The Testo 549i Smart Probe High-Pressure Gauge lets you read system pressures wirelessly on your smartphone or tablet, making servicing and troubleshooting on air conditioning and refrigeration units quicker and cleaner.

No more wrestling with long manifold hoses; this compact probe connects directly to the pressure port, minimising refrigerant loss. It's a game-changer for tight spots or high-up rooftop installs where a full manifold is just clumsy.

Who It's Best For

• HVAC/R service techs doing diagnostics.
• Installers needing quick pressure checks.
• Refrigeration apprentices learning system parameters.
• Anyone wanting to minimise refrigerant loss during checks.

Compatibility

This Testo 549i probe connects directly to a 7/16" - UNF pressure connection, commonly found on many refrigeration and air conditioning systems. It's rated for a wide range of refrigerants including CFC, HFC, HCFC, N (nitrogen), H₂O (water), and CO₂.

For app control, you'll need a mobile device running iOS 13.0 or newer, or Android 8.0 or newer, with Bluetooth 4.2. If you're running a different model, check fittings and specs before ordering.

Features

• Wireless Pressure Measurement: Connects directly to the pressure port, sending readings to your smartphone via Bluetooth up to 100 metres.
• Minimal Refrigerant Loss: No need for manifold hoses means less refrigerant escaping during connection and disconnection.
• Smart App Integration: View measurements as graphs or tables, and automatically calculate evaporation and condensation temperatures.
• Robust Construction: Built with durable plastic materials to handle typical job site conditions.
• Long Battery Life: Runs for up to 130 hours on 3 AAA micro batteries, reducing interruptions on long jobs.

Technical Specifications

In the Box

• 1x Testo 549i high-pressure gauge
• 3x AAA micro batteries
• 1x Calibration protocol

Using It on the Job

1. Before connecting, ensure the system is depressurised or isolated as required for your task. Always wear appropriate PPE like safety glasses and gloves.
2. Screw the Testo 549i directly onto the pressure port (7/16" - UNF). Hand-tighten firmly; do not overtighten.
3. Open the Testo Smart App on your smartphone or tablet and select the 549i. The app will automatically connect via Bluetooth.
4. Monitor pressure readings, calculate superheat/subcooling (with Testo 115i clamp thermometer), and log data directly in the app.
5. Once finished, unscrew the probe. If working on a refrigerant circuit, be mindful of any residual pressure release. Store the probe in a protective case.

Limitations and Safety Notes

• Refrigerant handling requires a current ARCtick licence in Australia. This tool measures pressure; it does not replace safe handling practices.
• Ensure the 7/16" - UNF connection is clean and free of debris before attaching to prevent leaks.
• Do not exceed the +65 bar overload pressure. Operating outside the specified range can damage the sensor and void warranty.
• Use only with compatible refrigerants and pressure media as listed.
• Always follow Australian standards and Safe Work guidance for all HVAC/R operations.

Field Tip

When you're trying to diagnose a weird pressure swing on a packed commercial rooftop, the 100m Bluetooth range on the 549i is a lifesaver. You can be down at the condenser, getting real-time readings while safely away from the fan, or checking the head unit without needing to climb back up.

Build a More Complete Diagnostic Kit

Pair the 549i with a Testo 115i clamp thermometer for superheat and subcooling calculations, or a Testo Smart Case for secure storage. For a complete digital manifold setup, combine with other Smart Probes like the Testo 557s.