Testo 552 micron gauge - You better look for something else.

[AS]

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 been frustrating.

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 is greater.

- 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.

AS

[Tony944]

micron gauge is very tricky device. You ca not adjust gauge to read zero unless you go into expanded scaling looking at perhaps couple thousand plus cost of instrument. other is your location altitude (elevation). you only can adjusted at your elevation location and that would also be in question. Many years ago I had contract where I needed Transducer in ( altitude of 100k with output 0-10 volts DC) company was in NM claiming that they use this device in shuttle going to the moon I sent it back three times never made it, I finally give up and vent back to something standard that worked thanks for my customer cooperation.

[AS]

The testo is advertised as a absolute pressure gauge, so it should read from 0 to atmospheric.

What kills me is that the published specs are different in the manual available to download online, the sales brochure, the specs given to retailers and in the printed owners manual that you get with the device.

Funny thing, the online and printed manual have the same publication number, but they are different at least, in the specs and the calibration procedure.

Testo sounds like a fishy company to me.

T>>I got a Testo 552 micron gauge at the same time I got the Bluvac, about