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Send emailThe distribution node is used to control the flow of cooling water to MKW (IKW) water chillers. The nodes are designated ESUCH Cxx-Vyy A, where xx in the type designation indicates the pump type and yy indicates the "kVS" value of the distribution valve. The valve control is provided by a BELIMO actuator. It is supplied in version "A" with a 0-10 V analogue controlled actuator.
The external control system provides continuous control of the water chiller output by changing the cooling water flow to the water chiller (so-called quantitative control method) using a 0-10 V signal. The water flowing through the node must not contain impurities, solid impurities and aggressive chemical substances that disturb copper, brass, stainless steel, zinc, plastics, rubber. The permitted operating parameters are as follows:
- maximum operating temperature of the medium +105 °C
- minimum operating temperature of the medium -10 °C
- maximum water pressure 1 MPa
- minimum water pressure 20 kPa
- maximum relative humidity of the ambient air (non-condensing environment) 90 % r. v.
- max. ethylene glycol concentration 40 %
- max. propylene glycol concentration 40 %
- ambient temperature range at the node installation site 0 °C ÷ 50 °C
The minimum operating water pressure ensures that no air is drawn in through the bleeder valve, which must be fitted at the highest point of the water circuit. When designing the location of the ESUCH node, we recommend the following principles:
- follow the manufacturer's instructions for the application of the water cooler
- the distribution node must always be fixed so that the pump motor shaft is in a horizontal position
- the distribution node must be in such a position as to ensure that it can be vented later
- when located in the ceiling, inspection and service access to the distribution node and the vent valve must be maintained
Dimensions and materials
Distribution nodes are manufactured in a range of nine sizes, which vary by pump type, three-way valve size and connection pipe diameter. The cooling water connection is unified on 22 and 28 mm diameter copper pipe. The flow rate and pressure drop of the distribution node is determined by the size of the control valve (kVS in the range of 0.6 to 16).
Performance
The distribution node is equipped with two ball valves at the inlet to ensure that the cooling circuit can be disconnected during repairs. On the connection side to the water cooler, the junction is fitted with flexible steel hoses to allow easy adjustment to the water cooler inlet spacing. The entire junction is thermally insulated with 13 mm thick Armaflex insulation. The Grundfos pump is fitted with an external insulation cover. A filter with a removable and cleanable filter insert is located between the inlet ball valve and the pump. The three-way valve is controlled by a BELIMO servo drive of type HT series. The distribution node is exclusively equipped with a servo drive HT 24-SR-T, which is designed for continuous control (control by analogue signal 0 to 10 V). The supply voltage of the HT 24-SR-T actuator is AC/DC 24 V.
The ESUCH unit is available in 2 versions:
- with pump - ESUCH Cxx Vyy A
- without pump - ESUCH C00 Vyy A
Regulation
The distribution node is installed in front of the water cooler. The pump ensures the circulation of water through the water cooler when there is insufficient pressure potential in the central chilled water distribution system. When maximum water chiller capacity is required, all cooling water flows through the water chiller. In the case of a minimum chiller capacity requirement, a portion of the three-way valve at the water outlet of the water chiller is closed and cooling water flows from the inlet through the three-way valve to the return (in this case the cooling water flow through the water chiller is equal to 0 m3/h). When partial chiller output is required, part of the water is discharged into the water chiller and part of the water is returned to the return line of the chilled water distribution system.
Assembly and Maintenance
The distribution node is connected to the chiller. The manifold must never be subjected to stresses and twisting of the connected pipework. Distribution nodes should be mounted on separate hangers using heating sleeves on the wall, pipe or an auxiliary structure. When located below the soffit, inspection and service access to the junction must be maintained for easy cable connection and possible maintenance. When installing the node, the filter must be turned with the drip pan down. If the filter is not positioned correctly, there is a risk of increased clogging and blockage of the filter. Reduced filter patency or even impassability results in a significant reduction in cooler performance.
Particularly during test operation, the filter drain pan should be checked and cleaned. If the filter is frequently clogged, the entire cooling circuit must be cleaned. Even during normal operation, the filter must be checked regularly. When cleaning the filter, it is necessary to close all water paths to minimize water leakage from the system. Always install the distribution unit so that air can escape to the water cooler vent points or the entire cooling circuit.
The manifold must always be mounted with the pump motor shaft in a horizontal position.
After the cooling water distribution system has been watered, the circulator must be vented according to the manufacturer's (Grundfos) instructions. On each pump, the speed (pump characteristics) can be switched by means of a button on the front.
Information
For larger valve sizes (kVS = 25 or 30) please contact the technical department of ELEKTRODESIGN Fans, Ltd. For these larger dimensions, a separate delivery of the three-way valve and pump in flanged version is possible for the purpose of installation in the cooling water distribution system by the installer. It is no longer possible to attach the nodes of these larger dimensions to the air handling unit.