ANNEX VIU.K.
SPECIFIC REQUIREMENTSU.K.
1. Rated operating conditions U.K.
The values of the rated operating conditions shall be specified by the manufacturer as follows:
For the temperature of the liquid: θmax, θmin,
for the temperature differences: Δθmax, Δθmin,
subject to the following restrictions: 
For the pressure of the liquid: The maximum positive internal pressure that the thermal energy meter can withstand permanently at the upper limit of the temperature.
For the flow rates of the liquid: qs, qp, qi, where the values of qp and qi are subject to the following restriction: 
For the thermal power: Ps.
2. Accuracy classes U.K.
The following accuracy classes are defined for thermal energy meters: 1, 2, 3.
3. MPEs applicable to complete thermal energy meters U.K.
The maximum permissible relative errors applicable to a complete thermal energy meter, expressed in percent of the true value for each accuracy class, are:
For class 1:
, with Ef, Et, Ec according to points 7.1 to 7.3.
For class 2:
, with Ef, Et, Ec according to points 7.1 to 7.3.
For class 3:
, with Ef, Et, Ec according to points 7.1 to 7.3.
The complete thermal energy meter shall not exploit the MPEs or systematically favour any party.
4. Permissible influences of electromagnetic disturbances U.K.
4.1.The instrument shall not be influenced by static magnetic fields and by electromagnetic fields at mains frequency.U.K.
4.2.The influence of an electromagnetic disturbance shall be such that the change in the measurement result is not greater than the critical change value as laid down in requirement 4.3 or the indication of the measurement result is such that it cannot be interpreted as a valid result.U.K.
4.3.The critical change value for a complete thermal energy meter is equal to the absolute value of the MPE applicable to that thermal energy meter (see point (3).U.K.
5. Durability U.K.
After an appropriate test, taking into account the period of time estimated by the manufacturer, has been performed, the following criteria shall be satisfied:
Flow sensors: The variation of the measurement result after the durability test, when compared with the initial measurement result, shall not exceed the critical change value.
Temperature sensors: The variation of the measurement result after the durability test, when compared with the initial measurement result, shall not exceed 0,1 °C.
6. Inscriptions on a thermal energy meter U.K.
Accuracy class
Limits of flow rate
Limits of temperature
Limits of temperature difference
Place of the flow sensor installation: flow or return
Indication of the direction of flow
7. Sub-assemblies U.K.
The provisions for sub-assemblies may apply to sub-assemblies manufactured by the same or different manufacturers. Where a thermal energy meter consists of sub-assemblies, the essential requirements for the thermal energy meter apply to the sub-assemblies as relevant. In addition, the following apply:
7.1.The relative MPE of the flow sensor, expressed in %, for accuracy classes:U.K.
where the error Ef relates the indicated value to the true value of the relationship between flow sensor output signal and the mass or the volume.
7.2.The relative MPE of the temperature sensor pair, expressed in %:U.K.
where the error Et relates the indicated value to the true value of the relationship between temperature sensor pair output and temperature difference.
7.3.The relative MPE of the calculator, expressed in %:U.K.
where the error Ec relates the value of the thermal energy indicated to the true value of the thermal energy.
7.4.The critical change value for a sub-assembly of a thermal energy meter is equal to the respective absolute value of the MPE applicable to the sub-assembly (see points 7.1, 7.2 or 7.3).U.K.
7.5.Inscriptions on the sub-assembliesU.K.
| Flow sensor: | Accuracy class |
| Limits of flow rate | |
| Limits of temperature | |
| Nominal meter factor (e.g. litres/pulse) or corresponding output signal | |
| Indication of the direction of flow | |
| Temperature sensor pair: | [X1Type identification (e.g. Pt100)] |
| Limits of temperature | |
| Limits of temperature difference | |
| Calculator: | Type of temperature sensors
|
Editorial Information
X1 Substituted by Corrigendum to Directive 2014/32/EU of the European Parliament and of the Council of 26 February 2014 on the harmonisation of the laws of the Member States relating to the making available on the market of measuring instruments (Official Journal of the European Union L 96 of 29 March 2014).