Mitsubishi Heavy Industries FDE112KXE6A, Service Manual

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 150 

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④

Installation of indoor unit (continued)

⑤

The indoor unit change procedure for duct type

Prepare a duct panel.

(1) Drill hole for duct

①

 While referring to the dimensions, cut the insulation.

②

 Cut sheet metal for the hole, and drill hole.

③

 Install the duct joint with screws attached to the panel.

④

 Install the bottom plate with screws attached to the panel.

⑤

 Set up as follows:

Changing the fan tap

Change the fan tap to the high speed by the remote controller.
[Method]

①

 Stop the operation of air conditioner. Press          (SET) button and         (MODE) button

for 3 seconds at the same time.

②

 Select “                           ” (Indoor Unit Function) and press         (SET) button.

③

 Select “                       ” (Fan Speed Setting) of No.”02” and press         (SET) button.

④

 Select “                       ” (High Fan Speed 1) and press         (SET) button.

⑤

 Press            button to exit.

As for details, refer to the installation manual of remote controller.

Invalidating the louver switch

Invalidate the louver switch by the remote controller.
[Method]

①

 Stop the operation of air conditioner. Press         (SET) button and         (MODE) button 

for 3 seconds at the same time.

②

 Select “                          ” (Remote Controller Function) and press         (SET) button.

③

 Select “                      ” (Louver Switch Setting) of No. “07” and press         (SET) button.

④

 Select “                   ” (Louver Switch Invalid) and press         (SET) button.

⑤

 Press            button to exit.

As for details, refer to the installation manual of remote controller.

(2) Duct work

Request

●

Calculate air flow and the static pressure to select the duct’s length and shape.

Indoor unit

Hose

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.

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.

⑦

Drain pipe (continued)

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. 

⑦

Drain pipe (continued)

⑧

Wiring-out position and wiring connection

⑨

Panel installation

⑩

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 (220-240VAC on the terminal block 

L

 and  

N

) 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) and the wiring cover (2 screws).
2. Hold each wiring inside the unit and fasten them to terminal block securely.
3. Take out the wiring to upper direction of wiring cover, and fix the wiring with clamp.
4. Install the removed parts back to original place.

Caution
Make sure to install the wiring cover. Otherwise it may cause dew condensation into the control 

box.

●

Attach the panel on the indoor unit after electrical wiring work.

●

Refer to attached manual for panel installation for details.

●

Check the following items after all installation work completed.

6.  Make sure to install the indoor unit horizontally. Confirm the 

levelness of the indoor unit with a level gauge or transpar-
ent  hose  filled  with  water.  Keep  the  height  difference  at 
both ends of the indoor unit within 3mm.

7.  Tighten  four  upper  nuts  and  fix  the  unit  after  height  and 

levelness adjustment.

Caution

●

Do not adjust the height by adjusting upper nuts. It will cause unexpected stress on the indoor 
unit and it will lead to deformation of the unit, failure of attaching a panel.

●

Make sure to install the indoor unit horizontally and set the gap between the unit underside and 
the  ceiling  plane  properly.  Improper  installation  may  cause  air  leakage,  dew  condensation, 
water leakage and noise.

●

Make sure there is no gap between decoration panel and ceiling surface, and between decora-
tion panel and the indoor unit. The gap may cause air leakage, dew condensation and water 
leakage.

●

In case decorative panel is not installed at the same time, or ceiling material is installed after 
the unit installed, avoid dust coming into the indoor unit.

  CATEGORY 

NUMBER 

FUNCTION 

SETTING

02

  CATEGORY 

NUMBER 

FUNCTION 

SETTING

07 

⑤

The indoor unit change procedure for duct type (continued)

Caution

●

Take care that the static pressure does not exceed 30 Pa.

The indoor unit has condensation owing to the decrease of air flow, may 
cause wetting the ceiling and household goods.

Request

●

The duct should be minimum bends. (Make the bend radius as 

large as possible.)

●

Conduct the duct work before ceiling attachment.

(3) Connecting duct for outside air intake

①

 Outside air intake

●

Use the intake, which is easier for work, either at the rear or the side.

②

 Duct connection

●

Connect the 125 mm diameter duct, using the duct flange for 125mm diameter duct. (Clamp with 

band)

●

Insulate the duct to prevent condensation.

Pipe cover (small)

(For insulation) (Accessory)

Pipe cover 

(For insulation)

(Prepare on site)

Unit

Pipe cover (big)

(For insulation) (Accessory)

VP-20

(Prepare on site)

Joint for VP-20

(Prepare on site)

VP-25

(Prepare on site)

Drain hose (Accessory)

Drain socket

 Clamp (Accessory)

(No adhesive allowed)

Unit

Pipe cover (small)

(For insulation) (Accessory)

Pipe cover (For insulation)

(Prepare on site)

Pipe cover (big)

(For insulation) 

(Accessory)

VP-20

(Prepare on site)

Joint for VP-20

(Prepare on site)

Drain hose

(Accessory)

Drain socket

Drain socket

The step part

Drain hose

 Clamp (Accessory)

Connect

No adhesive allowed

Wiring input port

Control box

Wiring cover

Wiring cover

Clamp

Wiring

CNU

Earth

Indoor power 

source line

Remote controller line

Signal line (Shielded cord)

Signal side 

terminal block

Power source side 

terminal block

Earth

(Signal line)

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.

L

L

N

N

Fasten the screw securely

Hose clamp

Drain hose

Drain socket

Metal plate

10mm

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

Outlet

Cut.

Duct joint

Bottom plate

Control Box

[Upward]

40

80

100

155

27

27

37

20

150

150
490

30

150

20
30

40 45

120

120

45 40 40

Indoor unit

Selling surface

Air supply

Supply air duct
(Prepare on site)

Insulate duct

Air return

Bad example

Bad example

Good example

50

6.5

7

7.5

7.8

40

30

20

10

0

Upper limit

Upper limit

High

Low

Air flow (m

3

/min)

Static pressure (Pa)

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.

●

When drain pipe is set to rising in the nearest of the unit, use the VP-20 pipe.
When drain pipe is set to after the horizontal pulling, use the VP-25 and above pipe.

● 

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.

Supporting metal

No bump

No trap

Not touching the water

Trapped air will 

generate noises.

Air vent

Insulation material

1.5m ~ 2m

Descending slope greater than 1/100

Descending slope greater than 1/100

VP-30 or bigger

As wide as possible 

(about100mm)

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.

Drain test

● 

After installation of drain pipe, make sure that drain system work in good condition and no 

water leakage from joint and drain pan. Check if the motor sound of drain pump is normal 

or not.

● 

Do drain test even if installation of heating season.

● 

For new building cases, make sure to complete the test before hanging the ceiling.

1.  Remove the drain grommet, and pour water of about 1000cc into the drain pan in the 

indoor unit by pump so as not to get the electrical component wet.

2.  Make sure that water is drained out properly and there is no water leakage from any joints 

of the drain pipe at the test.

  Confirm that the water is properly drained out while 

the drain motor is operating. At the drain socket 

(transparent), it is possible to check if the water is 

drained out properly.

3.  Unplug the drain plug on the indoor unit to remove 

remaining water on the drain pan after the test, and 

re-plug it.

4.   Make  sure  to  install  the  grommet  back  to  original 

place.

5.   Insulate the drain pipe properly finally.

600mm or less

Joint for VP-20 (Prepare on site)

295 to 325mm

100mm or less

Pump

Remove grommet

Make sure to install 

it back after test.

Insert the edge of water pump 

hose in the drain pan.

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

PJC012D116

B