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.
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.