Product Core Brief

• Model: ZR22G
• Brand: YOKOGAWA
• Series: EXAxt
• Core Function: Measures oxygen concentration in combustion exhaust directly in-situ without sampling.
• Product Type: Split-Type Zirconia Oxygen Probe
• Key Specs: 0.01–100 vol% O2 | 0–700°C | 5s Response Time
• Condition: New Surplus / Original

Product Introduction

YOKOGAWA ZR22G is a split-type in-situ zirconia oxygen probe for combustion control. This YOKOGAWA ZR22G sensor installs directly into flues, eliminating extractive sampling lines and reducing maintenance.

Engineered for harsh environments, the YOKOGAWA ZR22G handles sample gas temperatures up to 700°C. It delivers a 5-second response time and supports HART digital communication for remote diagnostics.

Key Technical Specifications

Quality Control Process

We don’t just ship these probes blindly. Every YOKOGAWA ZR22G undergoes a rigorous bench validation. We verify the internal heater element resistance matches factory specs using precision multimeters. Thermocouple output is checked against a calibrated reference to ensure accurate temperature compensation. We then perform a span gas calibration test using certified reference air to confirm linearity across the 0-25% range. Finally, HART communication is verified to ensure self-diagnostics and sensor resistance checks are fully functional. Units failing any test are quarantined.

Replacement Pitfall Guide

❗ Verify Insertion Length: The ZR22G comes in lengths from 0.15m to 5.4m. Guessing the insertion depth will put the sensor in the wrong temperature zone or cause it to hit the opposite wall. Measure from the flange face to the centerline of the stack.

❗ Check Reference Gas Method: This probe uses a zirconia cell that requires a reference gas. Confirm whether your application uses natural convection (-C), instrument air (-E), or pressure compensation (-P). Using the wrong reference method will cause immediate reading drift.

❗ High-Temp Adapter Requirement: If your stack gas exceeds 700°C, you cannot use the standard probe alone. You must pair it with a high-temperature adapter (ZO21P-H) and a 0.15m probe. Ignoring this will melt the sensor assembly.

❗ Heater Burn-In: New or long-stored probes often need a controlled heat-up. Do not apply full power to a cold zirconia cell. Ramp the temperature slowly to prevent thermal shock cracking of the ceramic element.

Keep these in mind and you’ll cut 90% of rework time.

Compatibility Matrix & Benchmarks

• Measurement Drift: ±2% F.S./month (Zero and Span)
• Repeatability: ±0.5% F.S. (0-5 vol% O2 range)

Need help with the converter pairing? The ZR22G probe must be matched with the right ZR402G converter for your application.