25
All copying, even partial, of this manual is strictly forbidden.
RG66007970 - Rev 01
12
WaTeR CIRCUIT
When setting up the water circuit of the unit, it is advisable to follow the directions below and in any case comply with local or national regulations�
Connect the pipes to the chiller using flexible couplings to prevent the transmission of vibrations and to compensate thermal expansions�
It is recommended to install the following components on the pipes:
-
temperature and pressure indicators for routine maintenance and monitoring of the unit� Checking the pressure on the water side will enable you to verify
whether the expansion tank is working efficiently and to promptly detect any water leaks within the equipment�
-
Traps on incoming and outgoing pipes for temperature measurements, which can provide a direct reading of the operating temperatures�
-
Regulating valves (gate valves) for isolating the unit from the water circuit�
-
Metal mesh filter (supplied), with a mesh size no greater than 1 mm, to be fitted on the inlet pipe to protect the exchanger from scale or impurities
present in the pipes.
-
Air vent valves, to be placed at the highest points of the water circuit for the purpose of bleeding air� The internal pipes of the unit are fitted with small
air vent valves for bleeding the unit itself� This operation may only be carried out when the unit is disconnected from the power supply�
-
Drainage valve and, where necessary, a drainage tank for emptying out the equipment for maintenance purposes or when the unit is taken out of serv-
ice at the end of the season� A 1” drainage valve is provided on the optional water buffer tank: this operation may only be carried out when the unit is
disconnected from the power supply�
It is of fundamental importance that the incoming water supply is hooked up to the connection marked “Water Inlet”�
otherwise the evaporator would be exposed to the risk of freezing since the antifreeze thermostat would not be able to perform its function; moreover the
reverse cycle would not be respected in the cooling mode, resulting in additional risks of malfunctioning�
The dimensions and position of plumbing connections are shown in the dimension tables at the end of the manual�
The water circuit must be set up in such a way as to guarantee that the nominal flow rate of the water supplied to the evaporator remains constant (+/- 15%)
in all operating conditions�
A standard feature of MPI DC units is a device for controlling the flow rate (flow switch or differential pressure switch) in the water circuit in the immediate
vicinity of the evaporator�
12.1
WaTeR COnTenT WIThIn The SySTeM anD ChaRGInG OF eXPanSIOn TanK
In models without buffer tank it is necessary to assure that the content of water within the system does not fall below 4�5 litres/kW in the case of heat pump
models� This level is necessary to prevent the water temperature from falling below the indoor unit enabling threshold during defrost cycles�
n.B. kW in reference to rated capacity
The expansion tank is pre-charged to a pressure of 1�5 bars, sufficient for systems with a maximum height difference (H in the figure at the side) of 13 metres�
For greater height differences, refer to the table below in order to adjust the charging pressure of the expansion tank accordingly�
In no case should you exceed the maximum height difference Hmax = 35 m�
leGenD
h
Height difference of system
p
i
Charging pressure of expansion tank
C
max
Maximum system water content
Models
h
(m)
p
i
(bar)
C
max
(l)
MPI DC 08-029
<13
1,5
145
15
1,7
133
20
2,2
105
25
2,7
77
30
3,1
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