Vertiv Liebert HPC-M Serie Manuel De Service page 6

3 --- Installation
3.1 --- Hydraulic connections
3.1.1 --- Hydraulic circuit construction (Fig. b)
The piping must be connected to the chiller as shown in
Fig. 2. Construct a chilled water circuit as described be-
low, see Fig. b:
1) Place shut---off valves within the circuit to allow servic-
ing.
2) Install a pump system calculated for the flow rate re-
quired at a pressure head equal to the sum of all the
pressure drops (see project data).
The refrigerating units can be equipped, upon request,
with pumps having delivery and head as indicated in
Tab.6.
3) Install manometers at the chiller inlet/outlet.
4) Install thermometers at the chiller inlet/outlet.
5) Connect the pipes to the chiller by flexible joints to
avoid transmitting vibrations and to balance the ther-
mal expansion; proceed in the same way as with the
pump assembly outside the chiller.
6) It is useful to include a water pressure switch to give an
early warning of low water pressure.
7) Place a mesh filter at the inlets of the pump and of the
water chiller
8) Install, at the highest points in the circuit, apparatus
which allows the bleeding of air and also the filling of
glycol.
9) Place a drain valve at the lowest points in the circuit.
10)Install a water fill group including the following:
a) filling meter;
b) manometer
c) non return valve
d) air separator
e) removable supply tube, which must be disconnected
after each charge/topping up.
11)For maximum protection ensure that all tubing ex-
posed to low outdoor temperatures is fitted with anti----
freeze heaters and insulated using closed cell synthetic
rubber (elastomer).
12)The circuit must include an expansion tank (with safe-
ty valve) with suitable capacity.
Note:
If the water chiller is complete with the expansion tank
(supplied as an option), check if the capacity is enough or
possibly install a second tank in the circuit (see par. 8.3).
Follow the indications in Fig. d for the correct sizing.
Note:
The whole circuit must contain a water volume suitable for
the capacity of the installed refrigerating unit. Check if the
inertial capacity given by the sum of the hydraulic volume
inside the machine and the system volume is sufficient, or
possibly install a tank in the circuit. Follow the indications
in Fig. c for the correct sizing.
Note:
The hydraulic circuit must ensure a constant water deliv-
ery to the evaporator in every operating condition. Other-
wise, the compressors can break due to repeated returns
of liquid refrigerant on their suction.
Note:
In the chiller with pumps and in all freecooling units, water
quality has to be in accordance with VDI 2035.
3.1.2 --- Additional of water and ethylene glycol
Very Important:
Add water and ethylene glycol in the circuit with a % de-
pending on the min. temperature of the outside air ex-
pected in the installation site. Do not exceed the nominal
operating pressure of the circuit's components.
Notes:
S To avoid stratification run the circulation pump for at
least 30 mins. after adding any glycol.
If the pumps are fitted on the chiller, they have to be
run all together.
S Water glycol fluid mixture has to be circulated inside
the chiller hydraulic parts including freecooling coils
and by---pass pipes; in order to do it move the 3---way
valve on both positions for the time necessary.
S After adding water to the hydraulic circuit always dis-
connected the water supply coming from the sanitary
circuit; this avoids the danger of glycol entering the
sanitary water circuit.
S After any topping---up of water check the concentra-
tion and add glycol if necessary.
3.1.3 --- Water--- glycol mixture
Water---glycol mixtures are used as the thermal carrier
fluid in very cold climates or with temperatures below zero
degrees centigrade.
Determine the % ethylene glycol which must be added to
the water, with the assistance of Tab. a.
Tab. a --- Ethylene glycol to be added to water (% in weight
of total mixture)
Ethylene glycol
(% in weight)
Freezing tempera-
o
ture, C (*)
Mixture density at
o
20 C (*), kg/l
(*) Values are for Shell antifreeze 402. For different brands, check
manufacturer's data.
For the water charges in the circuit refer to the Tab.1 In-
ternal hydraulic volume. If the buffer tank is installed on
the machine, add the tank hydraulic volume.
ALWAYS CHARGE THE HYDRAULIC CIRCUIT
WITH THE REQUIRED GLYCOL % NECESSARY
FOR THE MIN. AMBIENT TEMPERATURE OF THE
INSTALLATION SITE, FAILING TO COMPLY WITH
THIS INSTRUCTION SHALL INVALIDATE THE
UNIT WARRANTY.
3.2 --- Connection of the safety valve discharge
On the refrigerating circuit safety valves are installed on
the high and low pressure sides: the discharge of these
valves must be conveyed outside through a suitable pipe,
having a diameter of at least that of the valve discharge,
without burdening the valve body; convey the discharge to
areas where the jet cannot harm people.
English
0 10 20 30
0 ---4.4 ---9.9 ---16.6
--- 1.017 1.033 1.048
40 50
---25.2 ---37.2
1.064 1.080
3