Energy Saving System Pump Control; Hydraulic Circuit Content - Hitecsa EWMIG 236 Manuel D'installation, D'utilisation Et D'entretien

II.6.3

ENERGY SAVING SYSTEM PUMP CONTROL

The unit manages the pump unit, striving for the highest energy savings. When the machine reaches the set point and the regulator detects that the
thermal/cooling load is null, the pump is turned off for a set time (10'). Following regular intervals of time (10'), the pump is turned back on for some
seconds (60"). If, in these situations, it is necessary to activate the compressor, the unit starts generating heating/cooling capacity again. Otherwise, the
pump is turned off to wait for the following cycle. The times can be changed from a parameter under the maintenance menu (see the manual of the
electronic control).
II.6.4

HYDRAULIC CIRCUIT CONTENT

For proper unit operation, a minimum amount of water must be ensured in the hydraulic system. The minimum water content is established on the basis
of the unit's nominal cooling capacity (table A Technical Date), multiplied by the coefficient expressed in l/kW.
If the amount of water in the system is less than the indicated amount, install an additional storage tank.
Standard set-up
The units are installed in systems where the pumping unit and the thermal inertia are provided by the user. The pump must be installed with the
supply pressing against the machine's water intake.
2
3
Pump and Tank & Pump installation
The units are equipped with a pump or with a pump and a buffer tank. The unit's hydraulic circuit is complete with an expansion tank and safety valve,
air bleed and drain valves.
Pump and Tank & Pump with Modulating Pump
○
The units are equipped with an electric pump featuring constant speed control for variable flow rate systems. The unit 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 so that the water flow rate reaches each area, read the differential pressure
value on the control panel. The value is the set-point that is to be assigned to the differential pressure to control. 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 has the function to enable circulation of the minimum flow rate, especially during starting and switch-off transients of the unit
without interrupting flow to the evaporator. The minimum flow rate value is contained in the "Hydraulic data" section.
○
With the electric pump featuring constant speed control it is also possible to effectively manage the start-up while the system is cold, by modulating
the speed, allowing you to reach the operating temperatures more quickly.
Range Adjustment type
EWMIG 236÷260 AdaptiveFunction Plus
SECTION II: INSTALLATION AND MAINTENANCE
Specific capacity
2 l/kW
1
2
3
1
1 Compact-I
1
37
Compact-I
Inertial storage tank (if necessary)
Hydraulic pump