Leak Test And Evacuation - Bosch LWPS 3 Montage- Und Gebrauchsanweisungen

LWPS 3 - LWPS 14
Seal a small opening Seal a small opening
Seal small gaps around
around the pipings around the pipings
the pipe, e.g. with silicon.
with gum type sealer. with gum type sealer.
Trap Siphon

7.4 Leak test and evacuation

Air and moisture in the cooling system have unwanted effects
as outlined below.
1) The pressure in the system increases.
2) The operating current increases.
3) The cooling (or heating) output falls.
4) Moisture in the cooling circuit can freeze and block the
capillary tubes.
5) Water can cause corrosion on parts in the cooling
system.
This means that the indoor and outdoor unit, as well as the con-
nection pipe, must be checked for leaks and pumped empty to
remove any non-condensable gases and moisture from the
system.
7.4.1 Preparation
Ensure that each pipe (liquid and air side) between the indoor
and outdoor unit is connected correctly and the wiring for the
test operation has been carried out. Remove the maintenance
valve caps from both the gas and liquid side of the outdoor unit.
Ensure that both maintenance valves on the liquid and air side
of the outdoor unit are closed at this point.
7.4.2 Leak test
Connect the multi-way valve (with pressure gauges) and

dry nitrogen gas cylinder with the filling hoses on this
maintenance connection.
NOTE
A multi-way valve must be used for the leak test. If no multi-
way valve is available, an isolating valve can also be used. The
"Hi" lever on the 3-way valve must be closed at all times.
The system may be charged with max. 3.0 MPa dry nitro-

gen. The cylinder valve must be closed with a pressure of
3.0 MPa. The next step is to search for leaks with liquid
soap.
NOTE
In order to prevent liquid nitrogen from entering the cooling
system, the top side of the gas cylinder must be higher than
the bottom side when pressure is building in the system.
1) The gas cylinder is usually used in an upright position.
Check all pipe connections (indoor and outdoor) and main-
tenance valves of the air and liquid side for leaks. Bubbles
indicate a leak. The soap must be wiped away with a clean
cloth.
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Siphon
452162.66.16a · FD 0108
2) If no leaks are identified in the system, reduce the nitrogen
pressure by removing the filling hose connection from the
gas cylinder. When the system pressure is normal again,
the hose must be removed from the gas cylinder.
7.4.3 Evacuation
1) Connect the end of the filling hose mentioned above to the
vacuum pump to pump the pipework and indoor unit
empty. The levers "Lo" and "Hi" on the multi-way valve
must be open. Start the vacuum pump. The duration of the
pumping empty process varies with different lengths of
the pipework and the pump output. The following table
shows the time required for pumping empty.
Time required for pumping empty with a
0.11m_/hour vacuum pump
Length of the pipework
less than 10 m
30 min. or longer
0.6 mbar or less
2) Close the levers "Lo" and "Hi" on the multi-way valve at the
desired vacuum pressure and switch off the vacuum
pump.
Finally
1) Open the valve handle on the liquid side completely in an
anti-clockwise direction with a maintenance valve key.
2) Open the handle of the valve on the gas side completely in
an anti-clockwise direction.
3) Loosen the filling hose connected to the air side slightly
from the maintenance connection to reduce the pressure,
then remove the hose.
4) Tighten the screw nuts and caps on the air side mainte-
nance connection again with an adjustment key. This pro-
cess is very important to prevent leaks on the system.
5) Position the valve caps on the air and liquid side mainte-
nance valves again and tighten. The purging with the vac-
uum pump is complete. The split-heat pump is now ready
for test operation.
English
Length of the pipework
more than 10 m
60 min. or longer
EN-13