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The Nova 253 Series Continuous Analyzers for Low Range Dew Point have been designed primarily for accurate dew point analysis of heat treating atmospheres, instrument air, or other applications which may have typical dew points that are lower than what can be read by standard dew point analyzers, such as the Nova 257 Series. For analysis of dry non-corrosive industrial gases, or dry oil-free air. The dielectric ceramic sensor provides stable and accurate measurements and is not affected by most gas compositions, except those containing ammonia or corrosive gases such as SO2, SO3, and HCl.

A built-in sample pump draws in samples that are at or near atmospheric pressure. Alternatively, a regulator can be supplied where the sample gas is under pressure. The sample flow is shown on a small rotameter with flow control valve. The analyzer reads the dew point continuously with digital display and 4-20mA output.
Unit of Measure


Method of Detection

N/A Dielectric polymer sensor that changes capacitance with moisture variation

Ranges Available

N/A -112°F to +86°F -80°C to +30°C



Accuracy & Repeatability

N/A ±2°C Dew Point from -80 to -17°C; ±1°C Dew Point from -17 to 30°C ±2°F Dew Point from -112 to 0°F; ±1°F Dew Point from 0 to 86°F


N/A ±2% of full scale per month maximum

Response Time (T-90)

N/A Less than 60 seconds to T90 at higher dew points; Lower dew points may take an hour or more to dry down from ambient air

Ambient Temperature Range

N/A -18 to 49 ºC0 to 120 ºF


N/A ±2°F / °C over measurement range

Size & Weight

N/A Approx. 51 x 41 x 26 cm @ 10 kg (20" H x 16" W x 10" D @ 20lbs)


N/A 115 VAC, 60 Hz 220 VAC, 50 Hz also available

Output Options

N/A 4-20mA output, isolated or non-isolated


N/A High or low dew point alarm with relay contact

Hazardous Area Rating Options

N/A General Purpose, Non-Hazardous



    For checking lower range dew points of air, hydrogen/nitrogen atmospheres or other dry-oil free gases.


N/A • Low range of -80° to +30°C (or -112° to +86°F) dew point
• Rugged design that is easy to operate
• Use on any non-corrosive industrial gases or air
• Long-life dielectric ceramic sensor
• Can be calibrated in the field
• Bright digital readout
• Built-in sample pump or pressure regulator, and filter
• 4-20mA output, non-isolated
• NEMA 4 enclosure standard


N/A • High or Low dew point alarm
• Isolated 4-20mA recorder outputs
• NEMA 12, 4X, or rack mount enclosures available



  • On analyzed dry nitrogen for zero
  • On known, current ambient air dew point for span
  • Alternatively, the analyzer may be returned to Nova for a certified calibration

Unique Applications


    The 253 Series may not be appropriate for use when ammonia or other corrosive gases are present. All Nova analyzers are built using proven technologies and techniques. If this product does not suit your application, please contact Nova. In many cases, we are able to build an analyzer specific to your needs.

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