9 - WATER CONNECTIONS
For size and position of the heat exchanger water inlet and outlet
connections refer to the certified dimensional drawings supplied
with the unit. The water pipes must not transmit any radial or
axial force to the heat exchangers nor any vibration.
The water supply must be analysed and appropriate filtering,
treatment, control devices, isolation and bleed valves and circuits
built in, to prevent corrosion, fouling and deterioration of the
pump fittings. Consult either a water treatment specialist or
appropriate literature on the subject.
9.1 - Operating precautions
Design the water circuit with the least number of elbows and
horizontal pipe runs at different levels. The main points to be
checked for the connection are:
-
The use of different metals on hydraulic piping could generate
eletrolytic pairs and consequently corrosion. Verify then, the
need to install sacrificial anodes.
-
Comply with the water inlet and outlet connections shown on
the unit.
-
Install manual or automatic air purge valves at all high points
in the circuit(s).
-
Use a pressure reducer to maintain pressure in the circuit(s)
and install a safety valve as well as an expansion tank. Units
with hydraulic module and safety hydraulic components option
include the safety valve and expansion tank.
-
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 flexible connections to reduce vibration transmission.
-
If the insulation provided is not sufficient, insulate the cold-
water piping, after testing for leaks, both to reduce heat loss
and to prevent condensation.
-
Cover the insulation with a vapour barrier.
-
If the external water piping to the unit is in an area where the
ambient temperature can fall below 0°C, insulate the piping
and install an electric heater on the piping.
NOTE: For units without Safety hydraulic component option,
a screen filter must be installed as close as possible to the
heat exchanger and in a position that is easily accessible
for removal and cleaning. Units with a hydraulic module
include this filter.
The mesh size of the filter must be 1.2 mm. If this filter is
not installed, the plate heat exchanger can quickly become
contaminated at the first start-up, as it takes on the filter
function, and correct unit operation is affected (reduced
water flow due to increased pressure drop).
Damage due to absence of safety valve, expansion tank or
screen filter (i.e. without Safety hydraulic component option)
is not covered by the warranty.
Use of units in an open loop is forbidden.
Before the system start-up verify that the water circuits are
connected to the appropriate heat exchangers (e.g. no reversal
between evaporator and condenser).
Do not introduce any significant static or dynamic pressure into
the heat exchange circuit (with regard to the design operating
pressures).
Before any start-up verify that the heat exchange fluid is
compatible with the materials and the water circuit coating.
If additives or other fluids than those recommended by the
manufacturer are used, ensure that the fluids are not considered
as a gas, and that they belong to class 2, as defined in directive
2014/68/UE.
Recommendations on heat exchange fluids:
-
No NH
4+
ammonium ions in the water, these are very harmful
to copper. This is one of the most important factors for the
operating life of copper piping. A content of several tenths of
mg/l will badly corrode the copper over time (the plate heat
exchangers used for these units have brazed copper joints).
-
Cl
-
Chloride ions are detrimental for copper with a risk of
perforations by corrosion by puncture. If possible keep below
125 mg/l.
-
SO
4
2-
sulphate ions can cause perforating corrosion, if their
content is above 30 mg/l.
-
No fluoride ions (<0.1 mg/l).
-
No Fe
2+
and Fe
3+
ions with non-negligible levels of dissolved
oxygen must be present. Dissolved iron < 5 mg/l with dissolved
oxygen < 5 mg/l.
-
Dissolved silica: Silica is an acid element of water and can
also lead to risk of corrosion. Content < 1mg/l.
-
Water hardness: > 0.5 mmol/l. Values between 1 and 2.5 can
be recommended. This will facilitate scale deposit that can
limit corrosion of copper. Values that are too high can cause
piping blockage over time. A total alkalimetric titre (TAC) below
100 is desirable.
-
Dissolved oxygen: Any sudden change in water oxygenation
conditions must be avoided. It is as detrimental to deoxygenate
the water by mixing it with inert gas as it is to over-oxygenate it
by mixing it with pure oxygen. The disturbance of the oxygenation
conditions encourages destabilisation of copper hydroxides and
enlargement of particles.
-
Electric conductivity 10-600µS/cm
-
pH: Ideal case pH neutral at 20-25°C - (7 < pH < 8)
If the water circuit must be emptied for longer than one month,
the complete circuit must be placed under nitrogen charge to
avoid any risk of corrosion by differential aeration.
Filling, completing and draining the water circuit
charge must be done by qualified personnel, using
the air purges and materials that are suitable for
the products.
Charging and removing heat exchange fluids should be
done with devices that must be included on the water circuit
by the installer. Never use the unit heat exchangers to add
heat exchange fluid.
9.2 - Water connections
The diagram below illustrates a typical hydraulic installation.
When the hydraulic circuit is charged, use the air vents to
evacuate any residual air pockets.
EN-43
Dynaciat LG/LGN
Summary of Contents for DYNACIAT LG 080
Page 1: ...DYNACIAT LG LGN 07 2018 10188 Instruction manual...
Page 2: ...Dynaciat LG LGN EN 2...
Page 3: ...EN 3 Dynaciat LG LGN...
Page 67: ...EN 67 Dynaciat LG LGN...
