552i Wireless Digital Vacuum Probe - Vacuum Gauge for HVAC Systems with IP54 Protection – 45° Service-Port Design - HVAC Tool for AC/R System Evacuation with Bluetooth and App

So overall this is a good unit. I was slightly hesitant to buy a gauge that was 100% Bluetooth with no built-in screen. So far that hasn't been an issue and I do like being able to monitor it from inside the building or my truck. I believe the gauge is accurate and effective. I did originally have one major issue while learning how to use it. You must not get any refrigerant or nylog inside the probe. Apparently I got some nylog inside the fitting and it gave some bizarre readings. Look at the screenshots. I cleaned the unit with 99% alcohol I connected it directly to the vacuum pump and cleaned it out. Afterwards it was good and reliable. One big note! Do not apply excessive pressure to this probe! 300 PSI will destroy the gauge. I usually apply 10 PSI of pressure to the system before disconnecting the vacuum gauge to prevent contamination. Once it's disconnected I then charge the system to the maximum.

This German designed Testo vacuum probe is amazing and at half the cost of the ones with a digital LCD screen, this uses your iPhone or android as the readout. It works well for mini split vacuum monitoring, select "evacuation" from the long list of devices that app supports. And fire it up. Piece of cake. IMPORTANT.... Watch the triple evacuation video on Youtube from HVAC Tips guy ... I used his simple setup with two Appion Core removal tools. I did lose an hour wondering if the thing was working then I found and removed a "3rd" schrader valve, one was in the 5/8 Appion core removal tool, one in the 1/4" Appion core removal tool, in addition to the schrader inside the minisplit port. Once all three were gone, the vacuum sucked down fast and this gauge worked amazing. Was wondering if I should have bought CPS or another larger unit but paired with my iPhone over bluetooth it works great. VERY HAPPY with this gauge and price, it made the vacuum part of the DIY install go smooth. BTW, if you're wondering what a schrader valve is, it's the same little screw in tiny valve that holds air in your tires. It works one way. No mystery to that thing. Those Appion core removal tools worked great.

Just used this vacuum gauge with my Testo app. It made my life so much easier. I was able to connect flawlessly to the app and Moni Yi for the evacuation of the minisplit system. Nice to be able to triple evacuate and save the whole process. Very easy to use and well worth the cost. Nothing like doing things right and recording the entire process.

Fairly good distance, battery life is good, accurate, good app

I been using this product for a few days now and it’s worked like a champ rain or shine. I love it and it’s easy to use. Would be helpful if it came with some adapters such as a 90 or a 1/4” to 5/16” mini split adapter. Most mini split adapters you buy don’t have the stem in them to press the center pin that presses the stem down to open the service valve. I had to specifically buy one for using this tool on mini splits and that’s all I deal with. All around good product though.

put this on a refrigeration recovery tank while evacuating it. I was able to drift around over about 40 feet or so and occasionally look at my iPhone to see the evac was going. Very useful. Was easy to use and to get going. OTOH, the app menu is not totally intuitive so it took me a while to get going at first. After that was easy to use.

Muy bueno. Excelente producto

Why did you pick this product vs others?: Bought it. Worked Great, got it stolen. Bought another one. Still awesome. Would buy again.

Product works good. But can be hard on testo app to change from bars to microns. I haven’t figured it out, but I just googled the conversion.

Delle migliori sonde sul mercato.

El producto llegó dos días antes de lo previsto todo bien se nota de muy buena calidad, llegó con baterías nuevas ya le hice la primera prueba con ml bomba y todo bien aún no lo he puesto a prueba en campo.

Muy buen calidad, lecturas rápidas y precisas, configuren correctamente la app de testo por qué e visto comentarios de personas que se quejan pero es por qué no leen o configuran correctamente, el equipo está perfecto, ampliamente recomendado

Es una sonda de calidad. Lo que se espera de testo.. la interface bluetooth hacia el celular es genial. Las lectura es muy precisa