testo 557 Digital Refrigeration Gauge with Vacuum probe

The Testo 557 digital refrigeration gauge has a 4-way valve block, large backlit display and sight glass. Two NTC thermistor clamp probes provide superior accuracy of simultaneous, real-time superheat and sub-cooling readings. An external vacuum probe provides fast and more reliable evacuation of the system.

The wireless Bluetooth / App allows you to view measurement data on your Smartphone or Tablet, enabling you to quickly and conveniently complete and document your job. Then, be able to finalize the documentation and send the reports and invoice via email, right from the job site.

In addition to the 60 refrigerant profiles stored in the instrument, the App can also be used to download new refrigerants from the Internet directly into the digital manifold.

Why Make the Switch from Analogue to Digital Gauges

60 built in refrigerants 

Measures high side / low side pressures and temperatures

4-way valve block with 1/4 in. and 3/8 in. ports

External vacuum probe

App integration via Bluetooth (65 feet range)

More Information
Warranty2 Years
Technical Data
Storage Temperature-20 to + 60°C
Operating temperature-10 to +50 °C
Battery type 4 AA batteries
Battery life250 h (less with use Bluetooth & Backlit)
Dimensions265 x 48 x 19 mm
Instrument Sensor
Measuring range-50 to +150 °C 
Accuracy±0.5 °C 
Resolution0.1 °C /°F / °R 
Vacuum Measurement
Measuring range0-10,000 Microns
Accuracy -
Resolution10 Microns 
Low Pressure Probe Measurement
Measuring range-1 to 60 bar
Accuracy±0.5 % fs
Resolution0.1 psi (0.01 bar)
Overload 65 bar
What's Included

Testo 557 kit, digital manifold with Bluetooth / App; including 2 x NTC temperature clamp probes, external vacuum probe, batteries, case, certificate of conformity, and user's manual.

60 Built in refrigerants 

External vacuum probe for faster 
and more reliable evacuation of the system

4-way valve block with 
1/4 in. and 3/8 in. ports

On-site Reporting/ Monitoring 
Via Testo Refrigeration App