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.

The Testo High Pressure Gauge and Vacuum Gauge are vital tools in an HVAC kit. I recently installed a mini-split that required you to evac the linesets before releasing the refrigerant. I had decided on the Testo platform and already had their Digital Manifold, as well as their wireless probes. I decided to get their vacuum probe to add into the ecosystem. These connect very easily to the system, though I do recommend using them alongside with a core removal tool so you can easily isolate and disconnect them. Actually, the setup I used was: HVAC Port to Core Removal Tool. Once you remove the core, I connected that online to the Vacuum Pump. On the access port on the core removal tool, I had another core depressor (not remover) and then connected the vacuum gauge to the core depressor. This way, You can evac the system to the vacuum pump, and shut off to isolate the system to an evac standing test. I pumped the system down to 200-300 microns, and let it stand for 15-20 minutes. If the system doesn't rise past 500 microns within 10 minutes, its considered a 'leak-free' system, and ready to release refrigerant. At this time, I closed off the core depressor valve, so that everything was 'off' and the released the refrigerant. This is recommended so that refrigerant doesnt get into the vacuum gauge. Though I'm sure it would be fine, I wanted to take the extra precaution. I'm very happy with the testo tools, and that you can save all the data to the App for future review. Since these don't need to be connected with hoses, if you dont want to, you are also potentially losing less refrigerant when using them (talking about the high side pressure gauges, not the vacuum gauge).

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.

Seams durable & work well, but after 50' it's hit or miss & you must be line of sight.

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.

Very easy to use with app

Muy bueno. Excelente producto