Haier MRV II Instruction Manual

Haier MRVⅡ Air Conditioning

Haier MRVⅡ can be used in a large combination
with multiple outdoor units, it is only one system
and is the second generation of Haier C-MRV
product. Major features are energy saving,
intelligent control and precise temperature control,
for R410A system, that is more friendly for
environment as well.

To regulate the installation, commissioning and
maintenance procedure, and ensure the working
quality, also to improve the working efficiency, we
make this guide for reference.

This regulation is applicable for Haier A/C Elec.
Corp. Ltd.

Index

Part 1 Installat io n reg u latio n ------------------ --- ------------------- --3
Part 2 Commissioning & Maintenance for R22 system---- 22
Part 3 Debugging & Maintenance for R410A sy stem------- -85
Part 4 Wiring d iag ram--- ----------------- ------------------- -- -------136

Part 1 Installation regulation

1. Installation flowchart----------- ------- - ---------------- ------- ------------ -4

2. Equipment delivery---------------------------------------------------------5

3. Outdoor installation--------------------------------------------------------6

4. Indoor installation------------------------------------------------ ----------8

5. Piping work------------------------------------------------------------------12

6. Water drainage pipe installation------------ --------------------------14

7. Insulation treatment----------------------------------- -------------------15

8. Electric wiring--------------------------------------------------------------16

9. Pipe cleaning work--------------------------------------------------------18

10. Leakage test---------------------------------------------------------------19

11. Evacuation-----------------------------------------------------------------20

12. Additional Refrigerant Charging------------------------------------21

13. Trial operation--------- ----------------------------------------------------22

14. Transfer to user------------------ -----------------------------------------23

- 3 -

Part 1

1 Installation flowchart

Take training for the user

Every

unit should run normally

Recharge

the refrigerant due to

the actual pipe length and the

size

Vacuum

should be below 75

mmHg

Keep

the pressure at 28kgf/cm

for 24 hours

Keep

clean in the pipe

Select

the proper cable and wire

It

should be done for the whole

piping system

After installation

15. Transfer to the user

14. Debugging

and trial running

13. Additional

refrigerant charging

12. Evacuation

11. Leakage

testing

10. Cleaning

operation

9. Electric

installation

8. Heat insulation

Pay attention to the gradient

Keep dry, clean and hermetic

Prevent the ventilation in short
circuit. Easy for maintenance

Confirm the model to avoid the
mis-installation

Confirm the person

responsible

for each process

Prepare the material,equipment
and worker's training

Confirm the selected model,

position, pipe size, layout direction

Important points

in installation

7. Condensate

water drainage

6. Refrigerant

pipe layout

5. Outdoor

installation

4. Indoor

installation

3. Working

distribution

2. Working

preparation

1.Engineering drawing

before installation

Process

- 4 -

Part 1

2 Equipment delivery

2.1 After the equipment is delivered to the site, all relative persons should

join the unpacking and checking work.

2.2 Pay attention to the below points when unpacking:

a. Check the equipment name, model, specification and the quantity, etc.

b. Suspend the equipment to the site or near the site before unpacking

the unit. Forbidden to suspend the unit after unpacking to avoid being

damaged.

c. When unpacking, do not operate wildly to avoid being damaged.

d. Check if the accessories are complete due to the packing list after

unpacking. Any question, contact the after-sale persons.

- 5 -

Part 1

3 Outdoor installation

3.1 The unit should be placed far away the flammable, explosive or oily

place.

3.2 The noise and the outlet air should not affect the neighbors.

- 6 -

3.3 There should be enough space for air inlet, air outlet and

maintenance around the unit. Fluent ventilation and good heat release. If

there is obstacle above the unit, it must be over 2m away from the air

outlet, or there should be extended duct.

3.4 The floor and the steel bracket should be strong enough to afford the

1.5 times heavier than the unit running weight. The floor and the steel

bracket should be horizontal.

Part 1

3.5 The bottom of steel bracket should be made from 6# channel steel.

3.6 The floor should be over 100mm higher than the ground, and there

should be the drainage around to ensure the unit not being immersed in

the water.

3.7. The unit should be fixed firmly with the anti-vibration cushion.

3.8. The outdoor should be as near the indoor as possible. Shorten the

pipe and decrease the bend pipe. Pipe length can not exceed the

permitted range.

3.9 Avoid the dangerous place which could be easily damaged by

monsoon, typhoon and earthquake, if possible, do not install the unit in

the air.

- 7 -

Part 1

4 Indoor installation

A. With the shortest refrigerant pipe, and convenient to connect with

distributing pipe and water pipe. Water pipe should keep a 1% gradient

at least.

B. The place for indoor unit installation should be strong enough to

afford the unit weight and running shake.

C. Preset a checking hole near the indoor unit, and there should be

enough space for maintenance, and convenient to maintain or change

the PCB and motor.

D. Ensure air return and air discharging fluent, and prevent ventilation

in short circuit , also air return duct and air outlet duct is necessary.

E. Before installation, please check if the unit appearance has been

damaged or the other abnormal after being unpacked. Also please check

if the accessories are complete, and the accessories should be

transferred to the special person for proper preservation.

F. The unit should be fixed firmly to avoid falling and shaking. After

installing the indoor unit, please check it with a gradienter to ensure the

indoor unit is horizontal.

- 8 -

Part 1

4.1 Wall mounted unit installation

installation figure:

mounting plate

gas pipe

liquid pipe

indoor side

outdoor side

through-wall hole

wall thickness

through-wall hole section

adhesive tape

fresh air pipe

heat insulation

4.1.1 Fix the mounting plate, set the through-wall hole: install the unit on

smooth wall beside beam and pillar. Firstly , fix the mounting plate on the

wall with a steel nail ,use a thread with a screw ,drop it down vertically

from the central top of the mounting plate,(or you can use a gradienter)to

find the horizontal place and fix it. Drill holes in the wall according to the

wall mounting plate’s position , put plastic sleeve into the hole, then

fasten the plate securely with 4*25 screw .

4.1.2 Make through-wall hole : make a throughout hole in the wall , after

installation , please seal it with putty or gesso.

4.1.3 Hang the unit body onto the upper notches of the mounting

plate ,move the body from side to verify its secure fixing.

- 9 -

Part 1

4.2 Cassette unit installation

air outlet air outlet

air inlet

4.2.1 To ensure the air conditioner working effect, the installation height

should be less than 3m.

4.2.2 After installation on the ceiling ,check the unit’s horizontal level ,use

a gradienter to check it.

4.2.3 Set a checking hole bigger than 400*400mm for checking and

maintenance .

4.3 ESP duct unit installation

Ceiling

Air return

A

Building roof

Air return box

Air supply duct

Unit

Air outlet
grille

Air supply

Unit

Air return

Air return box

- 10 -

Part 1

4.3.1 The indoor unit can be installed on the ceiling, which height is no

more than 3m.

4.3.2 Install the unit with suspending pole, check if the installation place

can bear the unit.

4.3.3 Fix the indoor unit to the suspending bolt, if necessary, it is possible

to suspending the unit to the beam, etc.

4.3.4 Adjust the horizon with a gradienter or by the following method.

Make adjustment so that the relation between the lower surface of the

unit and water level in the hose becomes what is shown in the figure.

PVC pipe

0~5 mm

(0~0.2")

Piping side

Water level

make the piping side slightly lower.

Supply water

4.3.5 Notice for high static pressure duct unit

4.3.5.1 In order to reduce the noise level of the working room , it is better

not to install indoor unit in the working room ,especially for the room

where need a strict noise level. Indoor unit can be installed in a special

room or stair well, and connect with working room by air sending duct and

air return duct.

4.3.5.2 High static pressure duct unit is designed for duct type air

- 11 -

Part 1

sending,

it must connect with air sending and air return duct ,it is forbidden to blow

air into working room directly, otherwise the noise level will be so high

due to the high fan speed from the air outlet .

4.3.5.3 Connection between indoor unit and duct should be soft, and

connect a static pressure box out of unit to avoid shaking and noise pass

through the duct.

4.3.5.4 The design for air sending/return duct, static pressure box, and air

sending/return outlet should be done by the design organization with

relative competency to ensure indoor unit air sending character matches

the duct .

5 Piping work

Refrigerant pipe is made of phosphorus deoxidized copper seamless

steel pipe , weld them together with copper or phosphorus welding rod.

When carrying out this work please comply with the followings strictly :

dry ,clean, hermetic. Therefore, note the below items during working:

5.1 After cutting off the pipe refer to dimensions, blow it with nitrogen for

cleanness. For the pipe which diameter is over 25mm, the pipe inside

need to be cleaned with duster cloth for dust and copper scraps.

5.2 Cover the both ends of the pipe to prevent the dust , vapor and

impurity into the pipe.

5.3 Do not execute the piping work in the rain, moist air and water may

- 12 -

Part 1

cause system block.

5.4 When welding the pipe, please blow nitrogen to prevent oxidation,

pressure of nitrogen flow is about 0.02Mpa , otherwise the oxid layer on

pipe inside will clog the pipe or damage the compressor.

5.5 Welding connection needs a changeable diameter pipe, the pipe

inserted depth is : 10 mm : below φ19mm ; 15mm: above φ 22mm

5.6 When working on the end of the pipe with metal saw or file, do not let

the copper scrap into the pipe.

5.7 The flared type pipe made by expansion tools must conform to the

relative standard, if not, it must be reworked.

5.8 For flared type connection ，please daub some freeze oil on inside

and outside of pipe to avoid pipe bend.

5.9 Refrigerant pipe should be installed horizontally or vertically and as

short as possible ,protect the exposed part with ornament board. To avoid

wrong connection, the pipe need to be marked every other end, set a

bracket exclusively at the joint between piping and unit , do not make unit

afford any weight .

5.10 Branch pipe should be installed in horizontal or vertical direction,

otherwise that will affect the air conditioner effect.

Horizontal

Right

Floor

Wrong

Floor

- 13 -

Part 1

Vertical

Wrong Right

Floor

Floor

6 Water drainage pipe installation

6.1 Drain pipe should keep a 1% gradient at least towards water outlet

direction and as short as possible, if the pipe is made of hard PVC, then

set a suspender at interval of 2 meters to avoid the pipe bend.

For Cassette & Ceiling concealed unit

Suspension
bolts

Heat
insulation

Downgrade
of 1/100 or more

1.5m ~ 2m

6.2 Drain pipe diameter shall be equal or larger than that of indoor

unit ,normally drained water and forcedly drained water could not gather

together to one system.

6.3 Check if water drainage is smooth after installation, if the horizontal

drain pipe is too long , please set an air discharge hole at interval of 5

meters.

6.4 To avoid the drain pan distortion, the connection between drain pipe

and unit should be soft.

6.5 For the indoor unit whose pressure at condensing water drain pipe

- 14 -

Part 1

connection part is negative (cassette, ceiling concealed type) ,please

install a water return pipe for drain pipe.

6.6 Test the drain pipe after installation. Seal the water outlet of drain pan

and charge water to 2/3 part. Check the drain pan two hours later, if

there is no leakage, open the water outlet to ensure if the water drainage

is fluent and if the drain pipe connection is tight.

7 Insulation treatment

7.1 If the insulating layer of condensing water pipe is made of rubber, its

thickness should be over 10mm.

7.2 If the insulating layer of refrigerant pipe is rubber pad insulation pipe,

its thickness should be over 15mm, if the material of insulation layer is

fiberglass, the thickness should be over 20mm.

7.3 To do the refrigerant pipe insulation work , the straight pipe should be

done firstly, for the welding joint and the others that can be done after

checking work, then finish all the insulation work.

7.4 The gas pipe and liquid pipe should be treated separately

7.5 The joint of insulating material should be glued to ensure there is no

gap, wrap insulating material with adhesive tape, be not too tight and no

sense of looseness.

7.6 The pipe inside the ceiling needs not to be wrapped if unnecessary,

only stick the control cable with adhesive tape on the outer of insulating

layer, for R410A system, please refer to the below picture:

- 15 -

Part 1

R22 system: R410A system:

Connection wi re

Liquid pipe

Heat insulator

Gas pipe

Adhesive tape

over 20cm

Connection wire

Liquid pipe

Heat insulator

Gas pipe

Adhesive tape

8 Electric wiring

Air conditioner electric wiring should comply with the relative articles

in GB5024-96.

8.1 Electric wiring work should be done by the qualified electricians.

8.2 Indoor and outdoor unit should be grounded reliably, grounding

resistance should be less than 4Ω.

8.3 All the power cables and signal cables should pass through the wire

tube or wire groove. Power cable and signal wire should not go through

the same wire tube.

8.4 All cables must be copper core. Power cable and signal wire shall

keep a certain distance (about 200mm), or be laid on both sides of

refrigerant pipe , do not wind each other, fixing by this way can avoid

communication disturbance.

8.5 Power supply for indoor and outdoor can be different and supply the

power separately, but the indoor units connected with one outdoor should

use one power supply.

8.6The circuit breaker should be installed for every outdoor unit, the

- 16 -

Part 1

breaker’s capacity should be 1.5 times of outdoor’s max. running current

8.7 Indoor unit of the same outdoor system should use one power supply.

8.8 The recommended power cable is BV.BVR and V V cable ,do not use

YZW cable.

8.9 Signal wire must be double core shielded wire(1.5mm

2

) ,shielded

layer should be connected continuously on indoor unit and be insulated

with adhesive tape, grounded at single point on outdoor unit.

Communication wire is forbidden as O type.

8.10 When power cable over 10mm

2

is connected to the terminal block,

the cable terminal should be O type.

8.11 All the electric wires should not touch the refrigerant pipe directly,

because the insulating layer will get aging due to heat , then it will leak

and cause injury accident.

8.12 Power cable of 10HP outdoor unit should not be under 6mm

2

.

8.13 Power cable of indoor unit should not be under 2.5 mm

2

8.14The wire between wired controller and indoor unit is 0.5 mm

2

RVV,

polar connection. For the salve units in group control, only connect the

terminal B, C.

8.15 Central control wire is 1.5 mm

2

2-core shielded wire. Terminal P, Q

of communication bus line between indoor and outdoor is no polarity.

- 17 -

Part 1

9 Pipe cleaning work

Blow nitrogen is one way to clean impurity from pipe

Note: If you did not blow nitrogen when welding pipe , this method

can not clean the oxid on the pipe wall .

Connect the nitrogen with unit system via pressure relief valve,

adjust the valve to 5Kg/cm

2

, supply nitrogen to system, seal the pipe end

by hand or others , when the pipe pressure getting too high to be sealed ,

open the pipe quickly, repeat this procedure four or five times, the

impurity can be cleaned basically.

9.1 For MRV system , because the pipe is too thick , the cleaning work

should be carried segment by segment.

9.2 When cleaning the pipe , please ensure the pressure is high enough

and clean for some times, if the impurity can not be cleaned completely,

the filter in system and electric expansion valve will be clogged.

9.3 When opening the pipe please make sure to do it safely, prevent the

impurity blew out from hurting people.

- 18 -

Part 1

10 Leakage test

Connect nitrogen tank, pressure relief gauge, gauge manifold and

refrigerant system in turn, charge nitrogen to system both on high and

low pressure sides at same time, notice items:

10.1 Please must test system by nitrogen , do not use any other gas.

10.2 It is better to do the leakage test before connecting with outdoor unit,

because the stop valve of outdoor unit may leak due to welding or outside

force, then nitrogen will go into outdoor circle system.

10.3 Apply pressure both on gas and liquid sides at same time, pressure

charging work can be done by two or three steps , at first apply a lower

pressure to system, if no big leakage be found ,then apply a higher

pressure.

10.4 Check the welded joint and flared joint with suds one by one. If leaks,

air bubble will come out.

10.5 After leakage test, place the unit for 24 hours, if the pressure does

not go down, there is no leakage.(Environment temperature will affect

system pressure, generally , when the environment temperature changes

1 degree, system pressure will change 0.1 Kg/cm

2

.)

10.6 If the system pressure goes down over 0.3 Kg/cm

2

within 24 hours,

and no obvious leakage position can be found ,please check again

segment by segment , reduce the checking area.

10.7 After finding out the leakage and execute relative treatment , please

- 19 -

Part 1

apply the pressure again and observe for another 24 hours.

11 Evacuation

Connect the vacuum and refrigerant system via gauge

manifold ,draw out the air and moisture with vacuum pump from the pipe ,

then make system get vacuum and dry.

Important points:

11.1 Please must use vacuum pump to evacuate system, forbid to use

refrigerant to pile out the air from system.

11.2 The propositional vacuum pump is 40L/min, vacuum pointer should

be below -755mmHg.

11.3 It is better to operate evacuation treatment repeatedly , after 2 hours’

evacuation, charge some refrigerant to system , then evacuate for

another 2 hours, repeat to do it 2 or 3 times, the system can reach a high

vacuum level.

11.4 The vacuum should be maintained often to ensure it can reach high

vacuum level.

11.5 Because the electric expansion valve may be close, evacuation

work should be done both from high pressure and low pressure sides.

- 20 -

Part 1

12 Additional Refrigerant Charging

When the unit out of factory ,refrigerant charging amount is exclude

the refrigerant in the pipe , so after installation the piping, additional

refrigerant should be charged on site.

12.1 Connect the refrigerant tank, gauge manifold to high pressure and

low pressure stop valve via flexible hose in turn, open tank valve and pile

out the air in the pipe.

12.2 Additional charging amount should accord to the diameter and the

length of liquid pipe , final additional charging amount should be

marked on the outdoor nameplate.

12.3 Please must charge the additional refrigerant while weighing, forbid

to estimate according to current or voltage.

12.4 Additional refrigerant should be charged after evacuation or when

the system running in cooling mode.

12.5 Refrigerant should be charged into liquid pipe as liquid state ,if the

system is running in cooling mode , refrigerant should be gas state, or

compressor may be damaged.

- 21 -

Part 1

13 Trial operation

After testing leakage, evacuation and charging additional

refrigerant , before being electrified , please check the following items:

13.1 The capacity of indoor and outdoor without load, and the specs of

circuit breaker. Check if power cable is in compliance with the provision.

13.2 If the power cable is fixed reliably, grounding resistance should not

be over 4Ω

13.3 Check with 500V ohmmeter if the insulated resistor to ground is over

1MΩ.

13.4 Measure the voltage of power supply with multimeter and check if it

is within ±10% of rating voltage.

13.5 Check if the signal wire system is connected correctly according of

wiring diagram, if the shielded wire is grounded , if the diameter and color

match with the wiring diagram.

13.6 Check if the refrigerant piping is connected correctly according to

drawings, if the pipe diameter and branch pipe type are correct .

13.7 If the drainage testing for condensing drainage pipe has been done.

13.8 If the high pressure stop valve, low pressure stop valve and oil

equalized valve are open.

After checking over all above items, supply power to air conditioner, after

the compressor pre-heats for over 12 hours , system could start to run.

13.8.1 Make the system run both in cooling and heating mode

- 22 -

Part 1

13.8.2 Record the current , voltage, temperature and frequency after

system runs for 30 minutes.

13.8.3 If the failure code displays, then analyse and maintain the problem

according to relative technical data, also please record the treatment and

serial number of the unit.

13.8.4 Indoor unit can set address automatically and manually, here we

recommend the manual way.

14 Transfer to user

14.1Transfer relative documents to the user, including operation manual,

drawing list etc.

14.2 Record refrigerant piping length and additional refrigerant charging

amount on the inside of maintenance plate as reference for maintenance.

14.3 Make the record in duplicate, sign it by both sides and each side

shall keep one.

14.4 Bind up all the drawings and tables ( include unit number of each

room, electric wiring diagram, system drawing), transfer it to the user to

keep it well, also hand it over to the manager.

.14.5Leave the address and telephone number to user for service.

- 23 -

- 24 -

Part 2 Commissioning and Maintenance

for R22 System

1. Working preparation before commissioning

1.1 Outdoor checking------------------------------ --------------------- -----------------25

1.2 Indoor checking-------------------------------------------------- --------------------31

2. Cooling commissioning

2.1 Commissioning flowchart----------------- -------------------- -------------------42

2.2 Outdoor checking------------------------------ --------------------- -----------------43

2.3 Indoor checking-------------------------------------------------- --------------------47

3. Heating commissioning

3.1 Commissioning flowchart----------------- -------------------- -------------------48

3.2 Indoor and outdoor checking ---------------------------------------------------49

4. Trouble diagnose and trouble shooting

4.1 Indoor trouble diagnose and trouble shooting ---------------------------49

4.2 Outdoor trouble diagnose and trouble shooting ------------------------53

4.3 Problems during install ation----------------------------------------------------54

4.4 Diagnose method for damaged main parts------------------------- -------56

5. Attached tables

5.1 Table 1: Additional refrigerant charging table-----------------------------58

5.2 Table 2: Relative settings---------------------------------------------------------59

5.3 Table 3: Setting state of PC board when leaving factory and function
definition--------------------------------------------------------------------61

5.5 Table 4: System running technical data display--------------------------65

5.5 Table 5:Failure code ----------------------------------------------------------------70

5.6 Table 6: MRV system running data tracking list -----------------------77

5.7Table7:Analyse of MRV system debugging running data------------78

5.8 Data checking for MRV outdoor unit----------------------------------------79

Part 2

- 25 -

1. Working preparation before debugging

1.1 Outdoor checking

1.1.1 Refrigerant pipe length and drop height checking

Allowable refrigerant pipe length and height

Refrigerant pipe length(one way) Indoor unit, Max.

100m

Piping length between outdoor and the first

branch(main pipe)

Max. 70m

Piping length after the first branch Max. 50m

Piping length between outdoor units Less than 5m to the

first gather pipe

Outdoor is higher Max.50m

Height difference

between IU &OU

Indoor is higher Max.40m

Height difference between outdoor units( the

same system)

In horizon

Height difference between indoor units Max.20m

Voltage range

Rated voltage ±10%

Voltage decrease

when starting

Rated voltage ±15%

Voltage

Unbalance among

phases

Rated voltage ±3%

Part 2

- 26 -

Refrigerant piping length and height difference

Items Max.piping(

m)

Total piping length 250 La+Lb+Lc+LA+LB+LC+LD+LE+LF+L

G+LH+L1+L2+L3+L4+L5+L6

Actual(100)

Max. piping

length

Equivalent(

125)

LA+LB+LC+LD+ LG+LH+ L6

Max.piping length
after the first
branch

50 LG+LH+ L6

Main piping actual
length

70 LD

Height difference
between indoor
units

20 ------

Height difference
between outdoor
units

0 ------

① Oil equalization pipe (L1～L3)：L1≤5m L2≤5m L3≤5m；
② Balance pipe (L1'～L3')：L1'≤5m L2'≤5m L3'≤5m
③ Gas pipe ,liquid pipe：La+Lb≤5m Lb＋Lc≤5m Lb＋Ld＋Le≤5m Lb＋

Ld+Lf

Part 2

Height between indoor unit maxes at 20m

F

E

D

C

B

A

lowest indoor unit/ farthest indoor unit

L3

L2

L1

LF

L6

L5

LH

L4

LG

LE

LD

La

Lb

LB

LA

Lc

LC

≤ 50m

the first branch

50m（ if the indoor unit

is higer, it is 40m)

≤ 75m

MASTER
UNIT

SLAVE
UNIT

SLAVE
UNIT

SLAVE
UNIT

- 27 -

1.1.2 Outdoor pipe connection explanation

（take four outdoors in combination as an example）

1.1.3 Outdoor pipe size checking

Model

AU78N

MTAH

A

AU96N

MTAHA

AV16NMT

AHA

AV18NMT

AHA

AV20NMT

AHA

AV24NMT

AHA

AV26NMT

AHA

Capacity

（HP）

8 10 16 18 20 24 26

Gas pipe

(mm)

Φ28.5

8

Φ28.58

Φ38.1(Φ2

8.58×2)

Φ38.1(Φ2

8.58×2)

Φ38.1(Φ2

8.58×2)

Φ38.1(Φ2

8.58×3)

Φ44.5(Φ2

8.58×3)

Liquid

pipe

(mm)

Φ12.7 Φ12.7

Φ15.88(Φ

12. 7×2)

Φ15.88(Φ

12. 7×2)

Φ19.05(Φ

12. 7×2)

Φ19.05(Φ

12.7×3)

Φ22.22(Φ

12. 7×3)

Oil

equalizat

ion pipe

(mm)

—— —— Φ9.52 Φ9.52 Φ9.52 Φ9.52 Φ9.52

Balance

pipe

（mm）

—— —— Φ19.05 Φ19.05 Φ19.05 Φ19.05 Φ19.05

Part 2

Balance pipe ∮19.05

Balance pipe

∮19.05

To indoor
unit

Liquid pipe
gas pipe

Third gather pipe at
outdoor side

Third gather pipe at
outdoor side

Third gather pipe at
outdoor side

Lb

Ld

Lf

La

Lc

Le

Balance pipe ∮19.05

L1'

L2'

Oil equalization
pipe

∮9.52

Oil equalization
pipe

∮9.52

L3'

Oil equalization
pipe

∮9.52

L3 L2

SLAVE
UNIT

SLAVE
UNIT

SLAVE
UNIT

MASTER
UNIT

LA

L1

- 28 -

1.1.4 Additional refrigerant charging standard: refer to the following table,

and fill the refrigerant charging volume in the “ additional refrigerant

charging” list which on the front plate of outdoor unit.

1.1.4.1 MRV refrigerant charging standard
A． Refrigerant charging volume when out of factory

Outdoor
model

AU78NMTA

HA

AU96NMTA

HA

AU78NMTA

AA

AU96NMTA

AA

Standar
d
charging

13Kg 13Kg 10Kg 10Kg

Model

AV28N

MTAHA

AV30N

MTAHA

AV32NMT

AHA

AV34NMT

AHA

AV36NMT

AHA

AV38N

MTAHA

AV40N

MTAHA

Capacity

（HP）

28 30 32 34 36 38 40

Gas pipe

(mm)

Φ44.5

(Φ28.58

×3)

Φ44.5

(Φ28.58

×3)

Φ44.5

(Φ28.58

×4)

Φ44.5

(Φ28.58

×4)

Φ44.5(Φ2

8.58×4)

Φ50.8

(Φ28.58

×4)

Φ50.8

(Φ28.58

×4)

Liquid

pipe

(mm)

Φ22.22

(Φ12.

7×3)

Φ22.22

(Φ12.7×

3)

Φ22.22

(Φ12.7×4)

Φ22.22

(Φ12.7×4)

Φ22.22

(Φ12.7×4)

Φ25.4(Φ

12.7×4)

Φ25.4(Φ

12.7×4)

Oil

equaliza

tion pipe

(mm)

Φ9.52 Φ9.52 Φ9.52 Φ9.52 Φ9.52 Φ9.52 Φ9.52

Balance

pipe

（mm）

Φ19.05 Φ19.05 Φ19.05 Φ19.05 Φ19.05 Φ19.05 Φ19.05

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volume

B． Additional refrigerant charging volume on site

Additional charging standard of liquid pipe

Liquid pipe
Dia.

25.4 22.22 19.05 15.88 12.7 9.52 6.35

Additional
charging
volume
per meter
（kg/m）

0.53 0.4 0.28 0.2 0.12 0.06 0.03

Calculating method of additional refrigerant charging volume

● Charging volume of refrigerant pipe （ Additional charging
volume）:

length of liquid pipe× additional charging amount per meter liquid pipe

● Additional charging amount =（L1×0.53）+（L2×0.4）+（L3×0.28）
+（L4×0.2）+（L5×0.12）+（L6×0.06）+（L7×0.03）

L1: length of dia.25.4 liquid pipe

L2: length of dia.22.22 liquid pipe

L3: length of dia.19.05 liquid pipe

L4: length of dia.15.88 liquid pipe

L5: length of dia.12.7 liquid pipe

L6: length of dia.9.52 liquid pipe

L7: length of dia.6.35 liquid pipe
Remark: A, Charging volume when out of factory excludes refrigerant
in the pipe.

B, Actual additional charging amount should be within the

figure ±5％，which is calculated additional charging amount according
to the pipe length

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1.1.4.2 Max. refrigerant charging volume of system

Capacity 8HP/10HP 16/18/20HP 24/26/28/30HP 32/34/36/38/40HP

Volume（KG) 26 50 74 98

Remark: Max. refrigerant charging volume of system is standard

refrigerant charging amount when out of factory plus additional

refrigerant charging amount on site of all the units in whole system

1.1.5 Unit No. setting for slave units

Slave units No. Setting

1 2 3 4 Unit No.（Digital tube display）

ON ON ON/OFF ON/OFF 1

ON OFF ON ON/OFF 2

ON OFF OFF ON/OFF 3

OFF ON/OFF ON/OFF ON/OFF 4

After slave unit being electrified, it will show slave unit No. and capacity

at a cycle of 10 seconds within 3 minutes, 8HP unit, it displays “8”; 10

HP unit, it displays “10”., 3 minutes later, it only shows unit No.

1.1.6 Power cable and signal wire confirmation: The signal wire shielded

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layer of all indoors and outdoors should be connected together, and be

grounded on outdoor at single point, and be grounded on outdoor at single

point.

1.2 Indoor checking

1.2.1 Indoor unit pipe size checking

Model 22~45 56~90 112~140

Gas pipe (mm) Φ12.7 Φ15.88 Φ15.88

Liquid pipe(mm) Φ6.35 Φ9.52 Φ9.52

1.2.2 Power cable and signal wire confirmation: Indoor units of one system

use one power supply, The signal wire shielded layer of all indoors and

outdoors should be connected together, and be grounded on outdoor at

single point.

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