7.2 - Water connections
Make the plate heat exchanger hydraulic connections with
the necessary components, using material which will
guarantee that the screwed joints are leakproof.The typical
hydraulic circuit diagram shows a typical water circuit
installation in an air conditioning system.
For an application with a water circuit, the following
recommendations must be taken into account:
1. The eventual additional pump must be fitted
immediately before of the heat exchanger and after the
connection to the system return (unit without hydronic
module).
2. It is advisable to install shut-of valves to allow isolation
of the most important circuit components, as well as
the heat exchanger itself.
These valves (ball, globe or butterly valves) should
produce a minimum loss of charge when they are open.
3. Provide unit and system drains and vents at the lowest
system point.
4. Install purges in the higher sections of the installation.
5. Pressure ports and pressure gauges should be installed
upstream and downstream of the eventual additional
water pump.
6. All piping must be adequately insulated and supported.
Installation of the following components is obligatory:
1. The presence of particles in the water can lead to
obstructions in the heat exchanger.
It is therefore necessary to protect the heat exchanger
inlet with an extractable mesh filter. The filter mesh
opening must be at least 0.8 mm.
2. After assembling the system, or repairing the circuit,
the whole system must be thoroughly cleaned with
special attention paid to the state of the filters.
3. When water has to reach temperatures below 5°C, or
the equipment is installed in areas subject to
temperatures below 0°C, it is necessary to mix water
with inhibited ethylene glycol in suitable quantity.
4. If the unit is kept switched off during the winter period
at ambient temperatures below 0 °C and no glycol is
used in the hydraulic circuit, it is recommended to
drain the entire system through the discharge port (
point 3 in Figure 8).
7.2.1 - Anti-seizing pump
The 30RB___-9 units are equipped with protection
againstthe seizing of the pump motor shaft. To allow this
function,do not empty the system or disconnect the power
duringlong periods of inactivity.
In any case, if the pump rotor shaft seizes after a long
periodof inactivity, the user must do the following to
unblock (only 12-15 kW):
•
Disconnect the power
•
Remove the front panel
•
Unscrew the shaft-protection plug on the back of the
pump
•
Insert a screwdriver in the slot and turn the rotor
shaft
•
Remount the protection plug
•
Reconnect the power
7.2.2 - System cleaning and Water Characteristics
In the case of a new installation, or cleaning the circuit, itis
necessary to perform a preventive cleaning of the system.
In order to guarantee the good operation of the
product,each time you clean the system, replace the water
or addglycol.
Carrier recommendations on heat exchange luids:
•
No NH
ammonium ions in the water, they are very
4+
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 10 mg/l.
•
SO
sulphate ions can cause perforating corrosion, if
4–
their content is above 30 mg/l.
•
No fluoride ions (<0.1 mg/l).
•
No Fe
and Fe
ions with non negligible levels of
2+
3+
dissolved 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 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.
•
Specific resistance - electric conductivity: the higher
the specific resistance, the slower the corrosion
tendency. Values above 30 Ohm·m are desirable.
A neutral environment favours maximum specific
resistance values. For electric conductivity values in
the order of 20-60 mS/m can be recommended.
•
pH: Ideal case pH neutral at 20-25°C (7 < pH < 8).
pipe water content
Internal diameter
outer diameter
copper
12 mm
14 mm
14 mm
16 mm
16 mm
18 mm
20 mm
22 mm
25 mm
28 mm
32 mm
35 mm
steel
"12.7 mm (1/2")"
3/8" Gas
"16.3 mm (5/8")"
1/2" Gas
"21.7 mm (7/8")"
3/4" Gas
"27.4 mm (11/16")"
1" Gas
unit
Nominal water flow
Water contentsystem unit with expansion
vessel
Working pressure
Filling pressure
liters / meter
0.11 l/m
0.15 l/m
0.20 l/m
0.31 l/m
0.49 l/m
0.80 l/m
0.13 l/m
0.21 l/m
0.37 l/m
0.59 l/m
30rB
008_
012_
015_
Std
l/s
0,38
0.52
0.62
Min
l/s
0,12
0.12
0.12
Min
l
28
42
52
Max
l
100
100
100
Max
kPa
300
300
300
Min
kPa
120
120
120
19