Graywolf Zephyr II Differential Pressure Monitor

Overview

The Graywolf Zephyr II Differential Pressure Monitor is a portable, field-deployable instrumentation platform engineered for precise, real-time measurement of differential pressure, static pressure, temperature, and air velocity in HVAC systems, cleanrooms, fume hoods, containment enclosures, and environmental protection facility ductwork. It operates on the principle of high-stability capacitive micro-manometry, delivering traceable, low-drift pressure readings across a ±250 Pa (±1.0 in. w.c.) full-scale range—optimized for critical applications where small pressure differentials govern airflow direction, filtration integrity, and containment performance. Its auto-zero function actively compensates for thermal drift and mechanical relaxation over time, ensuring long-duration logging maintains sub-0.1 Pa repeatability without manual recalibration. Unlike fixed-mount transmitters, the Zephyr II supports dynamic point-of-use verification—enabling technicians to validate pressure gradients across filters, dampers, and room boundaries during commissioning, routine maintenance, or post-remediation verification.

Key Features

• Integrated auto-zeroing micro-manometer with <0.05 Pa resolution and ±0.25% FS accuracy at 23°C
• Dual-channel analog input: one for K-type thermocouple (–40°C to +1000°C), one for optional humidity sensor (via 2300AHTS probe)
• Built-in Pitot tube interface supporting velocity calculation from differential pressure using Bernoulli-derived algorithms; volume flow rate (VFR) automatically computed upon user-input duct geometry (rectangular, round, or oval cross-section)
• Backlit graphical LCD with intuitive step-through menu navigation—no external software or training required for basic operation
• RS-232 serial port (CF card adapter included) for bidirectional data exchange with GrayWolf DirectSense handheld computers and LAP-series mobile PCs, enabling synchronized multi-parameter logging, remote configuration, and GLP-compliant audit trails
• Ruggedized ABS housing rated IP54 for dust and splash resistance; operating range: 0–50°C, 5–95% RH non-condensing

Sample Compatibility & Compliance

The Zephyr II is validated for use in environments governed by ASHRAE Standard 62.1 (Ventilation for Acceptable Indoor Air Quality), ISO 14644-3 (Cleanroom testing protocols), and ISO 16813 (HVAC design and performance evaluation). Its pressure sensing architecture meets the stability and linearity requirements specified in EN 13779 Annex C for demand-controlled ventilation verification. When paired with the 2300AHTS probe, it satisfies OSHA 1910.134 Appendix A criteria for respirator fit-test chamber pressure monitoring. All firmware and calibration routines comply with NIST-traceable documentation practices and support 21 CFR Part 11–compatible electronic signatures when used within GrayWolf’s DirectSense ecosystem. No hazardous materials or proprietary consumables are required—calibration is performed via internal reference zero-point offset, eliminating need for external pressure standards during routine field use.

Software & Data Management

Data acquisition and reporting are fully integrated into GrayWolf’s DirectSense software suite (v5.2+), which provides time-synchronized multi-channel logging, customizable pass/fail thresholds, and automated report generation compliant with ISO/IEC 17025 documentation standards. Each measurement session records instrument ID, operator ID, timestamp (GPS-enabled when used with LAP PC), ambient conditions, and sensor configuration metadata. Audit logs capture all parameter changes, zeroing events, and export actions—supporting FDA and EPA regulatory audits. Raw CSV and XML exports are available for integration with LIMS platforms or building management systems (BMS) via OPC UA or Modbus RTU gateways (third-party adapters required).

Applications

• HVAC system balancing and TAB (Testing, Adjusting, Balancing) in commercial buildings and hospitals
• Filter integrity testing and pressure drop trending across HEPA/ULPA installations
• Fume hood face velocity verification per ANSI/ASHRAE 110 and NFPA 45
• Containment validation in pharmaceutical isolators and BSL-2/3 laboratories
• Stack and duct static pressure profiling for combustion efficiency analysis
• Environmental protection facility stack monitor calibration checks and continuous emission monitoring system (CEMS) auxiliary verification

FAQ

Does the Zephyr II require annual factory recalibration?
No—its auto-zero architecture eliminates routine recalibration. However, users may perform a field zero check against atmospheric reference before critical measurements. NIST-traceable calibration certificates are provided with initial shipment and recommended every 24 months for GLP/GMP compliance.
Can the Zephyr II measure negative pressure differentials in isolation rooms?
Yes—it measures bidirectional differentials from –250 Pa to +250 Pa with equal accuracy and resolution, making it suitable for airborne infection isolation room (AIIR) pressure mapping per CDC guidelines.
Is the 2300AHTS probe compatible with all Zephyr II units?
Yes—probe communication uses standardized GrayWolf serial protocol; firmware updates ensure backward compatibility across all Zephyr II production batches since 2018.
What is the battery life under continuous logging mode?
Up to 12 hours with alkaline AA cells; rechargeable NiMH packs extend runtime to 16 hours. Low-battery warning triggers at 15% remaining capacity, preserving last 10 minutes of unsaved data.
Does the instrument support custom unit conversions (e.g., mmH₂O to Pa)?
Yes—user-selectable pressure units include Pa, in. w.c., mmH₂O, psi, bar, and mbar; temperature defaults to °C but switches to °F; velocity units include m/s, ft/min, and knots.