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12. In the event that glycol is added to the water system as anti-freeze protection, pay attention to the fact that suction pressure will be
lower, the unit's performance will be lower and water pressure drops will be greater. All unit-protection systems, such as anti-freeze,
and low-pressure protection will need to be readjusted.
13. Before insulating water piping, check that there are no leaks.
5.8 Water treatment
Before putting the unit into operation, clean the water circuit.
The evaporator must not be exposed to flushing velocities or debris released during flushing. It is recommended that a
suitably sized bypass and valve arrangement is installed to allow flushing of the piping system. The bypass can be used
during maintenance to isolate the heat exchanger without disrupting flow to other units.
Any damage due to the presence of foreign bodies or debris in the evaporator will not be covered b y warranty.
Dirt, scales, corrosion debrits and other material can accumulate inside the heat exchanger and reduce its heat exchanging
capacity. Pressure drop can increase as well, thus reducing water flow. Proper water treatment therefore reduces the risk
of corrosion, erosion, scaling, etc.. The most appropriate water treatment must be determined locally, according to the type
of system and water characteristics.
The manufacturer is not responsible for damage to or malfunctioning of equipment caused by fa ilure to treat water or by
improperly treated water.
DAE Water quality requirements
Ph (25 °C)
Electrical conductivity [μS/cm] (25°C)
Chloride ion [mg Cl- / l]
Sulphate ion [mg SO42- / l]
Alkalinity [mg CaCO3 / l]
Total Hardness [mg CaCO3 / l]
Iron [mg Fe / l]
Ammonium ion [mg NH4+ / l]
Silica [mg SiO2 / l]
Chlorine molecular (mg Cl2/l)
5.9 Evaporator and recovery exchangers anti-freeze protection
All evaporators are supplied with a thermostatically controlled anti-freeze electrical resistance, which provides adequate
anti-freeze protection at temperatures as low as
However, unless the heat exchangers are completely empty and cleaned with anti-freeze solution, additional methods
must also be used against freezing.
Two or more of below protection methods shall be considered when designing the system as a whole:
−
Continuous water flow circulation inside piping and exchangers
−
Addition of an appropriate amount of glycol inside the water circuit
−
Additional heat insulation and heating of exposed piping
−
Emptying and cleaning of the heat exchanger during the winter season
It is the responsibility of the installer and/or of local maintenance personnel to ensure that described anti-freeze methods
are used. Make sure that appropriate anti-freeze protection is maintained at all times. Failing to follow the instructions
above could result in unit damage. Damage caused by freezing is not covered by the warranty.
5.10
Installing the flow switch
To ensure sufficient water flow through the evaporator, it is essential that a flow switch be installed on the water circuit.
The flow switch can be installed either on the inlet or outlet water piping. The purpose of the flow switch is to stop the unit
in the event of interrupted water flow, thus protecting the evaporator from freezing.
The manufacturer offers, as optional, a flow switch that has been selected for this purpose.
This paddle-type flow switch is suitable for heavy-duty outdoor applications (IP67) and pipe diameters in the range of 1" to
8".
The flow switch is provided with a clean contact which must be electrically connected to terminals shown in the wiring
diagram.Flow switch has to be tune to intervene when the evaporator water flow is lower than 50% of nominal flow rate.
5.11
Heat recovery
Units may be optionally equipped with heat recovery system.
Table 1 - Acceptable water quality limits
Shell&tube
.
-16°C.
BPHE
7.5 – 9.0
6.8 ÷ 8.4
< 800
< 500
< 70 (HP1);
< 150
< 300 (CO2)
< 100
< 100
< 100
< 200
< 200
75 ÷ 150
< 1
< 0.2
< 1
< 0.5
< 50
NO
< 5
< 0.5
D–EIMAC01502–18_03EN - 17/25
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