Water Connections - Riello NXHP Series Installation, Operation And Maintenance Instructions

2 - INSTALLATION OF UNIT
2.2.4 - Checks before system start-up
Before the start-up of the refrigeration system, the complete
installation, including the refrigeration system must be verified
against the installation drawings, dimensional drawings, system
piping and instrumentation diagrams, and wiring diagrams.
For these checks national regulations must be followed.
External visual installation checks:
■ Ensure that the machine is charged with refrigerant. Verify on
the unit nameplate that the 'fluid being transported' is R-290
and is not nitrogen.
■ Compare the complete installation with the refrigeration system
and power circuit diag rams.
■ Check that all components comply with the design specifications.
■ Check that all protection documents and equipment provided
by the manufacturer (dimensional drawings, P&ID, declarations
etc.) to comply with the regulations are present.
■ Verify that the environmental safety and protection and devices
and arrangements provided by the manufacturer to comply with
the regulations are in place.
■ Verify that all documents for pressure containers, certificates,
name plates, files, instruction manuals provided by the
manufacturer to comply with the regulations are present.
■ Verify the free passage of access and safety routes.
■ Verify the instructions and directives to prevent the deliberate
removal of refrigerant gases.
■ Verify the installation of connections.
■ Verify the supports and fixing elements (materials, routing and
connection).
■ Verify the quality of welds and other joints.
■ Check the protection against mechanical damage.
■ Check the protection against heat.
■ Check the protection of moving parts.
■ Verify the accessibility for maintenance or repair and to check
the piping.
■ Verify the status of the valves.
■ Verify the quality of the thermal insulation and of the vapour
barriers.

2.3 - 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 use of flexible tubing is mandatory to limit the forces applied
to the heat exchanger connectors.
The water supply must be analysed and appropriate filtering,
treatment, control devices, shut-off and bleed valves and circuits
built in, to prevent corrosion (example: damage to the protection
of the tube surface if the fluid is polluted), fouling and deterioration
of the pump fittings.
Before any start-up verify that the heat exchange fluid is compatible
with the materials and the water circuit coating.
In case additives or other fluids than those recommended by the
manufacturer are used, ensure that the fluids are not considered
as a gas.
Recommendations on heat exchange fluids:
■ No NH ammonium ions in the water, they are very detrimental for
4+
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
10 mg/l.
■ SO sulphate ions can cause perforating corrosion, if their
2-
4
content is above 30 mg/l.
■ No fluoride ions (<0.1 mg/l).
■ No Fe and Fe ions with non negligible levels of dissolved
2+ 3+
oxygen must be present. Dissolved iron < 5 mg/l with dissolved
oxygen < 5 mg/l.
■ Dissolved silicon: silicon is an acid element of water and can
also lead to corrosion risks. Content < 1mg/l.
■ Water hardness: >0.5 mmol/l. Values between 1 and 2.5
mmol/l 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 title (TAC)
below 100 mg/l 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: 0.001-0.06 S/m (10-600 µS/cm).
■ pH: Ideal case pH neutral at 20-25°C (7 < pH < 8).
CAUTION:
Charging, adding or draining fluid from the water circuit must
be done by qualified personnel, using air vents and materials
suitable for the products. Water circuit charging devices are
field-supplied.
The installation of an automatic air vent on the water loop
leaving the unit is mandatory. This air vent must be situated
on a well ventilated area without ignition source.
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.
CAUTION:
The use of units in an open water loop is forbidden. Do not
use the water loop of the unit to heat directly the pool water.
Use a well design water echanger and all the safety component
necessary on the pool system.
2.3.1 - 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.
■ All purges must be installed in an igntion source free
environment.
■ Make sure that no water above 75 °C can enter the unit water
circuit at any time during operation or maintenance.
■ Use a pressure reducer to maintain pressure in the circuit(s)
and install a relief valve as well as an expansion tank. Units
include a relief valve.
■ 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, both to reduce
thermal leaks and to prevent condensation.
■ Use thermal tape to seal joints and to seam the insulation.
23