testo Smart Probes

The Phone Is the Instrument

All the Smart Probes work the same way. There’s no display on the probe itself. It measures and transmits over Bluetooth, and the testo Smart App does the reading, the calculating and the reporting.

That’s not just a cost saving. It’s what makes reading several probes at once possible. A conventional instrument shows you what one sensor is doing in one place. Several probes on one screen show you what a whole system is doing at the same moment.

On a refrigeration system, that matters because the numbers that describe it are taken in different places: suction pressure at one point, liquid line temperature at another, discharge pressure somewhere else, and ambient and return air somewhere else again. Measured one at a time with one instrument, they describe four different moments of a system that has moved in between.

The Bluetooth range reaches up to 100 metres on the 115i, 549i and 605i, and 150 metres on the 552i. That covers an outdoor condensing unit and an indoor air handler, without anyone walking between them.

No Hoses, Less Refrigerant Lost

This is the best argument in the range, and it adds up over a year.

The 549i high pressure probe connects directly to the service port, with a 7/16 inch UNF connection. There’s no manifold, no hoses and no gauge set. Testo says that because no hoses are needed, no refrigerant is lost, or only very little.

A conventional manifold loses a small amount of refrigerant at each connection and disconnection, and the hoses hold a charge that goes to atmosphere when they come off. It’s a small loss per job, but a substantial one across a year, and with refrigerant costs and phase down schedules, it’s no longer a rounding error.

Two 549i probes with two 115i pipe clamp thermometers give superheat and subcooling on both sides of a system, calculated by the app rather than worked out from a pressure temperature chart.

The Range

Two combinations do most of the work. The 549i with the 115i gives superheat and subcooling. The 405i or 410i with the 605i gives heating and cooling output, because air volume, plus the temperature and humidity change across a coil, are what capacity is calculated from.

That second one is worth noting. Capacity is a calculation, not a measurement, and it needs airflow, temperature and humidity together. Two probes and the app produce it. Doing it any other way means three instruments and some arithmetic.

The 552i also connects to Testo’s testo 550s and testo 557s digital manifolds, as well as the app.

Reporting Without Going Back to the Office

The app displays readings as values, tables or graphs, and saves them as PDF or Excel files.

Measurement reports, with photos and comments, are created in the app and emailed from site, so the commissioning record or service report leaves before the van does. Measurement data is stored and can be retrieved, so a return visit starts with what was found last time.

For a contractor whose deliverable is a certificate rather than a repair, that’s the difference between a job finishing on site and finishing on a Friday evening.

Which Probes to Start With

The range is modular, so the sensible approach is to buy the two or three that match your work, and add more later.

For refrigeration and air conditioning service, two 549i and two 115i cover the core of it, and that’s what the testo Smart Case (refrigeration) is built to hold. Add a 605i for ambient conditions, and a 552i for evacuation.

For HVAC commissioning and airflow, the 410i for grilles and diffusers, the 405i for duct traverse, and the 510i for differential pressure are the starting three. The testo Smart Case (VAC) holds the 405i, 410i, 510i, 605i, 805i and 905i.

For heating work, the testo Smart Case (heating) holds the 115i, 410i, 510i, 549i and 805i.

For general service work where temperature is the main measurement, the 905i, 805i and 915i cover contact, non contact and probe based measurement.

Where They Sit Against the Bigger Instruments

Smart Probes aren’t a cheaper version of the testo 440 or testo 400. They’re a different approach.

The 440 and 400 are single instruments taking several probes, with built in measurement programmes, defined methods and formal reporting. That suits commissioning work where the output is a survey against a standard.

Smart Probes are individual sensors that live in a pocket and appear on a phone. That suits service, fault finding, and daily work where the question is what this system is doing right now.

ting. That suits commissioning work where the output is a survey against a standard.

Smart Probes are individual sensors that live in a pocket and appear on a phone. That suits service, fault finding and the daily work where the question is what is this system doing right now.