vrviii installation guide

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  • (9) Outdoor unit installation (10) Air tightness test (11) Vacuum drying (12) Additional refrigerant charge

    (1) Sleeve work (2) Indoor unit

    installation (6) Duct work (indoor)

    (3) Piping support

    (5) Drain piping work (8) Control wiring work (4) Refrigerant piping work

    Schematic Drawing of VRV Installation

    Flaring Bending Pipe

    expansion

    (7) Insulation work

  • 1. Work Flow by Process

    1

    Pre-work

    Determination of the work classification

    Preparation of the installation drawing Work

    (1) Sleeve work ...........................Consider the downward gradient of the drain p ipes. 2 (2) Indoor unit installation .............Confirm the model names to avoid any installation mistakes. 3 (3) Piping support ........................Use support s within the designated support intervals. 5 (4) Refrigerant piping work .........Pay attention to the principles of dry, clean and tight.9 (5) Drain piping work ..................Maintain a downward gradient of at least 1/100.22 (6) Duct work (indoor) ................Ensure that a sufficient airflow is maintained. 26 (7) Insulation work ......................Ensure that there are no gaps at the joints between insulation materials.27 (8) Control wiring work ...............Use applicable two-core wires.30 (Do not use multi-core.) (9) Outdoor unit installation ........Make considerations to prevent short-circuiting and maintain a workspace for servicing. 32 (10) Air tightness test Make a final confirmation that there is no pressure drop at 4 MPaG(580 PSI) for 24 hours.34 (11) Vacuum drying .Use a vacuum pump that can vacuum 100.7 kPaG(-14.6 PSI) or lower.. 36 (12) Additional refrigerant charge ...Enter the additional refrigerant charge amount onto the outdoor unit and the log book.39

    The above order represents the general procedure. It may differ depending on the local conditions and actual circumstances.

    *Please note that lengths without any units are all in millimeters (mm) throughout this document.

    Legend

    Caution: Points of caution at the job site

    One point lesson: Expertise gained from onsite work

    Case example: An actual example of onsite work

  • 2. Work by Process and Key Points (1) Sleeve work

    2

    D L1 R1

    L3

    R2

    L2

    D L1 R1

    L3

    R2

    L2

    Note that the beam structure limits the allowable area for the placement of through-holes.

    Cover both ends of the sleeves with masking tape to prevent any concrete from entering

    %UDQFK * DV/ LQH P P

    / LTXLG/ LQHP P

    ' UDLQ3LSHP P

    H/P or

    C/O

    +XPLGLW\

    ' HOKL 19 13 6 H/P / RZ $KPHGDEDG 19 13 6/ 9 H/P / RZ 3XQH 19 9 6 C/O / RZ 0 XPEDL 19 19 6 C/O +LJK %DQJDOXUX 19 9 6 C/O / RZ &KHQQDL 19 13 6 C/O +LJK + \ GHUDEDG 19 13 6/ 9 C/O / RZ . RONDWWD 19 13 6 C/O +LJK &KDQGLJDUK 19 13 6 H/P +LJK ' DLNLQ6WDQGDUG

    19 13 6 H/P +LJK

    Work procedure

    Meeting with the construction

    company

    Determination of the location and sleeve diameter

    Installation Confirmation

    ~Working points~ Determination of the placement of the through-holes Determine the placement so that the drain piping is at a downward gradient of at least 1/100. Consider the thickness of the insulation material when determining the sleeve diameters for

    refrigerant piping and drain piping.

    At least 3 x [(R1 + R2)/2]

    At least D/2

    Location into which the sleeve cannot be inserted through the beam

    At least D/4 and 150 mm

  • 2. Work by Process and Key Points (2) Installation of indoor units

    3

    Drain side

    Piping side

    Drain side

    Piping side

    1) 2) 3) 4)

    1) Transporting (1) Determine the transporting route. (2) Transport the indoor units to the installation location in the original packing. Do not remove the packing until it

    is to be installed. (3) When receiving the products, be sure to check for any blemishes or dents.

    How to prevent the installation of the wrong indoor unit model or in the wrong location.

    Before transporting the indoor unit, attach a sheet of paper to a visible spot on the packing that notes the installation location and the system number.

    2) Determination of installation location

    The following explains the procedure in the event an insert is not contained within the package.

    (1) Confirm the space required for servicing and installation. (2) Confirm the piping direction and air discharge direction.

    The space required for servicing and installation may differ depending on the model. Please confirm the details in the installation manual or the like.

    (3) Mark the center of the indoor unit with chalk lines, using the base point lines drawn on the floor as a guide.

    (4) Using the upper packing material, mark the suspension locations on the floor based on the

    center of the unit. (5) Use a laser pointer or the like to transfer the suspension location from the floor to the ceiling slab, and use a drill

    to open up a pilot hole.

    If a pilot hole for the anchors leads to a steel beam, be sure to try another location for the hole.

    1F reception room AC1-1

    Installation space for FXFQ

    Suspension location Laser pointer

    Ceiling

    Trans- porting

    ~Working points~ Installation procedures differ according to the indoor unit model. Be sure to conduct all work according to the accompanying installation manual.

    At least 1,500 mm

    At least 200 mm

    At least 1,500 mm

    At least 1,500 mm

    At least 1,500 mm At least 200 mm

    Work procedure

    Center of the unit

    Base point line

    Unit suspension location

    Upper packing material

    Determination of installation location

    Indoor unit installation

    Installation of suspension bolts

  • 2. Work by Process and Key Points (2) Installation of indoor units

    4

  • (2)Installation of indoor units

    5

    3) Installation of suspension bolts (1) Determine the length of the suspension bolts according to the height of the installation. (2) Before installing, place the nuts (2; locally procured parts) and washers (2; accessories) on the suspension bolt

    (double-nut on the lower side of the bolt).

    (3) After installing, adjust the nut on the lower side to the installation height. (4) For the upper washer, use the attached washer plate to secure.

    Check the installation manual for the installation height when attaching optional accessories.

    The height of the indoor unit can easily be adjusted by loosening the double nut. Re-tighten the double nut after completing adjustment.

    The suspension bolt size (M10 or W3/8) is compatible with all models. If the suspension bolt length is 1.5 m or longer, attach a steady brace

    on the longitudinal side of the suspension pitch.

    4) Indoor unit installation (1) Install the indoor unit level. (2) When installing manually, first hook the main unit's suspention bracket onto the suspension bolts on opposing

    corners to suspend the indoor unit. And, if suspending the indoor unit with a device such as a lifter, remove the lower nut on the suspension bolt before doing so.

    (3) After installing the indoor unit, be sure to protect it with a plastic bag or the like.

    If you assume that the temperature and humidity in the ceiling space exceed 30C and RH80%,

    reinforce the insulation (thickness) of the indoor unit. (Use polyethylene foam or glass wool with a thickness of at least 10 mm.)

    How to protect the indoor unit

    Why protect it? Dust and the like can get on the filter and heat exchanger, adversely affecting capacity.

    After all work is complete, be sure to remove the protective plastic covering and the like from the indoor unit.

    Washer plate (accessory)

    Insert

    [Secure the washer]

    Upper nut

    Washer (accessory)

    Suspension bracket

    Tighten (double-nut)

    An example of steady brace installation

    Steady brace bolt

    At l

    east

    1,5

    00

  • 2. Work by Process and Key Points (3) Piping support (Refrigerant and drain)

    6

    300~

    500

    150015001500150015001500

    300~ 500

    Indoor unit

    Refrigerant piping 19.1/9.5

    Supporting fixture

    Horizontal pipe

    Vertical pipe

    1) 2)

    1) Determination of location Interval for refrigerant piping support

    Adjust based on the liquid piping size when the liquid and gas piping are suspended together.

    Upon start and stop of the air conditioner, refrigerant pipes expand or contract due to

    temperature differences. While it may depend on the particular operation state, the pipi ng can expand or contract 10 mm for every 10 meters. Therefore, be sure to adhere to the required support interval.

    Interval for drain piping support (in the case of polyvinyl-chloride pipes)

    Pipe outer diameter (mm) =19.1 22.2~44.1 Support interval (m) =1.0 =1.5

    Pipe outer diameter (mm) =44.45 Support interval (m) =1.5

    Pipe inner diameter (mm) =40 =50 Support interval (m) =1.0 =1.2

    Pipe inner diameter (mm) =44 =56 Support interval (m) =1.5 At least one spot per floor

    Determination of location

    ~The purpose of piping supports~ 1. Prevention of sagging due to their own weight 2. Prevention of spot overloading due to pipe expansion and contraction as a result of

    temperature differences 1. Prevention of swaying and buckling due to their own weight

    Work procedure

    Installation of suspension bolts and supporting fixtures

  • (3) Piping support

    7

    Suspension band with turnbuckle

    Support of horizontal refrigerant piping

    Suspension band with turnbuckle

    Polyvinyl pipe

    Suspension bolt supporting fixture (for shaped steel)

    Suspension bolt supporting fixture (for flat decks)

    Vertical piping support (example)

    2) Installation of suspension bolts and supporting fixtures Horizontal piping support

    Minimize the length of the suspension bolts Consider the downward gradient when determining the

    length of the drain piping suspension bolts. When supporting the refrigerant piping, place a hard pad

    (e.g., polyvinyl-chloride pipe of width 150mm) between the supporting fixture and insulation material as shown in the photo to the right in order to prevent crushing of the insulation material

    from the weight of the piping.

    Never provide additional piping support from the piping.

    Vertical piping support

    Allow sufficient space for maintenance and insulation installation when determining the distance between the unit body surface and piping as well as the piping interval when many pipes are laid in parallel.

    Legs for vertical band Vertical band

    Battledore bolt T-shape leg with washer

    Special supporting fixtures for vertical piping

    Brazing areas

    ~Working points~ Attach refrigerant piping support on top of the insulation material. With regard to drain piping support, first secure the pipes directly with the supporting fixtures

    and then place the insulation materials on top of this. ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?

    Anchor

    Leg for v ertical band

    Vertical band

  • (3) Piping support

    8

    300~ 500 300~ 500

    300~ 500

    300~ 500 300~ 500

    300~ 500

    A+ B+ C= 300~ 500

    B

    C

    A

    A+ B+ C= 300~ 500

    B

    C

    A B

    C

    A

    Spot support (refrigerant piping)

    Support of refrigerant piping branch and bend

    As shown in the above illustration, it is easier to support the branch piping branches if a

    different interval is used for each support.

    Support around the indoor unit

    Through-hole support

    Support points

    =300

    =300

    Support point

    300~500

    Support points

    Support point

    ~Purposes~ 1. Prevention of overload on areas due to expansion 2. Prevention of overload on the connecting area to the unit due to expansion 3. Prevention of impact on waterproofing due to expansion

    300~500

  • (3) Piping support

    9

    Spot support (drain piping)

    Bend support

    Support around the indoor unit

    The horizontal section of the drain piping after the first upward section The piping connection with the drain hose

    accessory

    Through-hole support

    Drain hose accessory

    Support point

    300~500 300~500

    Support points

    =300

    =300

  • 2. Work by Process and Key Points (4) Refrigerant piping work

    10

    ~Working points~ Adhere to the following three basic principles when conducting refrigerant piping work:

    1) 2) 3)

    1) Protection (covering) Protection (covering) during storage and work involving refrigerant piping is the most important type of work in order to prevent water/moisture, contaminants or dust from entering into the piping.

    If water/moisture, contaminants or dust enter into the refrigerant piping, not only will it prevent

    the air conditioner from operating normally but it will also cause a malfunction of the machine and significant inconvenience for the customer. Your utmost effort is required in preventing this from occurring.

    During storage (1) Make sure to protect (cover) both pipe ends. Do not use piping that has not been protected (covered).

    (2) Do not lay refrigerant pipes directly onto a floor surface, but use a table or the like when placing them.

    Dry Clean Tight

    No water/moisture inside

    Do not let water/moisture in

    No dust/contaminants inside

    Do not let dust/contaminants in No leakage of refrigerant

    [The 3 basic principles of refrigerant piping]

    Protection (covering)

    Pipe processing

    Work procedure

    Water/ moisture

    sytamints Leak

    Unit connection

  • 2. Work by Process and Key Points (4) Refrigerant piping work

    11

    During work

    (1) Be sure to protect (cover) the ends even when leaving the pipes for a short period of time . (2) Be sure to protect (cover) the ends when pushing a pipe through a through-hole.

    [How to protect (cover)]

    The most reliable is the 'pinch method,' but taping can also be selected as an easy method depending on the site and time frame.

    A method by which the ends of the copper tube are closed off and the gaps are brazed.

    A method by which the ends of the copper tube are covered with vinyl tape

    Site Work period Protecting (covering) method

    1 month or more Pinching Outdoor

    Less than 1 month Pinching or taping

    Indoor Not considered Pinching or taping

    Pipe end

    Wrap the copper tube with tape.

    Cut flat

    Fold down Wrap with tape again

    Copper tube

    Braze

    Brazing filler metal

  • (4) Refrigerant piping work Protection-

    12

    2) Pipe processing FlaringThis is one method of connecting refrigerant piping of a diameter of 19.1 mm or smaller to an air

    conditioner.

    (1) Pipe cutting

    Use a pipe cutter with left rotation.

    Feed the blade of the pipe cutter bit by bit into the pipe with each rotation. Excessive feeding of the blade can disfigure the pipe so s pecial care is required.

    (2) Processing of the cut surface

    Remove burrs from the tip of the cut surface with a file.

    Remove burrs from the inner portion of the pipe, using a reamer or scraper. Use the file again in order to remove burrs from the tip. Use the reamer or scraper again in order to remove burrs from the inner portion of the pipe.

    When processing the cut surface, face it down to prevent any swarf from falling into the pipe. Make sure that the burrs are completely removed, as not removing the burrs sufficiently can

    result in a refrigerant gas leak at the flare.

    (3) Flaring

    Insert a flare nut into the pipe before flaring. Ensure that the size of the flare is within the prescribed range.

    Note that an appropriate size for the flare is virtually the same as that

    of the union.

    The size of the flare will become larger in proportion to Dimension A to the right. Note that Dimension A differs according to the flaring tool manufacturer.

    Pipe cutter

    Reamer

    Flaring tool

    File

    Facing down

    Facing down

    Burrs

    Scraper

    X Y

    X@Y

    A

  • (4) Refrigerant piping work Bending-

    13

    045

    90

    R

    045

    90

    LR

    Clamping lever

    Handle

    Handle

    Pipe

    YY

    BendingSome of the tools used to bend refrigerant pipes are electric-type, hydraulic-type, lever-type and ratchet-type benders . Following is a description of the work procedure with a lever-type bender:

    The bending dimensions depend on whether they are taken from

    the left or right end.

    (1) Measure the finished dimensions from the right or left end of the pipe.

    (2) Insert the pipe into the bender.

    Align the end of the handle with the '0' mark on the clamping lever.

    (3) Align the mark on the pipe with the 'R' or 'L' on the handle by adjusting the pipe.

    (4) Move the handle to bend the pipe to the desired angle.

    Bend the pipe slowly to prevent pleating or deformation of the inner curve of the pipe.

    Do not bend beyond 90. Make sure the minimum thickness (for pipe dia 6.4mm~12.7mm)

    Is 0.8mm, and should be 1.0 mm for pipe dia 15.88mm.

    If the handle does not have the 'L' mark (1) Mark the finished dimension from the left end.

    (2) Insert the copper tube into the bender Align the end of the handle with the '0' mark on the clamping lever.

    (3) Insert the same size of pipe into the bender slot so that the pipe becomes parallel to the clamping lever. Align the center line (middle) of that pipe with the mark on the pipe.

    (4) Use the handle to bend the pipe to the desired angle.

    X

    Deformation due to pleating Deformation due to

    damage Appropriate bend

    Lever-type bender

    End of the handle

    Mark

    X

    0

    From the right

    From the left

    Same size of pipe

    End of the handle

    Mark

    Y

    Clamping lever

    0

  • (4) Refrigerant piping work Pipe expansion -

    14

    Pipe expansionTwo pipes can be connected by expanding the end of the refrigerant pipe, inserting the other pipe in question inside and brazing the connection.

    (1) Remove the burrs on the cut surface with a reamer or scraper.

    Note that excessive deburring can thin the walls of the pipe and cause vertical (lengthwise)

    cracking when expanding.

    (2) Slightly expand the tip of the head.

    (3) Insert the other pipe fully into the tip portion of the head, close the lever and expand the pipe.

    (4) This may leave vertical scratches on the inner surface of the pipe so rotate the pipe to remove them.

    Expander

  • (4) Refrigerant piping work Pipe expansion -

    15

    BrazingBrazing refers to the use of a metal with a lower melting temperature than that of the base metal as well as the alloy of these metals as solder in order to joint the two base metals without melting them. To heat the solder, a combustion flame of flammable gas (e.g., acetylene, propane) and oxygen is used. The following is an explanation of the work procedure when using acetylene:

    If certification is required in your country, be sure to have all work conducted by a certified

    individual. Be sure to wear all the necessary protective gear (e.g., eye protectors, leather gloves), as fire is

    being used. Always have handy fire prevention equipment such as a fire extinguisher. For solder, use a phosphor copper metal (silver composition: 0%). Don't use a cutting torch.

    For brazing

    In order to ensure safety when lighting the flame, be sure to use an acetylene regulator with a

    flashback arrester.

    [Standards for selecting the outer diameter of the pipe to be brazed and nozzle diameter (French standards)]

    Outer diameter Nozzle diameter (mm) Nozzle number

    F6.4

    F9.5 F12.7

    F15.9

    F19.1

    1.2 #200

    F22.2 1.3 #225

    F25.4 1.4 #250

    F31.8 1.5 #315 F38.1 1.6 #400

    F44.5 1.7~1.8 #450~500

    If the nozzle is too large, it makes preheating and heating difficult. If too small, brazing takes too long. Use a nozzle that suits the outer diameter of the pipe to be brazed.

    For nitrogen replacement

    Welding torch

    Oxygen regulator

    Acetylene regulator (with flashback arrester)

    Twin hose

    Welding kit

    Nitrogen cylinder Nitrogen gas regulator Pressure hose

    Valve

    Tapered nozzle

  • (4) Refrigerant piping work Brazing-

    16

    N2 N2N2N2 N2

    Procedure 1. Confirmation of an appropriate gap between the pipe and joint

    An appropriate gap is when the pipe can be inserted into the joint and held upside down

    without falling.

    Procedure 2. Nitrogen replacement Purpose

    A voluminous oxide film develops on the inner surface of the pipe during brazing. The film can clog, among other parts, the solenoid valve, capillary tube and compressor's oil pump inlet, hampering normal operation. In order to prevent this from occurring, it is necessary to replace the air within the pipe with nitrogen. This work is referred to as nitrogen replacement.

    (1) Set up the required tools as shown below:

    It is even more effective to open up a small hole in the tape to release the nitrogen after

    covering the end of the pipe with tape or the like. Use of the tapered nozzle results in efficient replacement.

    (2) Adjust the nitrogen gas pressure to 0.02(MPaG) or so.

    If the nitrogen pressure is too high, it may cause the brazing filler metal (solder) not to reach completely around the pipe or pinholes to develop in it. Make sure that the pressure is not excessively high.

    Use of nitrogen with a purity of at least 99.99% is recommended. Be sure to note that use of a lesser purity nitrogen may likely result in oxide film formation.

    The effects of nitrogen replacement

    Taping Tapered nozzle Valve

    Nitrogen gas regulator

    Nitrogen cylinder

    Taping Pressure hose

    No nitrogen replacement The inner surface of the pipe has blackened

    due to the oxide film.

    Nitrogen replacement The inner surface of the piping is clean.

  • (4) Refrigerant piping work Brazing-

    17

    A and B Large temperature difference

    Uniform temperature around the

    circumference

    600C 780C 780C

    780C

    400C

    600C 780C 780C

    Non-uniform temperature around the circumference

    A and B Same temperature

    B A

    B

    A

    Procedure 3. Preheating

    Point 1: Heat both base metals evenly. (The inner and outer pipes and the circumference)

    Point 2: Heat until an appropriate temperature for applying the brazing filler metal (solder). 640~780C (where the base metals change color from reddish black to red)

    Point 3: Torch flame adjustment and flame intensity adjustment Conduct brazing with a reducing flame.

    (Roughly a 5 cm carburizing flame) Change the flame intensity according

    to the size of the base metal.

    Point 4: Flame angle (heat control)

    Make the flame angle 80 to 85.

    8085

    Flame core

    Carburizing flame

    Outer flame

    Inner pipe

    Outer pipe

    Inner pipe

    Outer pipe

    Appr

    opria

    te

    heat

    ing

    rang

    e

    Bro

    ad h

    eatin

    g ra

    nge

    Roughly 5 cm

    Too early to apply the brazing filler metal

    (base metal temperature of 500 to 600C)

    Appropriate timing for application of solder material

    (base metal temperature of 640 to 780C)

    Too late to apply the brazing filler metal

    (base metal temperature of 800 to 1,000C)

    Roughly 5 cm

  • (4) Refrigerant piping work Brazing-

    18

    Carburizing flame Carburizing flame

    Point 5: Visual confirmation Distance from the carburizing flame tip Flame location Flame direction

    Procedure 4. Brazing filler metal application

    Point 1: Confirm the range of brazing filler metal application (spread range)

    Roughly 5 mm

    2~3mm

    Distance from the carburizing flame tip Flame location

    Flame direction

    2~3 mm Flame loss

    Overlap Not overlapping results in a gas leak

  • (4) Refrigerant piping work Brazing-

    19

    Point 2: Confirm the volume of the brazing filler metal flow (differs according to the base metal heating range)

    Point 3: Melt the brazing filler metal from the rod tip (melt it gradually, gently applying it upon the base metal)

    Point 4: The angle of flame and brazing filler metal Increase the flame angle slightly compared to preheating

    Make the angle between the brazing filler metal and flame roughly 90.

    During preheating

    During brazing

    Appropriate heating range

    Excessively broad heating range

    Excessively narrow heating range

    Excessive flow of brazing filler metal

    Lack of flow of brazing filler metal

    Brazing filler metal

    Brazing filler metal

    Roughly 90

    80~85

    Hanging brazing filler metal

  • (4) Refrigerant piping work Brazing-

    20

    Point 5:Confirm visually. (Final confirmation of the distance from the carburizing flame tip, location of flame on the pipe

    It is relatively easy to apply the brazing filler metal when the pipe is facing down or side ways. But, if the pipe is facing up, it is relatively difficult to spread it and can result in a refrigerant leak. Therefore, make efforts to enable brazing with the pipe facing down or sideways.

    Do not turn off the nitrogen until the pipe is completely cooled down. If the nitrogen gas is stopped before the pipe has sufficiently been cooled down, it will result in the development of an oxide film on the inner surface of the pipe.

    1~2 mm

    Distance from the carburizing flame tip

    Location of flame on the pipe

    Flame direction (Move the flame up/down and

    left/right at a right angle to the pipe)

    Final confirmation

    2~3 mm

    Facing down Facing sideways Facing up

    Relatively easy Relatively difficult

  • (4) Refrigerant piping work Refrigerant branch pipe (REFNET joint)

    21

    AA

    Refrigerant branch pipe (REFNET joint)

    1. Install the REFNET joint horizontally or perpendicularly.

    2. Install the REFNET header horizontally.

    Example of liquid-side header installation Example of gas -side header installation

    Create at least 500 mm of a straight pipe section before and after branches when connecting refrigerant branch pipe to the field pipe. Bending the pipe too close to the branch can lead to complaints about abnormal noise.

    Example of refrigerant branch pipe installation

    Installing the REFNET joint while it is leaning at an angle can cause refrigerant drift, resulting

    in abnormal noise or preventing normal operation. Be sure to install it horizontally.

    Horizontal

    Perpendicular

    At least 500

    At least 500 At least 1,000

    Ceiling

    Supporting fixture (locally procured)

    Horizontal Horizontal

    Ceiling

    Mount (locally procured)

    A. Arrow view

  • (4) Refrigerant piping work Flare connection

    22

    3) Unit connection Flare connection

    (1) Apply refrigerant oil (ethereal oil, ester oil) to the inner

    surface of the flare . (2) Turn the flare nut 3 or 4 times to the machine union side by hand. Be sure to use the flare nuts that come with the unit.

    If the flare nut cannot be turned by hand, there may be a shaft misalignment of the flare and union. Please try again.

    (3) Tighten to the prescribed torque value using the torque wrench

    Tighten, using a technique that employs both the torque wrench and (spanner) monkey wrench.

    Be careful, as tightening excessively can cause gas leakage due to flare nut cracking and the like.

    When tightening with a spanner (monkey wrench) because a torque wrench is unavailable: When tightening a flare nut with a spanner, there comes a point where the tightening torque

    increases rapidly. From that point, tighten only with an angle shown in the table below.

    Note that tightening the flare nut with a spanner longer than the recommended tool length shown in the table below can result in excessive tightening.

    Marking the flare nut with a magic marker or the like after it has been tightened prevents the worker from forgetting to tighten the flare nut.

    Tightening torque standards for flare nuts

    Pipe outer diameter Tightening torque (Ncm) F 6.4 1420~1720 F 9.5 3270~3990

    F 12.7 4950~6030 F 15.9 6180~7540 F 19.1 9720~11860

    Pipe outer diameter Tightening angle (rough standard)

    Recommended length of tool being used

    F 6.4 60~90 Approx. 150 mm

    F 9.5 60~90 Approx. 200 mm F 12.7 30~60 Approx. 250 mm F 15.9 30~60 Approx. 300 mm

    F 19.1 25~35 Approx. 450 mm

    Torque wrench

    Refrigerant oil

    Marking

    Where the refrigerant oil is applied

    Tool length

  • 2. Work by Process and Key Points (5) Drain piping work

    23

    H

    H

    H

    H

    1) 2) 3)

    Do not connect drain pipes to the building's sanitary sewer pipes or waste pipes as it may cause an odor problem.

    Reverse gradient of the drain piping In some cases it is difficult to ensure the required drain piping gradient within the ceiling spaces when other piping and equipment crowd the area. Most of such problems can be averted by prior consultation with the installers handling the other equipment.

    1) Indoor unit side drain piping

    The installation procedures for drain piping at the indoor unit side differ by the model, so always check the installation manual before installing.

    Indoor units (FXMQ) in which the drain piping connection becomes a negative pressure require a drain trap (see below) for each unit. In addition, the drain trap requires a cleanout for cleaning.

    Work procedure

    Drain flow test

    ~Working points~ Ensure a downward gradient of the drain piping of at least 1/100. Keep the drain piping as short as possible in order to prevent air pockets.

    Indoor unit FXMQ

    Indoor unit FXMQ

    H: At least 50 mm

    Drain trap

    Cleanout

    Attach a cleanout to allow for cleaning

    Example of drain trap installation

    Indoor unit

    Downward gradient of at least 1/100 (1 cm/1 m)

    1/100 gradient

    Collective drain piping

    Indoor unit side drain

    piping

    Indoor unit installation

  • (5) Drain piping work

    24

    Drain-up height

    Main drain piping

    (1) Connect the attached drain hose (flexible type) to the indoor unit 's drain outlet. Be sure to use the drain hose that comes with the unit.

    The flexible type prevents any undue stress on the drain pan. Do not bend the drain hose in the middle so as to prevent any excessive force on it. Bending

    can lead to a water leak.

    (2) Tighten the indoor unit 's drain connection and drain hose with the attached hose band.

    Do not attach the indoor unit's drain connection and drain hose (accessory) with adhesive. It complicates removal of the drain hose from the machine during maintenance and the like.

    (3) Install the drain branch piping up to the main drain pipe.

    Refer to the illustration below for connection from the indoor unit to the main pipe.

    If the main drain pipe has already been installed and the required gradient for the drain branch piping cannot be achieved, maximize the drain-up height. (Confirm the drain-up height with the installation manual as it differs depending on the model.)

    Indoor unit

    Example of installation

    Allows for adjustment of the angle

    Drain pain Insulation material (band section)

    Insulation material (piping section)

    Attached drain hose

    Hose band

    Drain branch piping

    Main drain pipe

  • (5) Drain piping work

    25

    2) Collective drain piping

    An example of a connection from the main drain pipe to a vertical pipe

    It is ideal to use a Y joint. If it is not locally available, a T joint can also be used.

    Maximize the size of the main dr ain pipe as much as possible. Attach a cleanout (cap) at the top of the main drain pipe for water flow tests. Minimize the number of indoor units per group as few as possible in order to prevent the

    drain piping from becoming too long.

    Connection to vertical pipe with a Y joint Connection to vertical pipe using a T joint

    Cleanout

    T joint Y joint

    Example of drain piping installation

    Main drain piping

    Vertical drain piping

    Vent piping

    Drain branch piping

  • (5) Drain piping work

    26

    3) Drain flow test (1) Conduct a drain flow test before insulation work. (2) Use the cleanout on the main drain pipe for the water flow test.

    In the case of polyvinyl piping, use of colored adhesive prevents workers from forgetting to

    replace the plug.

    (Reference) Inner diameters of the main drain piping and vertical drain piping

    Calculate the drainage volume based on the number of indoor units connected to the main drain pipe. The inner diameter of the piping can be determined using the following method: 6 liters per hour per 1 HP is a rough measure for drainage volume from the indoor units.

    For example, in the event of 3 units with 2 HP and 2 units with 3 HP: 6 L/hr 2 HP 3 units + 6 L/hr 3 HP 2 units = 72 L/hr.

    (1) The relationship between the inner diameter of the main drain pipe and allowable drainage volume when using

    collective piping (in the case of an air vent)

    Note: Calculated assuming that the water ratio within the piping is 10%. Round off the allowable flow rate to the nearest whole number. The pipe after collection should have an inner diameter of at least 34 mm.

    (2) The relationship between the inner diameter of the vertical drain pipe and allowable drainage volume when using collective piping (in the case of an air vent)

    Note: Round off the allowable flow rate to the nearest 10. Vertical pipes within collective piping should have an inner diameter of at least 34 mm.

    Allowable flow rate [L/hr] PVC

    Inner piping diameter

    (Reference value: mm) Gradient=1/50 Gradient= 1/100 Comments

    PVC25 19 39 27

    PVC32 27 70 50

    Not suitable for the main drain piping due to the limited allowable flow rate

    PVC40 34 125 88

    PVC50 44 247 175

    PVC63 56 473 334

    Suitable for the main drain piping

    PVC Inner piping diameter

    (Reference value: mm) Allowable flow rate [L/hr] Comments

    PVC25 19 220

    PVC32 27 410

    Not suitable for vertical drain piping in the case of collective piping

    PVC40 34 730

    PVC50 44 1,440

    PVC63 56 2,760

    PVC75 66 5,710

    PVC90 79 8,280

    Can be used for vertical drain piping in the case of collective piping

  • 27

    ~Noise and vibration considerations~ Be sure to use canvas joints between the indoor unit and suction ducts as well as the indoor unit and

    discharge ducts. This is because they are useful in preventing reverberations when the product 's vibrations and operating noise travel through the building and ducts.

    Select suction and discharge grilles in consideration of the airflow rate so as to prevent any air distribution

    noise (wind roar).

    2. Work by Process and Key Points (6) Duct work (indoor)

    BE SURE: Be sure to insulate the discharge duct. Use canvas ducts with a metal framework on the inlet side. Consider the positioning of the suction and discharge grilles so as to prevent short-circuiting. Check the static pressure so the prescribed discharge air flow rate is being produced. Make it so the air filter is easy to remove when necessary.

    Work procedure

    Indoor unit installation

    Indoor unit

    Suspension bolt

    Canvas duct Canvas duct

    Air inlet/outlet installation Duct connection

  • 28

    2. Work by Process and Key Points (7) Insulation work

    [Materials] For the insulation, use materials that can sufficiently withstand the temperature of the piping.

    Heat-pump typeHeat resistant polyethylene foam (that can withstand temperatures over 120C) Cooling-only typePolyethylene foam (that can withstand temperatures over 70C)

    Polyethylene foam (heat resistant temperature: 70 ~ 80C)

    If you assume that the temperature and humidity around the refrigerant pipe might exceed 30C and RH80%, please use insulation with a thickness of 20 mm or more.

    Polyethylene foam insulation material cannot be used in some areas (Hong Kong) due to the fire codes. Therefore, confirm this in advance.

    Be sure to insulate connections (brazed, flared, etc.) after they have passed air tightness tests.

    Be sure to i nsulate both the gas and liquid piping individually.

    Be careful not to leave any gaps in the insulation joints. Be careful not to use damaged insulation material.

    Work procedure

    Refrigerant piping work

    Insulation work (other than the connections)

    Air tightness test

    Insulation work (the

    connections)

    Drain piping work

    Insulation work (other than the connections)

    Drain flow test Insulation work

    (the connections)

    Gap in the insulation joint Damaged insulation material

    Insulate both the gas and liquid piping together

    Insulate the gas and liquid piping individually

    Insulate only the gas piping

    Liquid piping

    Insulation material

    Gas piping

    Liquid piping

    Insulation material

    Gas piping

    Insulation material

    Gas piping

    Liquid piping

    Insulation material

    ~Working points~ Insulation work does not allow for checks/tests, so ensure that any maintenance and repair on the insulation joints and the like is done properly.

  • (7) Insulation work

    29

    Example of a polyvinyl tube being used

    Suspension band with turnbuckle

    Polyvinyl tube

    Indoor unit flares Use the following guide to conduct insulation work properly up to the base of the refrigerant piping on the

    indoor units.

    (1) Wind the joint insulation material (accessory) around the flares on both the liquid and gas piping. Always face the joint of the insulation material upward.

    (2) Securely fasten both ends of the joint insulation material with the clamp material (accessory). (3) Wind sealer over the joint insulation material only for flares on the gas piping side. Be sure to always conduct the above work after the air tightness test.

    Supporting fixture insulation

    When supporting the horizontal piping, the weight of the piping tends to crush the insulation at the support spots and cause condensation. At support spots, either reinforce the insulation material using tape with insulating properties or provide support with a hard-type wide polyvinyl tube to spread the weight.

    Be careful not to wind any adhesive tape used for a temporary hol d too tightly.

    Reinforcement of the insulation material cuts Insulation material shrinks with time, so it is recommended that the insulation material cuts be

    reinforced with tape with insulation material after applying a special adhesive (Synthetic Rubber Based).

    Flare insulation work guide Piping insulation

    material (machine side)

    Supporting fixture

    Insulating reinforcement tape (5t 50w)

    Insulation material

    (only gas piping side)

    Tighten the section that overlaps with the piping

    insulation material

    Sealer (accessory)

    Wind from the base of the machine to the upper portion of the flare nut connection Joint insulation material (accessory)

    Flare nut connection Face the joint

    upward

    Piping insulation material

    (locally procured)

    Attach to the base

    Clamp material (accessory)

  • (7) Insulation work

    30

    When inserting the insulation material into a gap

    In consideration of possible shrinking of the insulation material in the future, insert insulation material that is 200 mm longer than the gap into the gap. The work that follows is the same as the above -mentioned (3).

    Reinforcement of insulation material at bends

    Try to minimize the number of cuts in the insulation material (one cut is ideal). Consider where to cut the insulation material so that its reinforcement after bending can be

    conducted at a straight pipe portion.

    L + Approx. 200 mm of insulation material

    Special adhesive

    Reinforcement tape with insulation material

    L

    L+100

    L

  • (7) Insulation work

    31

    2. Work by Process and Key Points (8) Control wiring work

    If shielded wires are not properly grounded on one end, it can lead to communication problems. Therefore, when using a shielded wire, be sure to ground one end.

    1. Use wires of a thickness between 0.75 mm2 and 1.25 mm2.

    Thin type

    When wiring over an extended distance, transmission may become unstable due to the drop in voltage. Moreover, it predisposes the wiring to noise effects. Thick type

    When using daisy-chain wiring, 2 wires cannot be inserted into the indoor terminal block.

    2. Never use multi-core wiring (more than 2 cores).

    In the case of a thick type 2 wires cannot be inserted into the terminal block

    ~Working points~ Prepare a system diagram and check your work to prevent miswiring.

  • (8) Control wiring work

    32

    Indoor

    Indoor

    Normal condition (when sending)

    Interference condition (when sending)

    RC

    RC 4-core cable (stray capacitance between cables )

    Signal interference occurs, resulting in transmission errors.

    The same thing that happens when using multi-core cables will occur when many single-core wires are inserted into the conduit.

    3. Never bind communication wires over an extended distance. The insulation distance between wires shortens, predisposing the wires to interference.

    4. Never wire with bound control wiring

    Strong and weak currents may mix together, so it is recommended not to use multi-core wires.

    (It affects the wire withstanding voltage among other things.)

    5. Keep the control wiring and power wiring separate

    Due to the influence of the electrostatic and electromagnetic coupling, a disturbing wave that interferes

    with the signal wiring is induced, leading to malfunctions. When laying the signal wiring parallel to the power wiring, it is recommended to separate them with a

    distance shown in the table below:

    6. Use the same type of wires for power wiring within the same system.

    Power supply capacity for power wiring

    Separation distance between power wiring and control wiring for

    Daikin air conditioners

    Separation distance between power wiring for other equipment and

    control wiring for Daikin air conditioners

    Less than 10A At least 300 mm

    50A At least 500 mm

    100A At least 1,000 mm

    220V or more

    More than 100A

    At least 300 mm

    At least 1,500 mm

    Indoor unit

    Indoor unit

    RC

    RC

    [Poor example] [Good example]

    Remote control PCB

    Start/Stop (6-core wire)

    Remote control PCB

    Start/Stop

    [When using multi-core cables: Example of the VRV series ]

  • 33

    2. Work by Process and Key Points (9) Outdoor unit installation

    Precautions when preparing foundations for outdoor units

    Support the unit with a foundation that is at least 66 mm wide

    When attaching the rubber cushion, attach it to the whole bearing face of the foundation

    The height of the foundation should be at least 150 mm from the floor

    Secure the unit to the foundation using the foundation bolts, nuts and washers (Use four sets of M12-type foundation bolts, nuts and washers)

    The optimum length of the foundation bolts from the surface of the foundation is 20 mm

    Make considerations for the drain outlet

    Pay attention to the floor strength and waterproofing when installing outdoor units on the roof.

    Work procedure

    Outdoor unit installation

    Model A mm B mmRXYQ5P 635 497RXYQ8P

    RXYQ10PRXYQ12P,14PRXYQ16P,18P

    930 792

    1240 1102Foundation drawing for outdoor unit

    20

    Foundation preparation

    A

    B

    722~727 805

    100

  • 34

    Securing space for servicing/maintenance It is important to make considerations for space for servicing/maintenance.

    Note that replacement of the compressor may become difficult depending on the piping route.

    Prevention of short-circuiting Short-circuiting can occur if the outdoor unit is not installed in a location with good ventilation.

    Note that it may be necessary to install discharge ducts in cases as shown in the illustrations below:

    N = M when L = 1 m.

    K = M when L < 1 m.

    Note that Dimension K refers to the dimensions

    necessary when installing a single unit.

    Refer to 'Standards for installing

    upward-discharging outdoor units' when

    installing on each floor.

    No special measures are

    required if L = 3 m.

    If L < 3 m, a discharge duct wi th

    duct resistance of less than 8

    mmH2O is necessary.

    Dimension K for single unit installation requires being

    slightly larger.

    For anything 8 HP or above, use of small concrete blocks at the four bottom corners of the outdoor unit as a foundation is not possible. However, this is possible with the 5 HP models.

    Middle of the machine

    Required for any machine of at least 8 HP

    Middle of the machine

    Required for any machine of at least 8 HP

    Foundation

    Not enough space for servicing/maintenance! (Impossible to remove the compressor.)

    For short-circuiting

    prevention

    Discharge duct

    Installing under eaves Measures for obstacles above

  • 35

    At le

    ast 1

    .5m

    At le

    ast 1

    m

    At le

    ast 1

    mAt least 1

    .5mAt le

    ast 1m

    At least 1.5m

    At least 1.5m

    Considerations when installing inverter air conditioners Be sure to secure enough space for servicing/maintenance according to the instructions in the installation manual. Inverter air conditioners may induce noise from other electronic equipment. When selecting a location

    for installation, maintain sufficient di stances from radios, PCs, stereos and the like in consideration of the installation of the air conditioner and power wiring.

    Radios, PCs, stereos, etc.

    Indoor unit

    Indoor unit RC Cooling/ heating

    changeover RC

    Branching switch, overcurrent circuit breaker

    Branching switch, overcurrent circuit breaker

  • 36

    4.0

    3.5

    2.0

    1.5

    1.0

    0.5

    0

    4.0

    3.5

    2.0

    1.5

    1.0

    0.5

    0

    2. Work by Process and Key Points (10) Air tightness tests

    1) Evacuation of refrigerant piping

    Connect the gauge manifold to the service ports on the liquid and gas piping. Operate the vacuum pump for about 30 minutes, though it may differ depending the respective piping length.

    2) Nitrogen pressurization

    (1) Pressurize the liquid and gas piping for each refrigerant circuit according to the following steps: (Be sure to use nitrogen gas.) Step 1: Pressurize at 0.3 MPaG(43.51 PSI) for approx. 3 minutes

    Step 2: Pressurize at 1.5 MPaG(217.55 PSI) for approx. 5 minutes

    Step 3: Pressurize at 4.0 MPaG(580 PSI) for roughly 24 hours

    Even pressurized at 4.0 MPaG(580 PSI), a short time does not

    allow for detection of smaller leaks. Be sure to pressurize for 24 hours in Step 3.

    Never pressurize at a pressure above 4.0 MPaG(580 PSI) .

    ~Working points~ Be sure to evacuate the piping before the air tightness test. Be sure to always use nitrogen gas for the air tightness test. The air tightness test pressure is the design pressure for air conditioners.

    Work procedure

    Completion of refrigerant piping

    work

    Nitrogen pressurization

    Check for drop in pressure

    Pass

    Leak check

    Evacuation

    Example of the air tightness test

    Allows for detection of large leaks

    Allows for detection of smaller leaks

    [Time chart] Step3

    If no pressure drop, PASS

    Step1

    3 minutes 5 minutes Time

    24 hours

    Pressure

    MPaG

    Step2

  • (10) Air tightness tests

    37

    3) Check for pressure drop If there is no pressure drop, it has passed the test.

    Any differences in ambient temperature between during pressurization and during check for pressure drops will necessitate correction because pressure changes by roughly 0.01 MPaG per 1C. Correction value: (Temperature during pressurization Temperature during check) x 0.01 MPaG (Example)

    Pressure used for pressurization Ambient temperature Pressurization 4.00MPaG 25C

    24 hours later 3.95MPaG 20C

    In this case, the correction would be 0.05 MPaG so you can determine there has been no pressure drop (indicating a PASS).

    4) Leak check

    If a drop in pressure has been detected, search for the leak site by applying soapy water to the surface of the piping connections (flares, brazed spots) and charge the hose connections.

    It is rare to conduct an air tightness test on everything from the outdoor unit to indoor unit at the same time. If a pressure drop has been detected, it takes a lot of time to check where the leak is. An efficient method to check is on a block-by-block basis in accordance with the work schedule.

    After conducting the air tightness test, leaving the pressure between 0.2 and 0.3 MPaG in the piping allows for the prevention of contamination in the piping.

    The work can be conducted efficiently if the pressurization assembly

    is prepared beforehand.

    (1)

    (3)

    (2)

    Shaft

    (1) For each floor, check from the indoor unit to the

    vertical pipe within each shaft. (2) Check the above (1) and the vertical piping within

    each shaft. (3) Check all piping from the indoor unit to the vertical

    piping to the outdoor unit.

  • (10) Air tightness tests

    38

    2. Work by Process and Key Points (11) Vacuum drying

    ~What is vacuum drying?~ Using a vacuum pump, the moisture (liquid) in the piping is changed to vapor (gas) and expelled out of the piping in order to dry the inside of the piping. At 1 atmospheric pressure (101.3 kPa or 760 mmHg), the boiling point (evaporation temperature) for water is 100C. However, the closer the pressure within the piping comes to reaching a vacuum state as a result of using the vacuum pump, the lower the boiling point becomes. Once the boiling point falls below the outdoor temperature, the water will evaporate.

    If the outdoor air temperature is 7.2C, vacuum drying cannot be conducted unless the pressure is lowered below -100.3 kPaG (-752mmHg). Therefore, when conducting vacuum drying, 'selection and maintenance of the vacuum pump ' is important.

    Selection of the vacuum pump

    Note the following two points when selecting a vacuum pump.

    1. Select one that allows for pressure to be brought below 100.7 kPaG (-755 mmHG).

    2. Select one that allows for relatively high discharge volume. (One with at least 40 L/min. is recommended.) Before conducting the vacuum drying work, be sure to check with a vacuum gauge that the

    pressure reaches a level below -100.7 kPaG(-14.605 PSI) .

    Use s pecial tools for R410A (e.g., gauge manifold, charge hose). Reasons: Refrigerant oils differ between R410A and R22. Using different tools will result in

    refrigerant oils being mixed between the two, which will result in the development of impurities and the clogging of the refrigerant circuit.

    Water boiling point Absolute pressure Gauge pressure

    kPa mmHgG mmHg kPaG

    After passing air tightness test

    Vacuum drying

    Vacuum test Work

    procedure

    Necessary degree of vacuum

    Outdoor temperature range

    Evaporating point

    Temperature (C)

    Gau

    ge p

    ress

    ure

    kPaG

    (mm

    Hg)

    Abs

    olut

    e pr

    essu

    re k

    Pa

    (mm

    Hg)

    ?

  • 39

    There are two methods of vacuum drying depending on the onsite conditions so selectively use them. 1) Normal vacuum dryingThis is the common method.

    (1) Vacuum drying (1st time) Connect a gauge manifold to the service ports of the liquid and gas piping and operate the vacuum

    pump for at least 2 hours. (The pressure must be below -100.7 kPaG or -755 mmHg.) If the pressure does not fall below -100.7 kPaG or -755 mmHg even after vacuuming for 2 hours, there

    may either be moisture or a leak in the circuit. Vacuum for 1 more hour to confirm this . If the pressure does not fall below -100.7 kPaG or -755 mmHg even after vacuuming for 3 hours,

    check for the leak site. (2) Vacuum test

    Leave the system in a vacuum state below -100.7 kPaG or -755 mmHg for at least 1 hour and confirm that the gauge indicator does not rise.

    Conduct evacuation from both the liquid and gas piping. There are various types of functioning

    components in an indoor unit and evacuating only from one (liquid or gas) piping may result in a break in the vacuum state.

    If the gauge indicator rises, there may be moisture remaining or a leak in the circuit.

  • 40

    Additional refrigerant charge

    Vacuum state (1 hour)

    Vacuum drying (1 hour)

    Vacuum break

    Vacuum drying (2 hours)

    2) Special vacuum drying Special vacuum drying is conducted when there is a risk of moisture within the piping. For example, When work has been done during the rainy season and there is a risk of condensation within the piping When the work has taken a long time and there is a risk of condensation within the piping When there is a risk that rain has entered into the piping during work

    The special vacuum drying incorporates at least one vacuum break process using nitrogen gas during the normal vacuum drying process.

    (1) Vacuum drying (1st time) Connect a gauge manifold to the service ports of the liquid and gas piping and operate the vacuum

    pump for at least 2 hours. (The pressure must be below -100.7 kPaG or -755 mmHg.) If the pressure does not fall below -100.7 kPaG or -755 mmHg even after vacuuming for 2 hours, there

    may either be moisture or a leak in the line. Vacuum for 1 more hour to confirm this . If the pressure does not fall below -100.7 kPaG or -755 mmHg even after vacuuming for 3 hours,

    check for a leak site. (2) Vacuum break (1st time)

    Pressurize with nitrogen to 0.05 M PaG. (The nitrogen gas is a dry nitrogen, so breaking the vacuum state with it increases the effectiveness of the vacuum drying.)

    (3) Vacuum drying (2nd time) Operate the vacuum pump for at least 1 hour. Determinations: The pressure must reach at least -100.7 kPaG or -755 mmHg. If it does not even after 2 hours of operation, repeat steps (2) (vacuum break) and (3) (vacuum drying).

    (4) Vacuum test Leave the system in a vacuum state below -100.7 kPaG or -755 mmHg for at least 1 hour and confirm that the gauge indicator does not rise. If the gauge indicator rises, there may be moisture remaining or a leak in the circuit.

    Be sure to use nitrogen gas when conducting vacuum break.

    [Special vacuum drying time chart]

    Pressurized side

    Vacuumed side

    Atmospheric pressure

    +0.05 MPaG

    0 MPaG

    -26.7 kPaG

    -53.3 kPaG

    -80.0 kPaG

    -93.3 kPaG -101.3 kPaG

    -100.7 kPaG

    -100.7 kPaG

  • 41

    2. Work by Process and Key Points (12) Additional refrigerant charge

    (1) Calculation of the additional refrigerant charge amount Accurately assess the length of the refrigerant piping to calculate the amount of additional refrigerant charge.

    (For calculating the formula, refer to the equipment design materials for the respective models.)

    Be sure to enter the calculated additional refrigerant charge amount on the 'additional refrigerant charge instruction label' on the outdoor unit. (The data will be needed for maintenance.)

    (2) After completing the vacuum drying, leave the air conditioner OFF, open Valve A and charge the calculated additional refrigerant from the cylinder via the liquid side stop valve service port using pressure difference.

    Be sure to charge the refrigerant in a liquid state. (Cylinders with siphons allow for charging of liquid refrigerant in a standing position.)

    Use a digital scale to measure. If the refrigerant cannot be charged due to pressure equalization,

    (3) Close Valve A and then open Valve B. (4) Turn on the outdoor and indoor unit power supplies. (5) Completely open up the gas and liquid side stop valves.

    Be sure to charge refrigerant from the refrigerant charge port.

    (6) Turn the additional refrigerant charge operation to ON using the setting mode while leaving the air conditioner OFF. Refer to the 'Service Precautions' label on the outdoor unit's electrical box cover for the

    procedures regarding additional refrigerant charge operation.

    (7) Once the required volume of refrigerant has been charged, push the mode button (BS1) on the PCB (A1P) to

    stop the operation.

    Work procedure Additional

    refrigerant charge

    Calculation of additional refrigerant charge amount

    based on piping length

    Indoor unit

    Gas side stop valve

    Outdoor unit

    Liquid side stop valve

    Refrigerant cylinder with

    siphon

    Cylinder

    Gauge

    Gauge manifold

    Valve B

    Valve A

    Refrigerant charge port

    After completion of vacuum drying

  • 42

    Technical Question & Answer Quest. 1) Why centre support is required for 8 HP and 18 HP. However 8 HP ODU has no heavy material in side? Please give a clear reason.

    Ans: 1) The Supports required on three locations (both ends and middle) for 8 HP or more. Reason: To prevent sagging of casing. Incase of both side supports only, after long time nock frame and ODU leg may bend due to the compressor weight, so, inside parts may incline one side and may bulge (cramp) the adjacent plate. Small Casing is examined and confirmed that only two supports are sufficient at either ends. VRV III casing type is as follows: A) Small casing < Product width: 635mm> (VRVIII5-6HP) . . . ? B) Middle casing < Product width: 930mm> (VRVIII8-10HP) . . . C) Large casing < Product width: 1240mm> (VRVIII12-18HP) . . . About the selection of Pipe size: Quest. 2. If maximum length after first Refnet is >40M (i.e 90M) where all the pipe size has to be changed? Ans.2. If the pipe line exceed in circuit B then only in circuit B pipe size to be increased for 90M condition and not in circuit A. (Reference Topic & Page of ED 34-645B Sl. No. 6.5 Page 657/658).

    ODU

    IDU

    IDU

    IDU

    IDU Circuit B

  • NNoottee

  • TCDB001

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