MEASUREMENT RANGE AND MAXIMUM TOLERATED ERROR
As requested by the 2004/22 / EC (MID) Directive and by the norm EN14154, the measuring range of a water meter is determined by the ratio between the value of its permanent flow rate (Q3) and the one of the minimum flow rate (Q1). The meter can measure for short periods, without deteriorating, at the maximum flow rate (Q4).
As an example, if we find reported on the dial of a meter the information Q3 = 2.5 m3 / h R100H, R50V, this means that this meter can be used, when installed horizontally, up to a minimum flow rate of 25l /h while, if installed vertically, up to a minimum flow rate of 50l / h.
The overload flow is always 1.25 * Q3, in this case therefore, equal to 3,125m3 / h.
The MPE, positive or negative, on volumes between the transitional flowrate (Q2) (included) and the overload flowrate (Q4) is:
2% with a water temperature ≤ 30 ° C
3% with a water temperature > 30 ° C.
The MPE, positive or negative, on volumes between the minimum flowrate (Q1) and the transitional flowrate (Q2) (excluded) is equal to 5% regardless the water temperature.