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We reserve the right to make changes without notice
H 355 - IET 7143-7183 C1 Eng.
18.01.10 AM
Rev. 06
COSTER
13. ACCURACY OF THE CALCULATION UNIT
The maximum error of the calculation unit is less than that required by EN 1434 (2007) Directive.
This maximum error is shown in the following formula:
Ec% = ± (0.5 +
∆
T min
∆
T
)
where :
∆
T min =difference flow/return minimum (3°C)
∆
T = actual difference between flow and return
Examples : with actual
∆
T reale di 3 °C the maximum error accepted by the regulations becomes ± 1.5%
with actual
∆
T of 10°C the maximum error accepted by the regulations becomes ± 0.8%
with greater actual
∆
Ts the error is reduced.
14. ACCURACY OF THE PAIR OF TEMPERATURE SENSORS & OF THE SYSTEM
The maximum error of the pair of sensors is lower than that prescribed by the EN 1434 (2007) Directive.
The maximum error on the difference between the flow and return temperatures is given by the following formula:
Et% = ± (0.5 + 3
∆
T min
∆
T
) where :
∆
T min = difference flow/return minimum (3 °C)
∆
T = actual difference between flow and return
Examples : with actual
∆
T tof 3°C the maximum error accepted by the regulations becomes ± 3.5%
with actual
∆
T of 10°C the maximum error accepted by the regulations becomes ± 1.4%
with greater actual
∆
T the error is reduced.
THE TOTAL ERROR PERMITTED BY THE REGULATIONS FOR THE CALCULATION UNIT INCLUDING SEN-
SORS, IS THE SUM OF THE TWO PARTIAL ERRORS.
Examples : with actual
∆
T of 3°C the maximum error accepted by the regulations becomes ± 5%
with actual
∆
T the maximum error accepted by the regulations becomes ± 2.2%
with greater actual
∆
T the error is reduced.
