Mitsubishi Heavy Industries FDE112KXE6A, Service Manual

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 159 

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⑦

Drain pipe (continued)

⑥

Refrigerant pipe

⑦

Drain pipe

Caution

●

Use the new refrigerant pipe.

When re-using the existing pipe system for R22 or R407C, pay attention to the following items.

・

Change the flare nuts with the attached ones (JIS category 2), and reprocess the flare parts.

・

Do not use thin-walled pipes.

●

Use phosphorus deoxidized copper alloy seamless pipe (C1220T specified in JIS H3300) for refrigeration pipe installation.

In addition, make sure there is no damage both inside and outside of the pipe, and no harmful 

substances such as sulfur, oxide, dust or a contaminant stuck on the pipes.

●

Do not use any refrigerant other than R410A.

Using other refrigerant except R410A (R22 etc.) may degrade inside refrigeration oil. And air getting into 

refrigeration circuit may cause over-pressure and resultant it may result in bursting, etc.

●

Store the copper pipes indoors and seal the both end of them until they are brazed in order to avoid any dust, dirt or 

water getting into pipe. Otherwise it will cause degradation of refrigeration oil and compressor breakdown, etc.

●

Use special tools for R410 refrigerant.

Piping work

When conducting piping work, make sure to allow the pipes 
to be aligned in a straight line for at least 250 mm, as shown 
in the left illustration. (This is necessary for the drain pump 
to function)

Work procedure 

1.  Remove the flare nut and blind flanges on the pipe of the indoor unit.

※　

Make sure to loosen the flare nut with holding the nut on pipe side with a spanner and giving torque 

to the nut with another spanner in order to avoid unexpected stress to the copper pipe, and then 

remove them.

(Gas may come out at this time, but it is not abnormal.)

●　

Pay attention whether the flare nut pops out. (as the indoor unit is sometimes pressured.)

2. Make a flare on liquid pipe and gas pipe, and connect the refrigeration pipes on the indoor unit.

※

Bend  the  pipe  with  as  big  radius  as  possible  and  do  not  bend  the  pipe  repeatedly.  In 

addition, do not twist and crush the pipes.

※

Do a flare connection as follows:

●　

Make sure to loosen the flare nut with holding the nut on pipe side with a spanner and giving 

torque to the nut with another spanner in order to avoid unexpected stress to the copper 

pipe, and then remove them.

●　

When fastening the flare nut, align the refrigeration pipe with the center of flare nut, screw 

the  nut  for  3-4  times  by  hand  and  then  tighten  it  by  spanner  with  the  specified  torque 

mentioned in the table below. Make sure to hold the pipe on the indoor unit securely by a 

spanner when tightening the nut in order to avoid unexpected stress on the copper pipe.

3.  Cover the flare connection part of the indoor unit with attached insulation material after a gas 

leakage inspection, and tighten both ends with attached straps.

●

Make sure to insulate both gas pipes and liquid pipes completely.

※　

Incomplete insulation may cause dew condensation or water dropping. 

4.  Refrigerant is charged in the outdoor unit.

  As for the additional refrigerant charge for the indoor unit and piping, refer to the installation 

manual attached to the outdoor unit.

Caution

●　

Install the drain pipe according to the installation manual in order to drain properly.

  Imperfection in draining may cause flood indoors and wetting the household goods

，

etc.

●　

Do not put the drain pipe directly into the ditch where toxic gas such as sulfur, the other harmful and

  inflammable gas is generated. Toxic gas would flow into the room and it would cause serious 

damage to user’s health and safety (some poisoning or deficiency of oxygen). In addition, it may 
cause corrosion of heat exchanger and bad smell.

●　

Connect the pipe securely to avoid water leakage from the joint.

●　

Insulate the pipe properly to avoid condensation drop.

●　

Check if the water can flow out properly from both the drain outlet on the indoor unit and the end 
of the drain pipe after installation.

●　

Make sure to make descending slope of greater than 1/100 and do not make up-down bend and/or trap 
in the midway. In addition, do not put air vent on the drain pipe. Check if water is drained out properly 
from the pipe during commissioning. Also, keep sufficient space for inspection and maintenance.

Work procedure
1. Insert the supplied drain hose (the end made of soft PVC) to the step of the drain socket on the indoor unit
      and fix it securely with the clamp. Attach the hose clamp to the drain hose around 10mm from the end.

　　　●

Do not apply adhesives on this end.

　　　●

Do not use acetone-based adhesives to connect to the drain socket.

Pipe diameter

Tightening torque N·m

φ

 6.35

φ

 9.52

φ

 12.7

φ

 15.88

φ

 19.05

14 to 18
34 to 42
49 to 61
68 to 82

100 to 120

Strap (Accessory)

Pipe cover (Accessory)

The thickness of insulation should be 20mm or more.

2.  Prepare a joint for connecting VP-20 pipe, adhere and connect the joint to the drain hose 

(the end made of rigid PVC), and adhere and connect VP-20 pipe (prepare on site).

※

As for drain pipe, apply VP-20 made of rigid PVC which is on the market.

●　

Make sure that the adhesive will not get into the supplied drain hose.

    It may cause the flexible part broken after the adhesive is dried up and gets rigid.

●　

The flexible drain hose is intended to absorb a small difference at installation of the unit 
or  drain pipes. Intentional bending, expanding may cause the flexible hose broken and 
water leakage.

3.  Make sure to make descending slope of greater than 1/100 and do not make up-down bend 

and/or trap in the midway.

●

Pay attention not to give stress on the pipe on the indoor unit side, and support and fix 
the pipe as close place to the unit as possible when connecting the drain pipe.

●

Do not set up air vent.

●

When sharing a drain pipe for more than 
one  unit,  lay  the  main  pipe  100mm 
below  the  drain  outlet  of  the  unit.  In 
addition, select VP-30 or bigger size for 
main drain pipe.

⑦

Drain pipe (continued)

⑩

Tap selection on blower unit (when the high peformance filter is used)

⑧

Wiring-out position and wiring connection

⑨

Check list after installation

Drain pump operation 

○

In case electrical wiring work finished

Drain pump can be operated by remote controller (wired).

For the operation method, refer to  Operation for drain pump  in the installation manual for wiring 
work.

○

In case electrical wiring work not finished

     Drain pump will run continuously when the dip switch“SW7-1” on the indoor unit PCB is turned ON, the Connec-

tor CNB is disconnected, and then the power supply (230VAC on the terminal block 

①

 and 

②

) is turned ON.

     Make sure to turn OFF “SW7-1” and reconnect the Connector CNB after the test.

●　

Electrical installation work must be performed according to the installation manual by an 

electrical installation service provider qualified by a power provider of the country, and be 

executed according to the technical standards and other regulations applicable to electrical 

installation in the country. 

      Be sure to use an exclusive circuit.

●　

Use specified cord, fasten the wiring to the terminal securely, and hold the cord securely in 

order not to apply unexpected stress on the terminal.

●　

Do not put both power source line and signal line on the same route. It may cause miscommu-

nication and malfunction.

●　

Be sure to do D type earth work.

●　

For the details of electrical wiring work, see attached instruction manual for electrical wiring 

work.

1.  Remove a lid of the control box (2 screws).

2.  Hold each wiring inside the unit and fasten them to terminal block securely.

3.  Fix the wiring with clamps.

4.  Install the removed parts back to original place.

The fan tap’s factory setting is “Standard.” If you want to change it to the high static-pressure setting, 
you can avail yourself of the following two methods. Use one of the two methods to set the fan tap.
Make sure to perform the functional setting with remote controller.
Select [Indoor function] in the functional setting mode, and change the function number [01]
[High wall setting].
For operation method, refer to the user’s manual of the remote controller.

⑤

Duck Work (continued)

　 ●

When placing the inlet port to carry out suction from the bottom side, use the following 
procedure to replace the suction duct joint and the bottom plate.

●

Remove the screws which fasten the

●

Replace the removed bottom plate 

bottom plate and the duct joint on the

    and duct joint.

inlet port side of the unit.

　 ●

Fit the duct join with a screw; fit the bottom plate.

　 ●

Make sure to insulate the duct to prevent dewing on it.

④

Install the specific blowout duct in a location where the air will 
circulate to the entire room.

　 ●

The duct connection is specific to the 200 circular duct.

　 ●

Conduct the installation of the specific blowout hole and the 
connection of the duct before attaching them to the ceiling.

　 ●

Insulate the area where the duct is secured by a band for 
dew condensation prevention.

⑤

Make sure provide an inspection  hole on  the  ceiling.  It  is indispensable  to service elecric 
equipment, motor, functional components and cleaning of heat exchanger.

①

If a duct is not provided at the suction side but it is substituted with the space over the ceiling, 
humidity in the space will increase by the influence of capacity of ventilation fan, strength of 
wind blowing against the out door air louver, weather (rainy day) and others.

 a)Moisture in air is likely to condense over the external plates of the unit and to drip on the 

ceiling. Unit should be operated under the conditions as listed in the above table and within 
the limitation of wind volume. When the building is a concrete structure, especially immedi-
ately after the construction, humidity tends to rise even if the space over the ceiling is not 
substituted in place of a duct. In such occasion, it is necessary to insulate the entire unit with 
glass wool (25mm). (Use a wire net or equivalent to hold the glass wool in place.)

 b)It may run out the allowable limit of unit operation (Example: When outdoor air temperature 

is 35°C DB, suction air temperature is 27°C WB) and it could result in such troubles as 
compressor overload, etc..

 c)There is a possibility that the blow air volume may exceed the allowable range of operation 

due to the capacity of ventilation fan or strength of wind blowing against external air louver 
so that drainage from be heat exchanger may fall to reach the drain pan but leak outside 
(Example: drip on to the ceiling) with consequential water leakage in the room.

②

If vibration damping is not conducted between the unit and the duct, and between the unit and 
the slab, vibration will be transmitted to the duct and vibration noise may occur. Also, vibration 
may be transmitted from the unit to the slab. Vibration damping must be performed.

Notice

A specific cover plate is available when changing the 4 spot to the 3 spot, or when changing the 
3 spot to the 2 spot.
Note: Do not change from 2 spot to 1 spot.

Connecting the air intake/vent ducts

①

Fresh Air Intake

[for air intake duct only]

○

Use the side fresh air intake hole, or supply 

  through a part of the suction duct.

[for simultaneous air intake/vent]

○

Intake air through the suction duct. 

  (the side cannot be used)

②

Air Vent

○

Use the side air vent hole. 

  (always use together with the air intake)

○

Use the duct flange for the air intake/vent (sold separately; for 125 circular duct connection), 
and connect the 125 circular duct (tighten with band).

○

Insulate the duct to protect it from dew condensation.

Drain hose

600 max.

Joint for VP-20 (Prepare on site)

290~325

100 or less

unit (mm)

P.C. board

Fuse

For drain motor 
connector CNR (blue)

Single unit wiring connection

Multi unit wiring connection

CN CNS

CNV

CNT2

CNN CNH

CNZ

CNA

CND

CNK2

CNK1

Power source 
line clamp

Inner/outer
connecting line

Remote controller line

Earth

Power source side 
terminal block

Signal side 
terminal block

Function number A Functional content B Setting content C Default setting

01

High wall setting

Standard

○

High wall 1

Multi type

22~90

112

Single type

50~71

１００

Static

Pressure

Standard Tap

50

60

High Tap

85

90

140

Unit: Pa

125, 140

60
85

CAUTION

●　

Taps should not be used under static pressure outside the unit mentioned above. 
Dew condensation may occur with the unit and wet the ceiling or furniture.

●　

Do not use under static pressure outside the unit of 50Pa or less. Water drops may be 
blown from the diffuser outlet of the unit and wet the ceiling or furniture.

Secure with a band, etc.

Blowout

duct

Air conditioner main unit

Ceiling suriace

Suction grille

(Locality)

Suction grille

(option)

Suction hole

(marketed item)

(with air filter)

Inspection hole

Suction duct

(marketed item)

Blow outlet

Blowout duct

(optional or marketed item)

Bad example of duct work

For ventilation

Louver to

outdoor air

(Pipe side)

(Pipe side)

Side fresh air intake hole

Air vent hole

Fresh air intake through the

suction duct

Fresh air intake through the

suction duct

(Pipe side)

Air vent hole

Fresh air intake through the

suction duct

Refrigerant pipe

250mm

(Section where attached 

 in a straight line)

Drain socket

Drain hose

(Accessory)

Pipe cover (large)

(For insulation)

(Accessory)

VP20 joint

(Prepare on site)

VP20

(Prepare on site)

Pipe cover (small)

(For insulation) (Accessory)

Unit

Clamp (Accessory)

Pipe cover

(For insulation)

(Prepare on site)

Adhesion

Drain socket

Drain hose

Stage difflernce part

Insert water supply hose

for 20mm ~ 30mm to 

supply water.

(Insert hose facing

toward bottom.)

Attached drain hose clamp

Drain

piping

Main

unit

Drain situation can be checked with transparent socket.

If the electrical work has not been completed, connect a convex

joint in the drain pipe connection to provide a water inlet.

Then, check if water leaks from the piping system and that

drain flows through the drain pipe normally.

Pour water into a convex joint

Remove grommet

Make sure to Install

it back after test.

Connecting port of top drain pipe

Insulating material

Rubber stopper (to be removed)

Connecting port of bottom drain pipes

Standard hard polyvinyl

chloride pipes

Bad example of duct work

(

)

Signal side 
terminal block

 Indoor power source line

Power source side 
terminal block

Remote controller line

Power source 
line clamp

Signal line (Shielded cord)

Earth

CNV

CNS

CNI

CNT2

CNN CNH

CNZ

CNA

CND

CNK2

CNK1

Earth (Shielded cord)

●

Check the following items after all installation work completed.

Check if

Expected trouble

Check

The indoor and outdoor units are fixed securely?

Falling, vibration, noise

Inspection for leakage is done?

Insufficient capacity

Insulation work is properly done?

Water leakage

Water is drained properly?

Water leakage

Supply voltage is same as mentioned in the model name plate?

PCB burnt out, not working at all

There is mis-wiring or mis-connection of piping?

PCB burnt out, not working at all

Earth wiring is connected properly?

Electric shock

Cable size comply with specified size?

PCB burnt out, not working at all

Any obstacle blocks airflow on air inlet and outlet?

Insufficient capacity

Descending slope greater than 1/100

As wide as possible 

(about100mm)

Insulation material

Supporting metal

Descending slope greater than 1/100

Air vent

No bump

No trap

Not touching the water

Trapped air will 

generate noises.

VP-30 or bigger

1.5m~2m

Fasten the screw securely

Hose clamp Drain hose

Drain socket

Metal plate

10mm

Over 20mm

4.  Insulate the drain pipe.

●　

Be sure to insulate the drain socket and rigid PVC pipe installed indoors otherwise it may 

cause dew condensation and water leakage.

※　

After drainage test implementation, cover the drain socket part with pipe cover (small size), then 

use the pipe cover (big size) to cover the pipe cover (small size), clamps and part of the drain 
hose, and fix and wrap it with tapes to wrap and make joint part gapless.

Drain up

●　

The position for drain pipe outlet can be raised up to 600mm above the ceiling. Use elbows for 
installation to avoid obstacles inside ceiling. If the horizontal drain pipe is too long before vertical pipe, 
the backflow of water will increase when the unit is stopped, and it may cause overflow of water from 
the drain pan on the indoor unit. In order to avoid overflow, keep the horizontal pipe length and offset of 
the pipe within the limit shown in the figure below.

Otherwise, the construction point makes it same as drain pipe construction.

Drain test

1.  Conduct a drain test after completion of the electrical work.

2.  During the trail, make sure that drain flows properly through the piping and that no water 

leaks from connections.

3.  In case of a new building, conduct the test before it is furnished with the ceiling.

4.  Be sure to conduct this test even when the unit is installed in the heating season.

Procedures

1.  Supply about 1000 cc of water to the unit through the air outlet by using a feed water pump.

2.  Check the drain while cooling operation.

Outline of bottom drain piping work

●　

If the bottom drain piping can be done with a 

descending gradient (1/50-1/100), it is possible to 

connect the pipes as shown in the drawing below.

Uncoupling the drain motor connector

●　

Uncouple the connector CNR for the drain motor 

as illustrated in the drawing on the right.

Note: If the unit is run with the connector coupled, 

drain water will be discharged from the upper drain 

pipe joint, causing a water leak.