Water Connections; Connection To The System - Hitecsa EWMIM 117 Mode D'emploi

II.6

WATER CONNECTIONS

II.6.1

CONNECTION TO THE SYSTEM

IMPORTANT!
The layout of the water system and connection of
the system to the unit must be carried out in
conformity with local and national rules in force.
IMPORTANT!
It is advisable to install shut-off valves that isolate
the unit from the rest of the system. Mesh filters
with a square section (longest side = 0.8 mm), of a
suitable size and pressure drop for the system,
must be installed. Clean the filter from time to time.
IMPORTANT!
The expansion tank on the machine is sufficient to
protect the unit. The installer is in charge of sizing
and installing the system's expansion tank.
○ The unit is equipped with male threaded hydraulic connections and
manual air vent valve placed inside the cabinet.
○ It is advisable to install cut-off valves that isolate the unit from the
rest of the system and elastic connection joints.
○ It is mandatory to install a square metal mesh filter (longest side =
0.8 mm) of adequate size and pressure drops for the system on the unit
return pipes.
○ The expansion tank on the machine has limited capacity to protect
the hydraulic circuit inside the machine.
○ The rate of the water that flows through the heat exchanger must not
drop below the value corresponding to a temperature differential of 8°C.
○ During long periods of inactivity, it is advisable to drain the water
from the system.
○ It is possible to avoid draining the water by adding ethylene glycol to
the water circuit (see Protecting the unit from frost).
PUMP installation P0/ASP0
o The units are equipped with a 3-speed electronic circulator, which
can be selected from the selectors on board. The maximum speed it set
by default. The unit's hydraulic circuit is complete with an expansion
tank and safety valve, air bleed and drain valves.
Example with a 3-way valve on the last terminal
PUMP P1/ASP1 installation
o The units are equipped with a hydraulic pump at a fixed speed for
systems where higher head than the nominal flow rates is required. The
unit's hydraulic circuit is complete with an expansion tank and safety
valve, air bleed and drain valves.
PUMP installation PI0/ASPI0
○ The units are equipped with an electronic circulator with continuous
speed regulation for variable flow rate systems. The units is complete
with a sensor to measure the pressure difference between the system's
flow and return pressure. During the installation phase, the unit must be
set by following the simple procedure. With the system completely open
(all terminals open) so that the water flow rate reaches each area, the
automatic machine calibration process must be started from the
relevant screen on the control panel. The self-calibration procedure
allows the machine to automatically set the differential pressure value
that must be maintained. The process is fully automatic and you must
only follow the instructions that appear on the control panel. In the case
of system partialisation with the terminals or areas closed, the pressure
differential value is kept constant by decreasing the flow rate. The unit's
hydraulic circuit is complete with an expansion tank and safety valve, air
bleed and drain valves.
○ For proper operation of the unit with this type of system set-up, you
must comply with the basic rule, meaning that there must always be a
circuit branch that enables circulation of water. This can be obtained
with a type of board like the one indicated in the figure, meaning with
one of the terminals equipped with a 3-way valve whilst all the
remaining ones can be equipped with a 2-way shut-off valve.
Alternatively, there can be a bypass located in a certain point of the
hydraulic circuit. It is recommended to place the bypass or 3-way valve
as far away as possible from the unit. The bypass enables circulation
with the minimum flow rate, especially during the transitory unit start-up
and switch-off without interrupting the flow to the evaporator.
o With the circulator operating with continuous regulation, it is also
possible to start-up a cold system by modulating the speed and
enabling it to reach the operating temperature more rapidly.
Example with a Bypass on the circuit
P0/PI0/P1
Once the connections to the unit are made, check that none of the
pipes leak, and bleed the air from the system. The rate of the water that
flows through the heat exchanger must not drop below the value
corresponding to a temperature differential of 8°C. The minimum flow
rate to be guaranteed to the machine is 1450 l/h. If the flow rate drops
below this value, the flow alarm may be triggered.
29
SECTION II: INSTALLATION AND MAINTENANCE
P0/PI0/P1