Series-420

Supported Applications

The Dwyer® Series 420 Durablock® Inclined-Vertical Manometers are precision instruments designed for the measurement of low differential pressures in laboratory and test applications. The series is utilized to measure air velocity, static pressure, furnace draft, and air filter pressure drop.

Operating Conditions & Performance

The Series 420 manometers operate with a maximum total pressure rating up to 100 PSIG and are rated for temperatures up to 150°F. For laboratory applications requiring an accuracy of ±2%, specific precautions regarding duct diameter, traverse technique, and straightener usage must be observed as detailed in the operating instructions.

Performance specifications from the series data sheet indicate an accuracy class of ±0.25%. The inclined range bore features a length up to 20" on select models (e.g., Model 424-10) to provide multiplication of indicating fluid movement for critical lower-range measurements.

Configuration Options

The series encompasses single column and double column configurations with varying inclined and vertical ranges. Standard accessories included with the manometers are two 3 ft lengths of clear plastic tubing, rapid shut-off type "a" connections, and gage fluid (two 1 oz bottles of .826 red gage fluid; 1.91 blue gage oil is specified for models 421-23 and 422-23). Double column models include two sets of 1/8" NPT tubing adapters.

Available measurement ranges documented in the series specification table include:

• Inclined Ranges (Inches of Water): 0 to 2.0 and 0 to 1.0, with minor divisions as small as .01.
• Vertical Ranges (Inches of Water): Configurations include spans such as 2.1 to 10, 1.1 to 5, and 1.1 to 10, with minor divisions typically at .10.
• Inclined Scale Lengths: Options range from 6-1/2" up to 20", depending on the model configuration.

The series supports metric ranges and divisions in millimeters for single column models, as noted in specification warnings. Process connections utilize rapid shut-off type "a" connectors compatible with vinyl tubing (3/16" I.D.) or adapters such as 1/8" NPT tube adapters.

Key Product Differences

The Series 420 family includes distinct model families differentiated by column configuration and scale dimensions:

• Model 424-10 (Single Column): Features an inclined range of 0 to 2.0 inches of water with a 20" inclined scale length, paired with a vertical range of 2.1 to 10.
• Models 421-5 and 421-10 (Single Column): Offer an inclined range of 0 to 1.0 inches of water with a 6-1/2" scale length; vertical ranges vary between 1.1 to 5 and 1.1 to 10.
• Models 422-5 and 422-10 (Double Column): Provide an inclined range of 0 to 1.0 inches of water with a 6-1/2" scale length; vertical ranges vary between 1.1 to 5 and 1.1 to 10.

Dimensions (A through G) and weight vary by model, ranging from approximately 4 lb-12 oz for smaller single column units up to 22 lb-12 oz for the larger Model 424-10 configuration.