• Exclusively use insulated copper pipes specific for refrigeration which are supplied clean and sealed at
their ends.
The refrigerant connections of the internal unit are behind the electric panel, the ones of the external units
are on the right side and, in order to access them, it is necessary to remove the guard. (fig.9-10)
U1. Internal unit 5/8" gas line.
U2. 3/8" internal unit liquid line.
U3. External unit 5/8" gas line valve.
U4. 3/8" external unit liquid line valve.
•
Identify the path of the pipes in order to reduce length and bends of the pipes as much as possible and
to obtain maximum performance of the system.
•
Insert the refrigerant lines in a cable gland duct (possibly with internal separator) of the appropriate
dimensions fixed to the wall through which the pipes and the electric cables will pass.
•
Cut the pipe sections abounding of approximately 3-4 cm on length.
Cut exclusively using a wheel pipe cutter while tightening at small intervals in
order not to crush the pipe.
•
Remove possible burrs using the specific tool.
• Insert the fixing nut in the pipe before flaring (fig.11).
• Flare the ends of the pipes using the specific tool flawlessly without breakages, cracks or cleavage
(fig.11).
•
Manually screw the nut of the pipe on the coupling thread.
• Screw completely using a fork wrench to keep the threaded part of the coupling stationary.
On the nut, use a torque wrench calibrated with the following values based on the dimensions of the
pipes to avoid deformations:
• Diameter 3/8'' 34 N.m < tightening torque < 42 N.m
• Diameter 5/8'' 68 N.m < tightening torque < 82 N.m
3.1.1 - Tests and checks
Once the connections are complete, check for perfect sealing of the refrigerant system.
To carry out the operations described below it is necessary to use a manometer unit specific for R410A
and a vacuum pump with minimum flow rate of 40 l/min:
a. Unscrew the caps of the service valves stems, both of the gas and of the liquid (fig. 13).
b. Connect the vacuum pump and manometer unit by means of the flexible pipes with 5/16" coupling
to the service connection of the gas line (fig.14).
c.
Switch on the pump and open the taps of the manometer unit.
d. Lower pressure up to -101kPa (-755mmHg, -1bar).
e.
Maintain underpressure for at least 1 hour.
f.
Close the taps of the manometer unit and switch off the pump.
g. After 5 minutes, only if pressure remained at -101kPa (-755mmHg, -1bar), pass to the operation at
step "h".
If pressure inside the circuit raised to a value higher than -101kPa (-755mmHg, - 1bar), it is neces-
sary to proceed with the search for the leak (by means of soap solution with refrigerant circuit under
nitrogen pressure ~ 30 bar).
Once the leak has been detected and repaired, it is necessary to restart from step "c".
EN - 12
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