6.2 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.
6.3 Additional notes on connecting
the refrigerant piping
When combining the outdoor unit with the different
indoor units, the refrigerant piping connection may
differ. Install the corresponding expansion fittings
(sleeves) on the distributors. Depending on the
number of distributors and total length of the liquid
line, add refrigerant when commissioning the
system for the first time (see
6.4 ‘Adding refrigerant’ on page 27
).
6.4 Adding refrigerant
The unit contains a basic quantity of refrigerant.
Furthermore, an additional amount of refrigerant
must be added, in accordance with the following
table:
Component
Fill factor
Length of the liquid pipe 1/4"
0.023 kg/m
Length of the liquid pipe 3/8"
0.060 kg/m
Number of distribution units (4-fold)
0.1 kg/unit
Number of Y-pieces
0.1 kg/unit
CAUTION!
Wear protective clothing when handling refrig-
erant.
DANGER!
Only refrigerant in a liquid state may be used to
fill the cooling cycle!
NOTICE!
Check the overheating to determine the refrig-
erant fill quantity.
NOTICE!
The escape of refrigerant contributes to cli-
matic change. In the event of escape, refrig-
erant with a low greenhouse potential has a
lesser impact on global warming than those
with a high greenhouse potential. This device
contains refrigerant with a greenhouse poten-
tial of 1975. That means the escape of 1 kg of
this refrigerant has an effect on global warming
that is 1975 times greater than 1 kg CO
2
,
based on 100 years. Do not conduct any work
on the refrigerant circuit or dismantle the
device - always enlist the help of qualified
experts.
27
Summary of Contents for MVV 1200 Dc
Page 67: ......
