Midea MUE-48HRFN1-M, Руководство по обслуживанию

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76

After the vacuum drying process is carried
out, the additional refrigerant charge
process needs to be performed.

The outdoor unit is factory charged with
refrigerant. The additional refrigerant
charge volume is decided by the diameter
and length of the liquid pipe between indoor
and outdoor unit. Refer the following
formula to calculate the charge volume.
Diameter of
liquid pipe
(mm)
Φ6.35 Φ9.52
Formula V=15g/m×(L -7.5) V=30g/m×(L -7.5)
V: Additional refrigerant charge volume (g).
L: The length of the liquid pipe (m).
Note:

Refrigerant may only be charged after
performed the vacuum drying process.

Always use gloves and glasses to protect
your hands and eyes during the charge
work.

Use electronic scale or fluid infusion
apparatus to weight refrigerant to be
recharged. Be sure to avoid extra
refrigerant charged, it may cause liquid
hammer of the compressor or protections.

Use supplementing flexible pipe to connect
refrigerant cylinder, pressure gauge and
outdoor unit. And The refrigerant should be
charged in liquid state. Before recharging,
The air in the flexible pipe and manifold
gauge should be exhausted.

After finished refrigerant recharge process,
check whether there is refrigerant leakage
at the connection joint part. (Using gas
leakage detector or soap water to detect).
12.8 Engineering of insulation
12.8.1 Insulation of refrigerant pipe
1 Operational procedure of refrigerant
pipe insulation
Cut the suitable pipe → insulation (except joint
section) → flare the pipe → piping layout and
connection→ vacuum drying → insulate the
joint parts
2
Purpose of refrigerant pipe insulation

During operation, temperature of gas pipe
and liquid pipe shall be over-heating or
over-cooling extremely. Therefore, it is
necessary to carry out insulation; otherwise
it shall debase the performance of unit and
burn compressor.

Gas pipe temperature is very low during
cooling. If insulation is not enough, it shall
form dew and cause leakage.

Temperature of gas pipe is very high
(generally 50-100
℃
) during heating.
Insulation work must be carried out to
prevent hurt by carelessness touching.
3
Insulation material selection for
refrigerant pipe

The burning performance should over
120
℃

According to the local law to choose
insulation materials

The thickness of insulation layer shall be
above 10mm.If in hot or wet environment
place, the layer of insulation should be
thicker accordingly.
4 Installation highlights of insulation
construction

Gas pipe and liquid pipe shall be insulated
separately, if the gas pipe and liquid pipe
were insulated together; it will decrease the
performance of air conditioner.
Liquid pipe Insulation meterial Gas pipe

The insulation material at the joint pipe
shall be 5~10cm longer than the gap of the
insulation material.

The insulation material at the joint pipe
shall be inserted into the gap of the insulation
material.