Series-LFM

Supported Applications

The Dwyer Series LFM In-Line and Panel Mount Flowmeters measure the flow of water and other compatible liquids. Designed for indoor locations free from excess vibration and away from direct sunlight, these variable area flowmeters feature dual scales providing direct reading in both GPM (gallons per minute) and LPM (liters per minute). The series is specified for use with water service.

Operating Conditions & Performance

The Series LFM offers an accuracy of ±5% full scale. Pressure ratings vary by temperature; at 68°F (20°C), the pressure limit is 87 psi (6 bar). When using 90° elbow fittings, the rating increases to 116 psi (8 bar) at 68°F (20°C). Higher temperatures reduce allowable operating pressure according to the provided temperature vs. pressure chart.

Installation requires a vertical plane aligned with existing plumbing and structural support at the top and bottom of the unit; the instrument should not support pipe weight. The polycarbonate body is adversely affected by ultraviolet light, restricting use to indoor environments or areas without direct sunlight.

Configuration Options

The series encompasses six model families (LFMA through LFMF) with scale lengths ranging from 3-15/16 in (100.01 mm) for the LFMA to 11-27/64 in (290.12 mm) for the LFMF. Flow ranges span from 0.1 to 1 GPM (0.5 to 4 LPM) up to 7 to 70 GPM (25 to 250 LPM).

Wetted materials are configured by model series:

• Body: Polycarbonate
• Float and Rod: S.S.316
• O-rings: Fluoroelastomer
• Flange Nut: ABS (all models)
• Float Stop: ABS for LFMA, LFMB, and LFMC; Polypropylene for LFMD, LFME, and LFMF.

Process connections vary by model size. Standard configurations include male NPT fittings (1/2", 3/4", 1", or 2"). Optional connection types available depending on the specific model series include:

• Metric union connectors (20 mm, 32 mm, 40 mm, and 63 mm)
• Female NPT fittings
• 90° male NPT elbow fittings

An optional NIST traceable calibration certificate for variable water flowmeters (NISTCAL-FL2) is available.

Key Product Differences

The series distinguishes models by scale length, connection size, and material composition of the float stop. Models LFMA, LFMB, and LFMC utilize ABS for the float stop, while larger flow capacity models (LFMD, LFME, LFMF) use Polypropylene.

Connection materials also vary: 1/2" and 3/4" male NPT fittings on smaller series are typically ABS. Larger connections (3/4", 1", and 2") utilize PA66 nylon for female threads or specific metric unions, while PVC is used for certain elbow fitting options.

Model-specific dimensional differences include overall length (Dimension C) ranging from 6-45/64 in (170.26 mm) on the LFMA to 15-3/4 in (400.05 mm) on the LFMF, and diameter (Dimension B) increasing with flow capacity.