SMMS High-Wall Type
Installation Manual
– 14 –
EN
Tightening connection
CAUTION
• Do not apply excessive torque. Otherwise, the
nut may crack depending on the conditions.
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Tightening torque of flare pipe connections
Pressure of R410A is higher than that of R22.
(Approx. 1.6 times) Therefore, using a torque
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.
REQUIREMENT
Tightening with an excessive torque may crack the
nut depending on installation conditions.
Tighten the nut within the specified tightening
torque.
Piping with outdoor unit
• Shape of valve differs according to the outdoor
unit.
For details of installation, refer to the Installation
Manual of the outdoor unit.
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.
Airtight test/Air purge, etc.
For airtight test, air purge, addition of refrigerant,
and gas leak check, follow the Installation Manual
attached to the outdoor unit.
Open fully valves of the outdoor
unit
Gas leak check
Check with a leak detector or soap water whether
gas leaks or not, from the pipe connecting section
or cap of the valve.
REQUIREMENT
Use a leak detector manufactured exclusively HFC
refrigerant (R410A, R134a, etc.).
(Unit: N•m)
Outer dia. of copper pipe
Tightening torque
6.4 mm (dia.)
14 to 18 (1.4 to 1.8 kgf•m)
9.5 mm (dia.)
33 to 42 (3.3 to 4.2 kgf•m)
12.7 mm (dia.)
50 to 62 (5.0 to 6.2 kgf•m)
15.9 mm (dia.)
68 to 82 (6.8 to 8.2 kgf•m)
Work using double spanner
Fix with vinyl tape
Heat insulator
(attached)
Local side pipe
14-EN
