Mitsubishi Heavy Industries FDT28KXE6A Service Manual page 141

Installation of indoor unit (continued)
6. Make sure to install the indoor unit horizontally. Confi rm the
levelness of the indoor unit with a level gauge or transparent hose
fi lled with water. Keep the height difference at both ends of the
indoor unit within 3mm.
7. Tighten four upper nuts and fi x 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, and generating noise from the
fan.
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.
Even after decorative panel attached, still the unit height can be adjusted fi nely. Refer to the
installation manual for decorative panel for details.
Make sure there is no gap between decoration panel and ceiling surface, and between decoration
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, put the cardboard template for installation attached on the package (packing material
of cardboard box) on the bottom of the unit in order to avoid dust coming into the indoor unit.
Refrigerant 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 fl are nuts with the attached ones (JIS category 2), and reprocess the fl are parts.
Do not use thin-walled pipes.
Use phosphorus deoxidized copper alloy seamless pipe (C1220T specifi ed 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 fl are nut and blind fl anges on the pipe of the indoor unit.
Make sure to loosen the fl are 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 fl are nut pops out. (as the indoor unit is sometimes pressured.)
2. Make a fl are 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 fl are connection as follows:
Make sure to loosen the fl are 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 fl are nut, align the refrigeration pipe with the center of fl are nut, screw the nut
for 3-4 times by hand and then tighten it by spanner with the specifi ed 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 fl are 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.
Pipe diameter Tightening torque N·m
6.35 14 to 18
34 to 42
9.52
12.7 49 to 61
15.88 68 to 82
100 to 120
19.05
Drain pipe
Caution
Install the drain pipe according to the installation manual in order to drain properly.
Imperfection in draining may cause fl ood 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
infl ammable gas is generated. Toxic gas would fl ow into the room and it would cause serious
damage to user's health and safety (some poisoning or defi ciency 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 fl ow 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 suffi cient space for inspection and
maintenance.
Indoor unit
hose
Strap (Accessory)
Pipe cover (Accessory)
The thickness of insulation should be 20mm or more.
138
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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 1. Insert the supplied drain hose (the end made of soft PVC) to the step of the drain socket on
and fix it securely with the clamp. Attach the hose clamp to the drain hose around 10mm from the end. the indoor unit and fi x it securely with the clamp.
Do not apply adhesives on this end.
Do not apply adhesives on this end.
●
Fasten the screw securely
Hose clamp Drain hose
Drain socket
The step part
Drain hose
Drain socket
Metal plate
10mm
Drain socket
The step part Drain hose
No adhesive allowed
No adhesive allowed
2. Prepare a joint for connecting VP-20 pipe, adhere and connect the joint to the drain hose (the end
2. Prepare a joint for connecting VP-20 pipe, adhere and connect the joint to the drain hose
made of rigid PVC), and adhere and connect VP-20 pipe (prepare on site).
(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.
※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.
Make sure that the adhesive will not get into the supplied drain hose.
● It may cause the fl exible part broken after the adhesive is dried up and gets rigid.
It may cause the flexible part broken after the adhesive is dried up and gets rigid.
The fl exible drain hose is intended to absorb a small difference at installation of the unit or drain
The flexible drain hose is intended to absorb a small difference at installation of the unit or drain pipes.
● pipes. Intentional bending, expanding may cause the fl exible hose broken and water leakage.
Do not bend or make an excess offset on the drain hose as shown in the picture.
Bend or excess offset will cause drain 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 fi x the pipe
as close place to the unit as possible when connecting the drain pipe.
Do not set up air vent.
Supporting metal
1.5m ~ 2m
Air vent
Insulation material
Descending slope greater than 1/100
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.
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 fi x 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 backfl ow of water will increase when the unit is stopped, and it may cause overfl ow of
water from the drain pan on the indoor unit. In order to avoid overfl ow, keep the horizontal pipe
length and offset of the pipe within the limit shown in the fi gure below.
295 to 325mm
Drain hose
Joint for VP-20
(Prepare on site)
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. 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.
Confi rm 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. And insulate the drain
pipe properly fi nally.
-
pipe cover (big)
Joint for VP-20
(For insulation)
(Prepare on site)
(Accessory) pipe cover (big)
Joint for VP-20
(For insulation)
(Prepare on site)
(Accessory)
Unit
Unit
VP-20
Drain hose
(Prepare on site)
(Accessory)
Connect
VP-20
Drain hose
Clamp
(Accessory) (Prepare on site)
(Accessory Pipe cover (small)
Drain socket
Connect
(For insulation)
Clamp
(Prepare on site)
Pipe cover (small) (Accessory) Pipe cover (small)
Drain socket
(For insulation)
(For insulation)
(Accessory)
(Prepare on site)
Pipe cover (small)
(For insulation)
(Accessory)
Over 20mm
Trapped air will
No bump
generate noises.
No trap
Not touching the water
As wide as possible
(about100mm)
VP-30 or bigger
Descending stop greater than 1/100
100 or less
Drain plug
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