Dual-sensor moisture meter for parquet and timber — MERLIN HM9 DUO

The MERLIN HM9 DUO is a dual-sensor pinless wood moisture meter for parquet from 5 mm thick and boards or beams from 25 mm thick.

Move between flooring checks and thicker timber with one instrument. The DUO combines the functions of the HM9 WS5 and HM9 WS25, making it useful for parquet installers, joiners and workshops that handle both thin flooring elements and substantial boards. Its narrow front sensor helps you work on narrower surfaces while the underside sensor serves thicker stock.

Select the front sensor for suitable flooring from 5 mm thick: its published scanning depth is 8 mm. Select the underside sensor for boards and beams from 25 mm thick: its published scanning depth is 40 mm. These are two distinct sensor configurations, not continuously adjustable depth from 8 to 40 mm. Each workpiece must cover the chosen sensor and provide the contact required by the instructions.

The capacitive / dielectric sensor responds to the moisture-dependent electrical properties of wood. Choose from 21 calibration groups across a dry-density range of 175–1075 kg/m³. Automatic temperature compensation and a self-calibration function support routine checks; the illuminated display shows moisture, wood group, dry density and minimum wood thickness.

Select the wood group using the species and its actual dry density. Place the entire sensor surface against a clean, flat area of wood and keep the meter still while taking the reading. Check several positions on each piece and compare them before making a processing decision. The workpiece must cover the sensor and meet the minimum thickness for the selected model.

Rough surfaces, incomplete contact, unsuitable density settings and material beneath a thin workpiece can affect the reading. The stated scanning depth is not proof of moisture uniformity through a thicker board or beam. Follow the supplied instructions; near or above fibre saturation, treat high readings as an indication rather than a precise drying endpoint.

• Front sensor: minimum wood thickness 5 mm; published scanning depth 8 mm
• Underside sensor: minimum wood thickness 25 mm; published scanning depth 40 mm
• Combines HM9 WS5 and HM9 WS25 functions in one instrument
• Measurement principle: pinless, capacitive / dielectric
• Wood groups: 21 selectable calibration groups
• Dry-density setting range: 175–1075 kg/m³
• Published display range: 2–99% wood moisture
• Display resolution: 0.1%; resolution is not measurement accuracy
• Automatic temperature compensation and self-calibration function
• Backlit display, battery indication and automatic switch-off
• Power: 4 × 1.5 V AA alkaline batteries
• Operating temperature: 0 to +40 °C
• Storage temperature: −20 to +60 °C
• Instrument dimensions: 150 × 73 × 23 mm
• Manufacturer-stated weight with batteries: 215 g
• Manufacturer: MERLIN Technology, Austria

MERLIN HM9 DUO meter, soft case, batteries and operating instructions. A calibration certificate is not explicitly included in Bioevibul’s stated DUO package.

Choose HM9 WS13 for furniture stock from 13 mm thick, HM9 WS25 for timber from 25 mm thick, or HM9 DUO when your work includes both flooring from 5 mm and thicker boards or beams from 25 mm.