TBI.1 1-2 — Flow switch 3 input (Zone2) Refer to SW3-3 in <6-7. DIP switch setting>.
IN8 TBI.3 1-2 — Electric energy meter 1

Refer to <6-7. DIP switch setting>.IN9 TBI.3 3-4 — Electric energy meter 2

IN10

TBI.3 5-6 — Heat meter

*1. If using outdoor thermostat for controlling operation of heaters, the lifetime of the heaters and related parts

may be reduced.

*2. To turn on the boiler operation, use the main controller to select “Boiler” in “External input setting“ screen in

the service menu.

Table 2 Outputs

Name

Terminal block

Connector

Item OFF ON

OUT1

TBO.1 1-2 CNP1 Water circulation pump 1 output (Space heating & DHW) OFF ON

OUT2

TBO.1 3-4 — Water circulation pump 2 output (Space heating for Zone1) OFF ON

OUT3

TBO.1 5-6 —

Water circulation pump 3 output (Space heating for Zone2) *1

OFF ON

2-way valve 2b output *2

OUT4

TBO.2 4-6 CNV1 3-way valve output Heating DHW

OUT5

TBO.2 1-2

— Mixing valve output *1 Stop

Close

TBO.2 2-3 Open

OUT6

—

CNBH 1-3

Booster heater 1 output OFF ON

OUT7

—

CNBH 5-7

Booster heater 2 output OFF ON

OUT9

TBO.4 3-4 CNIH Immersion heater output OFF ON

OUT10

TBO.3 1-2 — Boiler output OFF ON

OUT11

TBO.3 3-4 — Error output Normal Error

OUT12

TBO.3 5-6 — Defrost output Normal Defrost

OUT13

TBO.4 1-2 — 2-way valve 2a output *2 OFF ON

OUT14

— CNP4 Water circulation pump 4 output (DHW) OFF ON

OUT15

TBO.3 7-8 — Comp ON signal OFF ON

Do not connect to the terminals that are indicated as “—” in the “Terminal block” eld.
*1. For 2-zone temperature control.
*2. For 2-zone valve ON/OFF control.

Symbol Name
TB1 Terminal block <Power supply, Outdoor unit>
ECB1

Earth leakage circuit breaker for booster heater

ECB2

Earth leakage circuit breaker for immersion heater

MP1

Water circulation pump 1(Space heating & DHW)

MP2

Water circulation pump 2 (Space heating for Zone1)(Local supply)

MP3

Water circulation pump 3 (Space heating for Zone2)(Local supply)

MP4 Water circulation pump 4 (DHW)
3WV 3-way valve
2WV2a 2-way valve (For Zone 1)(Local supply)
2WV2b 2-way valve (For Zone 2)(Local supply)
MXV Mixing valve (Local supply)
BHT Thermostat for booster heater
BHF Thermal fuse for booster heater
BH1 Booster heater 1
BH2 Booster heater 2
BHC1 Contactor for booster heater 1
BHC2 Contactor for booster heater 2
BHCP Contactor for booster heater protection
IHT Thermostat (xed temp.) for immersion heater
IH Immersion heater
IHC Contactor for immersion heater

Symbol Name
TH1 Thermistor (Room temp.)(Option)
TH2 Thermistor (Ref. liquid temp.)
THW1 Thermistor (Flow water temp.)
THW2 Thermistor (Return water temp.)
THW5 Thermistor (DHW tank water temp.)
THW6 Thermistor (Zone1 ow temp.)(Option)
THW7 Thermistor (Zone1 return temp.)(Option)
THW8 Thermistor (Zone2 ow temp.)(Option)
THW9 Thermistor (Zone2 return temp.)(Option)
THWB1 Thermistor (Boiler ow temp.)(Option)
THWB2 Thermistor (Boiler return temp.)(Option)
IN1 Room thermostat 1 (Local supply)
IN2 Flow switch 1 (Local supply)
IN3 Flow switch 2 (Local supply)
IN4 Demand control (Local supply)
IN5 Outdoor thermostat (Local supply)
IN6 Room thermostat 2 (Local supply)
IN7 Flow switch 3 (Local supply)
IN8 Electric energy meter 1 (Local supply)
IN9 Electric energy meter 2 (Local supply)
IN10 Heat meter (Local supply)
FLOW TEMP. CONTROLLER (FTC5)

TBO.1-4

Terminal block <Outputs>
TBI.1-3 Terminal block <Signal Inputs, Thermistor>
F1 Fuse (T10AL250V)
F2 Fuse (T6.3AL250V)
SW1-5 DIP switch *See 6-7. DIP switch setting.
X1-15 Relay
LED1 Power supply (FTC5)
LED2 Power supply (Main controller)
LED3 Communication (FTC5-Outdoor unit)
LED4 Reading or writing data to SD card
CNPWM

Pump speed control signal for MP1

CN108 SD card connector

OCH570

2 2 2

ECB1

L2
(3)L1(1)L3(5)

BHCP

BLK

BLK

WHT

WHTWHT

BLK

REDRED

BLU/No.4

WHT/No.2

WHT/No.3

WHT/No.1

BLU/No.5

BLU/No.6

RED

VLT

VLT

PNK

PNK

GRY

GRY

BHC2

BHC1

BHT

642

531

A1

A2

642

531

A1

A2

BH1

BHF

BH2

2

4

6

Power supply

to Booster heater

642

531

A1

A2

2

2

2

2

2

1

1

3

5

7

3

1

3

3~ 230V 50Hz

CNBHT
(BLK)

CNBC
(GRY)

CNBH
(WHT)

WHT

WHT

1

3

5

7

X6

X7

1

3

1

3

CNBHT

(BLK)
CNBC
(GRY)

CNBH
(WHT)

NL

S3S2S1

NL

S3S2S1

To outdoor

unit

TB1

ORN

ORN

YLW

YLW

GRN/YLW

To outdoor

unit

Power supply
~/N 230V 50Hz

TB1

ORN

BLU

RED

BLU

RED

YLW

GRN/YLW

1

3

CN3C
(BLU)

BLK

BLK

BLK

BLK

1

3

ORN

BRN

CN3C
(BLU)

ORN

ORN

BRN

YLW

Indoor unit powered

by independent source

Indoor unit powered

via outdoor unit

CIRCUIT

BREAKER

1

3

CN3C
(BLU)

1

3

CNPWM

(WHT)

LED1

LED2

LED3

LED4

TBI.1

TBI.2

1310 12 141174 65 932 811310 12 141174 65 932 811310 12 141174 65 932 81

IN6

IN1

IN2

IN3

IN4

IN5

IN7

THW8

THW7

THW6

THW9

THWB1

THWB2

t°t°t°t°t°t

°

Main

controller

1

+

-+-+-

2

1

2

CN20

(RED)

TH1

t

°

1

3

CN21

(YLW)

TH2

t

°

1

4

THW1

THW2

CNW12

(RED)

t°t

°

1

2

THW5

CNW5

(WHT)

t

°

CN108

5

1

Wireless receiver

(Option)

WiFi adapter

(Option)

5

1

5

1

CNRF
(WHT)

CN105
(RED)

CN22
(BLU)

1

5

Close

Open

N

TBO.2

TBO.1

F1

F2

MXV

M

1

~

MP2

MP1

M

1

~

CNV1
(WHT)

X4

X14

X3

X2

X1

X5B

X5A
1
2
3
4
5
6

1
2
3
4
5
6

1

1

3

3

3

CNP1
(WHT)

CNP4
(RED)

CNPWM
(WHT)

TBO.1

TBO.2

TBO.3

TBO.4

CNP1

(WHT)

CNP4
(RED)

CNV1

(WHT)

CN22
(BLU)

CNIT
(BLU)

TAB1

CN01

(WHT)

F2 F1

6.3A 250V 10A 250V

SW1

SW2

SW3

SW4

SW5

1

8

1

8

1

1

5

1
3

1
3

8

1

8

1

6

CN01
(WHT)

CN01

(WHT)

2

1

4
6

2

1

1
2
4
6

4
6

CNBH
(WHT)

CNBC
(GRY)

1

1

3

1
2

1
2

1
2

CNBHT

(BLK)

1

3

7

1

3

CNIH

(ORN)

1

4

1

3

CNW5
(WHT)

CN21
(YLW)

CNW12

(RED)

CN20
(RED)

TBI.2

MP3

M

1

~

IN8

IN9

IN10

TBI.3

TBI.3

1

4

CN1A

(WHT)

TBI.1

2WV2b

M

1

~

M

1

~

MP4

M

1

~

1

3

L

(1)N(3)

ORN

RED

BLU

BLU

RED

ORN

IHC

IHT

IH

642

531

A1

A2

A B

2

4

Immersion heater (1Ph3kW)(Option)

Power supply

to Immersion heater

~/N 230V 50Hz

1

2

CNIH
(ORN)

3

3WV

M

1

~

ECB2

1

2
4

6

CN01
(WHT)

Tool

Tool

Conductor

Conductor

Outline view Top view

<How to use TBO.1 to 4>

Connect them using either way as shown below.

X15

X12

TBO.3

X11

X10
1

2
3
4
5
6
7
8

Signal output

(Boiler)

Signal output

(Error)

Signal output

(Defrost)

Signal output

(Comp ON)

1
2
3
4
5
6

TBO.4

M

2WV2a

1

3

X9

X8

X13

CNIH

(ORN)

1
2
3
4
5
6

1
2
3
4
5
6

1
2
3
4
5
6
7
8

1
2
3
4
5
6

12 146 108

137 11945321

12 146 108

137 11945321

12 146 108

137 11945321

13

6-4. EHST20C-TM9C, EHPT20X-TM9C

Table 1 Signal Inputs

Name

Terminal block

Connector

Item OFF (Open) ON (Short)
IN1 TBI.1 13-14 — Room thermostat 1 input Refer to SW2-1 in <6-7. DIP switch setting>.
IN2 TBI.1 11-12 — Flow switch 1 input Refer to SW2-2 in <6-7. DIP switch setting>.
IN3 TBI.1 9-10 — Flow switch 2 input (Zone1) Refer to SW3-2 in <6-7. DIP switch setting>.
IN4 TBI.1 7-8 — Demand control input Normal Heat source OFF/ Boiler operation *2
IN5 TBI.1 5-6 — Outdoor thermostat input *1 Standard operation Heater operation/ Boiler operation *2
IN6 TBI.1 3-4 — Room thermostat 2 input Refer to SW3-1 in <6-7. DIP switch setting>.
IN7 TBI.1 1-2 — Flow switch 3 input (Zone2) Refer to SW3-3 in <6-7. DIP switch setting>.
IN8 TBI.3 1-2 — Electric energy meter 1

Refer to <6-7. DIP switch setting>.IN9 TBI.3 3-4 — Electric energy meter 2

IN10

TBI.3 5-6 — Heat meter

*1. If using outdoor thermostat for controlling operation of heaters, the lifetime of the heaters and related parts may

be reduced.

*2. To turn on the boiler operation, use the main controller to select “Boiler” in “External input setting“ screen in the

service menu.

Table 2 Outputs

Name

Terminal block

Connector

Item OFF ON

OUT1

TBO.1 1-2 CNP1 Water circulation pump 1 output (Space heating & DHW) OFF ON

OUT2

TBO.1 3-4 — Water circulation pump 2 output (Space heating for Zone1) OFF ON

OUT3

TBO.1 5-6 —

Water circulation pump 3 output (Space heating for Zone2) *1

OFF ON

2-way valve 2b output *2

OUT4

TBO.2 4-6 CNV1 3-way valve output Heating DHW

OUT5

TBO.2 1-2

— Mixing valve output *1 Stop

Close

TBO.2 2-3 Open

OUT6

—

CNBH 1-3

Booster heater 1 output OFF ON

OUT7

—

CNBH 5-7

Booster heater 2 output OFF ON

OUT9

TBO.4 3-4 CNIH Immersion heater output OFF ON

OUT10

TBO.3 1-2 — Boiler output OFF ON

OUT11

TBO.3 3-4 — Error output Normal Error

OUT12

TBO.3 5-6 — Defrost output Normal Defrost

OUT13

TBO.4 1-2 — 2-way valve 2a output *2 OFF ON

OUT14

— CNP4 Water circulation pump 4 output (DHW) OFF ON

OUT15

TBO.3 7-8 — Comp ON signal OFF ON

Do not connect to the terminals that are indicated as “—” in the “Terminal block” eld.
*1. For 2-zone temperature control.
*2. For 2-zone valve ON/OFF control.

Symbol Name
TB1 Terminal block <Power supply, Outdoor unit>
ECB1

Earth leakage circuit breaker for booster heater

ECB2

Earth leakage circuit breaker for immersion heater

MP1

Water circulation pump 1(Space heating & DHW)

MP2

Water circulation pump 2 (Space heating for Zone1)(Local supply)

MP3

Water circulation pump 3 (Space heating for Zone2)(Local supply)

MP4 Water circulation pump 4 (DHW)
3WV 3-way valve
2WV2a 2-way valve (For Zone 1)(Local supply)
2WV2b 2-way valve (For Zone 2)(Local supply)
MXV Mixing valve (Local supply)
BHT Thermostat for booster heater
BHF Thermal fuse for booster heater
BH1 Booster heater 1
BH2 Booster heater 2
BHC1 Contactor for booster heater 1
BHC2 Contactor for booster heater 2
BHCP Contactor for booster heater protection
IHT Thermostat (xed temp.) for immersion heater
IH Immersion heater
IHC Contactor for immersion heater

Symbol Name
TH1 Thermistor (Room temp.)(Option)
TH2 Thermistor (Ref. liquid temp.)
THW1 Thermistor (Flow water temp.)
THW2 Thermistor (Return water temp.)
THW5 Thermistor (DHW tank water temp.)
THW6 Thermistor (Zone1 ow temp.)(Option)
THW7 Thermistor (Zone1 return temp.)(Option)
THW8 Thermistor (Zone2 ow temp.)(Option)
THW9 Thermistor (Zone2 return temp.)(Option)
THWB1 Thermistor (Boiler ow temp.)(Option)
THWB2 Thermistor (Boiler return temp.)(Option)
IN1 Room thermostat 1 (Local supply)
IN2 Flow switch 1 (Local supply)
IN3 Flow switch 2 (Local supply)
IN4 Demand control (Local supply)
IN5 Outdoor thermostat (Local supply)
IN6 Room thermostat 2 (Local supply)
IN7 Flow switch 3 (Local supply)
IN8 Electric energy meter 1 (Local supply)
IN9 Electric energy meter 2 (Local supply)
IN10 Heat meter (Local supply)
FLOW TEMP. CONTROLLER (FTC5)

TBO.1-4

Terminal block <Outputs>
TBI.1-3 Terminal block <Signal Inputs, Thermistor>
F1 Fuse (T10AL250V)
F2 Fuse (T6.3AL250V)
SW1-5 DIP switch *See 6-7. DIP switch setting.
X1-15 Relay
LED1 Power supply (FTC5)
LED2 Power supply (Main controller)
LED3 Communication (FTC5-Outdoor unit)
LED4 Reading or writing data to SD card
CNPWM

Pump speed control signal for MP1

CN108 SD card connector

1. Symbols used in wiring diagram are, : connector, : terminal
block.

2. Indoor unit and outdoor unit connecting wires have polarities, make
sure to match terminal numbers (S1, S2, S3) for correct wirings,

3. Since the outdoor unit side electric wiring may change, be sure to
check the outdoor unit electric wiring diagram for service.

OCH570

1

3

5

7

X6

X7

1

3

1

3

CNBHT

(BLK)
CNBC
(GRY)

CNBH
(WHT)

NL

S3S2S1

NL

S3S2S1

To outdoor

unit

TB1

ORN

ORN

YLW

YLW

GRN/YLW

To outdoor

unit

Power supply

~/N 230V 50Hz

TB1

ORN

BLU

RED

BLU

RED

YLW

GRN/YLW

1

3

CN3C
(BLU)

BLK

BLK

BLK

BLK

1

3

ORN

BRN

CN3C
(BLU)

ORN

ORN

BRN

YLW

Indoor unit powered

by independent source

Indoor unit powered

via outdoor unit

CIRCUIT

BREAKER

1

3

CN3C
(BLU)

1

3

CNPWM

(WHT)

LED1

LED2

LED3

LED4

TBI.1

TBI.2

1310 12 141174 65 932 811310 12 141174 65 932 811310 12 141174 65 932 81

IN6

IN1

IN2

IN3

IN4

IN5

IN7

THW8

THW7

THW6

THW9

THWB1

THWB2

t°t°t°t°t°t

°

Main

controller

1

+

-+-+-

2

1

2

CN20

(RED)

TH1

t

°

1

3

CN21

(YLW)

TH2

t

°

1

4

THW1

THW2

CNW12

(RED)

t°t

°

1

2

THW5

CNW5

(WHT)

t

°

CN108

5

1

Wireless receiver

(Option)

WiFi adapter

(Option)

5

1

5

1

CNRF
(WHT)

CN105
(RED)

CN22
(BLU)

1

5

Close

Open

N

TBO.2

TBO.1

F1

F2

MXV

M

1

~

MP2

MP1

M

1

~

CNV1

(WHT)

X4

X14

X3

X2

X1

X5B

X5A
1
2
3
4
5
6

1
2
3
4
5
6

1

1

3

3

3

CNP1
(WHT)

CNP4
(RED)

CNPWM

(WHT)

TBO.1

TBO.2

TBO.3

TBO.4

CNP1
(WHT)

CNP4
(RED)

CNV1
(WHT)

CN22
(BLU)

CNIT
(BLU)

TAB1

CN01
(WHT)

F2 F1

6.3A 250V 10A 250V

SW1

SW2

SW3

SW4

SW5

1

8

1

8

1

1

5

1
3

1
3

8

1

1
2
3
4
5
6

1
2
3
4
5
6

1
2
3
4
5
6
7
8

1
2
3
4
5
6

8

1

6

CN01
(WHT)

CN01

(WHT)

2

1

4
6

2

1

1
2
4
6

4
6

CNBH

(WHT)

CNBC
(GRY)

1

1

3

1
2

1
2

1
2

CNBHT

(BLK)

1

3

7

1

3

CNIH

(ORN)

1

4

1

3

CNW5
(WHT)

CN21

(YLW)

CNW12

(RED)

CN20
(RED)

TBI.2

12 146 108

137 11945321

12 146 108

137 11945321

12 146 108

137 11945321

MP3

M

1

~

IN8

IN9

IN10

TBI.3

TBI.3

1

4

CN1A
(WHT)

TBI.1

2WV2b

M

1

~

M

1

~

MP4

M

1

~

1

3

L

(1)N(3)

ORN

RED

BLU

BLU

RED

ORN

IHC

IHT

IH

642

531

A1

A2

A B

2

4

Immersion heater (1Ph3kW)(Option)

Power supply

to Immersion heater

~/N 230V 50Hz

1

2

CNIH
(ORN)

3

3WV

M

1

~

ECB2

1

2
4

6

CN01

(WHT)

X15

X12

TBO.3

X11

X10
1

2
3
4
5
6
7
8

Signal output

(Boiler)

Signal output

(Error)

Signal output

(Defrost)

Signal output

(Comp ON)

1
2
3
4
5
6

TBO.4

M

2WV2a

1

3

X9

X8

X13

CNIH

(ORN)

Tool

Tool

Conductor

Conductor

Outline view Top view

<How to use TBO.1 to 4>

Connect them using either way as shown below.

14

6-5. EHST20C-MEC, EHST20D-MEC, EHST20D-MHC

Table 1 Signal Inputs

Name

Terminal block

Connector

Item OFF (Open) ON (Short)
IN1 TBI.1 13-14 — Room thermostat 1 input Refer to SW2-1 in <6-7. DIP switch setting>.
IN2 TBI.1 11-12 — Flow switch 1 input Refer to SW2-2 in <6-7. DIP switch setting>.
IN3 TBI.1 9-10 — Flow switch 2 input (Zone1) Refer to SW3-2 in <6-7. DIP switch setting>.
IN4 TBI.1 7-8 — Demand control input Normal Heat source OFF/ Boiler operation *2
IN5 TBI.1 5-6 — Outdoor thermostat input *1 Standard operation Heater operation/ Boiler operation *2
IN6 TBI.1 3-4 — Room thermostat 2 input Refer to SW3-1 in <6-7. DIP switch setting>.
IN7 TBI.1 1-2 — Flow switch 3 input (Zone2) Refer to SW3-3 in <6-7. DIP switch setting>.
IN8 TBI.3 1-2 — Electric energy meter 1

Refer to <6-7. DIP switch setting>.IN9 TBI.3 3-4 — Electric energy meter 2

IN10

TBI.3 5-6 — Heat meter

*1. If using outdoor thermostat for controlling operation of heaters, the lifetime of the heaters and related parts may

be reduced.

*2. To turn on the boiler operation, use the main controller to select “Boiler” in “External input setting“ screen in the

service menu.

Table 2 Outputs

Name

Terminal block

Connector

Item OFF ON

OUT1

TBO.1 1-2 CNP1 Water circulation pump 1 output (Space heating & DHW) OFF ON

OUT2

TBO.1 3-4 — Water circulation pump 2 output (Space heating for Zone1) OFF ON

OUT3

TBO.1 5-6 —

Water circulation pump 3 output (Space heating for Zone2) *1

OFF ON

2-way valve 2b output *2

OUT4

TBO.2 4-6 CNV1 3-way valve output Heating DHW

OUT5

TBO.2 1-2

— Mixing valve output *1 Stop

Close

TBO.2 2-3 Open

OUT6

—

CNBH 1-3

Booster heater 1 output OFF ON

OUT7

—

CNBH 5-7

Booster heater 2 output OFF ON

OUT9

TBO.4 3-4 CNIH Immersion heater output OFF ON

OUT10

TBO.3 1-2 — Boiler output OFF ON

OUT11

TBO.3 3-4 — Error output Normal Error

OUT12

TBO.3 5-6 — Defrost output Normal Defrost

OUT13

TBO.4 1-2 — 2-way valve 2a output *2 OFF ON

OUT14

— CNP4 Water circulation pump 4 output (DHW) OFF ON

OUT15

TBO.3 7-8 — Comp ON signal OFF ON

Do not connect to the terminals that are indicated as “—” in the “Terminal block” eld.
*1. For 2-zone temperature control.
*2. For 2-zone valve ON/OFF control.

1. Symbols used in wiring diagram are, : connector,

: terminal block.

2. Indoor unit and outdoor unit connecting wires have polarities,

make sure to match terminal numbers (S1, S2, S3) for

correct wirings,

3. Since the outdoor unit side electric wiring may change, be
sure to check the outdoor unit electric wiring diagram for

service.

Symbol Name
TB1 Terminal block <Power supply, Outdoor unit>
ECB2

Earth leakage circuit breaker for immersion heater

MP1

Water circulation pump 1(Space heating & DHW)

MP2

Water circulation pump 2 (Space heating for Zone1)(Local supply)

MP3

Water circulation pump 3 (Space heating for Zone2)(Local supply)

MP4 Water circulation pump 4 (DHW)
3WV 3-way valve
2WV2a 2-way valve (For Zone 1)(Local supply)
2WV2b 2-way valve (For Zone 2)(Local supply)
MXV Mixing valve (Local supply)
IHT Thermostat (xed temp.) for immersion heater
IH Immersion heater
IHC Contactor for immersion heater

Symbol Name
TH1 Thermistor (Room temp.)(Option)
TH2 Thermistor (Ref. liquid temp.)
THW1 Thermistor (Flow water temp.)
THW2 Thermistor (Return water temp.)
THW5 Thermistor (DHW tank water temp.)
THW6 Thermistor (Zone1 ow temp.)(Option)
THW7 Thermistor (Zone1 return temp.)(Option)
THW8 Thermistor (Zone2 ow temp.)(Option)
THW9 Thermistor (Zone2 return temp.)(Option)
THWB1 Thermistor (Boiler ow temp.)(Option)
THWB2 Thermistor (Boiler return temp.)(Option)
IN1 Room thermostat 1 (Local supply)
IN2 Flow switch 1 (Local supply)
IN3 Flow switch 2 (Local supply)
IN4 Demand control (Local supply)
IN5 Outdoor thermostat (Local supply)
IN6 Room thermostat 2 (Local supply)
IN7 Flow switch 3 (Local supply)
IN8 Electric energy meter 1 (Local supply)
IN9 Electric energy meter 2 (Local supply)
IN10 Heat meter (Local supply)
FLOW TEMP. CONTROLLER (FTC5)

TBO.1-4

Terminal block <Outputs>
TBI.1-3 Terminal block <Signal Inputs, Thermistor>
F1 Fuse (T10AL250V)
F2 Fuse (T6.3AL250V)
SW1-5 DIP switch *See 6-7. DIP switch setting.
X1-15 Relay
LED1 Power supply (FTC5)
LED2 Power supply (Main controller)
LED3 Communication (FTC5-Outdoor unit)
LED4 Reading or writing data to SD card
CNPWM

Pump speed control signal for MP1

CN108 SD card connector

OCH570

Tool

Tool

Conductor

Conductor

Outline view Top view

<How to use TBO.1 to 4>

Connect them using either way as shown below.

NL

S3S2S1

NL

S3S2S1

To outdoor

unit

TB1

ORN

ORN

YLW

YLW

GRN/YLW

To outdoor

unit

Power supply
~/N 230V 50Hz

TB1

ORN

BLU

RED

BLU

RED

YLW

GRN/YLW

1

3

CN3C
(BLU)

BLK

BLK

BLK

BLK

1

3

ORN

BRN

CN3C
(BLU)

ORN

ORN

BRN

YLW

Indoor unit powered

by independent source

Indoor unit powered

via outdoor unit

CIRCUIT

BREAKER

1

3

CN3C
(BLU)

1

3

CNPWM

(WHT)

LED1

LED2

LED3

LED4

TBI.1

TBI.2

1310 12 141174 65 932 811310 12 141174 65 932 811310 12 141174 65 932 81

IN6

IN1

IN2

IN3

IN4

IN5

IN7

THW8

THW7

THW6

THW9

THWB1

THWB2

t°t°t°t°t°t

°

Main

controller

1

+

-+-+-

2

1

2

CN20

(RED)

TH1

t

°

1

3

CN21

(YLW)

TH2

t

°

1

4

THW1

THW2

CNW12

(RED)

t°t

°

1

2

THW5

CNW5

(WHT)

t

°

CN108

5

1

Wireless receiver

(Option)

WiFi adapter

(Option)

5

1

5

1

CNRF
(WHT)

CN105

(RED)

CN22
(BLU)

1

3

5

7

1

5

Close

Open

N

X6

X7

TBO.2

TBO.1

F1

F2

MXV

M

1

~

MP2

MP1

M

1

~

1

3

CNV1

(WHT)

1

3

CNBHT

(BLK)
CNBC
(GRY)

CNBH
(WHT)

X4

X14

X3

X2

X1

X5B

X5A
1
2
3
4
5
6

1
2
3
4
5
6

1

1

3

3

3

CNP1
(WHT)

CNP4
(RED)

CNPWM

(WHT)

TBO.1

TBO.2

TBO.3

TBO.4

CNP1
(WHT)

CNP4
(RED)

CNV1
(WHT)

CN22
(BLU)

CNIT
(BLU)

TAB1

CN01
(WHT)

F2 F1

6.3A 250V 10A 250V

SW1

SW2

SW3

SW4

SW5

1

8

1

8

1

1

5

1
3

1
3

8

1

8

1

6

CN01
(WHT)

CN01
(WHT)

2

1

4
6

2

1

1
2
4
6

4
6

CNBH

(WHT)

CNBC

(GRY)

1

1

3

1
2

1
2

1
2

CNBHT

(BLK)

1

3

7

1

3

CNIH
(ORN)

1

4

1

3

CNW5
(WHT)

CN21

(YLW)

CNW12

(RED)

CN20
(RED)

TBI.2

MP3

M

1

~

IN8

IN9

IN10

TBI.3

TBI.3

1

4

CN1A

(WHT)

TBI.1

2WV2b

M

1

~

M

1

~

MP4

M

1

~

1

3

L

(1)N(3)

ORN

RED

BLU

BLU

RED

ORN

IHC

IHT

IH

642

531

A1

A2

A B

2

4

Immersion heater (1Ph3kW)

Power supply

to Immersion heater

~/N 230V 50Hz

1

2

CNIH
(ORN)

3

3WV

M

1

~

ECB2

1

2
4

6

CN01

(WHT)

X15

X12

TBO.3

X11

X10
1

2
3
4
5
6
7
8

Signal output

(Boiler)

Signal output

(Error)

Signal output

(Defrost)

Signal output

(Comp ON)

1
2
3
4
5
6

TBO.4

M

2WV2a

1

3

X9

X8

X13

CNIH
(ORN)

1
2
3
4
5
6

1
2
3
4
5
6

1
2
3
4
5
6
7
8

1
2
3
4
5
6

12 146 108

137 11945321

12 146 108

137 11945321

12 146 108

137 11945321

15

6-6.

EHPT20X-MHCW, EHST20C-MHCW, EHST20D-MHCW

1. Symbols used in wiring diagram are, : connector, :
terminal block.

2. Indoor unit and outdoor unit connecting wires have polarities, make
sure to match terminal numbers (S1, S2, S3) for correct wirings,

3. Since the outdoor unit side electric wiring may change, be sure to
check the outdoor unit electric wiring diagram for service.

Table 1 Signal Inputs

Name

Terminal block

Connector

Item OFF (Open) ON (Short)
IN1 TBI.1 13-14 — Room thermostat 1 input Refer to SW2-1 in <6-7. DIP switch setting>.
IN2 TBI.1 11-12 — Flow switch 1 input Refer to SW2-2 in <6-7. DIP switch setting>.
IN3 TBI.1 9-10 — Flow switch 2 input (Zone1) Refer to SW3-2 in <6-7. DIP switch setting>.
IN4 TBI.1 7-8 — Demand control input Normal Heat source OFF/ Boiler operation *2
IN5 TBI.1 5-6 — Outdoor thermostat input *1 Standard operation Heater operation/ Boiler operation *2
IN6 TBI.1 3-4 — Room thermostat 2 input Refer to SW3-1 in <6-7. DIP switch setting>.
IN7 TBI.1 1-2 — Flow switch 3 input (Zone2) Refer to SW3-3 in <6-7. DIP switch setting>.
IN8 TBI.3 1-2 — Electric energy meter 1

Refer to <6-7. DIP switch setting>.IN9 TBI.3 3-4 — Electric energy meter 2

IN10

TBI.3 5-6 — Heat meter

*1. If using outdoor thermostat for controlling operation of heaters, the lifetime of the heaters and related parts may

be reduced.

*2. To turn on the boiler operation, use the main controller to select “Boiler” in “External input setting“ screen in the

service menu.

Table 2 Outputs

Name

Terminal block

Connector

Item OFF ON

OUT1

TBO.1 1-2 CNP1 Water circulation pump 1 output (Space heating & DHW) OFF ON

OUT2

TBO.1 3-4 — Water circulation pump 2 output (Space heating for Zone1) OFF ON

OUT3

TBO.1 5-6 —

Water circulation pump 3 output (Space heating for Zone2) *1

OFF ON

2-way valve 2b output *2

OUT4

TBO.2 4-6 CNV1 3-way valve output Heating DHW

OUT5

TBO.2 1-2

— Mixing valve output *1 Stop

Close

TBO.2 2-3 Open

OUT6

—

CNBH 1-3

Booster heater 1 output OFF ON

OUT7

—

CNBH 5-7

Booster heater 2 output OFF ON

OUT9

TBO.4 3-4 CNIH Immersion heater output OFF ON

OUT10

TBO.3 1-2 — Boiler output OFF ON

OUT11

TBO.3 3-4 — Error output Normal Error

OUT12

TBO.3 5-6 — Defrost output Normal Defrost

OUT13

TBO.4 1-2 — 2-way valve 2a output *2 OFF ON

OUT14

— CNP4 Water circulation pump 4 output (DHW) OFF ON

OUT15

TBO.3 7-8 — Comp ON signal OFF ON

Do not connect to the terminals that are indicated as “—” in the “Terminal block” eld.
*1. For 2-zone temperature control.
*2. For 2-zone valve ON/OFF control.

Symbol Name
TB1 Terminal block <Power supply, Outdoor unit>
ECB2

Earth leakage circuit breaker for immersion heater

MP1

Water circulation pump 1(Space heating & DHW)

MP2

Water circulation pump 2 (Space heating for Zone1)(Local supply)

MP3

Water circulation pump 3 (Space heating for Zone2)(Local supply)

MP4 Water circulation pump 4 (DHW)
3WV 3-way valve
2WV2a 2-way valve (For Zone 1)(Local supply)
2WV2b 2-way valve (For Zone 2)(Local supply)
MXV Mixing valve (Local supply)
IHT Thermostat (xed temp.) for immersion heater
IH Immersion heater
IHC Contactor for immersion heater

Symbol Name
TH1 Thermistor (Room temp.)(Option)
TH2 Thermistor (Ref. liquid temp.)
THW1 Thermistor (Flow water temp.)
THW2 Thermistor (Return water temp.)
THW5 Thermistor (DHW tank water temp.)
THW6 Thermistor (Zone1 ow temp.)(Option)
THW7 Thermistor (Zone1 return temp.)(Option)
THW8 Thermistor (Zone2 ow temp.)(Option)
THW9 Thermistor (Zone2 return temp.)(Option)
THWB1 Thermistor (Boiler ow temp.)(Option)
THWB2 Thermistor (Boiler return temp.)(Option)
IN1 Room thermostat 1 (Local supply)
IN2 Flow switch 1 (Local supply)
IN3 Flow switch 2 (Local supply)
IN4 Demand control (Local supply)
IN5 Outdoor thermostat (Local supply)
IN6 Room thermostat 2 (Local supply)
IN7 Flow switch 3 (Local supply)
IN8 Electric energy meter 1 (Local supply)
IN9 Electric energy meter 2 (Local supply)
IN10 Heat meter (Local supply)
FLOW TEMP. CONTROLLER (FTC5)

TBO.1-4

Terminal block <Outputs>
TBI.1-3 Terminal block <Signal Inputs, Thermistor>
F1 Fuse (T10AL250V)
F2 Fuse (T6.3AL250V)
SW1-5 DIP switch *See 6-7. DIP switch setting.
X1-15 Relay
LED1 Power supply (FTC5)
LED2 Power supply (Main controller)
LED3 Communication (FTC5-Outdoor unit)
LED4 Reading or writing data to SD card
CNPWM

Pump speed control signal for MP1

CN108 SD card connector

OCH570

16

Automatic switch to backup heat source operation

Back-up heat source operation (*1) will automatically run when the outdoor unit stops abnormally. To enable the function, switch DIP SW 2-5 to ON. During the back­up operation, an error code(s) and the contact number will be displayed alternately. External output (OUT11) will be available.
To clear the fault(s), reset the power breakers on the indoor and outdoor units.

<Applicable error codes (*2)>
E6 to E9, ED, P6, P8, U1 to U8, UD, UE, UF, UL, UP

(*1) Prolonged running of the back-up operation may affect the life of the heat source.
(*2) For safety reasons, this function is not available for certain faults. (System operation must be stopped and only pump keeps running.)

6-7. DIP switch setting

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. To move the switch you will need to use a pin or the

corner of a thin metal ruler or similar.

DIP switch settings are listed below in the table below.
Before changing any switch settings, ensure power supplies to indoor and out­door units are isolated/powered off.

DIP switch Function OFF ON

Default settings:

Indoor unit model

SW1

SW1-1 Boiler WITHOUT Boiler WITH Boiler OFF

SW1-2 Heat pump maximum outlet water temperature 55ºC 60ºC ON *1

SW1-3 DHW tank WITHOUT DHW tank WITH DHW tank ON

SW1-4 Immersion heater WITHOUT Immersion heater WITH Immersion heater

OFF:

EH*T20*-*C

ON : EH*T20*-*HC*

SW1-5 Booster heater WITHOUT Booster heater WITH Booster heater

OFF:

EH*T20*-M*C*

ON :

EH*T20*-*M 2/6/9*C

SW1-6 Booster heater function For heating only For heating and DHW

OFF:

EH*T20*-M*C*

ON :

EH*T20*-*M 2/6/9*C

SW1-7 Outdoor unit type Split type Packaged type

OFF: EHST20*-*M**C*
ON :

EHPT20X-*M**C*

SW1-8 Wireless remote controller

WITHOUT Wireless remote controller

WITH Wireless remote controller OFF

SW2

SW2-1 Room thermostat1 input (IN1) logic change

Zone1 operation stop at thermostat short

Zone1 operation stop at thermostat open

OFF

SW2-2 Flow switch1 input (IN2) logic change Failure detection at short Failure detection at open OFF

SW2-3 Booster heater capacity restriction Inactive Active

OFF: Except

EH*T20*-VM2*C

ON : EH*T20*-VM2*C

SW2-4 — — — OFF

SW2-5

Automatic switch to backup heat source operation

(When outdoor unit stops by error)

Inactive Active *2 OFF

SW2-6 Mixing tank WITHOUT Mixing tank WITH Mixing tank OFF

SW2-7 2-zone temperature control Inactive Active *6 OFF

SW2-8 Flow sensor WITHOUT Flow sensor WITH Flow sensor ON

SW3

SW3-1 Room thermostat 2 input (IN6) logic change

Zone2 operation stop at thermostat short

Zone2 operation stop at thermostat open

OFF

SW3-2 Flow switch 2 input (IN3) logic change Failure detection at short Failure detection at open OFF

SW3-3 Flow switch 3 input (IN7) logic change Failure detection at short Failure detection at open OFF

SW3-4 Electric energy meter WITHOUT Electric energy meter WITH Electric energy meter OFF

SW3-5 Heating mode function *3 Inactive Active ON

SW3-6 2-zone valve ON/OFF control Inactive Active OFF

SW3-7 Heat exchanger for DHW Coil in tank External plate HEX ON

SW3-8 Heat meter WITHOUT Heat meter WITH Heat meter OFF

SW4

SW4-1 — — — OFF

SW4-2 — — — OFF

SW4-3 — — — OFF

SW4-4

Indoor unit only operation (during installation work) *4

Inactive Active OFF

SW4-5 Emergency mode (Heater only operation) Normal

Emergency mode (Heater only operation)

OFF *5

SW4-6 Emergency mode (Boiler operation) Normal Emergency mode (Boiler operation) OFF *5

SW5

SW5-1 — — — OFF

SW5-2 — — — OFF

SW5-3

SW5-4

SW5-5

SW5-6

SW5-7

SW5-8 — — — OFF

Note: *1. When the cylinder unit is connected with a PUHZ-RP/SUHZ-SW outdoor unit of which maximum outlet water temperature is 55ºC, DIP SW1-2

must be changed to OFF.

*2. External output (OUT11) will be available. For safety reasons, this function is not available for certain errors. (In that case, system operation

must be stopped and only the water circulation pump keeps running.)

*3. This switch functions only when the cylinder unit is connected with a PUHZ-FRP outdoor unit. When another type of outdoor unit is con-

nected, the heating mode function is active regardless of the fact that this switch is ON or OFF.
*4. Space heating and DHW can be operated only in indoor unit, like an electric boiler. (Refer to "Indoor unit only operation" in page 44. )
*5. If emergency mode is no longer required, return the switch to OFF position.
*6. Active only when DIP SW3-6 is set to OFF.

SW1

SW3

SW4

SW2

SW5

SW5-3 SW5-4 SW5-5 SW5-6 SW5-7
EHST20C-*M*C* ON ON ON ON OFF
EHST20D-*M*C* ON OFF OFF ON OFF
EHPT20X-*M*C* OFF OFF OFF OFF OFF

Capacity code

OCH570

L

N

S1

S2

S3

S1

S2

S3

TB1

L

N

ECB1

L

N

ECB2

L

N

17

FIELD WIRING

7

Breaker abbreviation Meaning

ECB1 Earth leakage circuit breaker for booster heater
ECB2 Earth leakage circuit breaker for immersion heater
TB1 Terminal block 1

Earth

leakage

circuit

breaker

*1

Wiring

circuit

breaker

or

Isolating

switch

Outdoor unit

Power

supply
~/N
230 V

50 Hz

Power

supply

~/N

230 V

50 Hz

Power

supply

~/N

230 V

50 Hz

Wiring

circuit

breaker or

Isolating

switch

Wiring

circuit

breaker or

Isolating

switch

To control
board

For
booster
heater
(Primary circuit)

For
Immersion
heater
(DHW tank)

Cylinder unit

Option 1: Cylinder unit powered via outdoor unit

<1 phase>

<Figure 7-1>

Electrical connections 1 phase

Description Power supply Capacity Breaker Wiring

Booster heater (Primary circuit) ~/N 230 V 50 Hz 2 kW 16 A *1 2.5 mm²

6 kW 32 A *1 6.0 mm²

Immersion heater (DHW tank) ~/N 230 V 50 Hz 3 kW 16 A *1 2.5 mm²

Wiring

Wiring No.

× size (mm²)

Cylinder unit - Outdoor unit *2 3 × 1.5 (polar)

Cylinder unit - Outdoor unit earth *2 1 × Min. 1.5

Circuit

rating

Cylinder unit - Outdoor unit S1 - S2 *3 230 V AC

Cylinder unit - Outdoor unit S2 - S3 *3 24 V DC

*1. A breaker with at least 3.0 mm contact separation in each pole shall be provided. Use earth leakage breaker (NV).

The breaker shall be provided to ensure disconnection of all active phase conductors of the supply.

*2. Max. 45 m

If 2.5 mm² used, Max. 50 m
If 2.5 mm² used and S3 separated, Max. 80 m

*3. The values given in the table above are not always measured against the ground value.

Note: 1. Wiring size must comply with the applicable local and national codes.

2.Indoorunit/outdoorunitconnectingcordsshallnotbelighterthanpolychloroprenesheathedexiblecord.(Design60245IEC57)
Indoorunitpowersupplycordsshallnotbelighterthanpolychloroprenesheathedexiblecord.(Design60227IEC53)

3. Install an earth longer than other cables.

4.Pleasekeepenoughoutputcapacityofpowersupplyforeachheater.Insufcientpowersupplycapacitymightcausechattering.

*1 If the installed earth leakage circuit

breaker does not have an over-current

protection function, install a breaker with
that function along the same power line.

Affix label A that is included with the manuals near each
wiring diagram for cylinder unit and outdoor units.

OCH570

L1

L2

S1

S2

S3

TB1

L2

L3

ECB1

L

N

ECB2

N

L3

L1

S1

S2

S3

L

N

18

Power

supply
3N~
400 V

50 Hz

Earth

leakage

circuit

breaker

*1

Wiring

circuit

breaker

or

Isolating

switch

Power supply

3~ 400 V 50 Hz (EH*T20*-YM*C)
3~ 230 V 50 Hz (EH*T20*-TM*C)

Power

supply
~/N
230 V

50 Hz

Wiring

circuit

breaker

or

Isolating

switch

Wiring

circuit

breaker

or

Isolating

switch

For
booster
heater
(Primary circuit)

For
Immersion
heater
(DHW tank)

To control
board

Outdoor unit

Cylinder unit

<3 phase>

<Figure 7-2>

Electrical connections 3 phase

Description Power supply Capacity (Indoor unit Ref.) Breaker Wiring

Booster heater (Primary circuit)

3~ 400 V 50 Hz 9 kW 16 A *1 2.5 mm²
3~ 230 V 50 Hz 9 kW 32 A *1 6.0 mm²

Immersion heater (DHW tank) ~/N 230 V 50 Hz 3 kW 16 A *1 2.5 mm²

Wiring

Wiring No.

× size (mm²)

Cylinder unit - Outdoor unit *2 3 × 1.5 (polar)

Cylinder unit - Outdoor unit earth *2 1 × Min. 1.5

Circuit

rating

Cylinder unit - Outdoor unit S1 - S2 *3 230 V AC

Cylinder unit - Outdoor unit S2 - S3 *3 24 V DC

*1. A breaker with at least 3.0 mm contact separation in each pole shall be provided. Use earth leakage breaker (NV).

The breaker shall be provided to ensure disconnection of all active phase conductors of the supply.

*2. Max. 45 m

If 2.5 mm² used, Max. 50 m
If 2.5 mm² used and S3 separated, Max. 80 m

*3. The values given in the table above are not always measured against the ground value.

Note: 1. Wiring size must comply with the applicable local and national codes.

2.Indoorunit/outdoorunitconnectingcordsshallnotbelighterthanpolychloroprenesheathedexiblecord.(Design60245IEC57)
Indoorunitpowersupplycordsshallnotbelighterthanpolychloroprenesheathedexiblecord.(Design60227IEC53)

3. Install an earth longer than other cables.

4.Pleasekeepenoughoutputcapacityofpowersupplyforeachheater.Insufcientpowersupplycapacitymightcausechattering.

*1 If the installed earth leakage circuit breaker

does not have an over-current protection

function, install a breaker with that function
along the same power line.

Afx label A that is included with the manuals near each
wiring diagram for cylinder unit and outdoor units.

OCH570

S1

S2

S3

L

N

L

N

CN01

CN01

CN01

CN01

S1

S2

S3

L

N

S1

S2

S3

S1

S2

S3

TB1

L

N

L

N

ECB1

ECB2

L

N

19

Initial settings
(Power supplied by

outdoor unit)

Modied settings
(Separate power

supply to the cylinder
unit)

Cylinder unit
control board

Cylinder unit
control board

White

BLACK

BLACK

YELLOW

BLACK

YELLOW

YELLOW

YELLOW

BLACK

White

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:

•Changetheinterconnectedwiringin thecontroland electricalboxofthe

cylinder unit (see Figure 7-3).

•TurntheoutdoorunitDIPswitchSW8-3toON.

•TurnontheoutdoorunitBEFOREthecylinderunit.

•Powerbyindependentsourceisnotavailableforparticularmodelsof

outdoor unit model. For more detail, refer to the connecting outdoor unit
Installation Manual.

Wiring

circuit

breaker

or

Isolating

switch

Power

supply
~/N
230 V

50 Hz

Earth

leakage

circuit

breaker

*1

Earth

leakage

circuit

breaker

*1

Wiring

circuit

breaker

or

Isolating

switch

Power

supply
~/N
230 V

50 Hz

Outdoor unit

Cylinder unit

Power

supply
~/N
230 V

50 Hz

Power

supply
~/N
230 V

50 Hz

Wiring

circuit

breaker

or

Isolating

switch

Wiring

circuit

breaker

or

Isolating

switch

For
booster
heater
(Primary circuit)

For
Immersion
heater
(DHW tank)

To control
board

<1 phase>

<Figure 7-4>

Electrical connections 1 phase

<Figure 7-3>

Description Power supply Capacity Breaker Wiring

Booster heater (Primary circuit) ~/N 230 V 50 Hz 2 kW 16 A *1 2.5 mm²

6 kW 32 A *1 6.0 mm²

Immersion heater (DHW tank) ~/N 230 V 50 Hz 3 kW 16 A *1 2.5 mm²

Cylinder unit power supply ~/N 230 V 50 Hz

Cylinder unit input capacity

Main switch (Breaker)

*1

16 A

Wiring

Wiring No.

× size (mm²)

Cylinder unit power supply 2 × Min. 1.5
Cylinder unit power supply earth 1 × Min. 1.5

Cylinder unit - Outdoor unit *2 2 × Min. 0.3
Cylinder unit - Outdoor unit earth —

Circuit

rating

Cylinder unit L - N *3 230 V AC
Cylinder unit - Outdoor unit S1 - S2 *3 —
Cylinder unit - Outdoor unit S2 - S3 *3 24 V DC

*1. A breaker with at least 3.0 mm contact separation in each pole shall be provided. Use earth leakage breaker (NV).

The breaker shall be provided to ensure disconnection of all active phase conductors of the supply.

*2. Max. 120 m
*3. The values given in the table above are not always measured against the ground value.

Note: 1. Wiring size must comply with the applicable local and national codes.

2.Indoorunit/outdoorunitconnectingcordsshallnotbelighterthanpolychloroprenesheathedexiblecord.(Design60245IEC57)
Indoorunitpowersupplycordsshallnotbelighterthanpolychloroprenesheathedexiblecord.(Design60227IEC53)

3. Install an earth longer than other cables.

4.

Please keep enough output capacity of power supply for each heater.

Insufcientpowersupplycapacitymightcausechattering.

*1 If the installed earth leakage circuit breaker

does not have an over-current protection

function, install a breaker with that function
along the same power line.

Affix label B that is included with the manuals near
each wiring diagram for cylinder unit and outdoor units.

OCH570

L1

L2

S1

S2

S3

S1

S2

S3

TB1

L2

L3

ECB1

ECB2

N

L3

L1

L

N

L

N

20

<3 phase>

<Figure 7-5>

Electrical connections 3 phase

Description Power supply Capacity (Indoor unit Ref.) Breaker Wiring

Booster heater (Primary circuit)

3~ 400 V 50 Hz 9 kW 16 A *1 2.5 mm²
3~ 230 V 50 Hz 9 kW 32 A *1 6.0 mm²

Immersion heater (DHW tank) ~/N 230 V 50 Hz 3 kW 16 A *1 2.5 mm²

Cylinder unit power supply ~/N 230 V 50 Hz

Cylinder unit input capacity

Main switch (Breaker)

*1

16 A

Wiring

Wiring No.

× size (mm²)

Cylinder unit power supply 2 × Min. 1.5
Cylinder unit power supply earth 1 × Min. 1.5

Cylinder unit - Outdoor unit *2 2 × Min. 0.3
Cylinder unit - Outdoor unit earth —

Circuit

rating

Cylinder unit L - N *3 230 V AC
Cylinder unit - Outdoor unit S1 - S2 *3 —
Cylinder unit - Outdoor unit S2 - S3 *3 24 V DC

*1. A breaker with at least 3.0 mm contact separation in each pole shall be provided. Use earth leakage breaker (NV).

The breaker shall be provided to ensure disconnection of all active phase conductors of the supply.

*2. Max. 120 m
*3. The values given in the table above are not always measured against the ground value.

Note: 1. Wiring size must comply with the applicable local and national codes.

2.Indoorunit/outdoorunitconnectingcordsshallnotbelighterthanpolychloroprenesheathedexiblecord.(Design60245IEC57)
Indoorunitpowersupplycordsshallnotbelighterthanpolychloroprenesheathedexiblecord.(Design60227IEC53)

3. Install an earth longer than other cables.

4.Pleasekeepenoughoutputcapacityofpowersupplyforeachheater.Insufcientpowersupplycapacitymightcausechattering.

For
booster
heater
(Primary circuit)

For
Immersion
heater
(DHW tank)

To control
board

*1 If the installed earth leakage circuit breaker

does not have an over-current protection

function, install a breaker with that function
along the same power line.

Affix label B that is included with the manuals near
each wiring diagram for cylinder unit and outdoor units.

Wiring

circuit

breaker

or

Isolating

switch

Power

supply
3N~
400 V

50 Hz

Earth

leakage

circuit

breaker

*1

Wiring

circuit

breaker

or

Isolating

switch

Earth

leakage

circuit

breaker

*1

Power

supply
~/N
230 V

50 Hz

Power

supply
~/N
230 V

50 Hz

Outdoor unit

Cylinder unit

Wiring

circuit

breaker

or

Isolating

switch

Wiring

circuit

breaker

or

Isolating

switch

Power supply

3~ 400 V 50 Hz (EH*T20*-YM*C)
3~ 230 V 50 Hz (EH*T20*-TM*C)

OCH570

11

8

27

19

20

18

17

3

4

25

28

7

12

26

5

15

13

29

23

14

6

7

24

Pa

10

9

B

A

30

32

32

33

31

31

30

22

*1

Pa

11

10

8

27

19

9

16

20

B

A

30

*1

32

33

18

17

30

30

35

37

21

3

4

25

28

7

5

15

13

29

23

32

14

6

7

24

36

12

26

21

WATER SYSTEM DIAGRAM

8

• Refer to <Table 4-1> for the part names.
*1 Refer to the following section [Local system].

<EHST20*-*M**C > (Split model system)

<EHST20*-MHCW> (UK Split model system) <Example>

<Figure 8-2>

<Figure 8-1>

Note

• To enable draining of the cylinder unit
an isolating valve should be posi-

tioned on both the inlet and outlet

pipework.

• Be sure to install a strainer on the inlet
pipework to the cylinder unit.

• Suitable drain pipework should be at-

tached to all relief valves in accord-

ance with your country’s regulations.

• A backow prevention device must be
installed on the cold water supply
pipework (IEC 61770)

• When using components made from
different metals or connecting pipes

made of different metals insulate the

joints to prevent any corrosive reac­tion taking place which may damage
the pipework.

Flare connection

Flare connection

Cylinder unit

Cylinder unit

Drain

Drain

Drain

Drain

Drain

Drain

Cold water

Cold water

DHW

DHW

Local system

Refrigerant pipe

Water pipe

Local system

Flexible hose

(Temporary connection)

Water
supply

Note

•

To enable draining of the cylinder unit
an isolating valve should be positioned
on both the inlet and outlet pipework.
No valve should be tted between the
expansion valve (item 35) and the cyl-

inder unit (safety matter).

• Be sure to install a strainer on the inlet

pipework to the cylinder unit.

• Suitable drain pipework should be at-

tached to all relief valves in accord-

ance with your country’s regulations.

• When using components made from

different metals or connecting pipes

made of different metals insulate the

joints to prevent any corrosive reac­tion taking place which may damage
any pipework.

• Filling loop’s exible hose must be re-

moved following the lling procedure.
Item provided with unit as loose ac-

cessory.

• Install the inlet control group (item 33)

above the level of the T&P relief valve
(item 19). This will ensure DHW tank
will not require drain-down to service/
maintain the inlet control group.

Refrigerant pipe

Water pipe

OCH570

10

9

30

*1

32

32

33

34

B

30

30

35

A

Pa

11

8

27

19

16

20

18

17

21

37

3

7

13

29

36

32

34

32

4

25

5

23

6

7

24

15

14

7

12

26

1

10

27

9

30

32

32

34

34

32

B

31

A

31

32

33

Pa

11

4

25

8

27

7

19

5

15

13

16

23

20

14

6

7

24

18

17

*1

7

30

22

12

26

22

<EHPT20X-MHCW> (UK Packaged model system) <Example>

Note

• To enable draining of the cylinder unit an
isolating valve should be positioned on
both the inlet and outlet pipework. No
valve should be fitted between the ex-

pansion valve (item 35) and the cylinder
unit (safety matter).

• Be sure to install a strainer on the inlet
pipework to the cylinder unit.

• Suitable drain pipework should be at-

tached to all relief valves in accordance

with your country’s regulations.

• When using components made from dif­ferent metals or connecting pipes made
of different metals insulate the joints to
prevent any corrosive reaction taking
place which may damage any pipework.

• Filling loop’s flexible hose must be re­moved following the filling procedure.
Item provided with unit as loose acces-

sory.

• Install the inlet control group (item 33)
above the level of the T&P relief valve
(item 19). This will ensure DHW tank
will not require drain-down to service/
maintain the inlet control group.

Model name EHPT20X-MHCW EHST20C-MHCW EHST20D-MHCW

Maximum supply pressure to the pressure reducing valve 16 bar 16 bar 16 bar
Operating pressure (Potable side) 3.5 bar 3.5 bar 3.5 bar
Expansion vessel charge setting pressure (Potable side) 3.5 bar 3.5 bar 3.5 bar
Expansion valve setting pressure (Potable side) 6.0 bar 6.0 bar 6.0 bar
Immersion heater specication (Potable side) * 3000 W, 230 V 3000 W, 230 V 3000 W, 230 V

DHW tank capacity 200 L 200 L 200 L

Mass of the unit when full 307 kg 320 kg 312 kg
Maximum primary working pressure 2.5 bar 2.5 bar 2.5 bar

* EN60335/Type 3000W single phase 230V 50Hz, length 460 mm.

Use only Mitsubishi Electric service parts as a direct replacement.

<Table 8-1>

<EHPT20X-*M*C> (Packaged model system)

Note

• To enable draining of the cylinder
unit an isolating valve should be po-

sitioned on both the inlet and outlet

pipework.

• Be sure to install a strainer on the inlet
pipework to the cylinder unit.

• Suitable drain pipework should be

attached to all relief valves in accord-

ance with your country’s regulations.

• A backflow prevention device must
be installed on the cold water supply
pipework (IEC 61770)

• When using components made from
different metals or connecting pipes

made of different metals insulate the

joints to prevent any corrosive reac­tion taking place which may damage
the pipework.)

<Figure 8-3>

<Figure 8-4>

Cylinder unit

Drain

Drain

Drain

Drain

Cold water

DHW

Local system

Main water supply

Flexible hose

(Temporary connection)

Cylinder unit

Drain

Drain

Cold water

DHW

Local system

Water
supply

Water pipe

Water pipe

• Refer to <Table 4-1> for the part names.
*1 Refer to the following section [Local system].

OCH570

1-zone temperature control

2-zone temperature control 1-zone temperature control with boiler

2-zone temperature control with boiler

1-zone temperature control (2-zone valve ON/OFF control)

23

Local system

3

7

5

2

4

6

8

9

11

1

12

10

Zone1

Zone2

1

2

3

5

6

4

Zone1

1

5

4

3

6

2

13

14

15

Zone1

2

13

14

15

7

5

4

3

6

1

8

9

11

12

10

Zone1

Zone2

* Flow switch specications: DC12 V / 1 mA / Both normally-open and normally-closed types can be used. (Set DIP switch 3 to select the logics. Refer to “6-7. DIP

switch setting”.)

1. Zone1 heat emitters (e.g. radiator, fan coil unit) (local supply)

2. Mixing tank (local supply)

3. Zone1 ow water temp. thermistor (THW6)

4. Zone1 return water temp. thermistor (THW7)

5. Zone1 water circulation pump (local supply)

6. Zone1 ow switch (local supply) *

7. Motorized mixing valve (local supply)

8. Zone2 ow water temp. thermistor (THW8)

9. Zone2 return water temp. thermistor (THW9)

Optional part : PAC-TH011-E

Optional part : PAC-TH011-E

10. Zone2 water circulation pump (local supply)

11. Zone2 ow switch (local supply) *

12. Zone2 heat emitters (e.g. underoor heating) (local supply)

13. Boiler ow water temp. thermistor (THWB1)

14. Boiler return water temp. thermistor (THWB2)

15. Boiler (local supply)

16. Zone1 2-way valve (local supply)

17. Zone2 2-way valve (local supply)

18. Bypass valve (local supply)

Optional part : PAC-TH011HT-E

1

Zone1

16

18

Zone1

Zone2

17

12

1

OCH570

24

Filling the cylinder unit (Primary circuit)

Draining the cylinder unit

WARNING: DRAINED WATER MAY BE VERY HOT

1. Before attempting to drain the cylinder unit isolate from the electrical supply to prevent the immersion and booster heaters burning out.

2. Isolate cold water feed to DHW tank.

3. Attach a hose to the DHW tank drain cock (No. 23 and 24 on Figure 4-1). The hose should be able to withstand heat as the draining water could be very hot. The
hose should drain to a place lower than the DHW tank bottom to encourage siphoning.
Open a hot water tap to start draining without a vacuum.

4. When the DHW tank is drained close drain cock and hot tap.

5. Attach hose to water circuit drain cock (No. 7 on Figure 4-1). The hose should be able to withstand heat as the draining water could be very hot. The hose should
drain to a place lower than the booster heater drain cock to encourage siphoning. Open the pump valve and the strainer valve.

6. Water remains in the strainer still after the cylinder unit was drained.
Drain the strainer by removing the strainer cover.

Initial ll procedure:

1. Ensure all pipe joints and ttings are tight and secure.

2. Open the most distant DHW tap/outlet.

3. Slowly/gradually open the mains water supply to begin lling unit and DHW pipework.

4. Allow most distant tap to run free and release/purge residual air from installation.

5. Close tap/outlet to retain fully charged system.

Initial ush procedure:

1. Energise system to heat-up cylinder contents to a temperature of approx. 30 – 40°C.

2. Flush/drain the water contents to remove any residue/impurities resulting from the installation works. Use the cylinder drain cock to safely discharge the warmed
water to drain via a suitable hose.

3. On completion, close drain cock, re-ll system and resume system commissioning.

Filling the cylinder unit (Potable/DHW circuit)

1. Check all connections including factory tted ones are tight.

2. Insulate pipework between cylinder unit and outdoor unit.

3.

Thoroughly clean and ush, system of all debris. (

Refer to 4.2 in the installation manual.)

4. Fill cylinder unit with potable water. Fill primary heating circuit with water and suitable anti-freeze and inhibitor as necessary. Alwaysuseallingloopwith

doublecheckvalvewhenllingtheprimarycircuittoavoidbackowcontaminationofwatersupply.

• Anti-freeze should always be used for packaged model systems. It is the responsibility of the installer to decide if anti-freeze solution should be used in split
model systems depending on each site’s conditions. Corrosion inhibitor should be used in both split model and packaged model systems.

• When connecting metal pipes of different materials insulate the joints to prevent a corrosive reaction taking place which will damage the pipework.

5. Check for leakages. If leakage is found, retighten the nut onto the connections.

6. Pressurise system to 1 bar.

7. Release all trapped air using air vents during and following heating period.

8. Top up with water as necessary. (If pressure is below 1 bar)

OCH570

F1 F2 F3 F4

25

CONTROLS

9

B C D

E

A

Main screen

9-1. Main Controller

<Main controller parts>

Let­ter

Name Function

A Screen Screen in which all information is displayed

B Menu Access to system settings for initial set up and

modications.

C Back Return to previous menu.
D Conrm Used to select or save. (Enter key)
E Power/Holiday If system is switched off pressing once will turn

system on. Pressing again when system is
switched on will enable Holiday Mode. Holding
the button down for 3 secs will turn the system

off. (*1)

F1-4 Function keys Used to scroll through menu and adjust settings.

Function is determined by the menu screen
visible on screen A.

*1
When the system is switched off or the power supply is disconnected,
the cylinder unit protection functions (e.g. freeze stat. function) will
NOT operate. Please beware that without these safety functions ena­bled the cylinder unit may potentially become exposed to damage.

<Main screen icons>

Icon Description

1 Legionella

prevention

When this icon is displayed ‘Legionella prevention
mode’ is active.

2 Heat pump

‘Heat pump’ is running.

Defrosting

Emergency heating

3 Electric heater When this icon is displayed the ‘Electric heaters’

(booster or immersion heater) are in use.

4 Target

temperature

Target ow temperature

Target room temperature

Compensation curve

5 OPTION Pressing the function button below this icon will

display the option screen.
6 + Increase desired temperature.
7 - Decrease desired temperature.
8 Z1

Z2 Pressing the function button below this icon

switches between Zone1 and Zone2.

Information Pressing the function button below this icon dis-

plays the information screen.
9 Space heating

mode

Heating mode

Zone1 or Zone2
10 DHW mode Normal or ECO mode
11 Holiday mode

When this icon is displayed ‘Holiday mode’ acti­vated.

12 Timer

Prohibited

Server control

Stand-by

Stand-by (*2)

Stop

Operating

13

Current
temperature

Current room temperature

Current water temperature of DHW tank

14

The Menu button is locked or the switching of the
operation modes between DHW and Heating op-

erations are disabled in the Option screen.(*3)

15

SD memory card is inserted. Normal operation.

SD memory card is inserted. Abnormal operation.

*2 This unit is in Stand-by whilst other indoor unit(s) is in operation

by priority.

*3 To lock or unlock the Menu, press the BACK and CONFIRM keys

simultaneously for 3 seconds.

12 11

1 32

10

9

4

7

6

5

15 14

13

8

OCH570

26

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.

1. Check all breakers and other safety devices are correctly installed and turn on power to the system.

2. When the main controller switched on for the rst time, the screen automatically goes to Initial settings menu, Language setting screen and Date/Time setting

screen in order.

3. Main controller will automatically start up. Wait approximately 6 minutes whilst the control menus load.

4. When the controller is ready a blank screen with a line running across the top will be displayed.

5. Press button E (Power) (refer to page 25) to turn on the system. Before turning on the system, perform initial settings as instructed below.

General Operation

● To nd the icon that you wish to set, use the F2 and F3 buttons to move between the icons.

● The highlighted icon will appear as a larger version of the center of the screen.

● Press CONFIRM to select and edit the highlighted mode.

●

Follow the <Main Controller Menu Tree> for further setting, using ▼▼ buttons for scrolling or F1 to F4 for selecting.

9-3. Main Settings Menu

The main settings menu can be accessed by pressing the MENU button. To re­duce the risk of untrained end users altering the settings accidentally there are
two access levels to the main settings; and the service section menu is password

protected.

User Level – Short press

If the MENU button is pressed once for a short time the main settings will be
displayed but without the edit function. This will enable the user to view current
settings but NOT change the parameters.

Installer Level – Long press

If the MENU button is pressed down for 3 secs the main settings will be displayed
with all functionality available.

The following items can be viewed and/or edited (dependent on access level).

• Domestic Hot water (DHW)

• Heating

• Schedule timer

• Holiday mode

• Initial settings

• Service (Password protected)

Main menu

Long Press

OCH570

27

<Main Controller Menu Tree>

Unrestricted access
Installer only

* Short press for 1 Zone system.

*

Main

menu

Main

menu

Main screen

Initial

Information

Option

F1

F4

Forced DHW

Hot Water (DHW)

<See section>

<See

section>

<See

section>

<See

section>

<See

section>

Menu

Long Press

Short Press

Heating

Holiday

mode

Initial

settings

Schedule timer

(Zone1)

(Zone2)

(

PREVIEW

)

(

EDIT

)

(

EDIT

)

(

EDIT

)

(

EDIT

)

DHW

DHW

Legionella

Legionella

Schedule2 period

preview screen

Schedule2 period setting screen1

Term setting

Schedule1/2 select

F4

Schedule

timer preview

F4

Schedule

timer preview

F4

Schedule timer preview

F4

Schedule timer preview

Zone1

Zone1

Zone2

Curve parameters

Curve parameters

Adjustment

Adjustment

Zone1

Zone2

Zone2

Day
select

Day
select

Day
select

Day
select

Day
select

Day
select

Time select

Time select

Time select

Time select

Time select

Time select

Temp.setting

Temp.setting

Temp.setting

Temp.setting

Schedule1

Schedule2

Heating

Heating

DHW

DHW

ON (

)/OFF

DHW ON (

)/Prohibited ( )/Timer ( )

Heating ON (

)/Prohibited ( )/Timer ( )

Consumed electrical energy

Delivered energy

Normal/Eco

DHW max. temp.

Hot water temp.

Frequency
Start time

Max. operation time
Duration of max. temp.

DHW max. temp. drop
DHW max. operation time

DHW mode restriction

Active/Non active

Room temp.(

) / Flow temp.(

)

/ Compensation curve(

)

Room temp.(

) / Flow temp.(

)

/ Compensation curve(

)

Compensation curve preview

Compensation curve edit

F1

F1

F3

F1

F2

F2

F2

F2 F4

F3

F3

F3

F4

F4

F3

F4

F2

F4

F3

F4

F2

F3

F4

DHW

Date/Time yyyy/mm/dd/hh:mm

EN/FR/DE/SV/ES/IT/DA/NL/FI/NO/PT/BG/PL/CS/RU

OFF/Room/Tank/Room&Tank

OFF/ON

hh:mm/hh:mm AM/AM hh:mm

°C/°F

Room RC zone select

Sensor setting

Zone1

Zone1

Zone2

Holiday mode setting

Heating room temp.

Heating room temp.

Heating ow temp.

Heating ow temp.

Zone2

Sensor setting

Sensor setting

Select Time/Zone

Select Time/Zone

TH1/Main controller/
Room RC1-8/ “Time/
Zone”

TH1/Main controller/
Room RC1-8/ “Time/
Zone”

Time setting

Time setting

Sensor setting

Sensor setting

Language

Summer time

Temp. display

Contact number

Time display

°C/°F

Room sensor settings

Heating

Active/Non active
Active/Non active

Long press

(

EDIT

)

F1 F2

Zone1/2 select

F1 F2

Zone1/2 select

<Continued to next page.>

F1

Zone1/2 select

F1

Zone1/2 select

F1 F2

Zone1/2 select

save

save

save

save

save

save

save

F4

Schedule

timer preview

F4

Schedule

timer preview

OCH570