Mitsubishi PUHZ-W90VHA Service Manual

AIR TO WATER HEAT PUMP

SERVICE MANUAL

R410A

August 2007

No. OCH419

[model name]

PUHZ-W90VHA

[Service Ref.]

PUHZ-W90VHA

CONTENTS

Note:

• This manual describes only

service data of PUHZ-W90VHA.

• RoHS compliant products have

<G> mark on the spec name plate.

PUHZ-W90VHA

1. SAFETY PRECAUTION

2. SPECIFICATIONS

3. DATA

4. OUTLINES AND DIMENSIONS

5. WIRING DIAGRAM

6. WIRING SPECIFICATIONS

7. REFRIGERANT SYSTEM DIAGRAM

8. TROUBLESHOOTING

9. DISASSEMBLY PROCEDURE

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PARTS CATALOG (OCB419)

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

2

4

5

7

8

9

10

11

38

1

SAFETY PRECAUTION

1-1. ALWAYS OBSERVE FOR SAFETY

Before obtaining access to terminal, all supply ciucuits must be disconnected.

1-2. CAUTIONS RELATED TO NEW REFRIGERANT

Cautions for units utilizing refrigerant R410A

Do not use refrigerant other than R410A.

If other refrigerant (R22 etc.) is used, chlorine in refrigerant can cause deterioration of refrigerant oil etc.

Use a vacuum pump with a reverse flow check valve.

Vacuum pump oil may flow back into refrigerant cycle and that can cause deterioration of refrigerant oil etc.

Use the following tools specifically designed for use with R410A refrigerant.

The following tools are necessary to use R410A refrigerant.

Tools for R410A
Gauge manifold
Charge hose

Gas leak detector

Torque wrench

Vacuum pump adaptor
Electronic refrigerant

charging scale

Keep tools with care.

If dirt, dust or moisture enters into refrigerant cycle, that can cause deterioration of refrigerant oil or malfunction
of compressor.

Do not use a charging cylinder.

If a charging cylinder is used, the composition of refrigerant will change and the efficiency will be lowered.

Ventilate the room if refrigerant leaks during operation. If refrigerant comes into contact with
a flame, poisonous gases will be released.

Charge refrigerant from liquid phase of gas cylinder.

If the refrigerant is charged from gas phase, composition change may occur in refrigerant and the efficiency
will be lowered.

[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.

[2] Additional refrigerant charge

When charging directly from cylinder

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

· Charging should be performed with the cylinder of syphon stood vertically. (Refrigerant is charged from liquid phase.)

2

Unit

Gravimeter

[3] Service tools

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

No. Specifications

 Gauge manifold ·Only for R410A

·Use the existing fitting

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

 Charge hose ·Only for R410A

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

 Electronic scale

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

 Adaptor for reverse flow check ·Attach on vacuum pump.

 Refrigerant charge base

 Refrigerant cylinder ·Only for R410A Top of cylinder (Pink)

Cylinder with syphon

 Refrigerant recovery equipment

specifications

. (UNF1/2)

1-3. CAUTIONS FOR REFRIGERANT PIPING WORK

Tools for R410A (The following table shows whether conventional tools can be used or not.)

Tools and materials Use R410A tools Can R22 tools be used?
Gauge manifold

Charge hose
Gas leak detector

Refrigerant recovery equipment
Refrigerant cylinder
Safety charger

Charge valve

Vacuum pump

Bender
Pipe cutter
Welder and nitrogen gas cylinder
Refrigerant charging scale

Vacuum gauge or thermis­tor vacuum gauge and
vacuum valve
Charging cylinder

: Prepare a new tool. (Use the new tool as the tool exclusive for R410A.)
: Tools for other refrigerants can be used under certain conditions.
: Tools for other refrigerants can be used.

Air purge, refrigerant charge
and operation check
Gas leak check
Refrigerant recovery
Refrigerant charge
Prevent compressor malfunction

when charging refrigerant by
spraying liquid refrigerant

Prevent gas from blowing out
when detaching charge hose

Vacuum drying and air
purge

Bend the pipes
Cut the pipes
Weld the pipes
Charge refrigerant
Check the degree of vacuum. (Vacuum

valve prevents back flow of oil and refri­gerant to thermistor vacuum gauge)
Refrigerant charge

Tool exclusive for R410A
Tool exclusive for R410A
Tool for HFC refrigerant
Tool exclusive for R410A
Tool exclusive for R410A
Tool exclusive for R410A

Tool exclusive for R410A

Tools for other refrigerants can
be used if equipped with adop­ter for reverse flow check
Tools for other refrigerants can be used
Tools for other refrigerants can be used
Tools for other refrigerants can be used
Tools for other refrigerants can be used
Tools for other refrigerants
can be used

Tool exclusive for R410A

(Usable if equipped

with adopter for rever­ se flow)

Can R407C tools be used?

(Usable if equipped

with adopter for rever­ se flow)

33

2

SPECIFICATIONS

Power supply Phase

㱢

Voltage V

Heating Capacity kW Heating(A2/W35)
(A2/W35) 2+)blub-yrD(erutarepmetriaedistuOPOC 㷄

1

230

50

7.0

3.40

2.06

noitidnocgnitarepolanimoNzHycneuqerF

etriaedistuOWktupnirewoP 㷄

1+)blub-teW(erutarepm

25.8

Heating Capacity kW Heating(A7/W35)
(A7/W35) 7+)blub-yrD(e

Cooling Capacity kW Cooling(A35/W7)
(A35/W7) EER

(COP) Outside air temperature (Dry-bulb) +35㷄

nimoN 㷄

Cooling Capacity kW Cooling(A35/W18)
(A35/W18) EER

(COP) Outside air temperature (Dry-bulb) +35㷄

animoN 㷄

9.0

3.90

2.31

25.8

7.1

2.00

3.55

20.4

7.1

3.70

1.92

20.4

rutarepmetriaedistuOPOC 㷄

6+)blub-teW(erutarepmetriaedistuOWktupnirewoP 㷄

tretaWnim/LwolfretawlanimoN 㷄

42+)blub-teW(erutarepmetriaedistuOWktupnirewoP 㷄

42+)blub-teW(erutarepmetriaedistuOWktupnirewoP 㷄

regnahcxetaehetalPtinuroodtuO

Model name ALFA LAVAL
Running current Heating

Cooling

(A7/W35) 04-03HCAA
(A35/W7) A

External finish

Start type
Protection devices

PUHZ-W90VHA

10.3

15.7

23.0

Galvanized plate

Munsell 3Y 7.8/1.1

Linear expansion valve

Hermetic twin rotary

TNB220FLHM1

1.3

Line start

HP switch

w

mm4.04:AAtnerruc.xaM

Ref.IN

(Heating)

mm2.862:BgnisacretuO

mm39:WlortnoctnaregirfeR

mm523:HrosserpmoC

mm96:DledoM

Ref.OUT
(Heating)

4WktuptuorotoM

setalp0

B

Thermistor

(TH32)

A

D

Water OUT

H

Water IN

Discharge thermo

WretaehesacknarC

Heat exchanger (Air)

(Water)

Fan Fan(drive)×No.

Fan motor output

Air flow

kW

3

m

/min

(CFM)
Defrost method
Noise level Heating dB

Cooling dB

Dimensions Width mm(in.)

Depth mm(in.)
Height mm(in.)

Refrigerant

Quantity kg(lbs)
Guaranteed operating Heating
range (Outdoor) Cooling

㷄
㷄

nim/LwolfretaW

0.67 (FV50S)

䊷

Plate fin coil

Plate heat exchanger

Propeller fan × 1

0.060
55

(1,940)

Reverse cycle

*2

49

*2

49

950 (37-3/8)

*1

330 +30

(13+1-3/16)

943 (37-1/8)

)sbl(gkthgieW

79 (174)

R410A

2.4 (5.3)

-20 䌾 +35

*4

-5

䌾 +46

10.0 䌾 25.8

65

]

60

55

*3

50

45

Maximum outlet water temptemperature [

40

-20 -15

*1 grill
*2 at distance of 1m from outdoor unit
*3 Hot gas with four-way valve
*4 With the optional air outlet guide, the operation at

-15㷄㩷outdoor temperature is possible.

-10 -5 0 5 10

Ambient t emperature []

erutarepmetretawteltuomumixaML)ledoM(liO

53+/03+)teltuo/telni(erutarepmetretaWnim/LwolfretawlanimoN 㷄

53+/03+)teltuo/telni(erutarepme

7+/21+)teltuo/telni(erutarepmetretaWnim/Lwolfretawla

81+/32+)teltuo/telni(erutarepmetretaWnim/Lwolfretawl

4

5

3

DATA

3-1. NOISE CRITERION CURVES

MICROPHONE

1.5m

1m

UNIT

GROUND

PUHZ-W90VHA

90

80

70

60

50

40

MODE

COOLING

HEATING

SPL(dB)

49
49

LINE

NC-70

NC-60

NC-50

NC-40

30

20

OCTAVE BAND SOUND PRESSURE LEVEL, dB (0 dB = 0.0002 bar)

10

APPROXIMATE
THRESHOLD OF
HEARING FOR
CONTINUOUS
NOISE

63 125 250 500 1000 2000 4000 8000

BAND CENTER FREQUENCIES, Hz

NC-30

NC-20

3-2. STANDARD OPERATION DATA

Mode Cooling (A35/W7) Heating (A7/W35)

Capacity W 7,100 9,000

Total

Input kW 3.55 2.31

Outdoor unit PUHZ-W90VHA

Phase, Hz 1, 50

Voltage V 230

Electrical circuit

Current A 15.7 10.3

Discharge pressure MPa 2.74 2.21

Suction pressure MPa 0.73 0.64

Discharge temperature

Condensing temperature

Refrigerant circuit

Suction temperature

Flow volume L/min 20.4 25.8

Water

Outlet water temperature

conditions

D.B.

Intake air temperature

Outdoor

conditions

The unit of pressure has been changed to MPa based on international SI system.
The conversion factor is : 1(MPa)=10.2(kgf/cm

W.B.

 74 65

 47









2

)

3-1

735

35 7

24 6

38

6

4

OUTLINES AND DIMENSIONS

PUHZ-W90VHA

24

39

ISO 228/1-G1 B

2-U Shaped notched holes

(Foundfation Bolt M10)

26998

417
370 19

28

53

2-12×36 oval holes

(Foundation Bolt M10)

Detail

Scale 1:3

Service panel

Left······Power supply wiring

Terminal Connections

Handle for moving

Right······Controller wiring

see Detail

119

34

40

Power supply wiring hole

(2-:27Knock Out)

682

Rear cover

Front cover

Unit : mm

Drain hole

(5-:33)

Rear Air Intake

Installation Feet

175 600 175

Side Air Intake

FOUNDATION

Please secure the unit firmly

with 4 foundation (M10) bolts.

(Bolts and washers must be

2 SERVICE SPACE 3 FOUNDATION BOLTS

Dimensions of space needed

for service access are

shown in the below diagram.

<Foundation bolt height>

purchased locally.)

Over300

500

330

30

Less than

Over

Over

500

Air Discharge

30

950

322

Handle for moving

Side Air Intake

Handle for moving

Rear Air Intake

473

943

Handle for moving

23

30 220 145 145 145

81 219

Over10

Service space

Over 10mm

Over 300mm

(4''

1 FREE SPACE (Around the unit)

The diagram below shows a

basic example.

Explantion of particular details are

given in the installation manuals etc.

Over 10mm

Over 00mm

57

Air Intake

Water OUT

Water IN

Handle for moving

77

WIRING DIAGRAM5

PUHZ-W90VHA

SYMBOL NAME SYMBOL NAME
TB1
TB2 Terminal Block<Controller>
TB3 Terminal Block<Controller>
MC
MF1
21S4
SV Solenoid Valve<Bypass Valve
63H
63HS
TH3
TH4
TH6
TH7
TH8

Terminal Block<Power Supply>

Motor for Compressor
Fan Motor

Solenoid Valve<Four-Way Valve

High Pressure Switch
High Pressure Sensor

Thermistor<Liquid>

Thermistor<Discharge>
Thermistor<Plate HEX Iiquid>
Thermistor<Ambient>
Thermistor<Heatsink>

>

>

P.B.

TABU/V/W
TABS/T
TABP1/P2
TABN1/N2

N.F.

LI,LO
NI,NO
EI,E2
52C

Power Circuit Board

Connection Terminal<U/V/W-Phase>
Connection Terminal<L/N-Phase>
Connection Terminal<DC Voltage>
Connection Terminal<DC Voltage>
Diode bridgeDS2, DS3
Power ModuleIPM

Noise Filter Circuit Board

Connection Terminal<L-Phase>

Connection Terminal<N-Phase>

Connection Terminal<Ground>
52C Relay

TH32 Thermistor<Inlet water>
LEV-A, LEV-B
DCL

Electronic Expansion Valve

Reactor

ACTM Active Filter Module

63HS

MF1

MS
3~

C. B.

1

CNS

(WHT)

TH7

TH6 TH3 TH4

TH32

t° t° t° t°

7

CNF1
(WHT)

3

2

1

CNDC

(PNK)

3

1

12

TH32

(BLK)

TRANS

t°

CNAC
(WHT)

1

3

TH7/6
(RED)

2

4

TH3

(WHT)

63H

2

TH4

(WHT)

1

3

63H

(YLW)

CN2

(WHT)

17

7

F3

F4

11121

63HS

(WHT)

21S4
(GRN)

LEV-A

34

21S4 SV

M

LEV-A
(WHT)

X52

LEV-B

M

1613

61

LEV-B

CNVMNT

(RED)

(WHT)

CN4

(WHT)

12

2

X55

SV2

1313

(BLU)

1

CNMNT

(WHT)

CN52C

(RED)

12

*1 MODEL SELECT

1=ON, 0=OFF

5

SW8

LED3

2

SYMBOL NAME

C.B.

SW1
SW2
SW6
SW8
LED3
F3, F4
X52, X55

I.F.

SW6

12345 6

Controller Circuit Board
Switch<Function Switch>
Switch<Function Switch>
Switch<Model Select>
Switch<Function Switch>
LED<Operation/Inspection Indicators>
Fuse<T6.3AL250V>
Relay
Interface Circuit Board

00101 0

*1

SW6

SW1

CNDM

CN3S
(RED)

(WHT)

CN51
(WHT)

SW2

1

3
1

3
1

5

6

3

6

5

3

I. F.

1

CNIF1

(RED)

6

1

CNIF2

(WHT)

3

1

CNIF3

(WHT)

5

1

CNIF4

(WHT)

7

3

4

7

TH8

t°

N. F.

BLU

WHT

52C

U

RED

A3 A4

NO

NI

U

BLK

BLU

CONTROLLER

BLU

TB2

1

2

E2

1

2

CN5

EI

PNK

A5

(BLK)

CN52C

(RED)

B1

3

YLW

2

2

ORN

B2 B3

BRN

TB3

LO

P. B.

TABV

WHT

V

MS
3~

BLK

CNDC

BLK

W

MC

L1

(PNK)

TABW

2

1

L2

ACTM

3

4

WHT

16

TABN1

N1
N2

BLK

P

Io

TABT

TABS

TABP1

BLU

WHT

RED

BLU

RED

N

L

POWER SUPPLY

~/N 230V 50Hz

YLW/GRN

TB1

3

1

(RED)

CNAC2

3

1

(WHT)

CNAC1

5

RED

A1

LI

WHT

A2

DS3

DS2

U

TABN2

WHT

RED

WHT

1

CNAF
(WHT)

6
1

CN2

IPM

(WHT)

7

TABP2

RED

1

CN3

(WHT)

2

2

1

CN5

(RED)

2

2

1

CN4

(WHT)

2

TABN
TABP

TABU

RED

U

DCL

RED

BLK

8

9

WIRING SPECIFICATIONS6

FIELD ELECTRICAL WIRING (power wiring specifications)

Outdoor unit power supply ~/N (single), 50Hz, 230 V

Outdoor unit Circuit Breaker capacity *1 25 A

)

2

Outdoor unit power supply, earth 3 × Min.4

Wiring

Controller-Outdoor unit *2 8 × Min.0.5 (polar)

size (mm

Wire No. ×

Outdoor unit L-N (single) AC 230 V

rating

Circuit

Controller-Outdoor unit DC 12 V

*1. A breaker with at least 3.0 mm contact separation in each pole shall be provided. Use non-fuse breaker (NF) or earth leak-

age breaker (NV).

*2. Max. 20 m

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

2.

Power supply cables and the cables between Controller and Outdoor unit shall not be lighter than polychloro-

SUHQHVKHDWKHGÀH[LEOHFDEOHV

(Design 60245 IEC 57

3. Be sure to connect the cables between Controller and Outdoor unit directly to the units (no intermediate
connections are allowed).
Intermediate connections may result in communication errors. If water enters at the intermediate connection

SRLQWLWPD\FDXVHLQVXI¿FLHQW

insulation to ground or a poor electrical contact .
(If an intermediate connection is necessary, be sure to take measures to prevent water from entering the
cables.)

4. Install an earth longer than other cables.

)

REFRIGERANT SYSTEM DIAGRAM7

PUHZ-W90VHA

Water OUT

Plate HEX

Water IN

TH32

TH6

CHECK/V

CHECK/V

Receiver

Strainer
(#100)

LEV-B

Strainer(#100) Strainer(#100)

REV/V

S/V

Strainer
(#100)

LEV-A

P-Sensor

COMP

CHECK/V

H/P SW

TH4

TH7

TH3

Distributor

TH8 P/B

Refrigerant flow in heating

Refrigerant flow in cooling

Symbol

COMP

H/P SW

Plate HEX

REV/V

S/V

CHECK/V

P-Sensor

P/B

LEV-A

LEV-B

TH32

TH3

TH4

TH6

TH7

TH8

Receiver

Part name

Compressor

High pressure switch (63H)

Plate Heat Exchanger

Reversing (4-way) valve (21S4)

Solenoid valve

Check valve

Pressure sensor (63HS)

Power board

Linear expansion valve -A

Linear expansion valve -B

Inlet water temperature thermistor

Liquid temperature thermistor

Discharge temperature thermistor

Plate HEX liquid temperature thermistor

Ambient temperature thermistor

Heatsink temperature thermistor

Receiver

Detail

DC inverter twin rotary compressor (Mitsubishi Electric Corporation)

For protection (OFF:4.15MPa)

ACH30 - 40 Plates (Alfa Laval)

Change the refrigerant circuit (Heating / Cooling) and for Defrosting

For production test use

High pressure / Low pressure / For production test use

For calculation of the condensing temperature from high pressure

Inverter power board

Heating:Secondary LEV Cooling:Primary LEV

Heating:Primary LEV Cooling:Secondary LEV

For freeze protection and for compressor frequency control

Heating:Evaporating temperature Cooling:Sub cool liquid temperature

For LEV control and for compressor protection

Heating:Sub cool liquid temperature Cooling:Evaporating temperature

For fan control and for compressor frequency control

For power board protection

For accumulation of refrigerant

10

11

TROUBLESHOOTING8

8-1. TROUBLESHOOTING

<Error code display by self-diagnosis and actions to be taken for service (summary)>

Present and past error codes are logged and displayed on the control board of outdoor unit. Actions to be taken for service,
which depends on whether or not the trouble is reoccurring at service, are summarized in the table below. Check the contents
below before investigating details.

Unit conditions at service

The trouble is reoccurring.

The trouble is not reoccurring.

Error code

Displayed

Not displayed

Logged

Not logged

Actions to be taken for service (summary)

Judge what is wrong and take a corrective action according
to “8-3. Self-diagnosis action table”.

Conduct troubleshooting and ascertain the cause of the
trouble.

Consider the temporary defects such as the work of
protection devices in the refrigerant circuit including
compressor, poor connection of wiring, noise and etc.
Re-check the symptom, and check the installation
environment, refrigerant amount, weather when the

trouble occurred, matters related to wiring

and etc.
Reset error code logs and restart the unit after finishing
service.
There is no abnormality in electrical component,
controller board, and etc.

Re-check the abnormal symptom.
Conduct troubleshooting and ascertain the cause of the

trouble
Continue to operate unit for the time being if the cause
is not ascertained.
There is no abnormality concerning of parts such as
electrical component, controller board, and etc.

.

8-2. CHECK POINT UNDER TEST RUN

Before test run

• After installation of outdoor units, piping work and electric wiring work, re-check that there is no water leakage, loosened con-

nections and incorrect polarity.

• Measure impedance between the ground and the power supply terminal block(L, N) on the outdoor unit by 500V Megger and

check that it is 1.0M or over.

+Don’t use 500V Megger to connecting wire terminal block(A1~A5, B1~B3) . This may cause malfunction.

• Turn on power supply 12 hours before test run in order to protect compressor.

• Make sure to read operation manual before test run. (Especially items to secure safety.)

8-3. SELF-DIAGNOSIS ACTION TABLE

<Abnormalities detected when the power is turned on>

Error Code

None

Abnormal point and detection method

—

 No voltage is supplied to terminal

block(TB1) of outdoor unit.
a) Power supply breaker is

b) Contact failure or disconnec-

c) Open phase (L or N phase)

 Electric power is not supplied

to power supply terminal of
noise filter circuit board / out­door power circuit board.
a) Contact failure of power

b) Open phase on the noise

 Electric power is not supplied to

outdoor controller circuit board.
a) Connector disconnected

Case

turned off.

tion of power supply
terminal

supply terminal

filter circuit board / outdoor
power circuit board
: Disconnection of terminal
LI, NI, LO, NO
: Disconnection of terminal
TABT or TABS

(CNDC)

Judgment and action

 Check following items.

a) Power supply breaker
b) Connection of power supply terminal block.

(TB1)

c) Connection of power supply terminal block.

(TB1)

 Check following items.

a) Connection of power supply terminal block.

(TB1)
Connection of terminal (LI, NI, LO, NO) on
the noise filter circuit board

b) Connection of terminal (TABT or TABS) on

outdoor power circuit board.
Refer to 8-6.

 Check connection of the CNDC connector,

on the outdoor power circuit board.
Refer to 8-6.

F5

63H connector open

Abnormal if 63H connector circuit is open
for 3 minutes continuously from being
switched on.
63H: High-pressure switch

 Disconnection of reactor (DCL)

 Disconnection of outdoor noise

filter circuit board or parts fail­ure in outdoor noise filter circuit
board

 Defective outdoor power circuit

board

 Defective outdoor controller

circuit board

 Disconnection or contact failure

of 63H connector on outdoor
controller circuit board

 Disconnection or contact failure

of 63H

 63H is working due to defective

parts.

 Defective outdoor controller

circuit board

 Check connection of reactor. (DCL)

Check connection of “L1” and “L2” on the
active filter module.(ACTM) Refer to 8-6.

 Replace outdoor noise filter circuit board.

Refer to 8-6.

 Replace outdoor power circuit board.

 Replace outdoor controller circuit board (When

items above are checked but the units cannot
be repaired.)

 Check connection of 63H connector on

outdoor controller circuit board.
Refer to 8-6.

 Check the 63H side of connecting wire.

 Check for continuity of 63H.

Replace high pressure swich if it is defective.

 Replace outdoor controller circuit board.

12

13

<Abnormalities detected while unit is operating>

Error Code

U1

Abnormal point and detection method

High pressure (High-pressure switch
63H activated)

Abnormal if high-pressure switch 63H is
activated ( + ) during compressor opera­tion.
+ 4.15 MPa

63H: High-pressure switch

Case

 Decreased water flow
 Clogged filter of water pipe
 Dirt of plate heat exchanger
 Locked water pump
 Malfunction of water pump
 Clogged or broken pipe
 Locked outdoor fan motor
 Malfunction of outdoor fan

motor

 Short cycle of outdoor unit

 Dirt of outdoor heat exchanger
 Decreased airflow caused by

defective inspection of outside
temperature thermistor
(It detects lower temperature
than actual temperature.)

 Disconnection or contact failure

of connector (63H) on outdoor
controller board

 Disconnection or contact failure

of 63H connection

 Defective outdoor controller

board

 Defective operation of linear

expansion valve

 Malfunction of fan driving

circuit

Judgment and action

~Check water circuit and repair the defect.

 Check piping and repair the defect.
~ Check outdoor unit and repair the defect.

 Check the detected temperature of outside

temperature thermistor on LED display.
(SW2: Refer to 8-7.)

~Turn the power off and check F5 is

displayed when the power is turned on again
When F5 is displayed, refer to “Judgment
and action” for F5.

 Check linear expansion valve.

Refer to 8-5.

 Replace outdoor controller board.

.

U2

U3

High discharging temperature

(1) Abnormal if discharge temperature
thermistor (TH4) detects 125 or
110 continuously for 5 minutes.
Abnormal if during defrosting and dis­ charge temperature thermistor (TH4)
detects 110 continuously for 30
minutes.

Open/short circuit of discharge
temperature thermistor (TH4)

Abnormal if open (3 or less) or short
(217 or more) is detected during
compressor operation.
(Detection is inoperative for 10 seconds to
10 minutes of compressor starting process
and for 10 minutes after or during defrost­ing.)

 Overheated compressor

operation caused by insufficient
refrigerant

 Defective thermistor
 Defective outdoor controller

board

 Defective operation of linear

expansion valve

 Disconnection or contact

failure of connector (TH4) on
the outdoor controller circuit
board.

 Defective thermistor
 Defective outdoor controller

circuit board

 Check intake super heat.

Check leakage of refrigerant.
Charge additional refrigerant.

Turn the power off and check if U3 is dis-

played when the power is turned ON again.

When U3 is displayed, refer to “Judgement

and action” for U3.

 Check linear expansion valve.

Refer to 8-5.

 Check connection of connector (TH4) on the

outdoor controller circuit board.
Check the lead wire for thermistor (TH4).
Refer to 8-6.



Check resistance value of thermistor (TH4) or
temperature on LED display.
(Thermistor/TH4: Refer to 8-5.)
(SW2 : Refer to 8-7.)

 Replace outdoor controller board.

Error Code

U4

Abnormal point and detection method

Open/short of outdoor unit thermistors
(TH3, TH32, TH6, TH7, and TH8)

Abnormal if open or short is detected
during compressor operation.
Open detection of thermistors TH3, TH32
and TH6 is not detected for 10 seconds to
10 minutes after compressor starting and
10 minutes after and during defrosting.
+Check which unit has abnormality in its
thermistor by switching the mode of
SW2.
(Refer to 8-7.)

Case

 Disconnection or contact failure

of connectors
Outdoor controller circuit
board: TH3,TH32,TH6/TH7
Outdoor power circuit board:

(

CN3

 Defective thermistor
 Defective outdoor controller

circuit board

)

Judgment and action

 Check connection of connector (TH3,TH32,

TH6/TH7) on the outdoor controller circuit board.
Check connection of connector (CN3) on the
outdoor power circuit board.
Check the lead wire for thermistor
(TH3,TH32,TH6,TH7,TH8). Refer to 8-6.

 Check resistance value of thermistor

(TH3,TH32,TH6,TH7,TH8) or check tempera­ture on LED display.
(Thermistor/TH3,TH32,TH6,TH7,TH8: Refer
to 8-5.)
(SW2 : Refer to 8-7)

 Replace outdoor controller circuit board.

U5

Thermistors

Symbol

Thermistor <Liquid temperature>

TH3

Thermistor <Inlet water temperature>

TH32

Thermistor <Plate HEX liquid temperature>

TH6

Thermistor <Ambient temperature>

TH7

Thermistor <Heatsink temperature>

TH8

Temperature of heatsink

Abnormal if heatsink thermistor(TH8)
detects temperature indicated 77.

Name

 The outdoor fan motor is

locked.

 Failure of outdoor fan motor
 Air flow path is clogged.
 Ambient temperature is high.
 Defective thermistor
 Defective input circuit of

outdoor power circuit board

 Failure of outdoor fan drive

circuit

Open detection Short detection

– 40 or below
– 40 or below
– 40 or below
– 40 or below
– 35 or below

 Check outdoor fan.

 Check air flow path for cooling.
 Check if there is something which causes

temperature rise around outdoor unit.

(Upper limit of ambient temperature is 46.)
Turn off power, and on again to check if U5
is displayed within 30 minutes.
If U4 is displayed instead of U5, refer to
error code U4.
 Check resistance value of thermistor (TH8)

or temperature by microcomputer.
(Thermistor/TH8: Refer to 8-5.)
(SW2 : Refer to 8-6)

 Replace outdoor power circuit board.
 Replace outdoor controller circuit board.

90 or above

102 or above

90 or above
90 or above

102 or above

U6

Power module

Check abnormality by driving power module
in case overcurrent is detected.
(UF or UP error condition)

 Defective outdoor power circuit

board

 Decrease of power supply voltage
 Loosen, disconnected or

reverse of compressor wiring
connection

 Defective compressor

14

 Replace outdoor power circuit board.
 Check facility of power supply.
 Correct the wiring (U

compressor. Refer to 8-6 (Outdoor power
circuit board).

 Check compressor referring to 8-4.

•V•

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