I got a Testo 552 micron gauge at the same time I got the Bluvac, about
which I posted not too long ago.
Unlike the good experience with the Bluvac, the Testo experience has
The reason to buy the 552 was because of the broad measuring range, from
Atmospheric pressure all the way down to 0 microns. The sales brochure
indicated accuracy of +/-10 microns under 1000 microns.
In real life things are different:
- The vacuum accuracy specs for the 552 are different depending on
where you read: Downloaded users manual from Testo, Sales brochure from
Testo, information provided by Testo to resellers, or the user's manual
that you get with the instrument; all of them are different. The worst
specs come with the instrument, which indicate that the accuracy for vac
under 1500 microns is +/- 75 microns or +/-10% of the reading, whichever
- The first 552 that I got read 460 microns when I had 36 microns on
Bluvac, recently calibrated at the factory. I mentioned the problem to
the seller, and they sent me a replacement, that read 320 microns when
at 36. The seller exchanged it once more, and the 2nd replacement read
320 microns as well. The problem is that all the 3 meters, read the
actual atmospheric pressure correctly, meaning that if you calibrate the
zero, the high end of the scale is going to be off. In any case, the
instruments were way outside any of the published accuracy specs.
I got the Testo from TruTechtools.com, on sale for $179 free shipping.
They were great in trying to make me a satisfied customer, but
unfortunatelly, Testo did not live up to their published specifications.