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Expansion vessels



Expansion vessels preloaded with replaceable membranes suitable to be installed in cold and hot water installations.
Manufactured according European Directive 97/23/CE for pressure vessels, two dish ends joined by welding process and procedures by homologated staff.
Models  DP/VA, DP/VAV y DP/VAO, are manufactured, tested, checked and verified by Mecalia.
Models DP/VA and DP/VAV for vertical position and DP/VAO for horizontal position

ApplicationsExpansion vessels models DP/VA, DP/VAV and DP/VAO are designed for cold and hot water installations,allowing the absorbing the volume rise caused by the increase of temperature in water, avoiding that pressure of the circuit exceeding the nominal pressu


Working Pressure: 10 bar
Max. Working Temp.: -10ºC up to +100ºC
Membrane: EPDM Replaceable
Marked: CE according Directive PED 97/23/CE.
Composition: Galvanized steel flange with internal polypropylene protection in the area in ​​contact with water.
Mixing: Hot or cold water
Colour: Blue RAL 5015 up to 500 lt and red RAL 3000 for 750 lt.
Operation: Once connected the expansion vessel to the circuit to which is intended, the pumps start to raise the pressure letting the water filling the membrane (image 1). The replaceable membrane avoids the contact between the air and the water, preventing any pressure loss, contamination or corrosion. The pump stops when the pressure reaches its maximum threshold value. There is the greatest quantity of water inside the tankk. The membrane is dilated and is occupies almsot all volume of the tank. If the installation requires it, the water starts flowing out of the tank without using the pump, using presure of the air that is inside the presurized chamber (image 2). The water continues flowing out, the membrane deflates until the presssure reaches the minimal pressure of the installation. At this state, the membrane is back to its initial dimensions, the pump starts again and a new cycle begins (image 3). When cold water is used, the quantity of water is the maximum possible for each moment, so pump insertions are reduced to the minimum. At the moment of setting up the vessel, the following points should be kept in mind: * Before proceeding to the installation, make sure that the expansion vessel volume has been calculated by authorized staff. * The expansion vessel must be placed on and inlet pipe of cold water, between the safety unit and the hot water producer, or the cold water network. * There must be no device which can close the connection between the expansion vessel and the hot water producer. *Avoid radiations near the expansion vessel to protect membrane against the possible rises in temperature. * The expansion vesssel will be installed in such way that airbeds cannot be produced. * For expansion vessel bigger or equal than 200 lt, a manometer or a cap must be installed on connection 7.
Maintenance: Maintenance must be carried out exclusively by authorized staff. At least once every six months, check through the inflating valve that pressure is correct. The measurement of these values ​​must be carried out with the water cold and depressurized. Never disassemble the vessel without having previously depressurized the installation. Standard pressure should be regular and adjusted according installation. When filling with water, make sure that the pressure indicated on the pressure gauge is slightly higher than the static pressure of the installation. Keep the installation at the maximum working temperature for half a day, remove the air from the system replacing it with water. Protect the vessel from weather inclemences.
Advantages: Water hammer decrease. Reduction of the consumption of water and electrical energy, due to the safety group, avoiding water leaks.