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Fig. 37: Tightening the fitting
1: Tighten with the first open-ended spanner
2: Counter with the second open-ended spanner
Pipe dimension in
Tightening torque in Nm
inches
1/4"
3/8"
1/2"
5/8"
3/4"
6.3 Additional notes on connecting
the refrigerant piping
n
When combining the outdoor unit with some
indoor units, the procedure for connecting the
refrigerant piping may differ. Install the pro-
vided reducer or expansion fittings to the
indoor unit.
n
If the basic length of the connecting line
exceeds 5m, add refrigerant when commis-
sioning the system for the first time (see
chapter "Adding refrigerant").
1
2
15-20
33-40
50-60
65-75
95-105
6.4 Leak testing
Once all the connections have been made, the
pressure gauge station is attached to the Schrader
valve as follows (if fitted):
red = small valve = high pressure
blue = large valve = suction pressure
Once the connection has been made successfully,
the leak test is carried out with dry nitrogen.
Leak testing involves spraying a leak detection
spray onto the connections. If bubbles are visible,
the connections have not been made properly. In
that case, tighten the connection or, if necessary,
create a new flange.
After completing a successful leak test, the excess
pressure in the refrigerant piping is removed and a
vacuum pump with an absolute final partial pres-
sure of min. 10 mbar is used to remove all of the
air and empty the pipes. Any moisture present in
the pipes will also be removed.
NOTICE!
A vacuum of at least 20 mbar must be pro-
duced!
The time required to generate the vacuum is
dependent on the final pressure pipe volume of the
indoor units and the length of the refrigerant piping.
However, the process will take at least 60
minutes. Once any foreign gases and humidity
have been completely extracted from the system,
the valves on the pressure gauge station are
closed and the valves on the outdoor unit are
opened as described in the "Commissioning" sec-
tion.
31
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