Mitsubishi MUH-GA20VB, MUH-GA25VB, MUH-GA35VB Service Manual

Revision A:

SPLIT-TYPE, HEAT PUMP AIR CONDITIONERS

●MUH-GA20VB- E2 and MUH-GA25VB - E2 have been added.

Please void OB387.

OUTDOOR UNIT

SERVICE MANUAL

HFC	No. OB387
utilized	REVISED EDITION-A
R410A

Wireless type

Models

MUH-GA20VB- E1

MUH-GA20VB- E2

MUH-GA25VB- E1

MUH-GA25VB- E2

MUH-GA35VB- E1

Indoor unit service manual

MSC-GA• VB Series	(OB385)
MSC-CA• VB Series	(OB393)
MSC-CB• VB Series	(OB439)

CONTENTS

MUH-GA20VB

MUH-GA25VB

MUH-GA35VB

NOTE:

1.TECHNICAL CHANGES ················

2.PART NAMES AND FUNCTIONS············

3.SPECIFICATION····················

4.NOISE CRITERIA CURVES ···············

5.OUTLINES AND DIMENSIONS ·············

6.WIRING DIAGRAM ··················

7.REFRIGERANT SYSTEM DIAGRAM ···········

8.PERFORMANCE CURVES ···············

9.ACTUATOR CONTROL·················

10.SERVICE FUNCTIONS·················

11.TROUBLESHOOTING ·················

12.DISASSEMBLY INSTRUCTIONS·············

13.PARTS LIST······················

14.RoHS PARTS LIST···················

•This service manual describes technical data of outdoor units.

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

For servicing of RoHS compliant products, refer to the RoHS Parts List.

Revision A:

• MUH-GA20VB- E2 and MUH-GA25VB- E2 have been added.

1 TECHNICAL CHANGES

MUH-A07YV- E1 MUH-GA20VB- E1

1.Indication of capacity has been changed. (BTU base kw)

2.Dimension of outdoor unit has been changed. (W780mm x H540mm x D255mm W800mm x H550mm x D285mm)

3.Stop valve cover has been added.

4.Outdoor fan motor has been changed. (RC6V20-AB RA6V21-AD)

5.Outdoor fan motor capacitor has been changed.

6.Compressor capacitor has been changed.

7.Outdoor heat exchanger has been changed. (L-BEND FLAT)

MUH-A09YV- E1 MUH-GA25VB- E1

1.Indication of capacity has been changed. (BTU base kw)

2.Dimension of outdoor unit has been changed. (W780mm x H540mm x D255mm W800mm x H550mm x D285mm)

3.Stop valve cover has been added.

4.Outdoor fan motor has been changed. (RA6V33-FB RA6V33-KB)

5.Outdoor fan motor capacitor has been changed.

6.Compressor capacitor has been changed.

7.Outdoor heat exchanger has been changed. (2 Row 1 Row)

MUH-A12YV- E1 MUH-GA35VB- E1

1.Indication of capacity has been changed. (BTU base kw)

2.Dimension of outdoor unit has been changed. (W780mm x H540mm x D255mm W800mm x H550mm x D285mm)

3.Stop valve cover has been added.

4.Outdoor fan motor has been changed. (RA6V33-FB RA6V33-KB)

5.Outdoor fan motor capacitor has been changed.

6.Compressor capacitor has been changed.

7.Size of stop valve (gas) has been changed.([12.7 [9.52)

8.Outdoor heat exchanger has been changed. (2 Row 1 Row)

MUH-GA20VB- E1 MUH-GA20VB- E2

1.Compressor has been changed. (BN092VHST KN092VDMHC)

2.Compressor capacitor has been changed.

3.Capillary tube has been changed.

4.Refrigerant filling capacity has been changed.

5.Deicer P.C. board has been changed.

MUH-GA25VB- E1 MUH-GA25VB- E2

1.Compressor has been changed. (RN104VHSHT KN104VTMHC)

2.Compressor capacitor has been changed.

3.Capillary tube has been changed.

4.Refrigerant filling capacity has been changed.

5.Deicer P.C. board has been changed.

2

2 PART NAMES AND FUNCTIONS

OUTDOOR UNIT

ACCESSORIES

MUH-GA20VB MUH-GA25VB MUH-GA35VB

MUH-GA20VB

MUH-GA25VB

MUH-GA35VB

Air inlet	)
back : MUH-GA20VB		<Outdoor unit: MUH type>
( back and side : MUH-GA25VB		1 Drain socket	1
MUH-GA35VB
Piping
Drain hose
Air outlet

Drain outlet

3 SPECIFICATION

Outdoor model

Outdoor unit power supply

Function

	Capacity		Capacity	kW
			Outdoor air flow	K /h
			Dehumidification	R/h
			Power outlet	A
			Running current	A
	Electrical	data	Power input	W
			Auxiliary heater	A(kW)
			Power factor	%
			Starting current	A
			Compressor motor current	A
			Fan motor current	A
		Coefficient of performance (C.O.P)
	Compressor		Model
			resistance (at 20:)	W
			Output
			Winding	"
	Fan	motor	Model	"
			Winding
			resistance (at 20:)
			Dimensions WOHOD	mm
			Weight	kg
			Sound level	dB
		remarks	Fan speed	rpm
	Special		Fan speed regulator
			capacity (R410A)
			Refrigerant filling	kg
			Refrigeration oil (Model)	cc

MUH-GA20VB - E1		MUH-GA20VB - E2
	Single phase		Single phase
	230V,50Hz		230V,50Hz
Cooling	Heating	Cooling	Heating
2.3	2.5	2.3	2.5
0.9	—	0.9	—
	1,800		1,800
	10		10
3.00	2.86	3.00	2.86
680	655	680	655
	—		—
99	100	99	100
	21		15.5
2.76	2.62	2.76	2.62
	0.25		0.25
3.22	3.62	3.22	3.62
RN092VHSHT		KN092VDMHC
	600		650
	C-R 3.87		C-R 3.62
	C-S 6.14		C-S 5.40
	RA6V21-AD		RA6V21-AD
WHT-BLK 366		WHT-BLK 366
BLK-RED 274		BLK-RED 274
	800o550o285	800o550o285
	32		29
	47		47
	745		745
	1		1
	0.65		0.60
	350 (NEO22)	350 (NEO22)

NOTE: Test conditions are based on ISO 5151.
Cooling : Indoor DB27°C WB19°C	Heating : Indoor	DB20°C
Outdoor DB35°C WB24°C	Outdoor	DB 7°C/WB 6°C
Indoor-Outdoor piping length : 5m
	3

			Outdoor model		MUH-GA25VB - E1
			Outdoor unit power supply		Single phase
					230V,50Hz
			Function		Cooling	Heating
	Capacity		Capacity	kW	2.65	3.0
			Outdoor air flow	K /h	1,902
			Dehumidification	R/h	1.1	—
			Power outlet	A		10
			Running current	A	3.43	3.43
	Electrical	data	Power input	W	785	785
			Auxiliary heater	A(kW)		—
			Power factor	%	100	100
			Starting current	A		22
			Compressor motor current	A	3.10	3.10
			Fan motor current	A		0.33
		Coefficient of performance (C.O.P)			3.23	3.66
	Compressor		Model		RN104VHSHT
			resistance (at 20:)	W	C-S 4.56
			Output			700
			Winding	"	C-R 3.40
	Fan	motor	Model	"	RA6V33-KB
			Winding		WHT-BLK 215
			resistance (at 20:)		BLK-RED 307
			Dimensions WOHOD	mm	800o550o285
			Weight	kg		32
			Sound level	dB		49
		remarks	Fan speed	rpm		855
	Special		Fan speed regulator			1
			capacity (R410A)
			Refrigerant filling	kg		0.80
			Refrigeration oil (Model)	cc	350	(NEO22)

NOTE: Test conditions are based on ISO 5151.

Cooling : Indoor DB27°C WB19°C

Outdoor DB35°C WB24°C

Indoor-Outdoor piping length : 5m

	MUH-GA25VB - E2		MUH-GA35VB - E1
	Single phase		Single phase
	230V,50Hz		230V,50Hz
	Cooling	Heating	Cooling	Heating
	2.65	3.0	3.5	3.7
	1.1	—	1.7	—
	1,902			1,902
	10			10
	3.43	3.43	4.65	4.34
	785	785	1,050	980
	—			—
	100	100	98	98
	19			27
	3.10	3.10	4.32	4.01
	0.33			0.33
	3.23	3.66	3.21	3.63
	KN104VTMHC		RN135VHSHT
	700			900
	C-R 3.62		C-R 2.79
	C-S 5.40		C-S 3.36
	RA6V33-KB		RA6V33-KB
	WHT-BLK 215		WHT-BLK 215
	BLK-RED 307		BLK-RED 307
	800o550o285		800o550o285
	30			35
	49			49
	855			855
	1			1
	0.65			0.80
	350 (NEO22)		620 (NEO22)
Heating : Indoor		DB20°C
	Outdoor	DB 7°C/WB 6°C

4

4 NOISE CRITERIA CURVES

MUH-GA20VB						FUNCTION		SPL(dB(A))	LINE
						COOLING
								47
						HEATING
					Test conditions,
						Cooling :DB35:			WB24:
	90					Heating :DB 7:			WB 6:
MICRO BAR	80
	70
dB re 0.0002
									NC-70
	60
LEVEL,									NC-60
PRESSURE	50
									NC-50
BAND SOUND	40
									NC-40
	30
OCTAVE
									NC-30
	20	APPROXIMATE
		THRESHOLD OF
		HEARING FOR							NC-20
		CONTINUOUS
		NOISE
	10	63	125	250	500	1000	2000	4000	8000

BAND CENTER FREQUENCIES, Hz

MUH-GA25VB						FUNCTION		SPL(dB(A))	LINE
MUH-GA35VB						COOLING		49
						HEATING
					Test conditions,
						Cooling :DB35:			WB24:
	90					Heating :DB 7:			WB 6:
MICRO BAR	80
	70
dB re 0.0002
									NC-70
	60
LEVEL,									NC-60
PRESSURE	50
									NC-50
BAND SOUND	40
									NC-40
	30
OCTAVE
									NC-30
	20	APPROXIMATE
		THRESHOLD OF
		HEARING FOR							NC-20
		CONTINUOUS
		NOISE
	10	63	125	250	500	1000	2000	4000	8000

BAND CENTER FREQUENCIES, Hz

OUTDOOR UNIT

1m

MICROPHONE

5

5 OUTLINES AND DIMENSIONS

MUH-GA20VB MUH-GA25VB MUH-GA35VB

OUTDOOR UNIT

Unit: mm

REQUIRED SPACE

Basically open 100mm or more without any obstruction in front and on both sides of the unit.

344.5

285

44 Air in

(MUH-GA25 /GA35VB)

400	Drain hole [42
Air in

Bolt pitch for installation 304~325

100mm	or
	more

		ore
m	or	m
200m

or	more

100mm

350m	m
	or
	m
	ore

2 holes 10X21	40	17.5
22.3	Air out	23

Handle

550

280	10		164.5
	150	69	99.5
		302.5

500 Bolt pitch for installation

800

Open two sides of left, right, or rear side.

Service panel

Liquid refrigerant pipe joint

Refrigerant pipe (flared) [6.35

-	-
35	43

Gas refrigerant pipe joint

Refrigerant pipe (flared) [9.52

170.5

Service port

6

6	WIRING DIAGRAM
MUH-GA20VB MUH-GA25VB MUH-GA35VB
OUTDOOR UNIT
						RT61	21S4
		TB2
	TO INDOOR UNIT CONNECTING 12V			RED		CN661	CN721
		3
						3 2 1 CN730
		N		BLK			SR62	CN711		WHT
									1
		CIRCUIT							2	BLK	MF
		BREAKER	BRN		DSAR			SR61	C65 3	RED
		TB1					NR61
		L				T61
				BLU
	SUPPLY 50Hz					F61
	POWER ~/N 230V	N				TAB20	52C			WHT
			PE			BRN
			GRN/YLW			4	3			C
					BLU				RED	S MC	R
								C1	BLK
SYMBOL	NAME		SYMBOL			NAME		SYMBOL			NAME
C1	COMPRESSOR CAPACITOR			MF		OUTDOOR FAN MOTOR		T61	TRANSFORMER
C65	OUTDOOR FAN CAPACITOR					(INNER FUSE)		TB1,TB2	TERMINAL BLOCK
DSAR	SURGE ABSORBER			NR61		VARISTOR		21S4	R.V. COIL
F61	FUSE(T2AL250V)			RT61		DEFROST THERMISTOR		52C	COMPRESSOR CONTACTOR

MC	COMPRESSOR(INNER PROTECTOR) SR61,SR62 SOLID STATE RELAY

NOTE:1. About the indoor side electric wiring refer to the indoor unit electric wiring diagram for servicing.

2.Use copper conductors only. (For field wiring)

3.Symbols below indicate.

/: Terminal block, : Connector

7

7 REFRIGERANT SYSTEM DIAGRAM

MUH-GA20VB MUH-GA25VB MUH-GA35VB				Unit:mm
OUTDOOR UNIT
	Refrigerant pipe [ 9.52
	(with heat insulator)			4-way valve

		Stop valve			Outdoor
		(with service
	Flared connection	port)	Muffler	Defrost	heat
					exchanger
				thermistor
				RT61

Compressor

Capillary tube

[3.0x[1.4x700 (MUH-GA20VB - E1

[3.0x[1.4x900 (MUH-GA20VB - E2

[3.0x[1.4x1000(MUH-GA25VB - E1

[3.0x[1.6x1500(MUH-GA25VB - E2 Flared connection [3.0x[1.4x500 (MUH-GA35VB)

Check valve

Strainer #100

)

)

)

)

R.V. coil heating ON cooling OFF

Stop valve	Capillary tube		)
	[3.0x[1.4x500 (MUH-GA20VB -	E1
Refrigerant pipe [6.35	[3.0x[1.4x300 (MUH-GA20VB -	E2	, MUH-GA35VB)
(with heat insulator)	[3.0x[1.4x600 (MUH-GA25VB -	E1	)
	[3.0x[1.6x750 (MUH-GA25VB -	E2	)

Refrigerant flow in cooling

Refrigerant flow in heating

8

MAX. REFRIGERANT PIPING LENGTH

		Refrigerant piping : m		Piping size O.D : mm		Length of connecting pipe : m
	Model	Max. length	Max. height
		A	B	Gas	Liquid	Indoor unit	Outdoor unit
	MUH-GA20VB	20				Gas 0.43	Gas 0
	MUH-GA25VB
			10	9.52	6.35
						Liquid 0.5	Liquid 0
	MUH-GA35VB	25

MAX. HEIGHT DIFFERENCE

Indoor unit

		Refrigerant Piping
	Max. height	Max. length
		A
	B
		Outdoor unit

ADDITIONAL REFRIGERANT CHARGE(R410A : g)

			Model	Outdoor unit precharged			Refrigerant piping length (one way)
					7m		10m		15m		20m		25m
	MUH-GA20VB - E1			650
	MUH-GA20VB - E2			600
	MUH-GA25VB - E1			800	0		60		160		260
	MUH-GA25VB - E2			650
	MUH-GA35VB - E1			800									360
									Calculation : Xg = 20g/m x (A-7)m
8			PERFORMANCE CURVES

MUH-GA20VB MUH-GA25VB MUH-GA35VB

The standard data contained in these specifications apply only to the operation of the air conditioner under normal conditions, since operating conditions vary according to the areas where these units are installed. The following information has been provided to clarify the operating characteristics of the air conditioner under the conditions indicated by the performance curve.

(1)GUARANTEED VOLTAGE

198~264V

(2)AIR FLOW

Air flow should be set at MAX.

(3) MAIN READINGS

(1)	Indoor intake air wet-bulb temperature :	°CWB	}
(2)	Indoor outlet air wet-bulb temperature :	°CWB		Cooling
(3)	Outdoor intake air dry-bulb temperature :	°CDB
(4)	Total input:	W	} Heating
(5)	Indoor intake air dry-bulb temperature :	°CDB
(6)	Outdoor intake air wet-bulb temperature :	°CWB
(7)	Total input :	W

Indoor air wet/dry-bulb temperature difference on the left side of the chart on page 10 shows the difference between the indoor intake air wet/dry-bulb temperature and the indoor outlet air wet/dry-bulb temperature for your reference at service.

9

How to measure the indoor air wet-bulb/dry-bulb temperature difference

1.Attach at least 2 sets of wet-and dry-bulb thermometers to the indoor air intake as shown in the figure, and at least 2 sets of wet-and dry-bulb thermometers to the indoor air outlet. The thermometers must be attached to the position where air speed is high.

2.Attach at least 2 sets of wet-and dry-bulb thermometers to the outdoor air intake. Cover the thermometers to prevent direct rays of the sun.

3.Check that the air filter is cleaned.

4.Open windows and doors of room.

5.Press the EMERGENCY OPERATION switch once(twice) to start the EMERGENCY COOL (HEAT) MODE.

6.When system stabilizes after more than 15 minutes, measure temperature and take an average temperature.

7.10 minutes later, measure temperature again and check that the temperature does not change.

INDOOR UNIT

OUTDOOR UNIT

Wet-and dry-bulb	Wet-and dry-bulb
thermometers	thermometers

8-1.CAPACITY AND THE INPUT CURVES

	8.5															10.011.0
	7.8															9.2 10.0
	7.1															8.3	9.1
	6.4															7.5	8.2
	5.8															6.8	7.4
					5.1											6.0	6.5
					MSC-GA20VB MUH-GA20VB				MSC-GA25VB MUH-GA25VB								MSC-GA35VB	MUH-GA35VB
	19.2										20.0						24.0
	17.8											18.5					22.1
	16.3												16.9				20.3
	14.8													15.4			18.4
	13.3														13.9		16.6
	11.8									12.3							14.7
			10.4							10.8							12.9
	8.9										9.2						11.1
					MSC-GA20VB MUH-GA20VB				MSC-GA25VB MUH-GA25VB								MSC-GA35VB	MUH-GA35VB

NOTE:The above curves are for the heating operation without any frost.

10

8-2.OUTDOOR LOW PRESSURE AND OUTDOOR UNIT CURRENT COOL operation

Both indoor and outdoor unit are under the same temperature/humidity condition.

Dry-bulb temperature	Relative humidity(%)
20	50
25	60
30	70

Air flow should be set at MAX.

The unit of pressure has been changed to MPa on the international system of units(SI unit system). The conversion factor is : 1(MPa[Gauge]) =10.2(kgf/f[Gauge] )

(kgf/F[Gauge])(MPa[Gauge]) MUH-GA20VB

	13		1.3
pressurelow		1.0										230V
	12		1.2
			1.1
	11
Outdoor	10		0.9
	9
			0.8
	8
			0.7
	7
							18 20				30 32 35(:)
		15							25
							50		60		70(%)
						Ambient temperature(˚C)
						Ambient humidity(%)
(kgf/F[Gauge])(MPa[Gauge]) MUH-GA25VB
	13	1.3
												230V
		1.2
pressure	12
	11	1.1
low	10	1.0
Outdoor
	9	0.9
	8	0.8
	7		0.7
							18 20				30 32
		15							25				35(:)
							50		60		70(%)
						Ambient temperature(˚C)
						Ambient humidity(%)
(kgf/F[Gauge])(MPa[Gauge]) MUH-GA35VB
	13	1.3
pressurelow												230V
	10	1.0
	12	1.2
	11	1.1
Outdoor	9	0.9
	8	0.8
	7			0.7
							18 20				30 32
		15							25				35(:)
							50		60		70(%)

Ambient temperature(˚C)

Ambient humidity(%)

Outdoor unit current (A)

Outdoor unit current (A)

Outdoor unit current (A)

MUH-GA20VB

4

230V

3

2

1		30 32 35(:)
15 18 20	25
50	60	70(%)

Ambient temperature(˚C)

Ambient humidity(%)

MUH-GA25VB

4

230V

3

2

1		30 32 35(:)
15 18 20	25
50	60	70(%)

Ambient temperature(˚C)

Ambient humidity(%)

MUH-GA35VB

6

230V

5

4

3		30 32 35(:)
15 18 20	25
50	60	70(%)

Ambient temperature(˚C)

Ambient humidity(%)

11