Refrigerant Piping - Toshiba MMK-AP0074MH-E Service Manual

SMMS High-Wall Type
9.

Refrigerant Piping

Refrigerant piping
1
Use copper pipe with 0.8 mm or more
thickness. (In case pipe size is dia. 15.9,
with 1.0 mm or more.)
2
Flare nut and flare works are also different
from those of the conventional refrigerant.
Take out the flare nut attached to the main
unit of the air conditioner, and use it.
REQUIREMENT
When the refrigerant pipe is long, provide support
brackets at intervals of 2.5 to 3 m to clamp the
refrigerant pipe. Otherwise, abnormal sound may
be generated.
CAUTION
IMPORTANT 4 POINTS FOR PIPING WORK
1. Remove dust and moisture from the inside of
the connecting pipes.
2. Tight connection (between pipes and unit)
3. Evacuate the air in the connecting pipes using
VACUUM PUMP.
4. Check the gas leakage. (Connected points)
Pipe size
(dia.: mm)
Gas side 9.5
Liquid side 6.4
19-EN
Installation Manual
Permissible piping length and
height difference
They vary according to the outdoor unit.
For details, refer to the Installation Manual attached
to the outdoor unit.
Flaring
• Cut the pipe with a pipe cutter.
Remove burrs completely.
Remaining burrs may cause gas leakage.
• Insert a flare nut into the pipe, and flare the pipe.
As the flaring sizes of R410A differ from those of
refrigerant R22, the flare tools newly
manufactured for R410A are recommended.
However, the
conventional tools can
be used by adjusting
projection margin of the
copper pipe.
M Projection margin in flaring: B (Unit: mm)
Rigid (Clutch type)
Outer dia. of Conventional
R410A tool used
copper pipe tool used
6.4, 9.5
0 to 0.5 1.0 to 1.5
12.7, 15.9
M Flaring dia. meter size: A (Unit: mm)
+ 0
A
-0.4
Outer dia. of copper pipe
R410A
6.4 9.1
9.5 13.2
12.7 16.6
15.9 19.7
* In case of flaring for R410A with the
A
conventional flare tool, pull it out approx.
0.5 mm more than that for R22 to adjust
to the specified flare size.
The copper pipe gauge is useful for
adjusting projection margin size.
– 19 –
SMMS High-Wall Type
Tightening connection
CAUTION
• Do not apply excessive torque. Otherwise, the
nut may crack depending on the conditions.
Outer dia. of copper pipe
6.4 mm
9.5 mm
12.7 mm
15.9 mm
M Tightening torque of flare pipe connections
Pressure of R410A is higher than that of R22.
(Approx. 1.6 times) Therefore, using a torque
B
wrench, tighten the flare pipe connecting sections
which connect the indoor and outdoor units of the
specified tightening torque.
Incorrect connections may cause not only a gas
leak, but also a trouble of the refrigeration cycle.
Align the centres of the connecting pipes and
tighten the flare nut as far as possible with your
fingers. Then tighten the nut with a spanner and
torque wrench as shown in the figure.
Work using double spanner
CAUTION
Tightening with an excessive torque may crack
the nut depending on installation conditions.
Tighten the nut within the specified tightening
torque.
Airtight test / air purge, etc.
For air tightness test, adding refrigerant, refer to the
Installation Manual attached to the outdoor unit.
CAUTION
Do not supply power to the indoor unit until the
(Unit: N•m) airtight test and vacuuming are completed. (If the
indoor unit is powered on, the pulse motor valve is
Tightening torque
fully closed, which extends the time for
14 to 18 (1.4 to 1.8 kgf•m)
vacuuming.)
33 to 42 (3.3 to 4.2 kgf•m)
50 to 62 (5.0 to 6.2 kgf•m)
63 to 77 (6.3 to 7.7 kgf•m)
Open the valve fully
Open the valve of the outdoor unit fully.
Heat insulation
Heat insulation for the pipes should be done
separately for the liquid side and gas side. Because
both of the liquid and gas side pipes become a low
temperature during cooling operation, sufficient
heat insulation should be done to prevent
condensation.
• Heat insulator with a heat resistance of 120 °C or
more must be used for the gas side pipe.
• The pipe connection section of the indoor unit
must be heat insulated securely and compactly
with the attached heat insulator.
Fix with vinyl tape
Heat insulator
(attached)
– 20 –
Installation Manual
Local side pipe
20-EN