Flow sizing: DN is nominal connection size; Qmin/Q1 is the lower measuring limit, Qt/Q2 the boundary between error bands, Qn/Qp or Q3 the nominal/permanent region, and Qmax/Qs or Q4 the upper/overload region in the respective document nomenclature. The older and newer designations should not be treated as interchangeable certification labels. R normally describes Q3/Q1; it is not an accuracy percentage. Maximum flow should not be used as an assumed continuous duty point.
Mechanical installation: The Kranti installation sheets call for flushing with a temporary spool, aligned pipes and parallel flanges, full pipe without air, flow-arrow direction, upstream/downstream isolation and slow commissioning to avoid surge. They show the dial upward on a horizontal pipe, upstream strainer/dirt box and downstream NRV. The Lehry sheet instead contains wording placing an NRV “before”; resolve the drawing/wording discrepancy for the supplied assembly. A vertical model such as the Fedrel vertical multijet is a specific product, not permission to install every multijet vertically. [S25 p.1; S26 p.1; S30 p.2; S28 p.1]
Electromagnetic installation: Kranti/Fedrel leaflets call for full pipe and 5D/3D straight runs. A larger disturbed upstream flow profile may need a manufacturer-specific installation prescription. Liner/electrode choice must match the actual liquid, concentration, abrasion and temperature; the highest temperature printed in a family brochure is not available with every liner. The Lehry selection chart gives CR/PU <60°C, PTFE <160°C, FEP <120°C and PFA <180°C, but its other technical blocks disagree. [S9 p.4; S22 p.2; S38 p.4]
Pressure and flange matching: 1 MPa = 10 bar. kgf/cm² is a different unit from bar; test pressure differs from maximum working pressure. PN16 drilling on a 1.0 MPa-rated mechanical meter does not make its body a 16-bar working-pressure product. Confirm flange standard, nominal size, PCD, holes, bolts, face type, pressure/temperature rating, face-to-face length and gasket before assuming interchangeability.
Accuracy basis: ±0.5% of reading and ±0.5% of full scale are different. At 10% of a selected full scale, ±0.5% FS is equivalent to ±5% of the actual reading (calculated illustration). “Repeatability,” “resolution” and “accuracy” are separate properties. The source conflicts matter particularly at low flow.
BMS/SCADA checklist: Confirm meter output (reed pulse, 4-20 mA, native RS485 or a separate converter), pulse factor, output voltage/current/contact limits, scaling, protocol, baud/parity, register addresses/data type/word order, termination, address count, cable length, isolation and power requirements. Confirm whether the counter is resettable and whether remote totals remain synchronized with the mechanical register. Several documents list interface names without these engineering details.
Smart-meter system boundary: An AMR-ready mechanical meter may still require RF/LoRa hardware, gateway, head-end software and billing software. A telemetry-enabled ultrasonic meter may include its radio but incur SIM/cloud recurring costs. Battery-life claims depend on the configuration and logging/transmission duty; the source documents do not establish performance under every deployment condition.
BTU scope: An energy meter needs flow, matched temperature measurements and a calculator with defined energy units and error limits. The provided price-list entries do not furnish complete sensor length/thermowell, ΔT, heat-calculation or installation packages. A flow-meter accuracy claim is not the overall heat-meter system accuracy.