16
Installation, operation and maintenance instructions - VMGFE102
•
Install thermometers in both the entering and leaving
water connections.
•
Install drain connections at all low points to allow the
whole circuit to be drained.
•
Install stop valves, close to the entering and leaving
water connections.
• Use
fl exible connections to reduce vibration transmis-
sion.
•
Insulate all pipework, after testing for leaks, both to
reduce thermal leaks and to prevent condensation.
•
Wrap the insulations with a demisting screen.
•
If the external unit water pipes are in an area where the
ambient temperature is likely to fall below 0°C, they
must be protected against frost (frost protection
solution or electric heaters).
NOTE: For units not equipped with a hydronic module a
screen fi lter must be installed. This must be installed on the
water entering pipes upstream of the pressure gauge. It must be
located in a position that is easily accessible for removal and
cleaning. The mesh size of the fi lter must be 1.2 mm.
The plate heat exchanger can foul up quickly at the initial unit
start-up, as it complements the fi lter function, and the unit
operation will be impaired (reduced water fl ow rate due to
increased pressure drop).
Units with hydronic module are equipped with this type of
fi lter.
Do not introduce any signifi cant static or dynamic pressure
into the heat exchange circuit (with regard to the design
operating pressures).
The products that may be added for thermal insulation of the
containers during the water piping connection procedure
must be chemically neutral in relation to the materials and
coatings to which they are applied.
11.2 - Hydronic connections
The hydronic circuit diagram shows a typical hydronic
installation. When charging the water circuit use air vents to
evacuate any residual air pockets.
11.3 - Frost protection
The plate heat exchangers, the piping and the hydronic
module pump can be damaged by frost, despite the built-in
anti-freeze protection of the units.
Frost protection of the plate heat exchanger and all hydronic
circuit components is guaranteed:
•
Down to -20°C by electric heaters (heat exchanger and
internal piping) that have an automatic supply (units
without hydronic module),
•
Down to -10°C by an electric heater on the heat
exchanger that has an automatic supply and by pump
cycling (units with hydronic module),
•
Down to -20°C by electric heaters (heat exchanger and
internal piping) that have an automatic supply and by
pump cycling (units with hydronic module and
“Reinforced frost protection” option).
Never switch off the water heat exchanger and hydronic
circuit heaters or the pump, otherwise frost protection
can-not be guaranteed. For this reason the main unit
disconnect switch as well as the auxiliary protection switch
for the heaters must always be left closed (for the location of
these components see the wiring diagram).
To ensure frost protection of the units with hydronic module
water circulation in the water circuit must be maintained by
periodically switching on the pump. If a shut-off valve is
installed, a bypass must be included as shown below.
Winter position
Water
network
Unit
Closed
Closed
Open
IMPORTANT: Depending on the atmospheric conditions in
your area you must do the following when switching the unit
off in winter:
•
Add ethylene glycol or propylene glycol with an adequate
concentration to protect the installation up to a
temperature of 10 K below the lowest temperature likely to
occur at the installation site.
•
If the unit is not used for an extended period, it should be
drained, and ethylene glycol or propylene glycol should be
charged in the heat exchanger as a safety precaution, using
the water inlet purge valve connection.
•
At the start of the next season, refi ll the unit with water and
add an inhibitor.
•
For the installation of auxiliary equipment, the instal-ler
must comply with basic regulations, especially for
minimum and maximum fl ow rates, which must be
between the values listed in the operating limit table
(application data).
•
To prevent corrosion by diff erential aeration, the complete
drained heat transfer circuit must be charged with nitrogen
for a period of one month.
11.4 - Protection against cavitation (option 116)
To ensure the durability of the pumps in the integrated
hydronic modules, the control algorithm of the AR05 units
incorporates anti-cavitation protection.
It is therefore necessary to ensure a minimum pump entering
pressure of 60 kPa (0.6 bar) during operation and at shut-
down. A pressure below 60 kPa will prohibit unit start-up or
cause an alarm with the unit shutting down. In order to
obtain suffi
cient pressure, it is recommended:
•
to pressurise the hydronic circuit between 100 kPa and
400 kPa (1 and 4 bar) maximum on the suction side of
the pump,
•
to clean the hydronic circuit before charging water (see
chapters 12.5 and 12.6),
•
to regularly clean the screen fi lter,
ATTENTION: The use the integrated hydronic kits for an open
loop is prohibited.
