Ventilation unit with heat recuperation
DUOVENT
®
COMPACT RV
23
5.2.11.2 ESU WATER HEATER OR ESUCH WATER COOLER CONTROL UNIT
The ESU or ESUCH unit must be ordered as a separate item because they are not included with the unit.
The mixing control unit is used to control the flow or temperature of heating (cooling) water to the water heaters/coolers. The ESU unit regulates
the heating water temperature at the inlet to the water heater by mixing the inlet water and return line, the ESUCH unit regulates the flow of
cooling water to the water cooler at a constant cooling water inlet temperature. (The designation xx in the type symbol indicates the type of
pump, indicates the Kv value of the mixing valve). The control is provided by a BELIMO servomotor. For control units in conjunction with
Digireg
®
control, it is necessary to use the design B, which features a three-point actuator, designed for control by a Digireg
®
controller.
I
n
addition to power regulation, the control system also provides protection of the water heater against freezing by means of the ESU unit. The
water flowing through the unit may not contain impurities, solid admixtures and aggressive chemicals that damage copper, brass, stainless
steel, zinc, plastics, rubber. The highest permitted operating parameters of the heating water are as follows:
–
–
–
Maximum water tempe110 °C
Maximum water pressure 1 MPa
Minimum water pressure 20 kPa
The water temperature must not fall below the ambient air temperature during operation, as there is a risk of condensation in the pump motor.
The minimum operating water pressure ensures that no air is sucked in by the vent valve, which must be mounted at the highest point of the
water circuit. For the ESUCH unit, it is always necessary to install insulation against condensation of air humidity on the surface of the node on
the entire node (suitable material is e.g. Armaflex).
Layout diagram of ESU node components Layout diagram of ESUCH components:
hot-water
exchanger
cold water
exchanger
The mixing unit is connected to the heater or cooler. The mixing unit must never be loaded by tension and twisting of the connected piping.
Mixing units should be mounted on separate hinges using heating sleeves on the wall, pipes or on an auxiliary structure. When placed under
the ceiling, it is necessary to maintain control and service access to the mixing unit for easy cable connection and service access. The filter
requires regular inspection, maintenance and cleaning. When assembling the node, it is necessary to turn the filter downwards with the sludge
pan. If the position is incorrect, there is a risk of increased clogging/choking of the filter.
Reduced throughput or even blockage of the filter
results in a significant decrease in heater power and increases the risk of frost heater.
Especially during the test operation, it is necessary to
check and clean the sludge pan. If the filter is often clogged, the entire heating circuit must be cleaned. Even during normal operation of the
device, it is necessary to check the filter regularly. When cleaning the filter, all water lines must be closed to minimize water leakage from the
system. Install the mixing unit to enable escape of the air to the heater or boiler circuit vent points. The mixing node must be fixed so that the
pump motor shaft is in a horizontal position. After flooding the system, the circulation pump must be bled according to the manufacturer's
instructions. During connection of the mixing node is is necessary to check correct setting of the valve and actuator. With an assembled mixing
unit, the position of the inner segment of the mixer can be identified by the shoulder on the front of the shaft extension. The perpendicular line
to the mounting surface at the three-way valve points to the axis of the inner segment. For the version with a three-way valve, proceed as
follows. Of the three paths, the valve always has the path to which the bevelled surface on the valve shaft points. With an assembled mixing
unit, the setting can be identified by the notch on the face of the shaft extension. The notch always points to a closed water line - see following
image.
Heating
Mixing
Cooling
Splitting
CAUTION!
!
The design of a suitable mixing unit must be
individually adapted to the conditions of the
application in order to ensure sufficient
valve authority!
