Mitsubishi Heavy Industries FDT28KXE6A Service Manual page 168

⑦Refrigerant 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.
※ I ncomplete 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
φ 6.35
14 to 18
φ 9.52
34 to 42
φ 12.7
49 to 61
φ 15.88 68 to 82
⑧Drain pipe
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.
1. A general-purpose hard PVC pipe VP-16 can be connected to the drain hose tip as a part of
drain piping.
2. Drain piping must be given a descending grade so that drain water may flow smoothly and it
must not have any trap or bump within the system.
(The pipe can be routed through the left, right, rear or bottom of the unit)
Hard PVC pipes (VP-16) laid indoors must be kept warm.
Vinyl tape
Use an attached insulation pad for heat insulation.
Position it so that the slit area faces upward.
165
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⑧Drain pipe (continued)
3. Pour water into the drain pan placed underneath the heat exchanger to make sure that it is
properly drained outdoors.
(For removal of the front panel, refer to ⑤Wiring-out position and wiring connection
No bumps
No traps
Not to be in water
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.
● Do drain test even if installation of heating season.
⑨Check list after installation
●Check the following items after all installation work completed.
Check if;
The indoor and outdoor units are fixed securely?
Inspection for leakage is done?
Insulation work is properly done?
Water is drained properly?
Supply voltage is same as mentioned in the model name plate?
There is mis-wiring or mis-connection of piping?
Earth wiring is connected properly?
Cable size comply with specified size?
Any obstacle blocks airflow on air inlet and outlet?
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in this manual.
Expected trouble Check
Falling, vibration, noise
Insufficient capacity
Water leakage
Water leakage
PCB burnt out, not working at all
PCB burnt out, not working at all
Electric shock
PCB burnt out, not working at all
Insufficient capacity
PHA012D033 PHA012D033