Series-WMH

Supported Applications

The Dwyer Series WMH High Temperature Multi-Jet Water Meters are mechanical, water totalizing meters designed for high-temperature applications up to 190°F (88°C). The series is intended for measuring and displaying total water usage in HVAC systems and hot water services where standard brass water meters may not maintain accuracy. These meters feature a multi-jet design with an integral strainer and are compatible specifically with water media.

Operating Conditions & Performance

The Series WMH operates within a process temperature limit of 190°F (88°C) and a pressure rating of 150 psi (10 bar). Accuracy is defined by flow regime: Transitional Flow accuracy is ±3% for the -A series, while Nominal Flow accuracy is ±1.5%. The meters require installation in a horizontal position with the register face pointing up to prevent leakage or damage.

Flow ranges vary by model size and unit of measurement:

• Gallons Per Minute (GPM): Ranges from 1 to 20 GPM, 2 to 30 GPM, 3 to 50 GPM, 5 to 100 GPM, and 8 to 160 GPM.
• Cubic Meters Per Hour (m³/h): Ranges from 0.12 to 1.5 m³/h, 0.2 to 2.5 m³/h, 0.25 to 3.5 m³/h, .48 to 6 m³/h, 0.8 to 10 m³/h, and 1.2 to 15 m³/h.

Electrical requirements are specified as 0.01A @ 24VAC/DC for the pulse output circuitry.

Configuration Options

The series offers configurable options across body sizes, coupling types, and display units to accommodate different piping standards and totalization needs.

• Body Sizes: Available in 5/8" x 1/2", 5/8" x 3/4", 3/4" SL, 3/4", 3/4" x 1", 1", 1-1/2", and 2" (metric equivalents: 15 mm through 50 mm).
• Couplings: NPT or BSPT optional couplings are offered to match regional piping standards.
• Totalizing Display Units: Models display total usage in Gallons (-A series) or cubic meters/hour (-B series). The maximum display capacity is 9,999,999.99 for gallon models and varies by metric model (e.g., 99,999.9999 m³).
• Pulse Output: A pulse output with frequency proportional to flow rate allows for remote totalization.

Pulse options include specific volume increments per pulse: 0.1 gal, 1 gal, 10 gal, and 100 gal (or metric equivalents of 1 L, 10 L, 100 L, and 1000 L).

Key Product Differences

The Series WMH distinguishes between two primary unit-of-measurement families: the -A series for Gallons (GPM) and the -B series for cubic meters per hour (m³/h). Model numbers follow a structured guide indicating the unit of measurement, size code, coupling type, and pulse rate. For example, model WMH-A-C-01 represents a 5/8" x 1/2" meter with Gallons output.

Wetted materials are consistent across the series: Body is Brass, Couplings are Brass, and the Measuring Chamber is Brass. The meters feature color-coded lead wires that are 4.5 (1.5m) long for electrical connection to external totalizers or controllers. Dimensions vary by size; overall lengths range from 6-1/2 in (165 mm) to 11-13/16 in (300 mm), with weights ranging from approximately 3.75 lb (1.7 kg) for the smallest sizes up to 18.74 lb (8.5 kg) for the largest.

Important installation notes state that pipe sealant tape should not be used on meter threads and connections must not be over-tightened beyond what is required to seal. The Series WMH is not field serviceable, and attempting repair may void the warranty.