8 - WATER CONNECTIONS
For size and position of the unit 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 desilting,
filtering, treatment, control devices, shut-off and bleed valves
built in, to prevent corrosion (example: damage to the protection
of the tube surface if the fluid is polluted), fouling and deterioration
of the water circuit.
Before any start-up verify that the heat exchange fluid is
compatible with the materials and the water circuit coating. The
use of different metals on hydraulic piping could generate
eletrolytic pairs and consequently corrosion. Verify then, the need
to install sacrificial anodes.
In case additives or other fluids than those recommended by
CIAT 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/EU.
CIAT recommendations on heat exchange fluids:
-
No NH
4+
ammonium ions in the water, they are very
detrimental for 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.
-
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 corrosion risks. Content < 1mg/l.
-
Water hardness: >0.5 mmol/l. Values between 0.5 and 1.5
mmol/l are 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 in primary domestic hot water loops
and for heating applications.
-
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 encou-rages destabilisation of copper
hydroxides and enlarge-ment of particles.
-
Electric conductivity 10-600 μS/cm
-
pH: Ideal case pH neutral at 20-25°C (7.5<pH<9).
Charging, adding or draining fluid from the water
circuit must be done by qualified personnel, using
air vents and materials suitable for the products.
The water circuit charging devices are field-
supplied.
Charging and removing heat exchange fluids
should be done with devices that must be included
on the water circuit by the installer.
8.1 - Operating precautions and
recommendations
The water circuit should be designed to have the least number
of elbows and horizontal pipe runs at different levels. Below the
main points to be checked for the connection:
-
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.
-
Use a pressure reducer to maintain pressure in the system
and install a relief valve and an expansion tank.
-
Units include a relief valve.
-
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 flexible connections to reduce vibration transmission.
-
Insulate all pipework, after testing for leaks, to prevent heat
loss.
-
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: A screen filter is installed on the water entering pipes
upstream of the pressure gauge at the unit inlet. It is located
in a position that is easily accessible for removal and
cleaning. The mesh size of the filter is 1.2 mm.
The plate heat exchanger can foul up quickly at the initial
unit start-up, as it complements the filter function, and the
unit operation will be impaired (reduced water flow rate due
to increased pressure drop).
Do not introduce any significant 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. This is also the case for
the products originally supplied by CIAT.
EN-23 AQUACIAT
CALÉO™
TD
