Daikin EUWAC5FBZW1 [7/28] Checking the water circuit
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Daikin EUWAC5FBZW1 [7/28] Checking the water circuit

Daikin EUWAC5FBZW1 [7/28] Checking the water circuit
EUWAC5~10FBZW1
Packaged air-cooled water chillers
4PW61657-1 – 07.2010
Installation and operation manual
4
CHECKING THE WATER CIRCUIT
The EUWAC units are equipped with a water inlet and water outlet for
connection to a chilled water circuit. This circuit must be provided by
a licensed technician and must comply with all relevant European
and national regulations.
Before continuing the installation of the EUWAC, check the following
points:
1 A circulation pump must be provided in such a way that it
discharges the water directly into the evaporator. A voltage-free
contact is provided in the switch box to steer the pump.
2 A flow switch must be installed in the water outlet pipe to prevent
the unit from operating at a water flow which is too low. A
terminal is provided in the switch box for the electrical
connection of the flow switch.
3 A wire mesh strainer must be installed at the pump suction to
protect the pump and the heat exchanger from foreign matter.
The mesh size has to be between 0.5 and 1.5 mm.
4 Drain taps must be provided at all low points of the system to
permit complete drainage of the circuit during maintenance or in
case of shut down.
5 Air vents must be provided at all high points of the system. The
vents should be located at points which are easily accessible for
servicing. The water inlet pipe is specially designed to obtain a
complete air purge of the evaporator.
6 Provide adequate safeguards in the water circuit to make sure
that the water pressure will never exceed the maximum
allowable working pressure.
CONNECTING THE WATER CIRCUIT
Piping connections (water inlet and outlet) must be made from the
right side of the water chiller. (See figure 1)
If air, moisture or dust get in the water circuit, problems may occur.
Therefore, always take into account the following when connecting
the water circuit:
1. Use clean pipes only.
2. Hold the pipe end downwards when removing burrs.
3. Cover the pipe end when inserting it through a wall so that no dust
and dirt enter.
WATER CHARGE, FLOW AND QUALITY
To assure proper operation of the unit, a minimum water volume is
required in the system and the water flow through the evaporator
must be within the operation range, specified in the table below.
The minimum water volume v [kg] in the system should moreover full
fill the criteria below:
The water quality must be in accordance with the specifications listed
in the table below.
PIPING INSULATION
The complete water circuit, inclusive all piping, must be insulated to
prevent condensation and reduction of the cooling capacity. Take into
account the following points when insulating the piping:
1 Provide a separate insulation for the water inlet and the water
outlet piping.
2 Thoroughly insulate around the pipe connections.
3 Use Armaflex material with thickness of 9 mm.
Protect the water piping against water freezing during winter period
(e.g. by using a glycol solution).
Minimum
water flow
Maximum
water flow
EUWAC5 16 l/min 64 l/min
EUWAC8 23 l/min 92 l/min
EUWAC10 28 l/min 112 l/min
v > (Q / 2) x t / (C x y)
Q highest cooling capacity of the unit within the range of
application (kW)
t antirecycling timer of unit (AREC)/2(s)=120 s
C specific heat capacity of the fluidum (kJ/kg°C)=4.186 kJ/kg°C for
water
y steplength (°C)
standard setting=3°C
(refer to the chapter “Operating the unit” for adjustments)
circulating
water
supply water
tendency if out
of criteria
Items to be controlled
pH at 25°C 6.8~8.0 6.8~8.0 corrosion + scale
Electrical conductivity [mS/m]
at 25°C
<40 <30 corrosion + scale
Chloride ion
[mg Cl
-
/l]
<50 <50 corrosion
Sulphate ion
[mg SO
4
2-
/l]
<50 <50 corrosion
M-alkalinity (pH4.8)
[mg CaCO
3
/l]
<50 <50 scale
Total hardness
[mg CaCO
3
/l]
<70 <70 scale
Calcium hardness
[mg CaCO
3
/l]
<50 <50 scale
Silica ion
[mg SiO
2
/l]
<30 <30 scale
Items to be referred to
Iron [mg Fe/l] <1.0 <0.3 corrosion + scale
Copper [mg Cu/l] <1.0 <0.1 corrosion
Sulphide ion
[mg S
2-
/l]
not detectable not detectable corrosion
Ammonium ion
[mg NH
4
+
/l]
<1.0 <0.1 corrosion
Remaining chloride [mg Cl/l] <0.3 <0.3 corrosion
Free carbide
[mg CO
2
/l]
<4.0 <4.0 corrosion
Stability index ——corrosion + scale
The water pressure should not exceed the maximum work-
ing pressure of 10 bar.
NOTE
Provide adequate safeguards in the water circuit to
make sure that the water pressure will never exceed
the maximum allowable working pressure.
4PW61657-1_digital_EN.book Page 4 Friday, August 27, 2010 8:09 AM

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