Leak Test And Evacuation - Dimplex LAK 6IMR Montage- Und Gebrauchsanweisung

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 sys-
tem.
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 out-
door 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 mainte-
nance 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.
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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.
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 re-
quired for pumping empty.
Length of the pipework
30 min. or longer
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 re-
move the hose.
4) Tighten the screw nuts and caps on the air side mainte-
nance connection again with an adjustment key. This proc-
ess 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.
452162.66.09 · FD 9512
LAW 6IMR - LAW 14ITR
Time required for pumping empty with a
0.11m_/hour vacuum pump
Length of the pipework
less than 10 m
0.6 mbar or less
more than 10 m
60 min. or longer
EN-13