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testo 557s – 4-Way Smart digital manifold with Bluetooth – techtown user review

testo 557s

Note: this review of the new testo 557s was written by a techtown member as part of our community tool review program. Scroll to the bottom of this article to learn more.For more information on the newest lineup of smart digital manifolds from testo, visit this recent article.

Here are my thoughts on the Testo 557S manifold after about a month’s use.

I have been in the HVAC/R trade for the past 25 years and have been reluctant to go digital – no logical reason perhaps just skeptical.

My go-to manifold has been the Yellow Jacket Brute manifold so it is what I am making comparisons to.

For lack of better words, I am quite pleased with it as evidenced by the fact that the old analog gauges have been moved deeper into the service truck where they are harder to get to.

I have only used the 557s standalone with the Bluetooth 552i micron gauge, 115i temperature clamps and the 605i temp/humidity probes. No experience with any Testo app thus far.

My first impression is that is solidly built, as are the sensors. I believe the manifold is produced in Germany and possibly the sensors as well although it does not specifically say so anywhere.

The screen is easy to read, the menus are intuitive and I like the “feel” of the buttons and valve knobs. The general construction and layout seem well thought out. The screen is recessed, helping prevent scratches. I like to put 3M screen protector on my Fluke meters so have done so on the Testo as well for peace of mind. The hook on the back is nice and folds away neatly.

The information on the screen when coupled with the Bluetooth sensors is very satisfying. I find myself checking superheat and subcooling often now since it is so easy.

I especially enjoy the pressure test and evacuation modes in addition to the main screen. Overall I can not fault this unit for anything of importance. The backlit screen is really nice when in darker scenarios.  

The battery life is impressive, the battery indicator still shows all three bars after is at least 20 hours of use and then mostly with the backlight on.

The sightglass is nice and bright whereas the Brute glass tends be a little dark.

I feel confident that the information provided is accurate and it is easier than ever to get superheat and subcooling readings.

The few quirks are minor and somewhat based the fact that I am used to the Brute; mentioned next in no particular order.

I find the knobs a little too close to each other for my liking (my hands are largish) I would not mind a slightly larger manifold to help spread them out a bit.

What initially “won me over” on the 557S was the “analog” pressure representation on the primary screen but sadly find it kind of useless;

They are no needles one can simply glance at and know where they “should be” like on analog gauges. What makes them particularly annoying is that the scales on them adjust as the operating pressures change. It would be better if the ranges were fixed based on the selected refrigerant (like analog gauges). It takes longer to figure them out than it does to simply look at the large numbers below them. The thought is nice but not well executed in my opinion. In the end not a big deal as I am getting used to looking at numbers now.

I find the hose connections too closely spaced for my liking and do not really like the ones on the side so far, I prefer them to connect on the back only. This could simply be because of my familiarity with the Brute manifolds.

I like the hook that can be tucked away when not wanted and so far really like it. I was however informed by a technician who has owned several Testo manifolds that the hook tends to pop out of the socket. Since the housing is a plastic material I am not hanging the manifold up in the truck where it is subjected to bumpy roads.

I would like if there was a mode to have it boot up with the backlight OFF instead of the default ON. During normal daylight I tend to forget to turn it off.

I wish the DELTA T mode would also connect to the 605i sensors but it appears it will only accept the 115i temperature clamps.

It would be nice if the micron gauge would start reading from atmospheric pressure and not at 20,000 (If I remember correctly).

Overall – highly recommended.

Once again, thanks to our community member for providing this excellent review of the new testo 557s smart digital manifold. If you would like to join our tool review program, please visit this page and submit your information.