EN 1488 pdf free download

EN 1488 pdf free download.Building valves-Expansion groups – Tests and requirements.
3.1 expansion group controls and limits the increase in fluid pressure, due to the normal increase in volume when water is heated, contained in a hot water heater, prevents the backflow of the heated water into the circuit and the contamination of water contained in the water heater with discharged water. An expansion group comprises, at least the following items in a single unit, in an upstream to downstream order as shown in table 1. 3.2 isolating valve allows the heated water produced to be isolated from the drinking water supply. If a second valve is to be fitted, it shall be between the check valve and the expansion valve. 3.3 check valve allows water to flow in the cold to hot direction when fitted to a water heater, and automatically prevents heated water returning to the cold water supply. 3.4 expansion valve limits the pressure of the water in the water heater to a predetermined value (valve) by discharging water to drain. 3.5 drain device allows the water heater to be drained without it having to be removed. The outlet connection is also used to discharge water from the expansion valve. 3.6 air gap prevents discharged water from returning to the expansion group and thus to the water heater. 3.7 pressure tapping allows pressure measuring equipment to be connected. 3.8 nominal set pressure (Pnmr) is the pressure of the expansion valve, which is set on production. 3.9 water tightness pressure (Pe) is the pressure up to which the expansion valve is closed (see figure 1). 3.10 initial opening pressure (Pdc) is the pressure at which the expansion valve opens for the first time, after a period of storage (see figure 1). 3.11 opening pressure (Po) is the pressure at which a flow rate of 2,4litres/hous of water is attained (see figure 1). 3.12 rating pressure (Pdn) is the pressure at which the water discharge capacity of the expansion valve corresponds to the rated flow (see figure 1 and table 7).4 Materials and surface finishes 4.1 General The selection of materials is the responsibility of the manufacturer, provided they satisfy the following requirements: a) Materials and coatings shall not contaminate the drinking water, when in normal or accidental contact, b) In a technical document, the manufacturer shall state the nature of the materials and coatings used. c) Materials with inadequate corrosion resistance shall have additional protection, d) The materials used shall not deteriorated at a temperature of95C for 1 hour and be suitable under the temperatures specified in the tests in this Standard, and e) The components making up the check valve shall be of a material resistant to scale formation. 4.2 Nature of materials Examples of bronze and brass, which may be used, without coating, for manufacturing purposes are given in table 2.6.3.1 Tightness test for the isolating valve at a pressure of 1.6 MPa (16 bar) Procedure: Connect the expansion group to a test circuit, the expansion group s water heater connction being open and turned down. Close the expansion group s isolating valve and apply upstream of the seat a water pressure of 1.6 MPa (16 bar) for a period of 60 s. Requirement: There shall be no discharge or leakage. 6.3.2 Expansion group tightness test 6.3.2.1 Procedure where the isolating valve stem is not sealed by an‘O’ ring Procedure: Connect the expansion group to a test circuit, close the expansion group’s water heater connection, maintain the expansion valve disc closed and open the isolating valve. Apply a water pressure of 1.6 MPa (16 bar) to the inlet connection of the expansion group for a period of 60 s. Requirement: There shall be no leakage of the expansion group body. 6.3.3.2 procedure where the isolating valve stem is sealed by an‘O’ ring Procedure: Connect the expansion group to a test circuit, close the expansion group’s water heater connection, maintain the expansion valve disc closed and open the isolating valve. Apply for 60 S a water pressure of 0.02 MPa (0.2bar) to the inlet connection of the expansion of the expansion group and then a water pressure of 1.6 MPa (16 bar) for a period of 60 s. Requirement: There shall be no leakage from the expansion group body.EN 1488 pdf download.