Testo® 556 RSA: First Impressions

Testo® 556: First Impressions

I’m new to the boards here and I’m not sure if this is the section I should post this in, so if I’m mistaken, please correct me.
I received the 556-1 wireless kit the recently and today was the first chance that I got to use it. The first machine it saw was a 3 ton coolair split that is having occaisional low pressure lock out problems. I’m the third tech on this call and I have not seen the machine until today so I figure this will be a good opportunity to see what this DRSA is all about.

Right off the bat it’s plain to see that this instrument, yes instrument is not for every job. It is rather bulky ( when in case ) and I can’t see techs climbing up and down ladders and running around mechanical rooms with it on a daily basis. I don’t know about you but I like to travel light and usually only carry a small tool bag. I’ll go back to the truck if I think I need gauges. All of my work is commercial and more often then not the problem is electrical in nature. Besides I think that most of us here can tell if a unit is running okay just by feel alone.

With that in mind I have to say that this is the first set of digital gauges that I have ever used and you know what ? I like them. On the call I was on today first tech says TXV is bad, second tech says unit is under charged and has dirty condenser coil. I check and find 125 foot pipe run, 2 liquid line driers ( one at c/u and one inside a/h ), poor airflow evap and excessive pressure drop at a/h. what the 556 allowed me to do was measure pressures,superheat and sub cooling at both locations record them and download them to my laptop all on site. Gauging up was easy and most important of all, quick. The ability to record and transfer the data gathered is not to be underestimated.

The 556 seems rugged enough for its intended use and was relatively easy to set up initially. The display is clear and easy to read and the backlight worked very well. What a pleasure it was to actually see superheat and subcool values along with pressure without having to stop and consult pt chart and then do calculation. I can see that the accuracy of this instrument is a vast improvement over analog gauges. I can tell you that I checked system with my Y/J manifold and when I disconnected them the low side gauge needle was stuck at 15 psi. They were less then a month old and weren’t dropped that I know of. If I wasn’t convinced before I am now.  

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Everyone – This is exactly what i’m trying to get at. It is s fact of life in most companys that you can’t always get the same tech back to the same call. The variability of readings across different gauges and techs is what I would like to see minimized. I Know that for a purely empirical test of analogs vs digital ( excuse me DRSA’s ) I would absolutely agree that duplicating sensor locations and hose connection locations is rule # 1.

The very reason that i even purchased the 556 was so that i could develop some level of confidence in the readings taken by multiple techs across all types of equipment in sometimes less than optimal conditions. Some techs have $400 multi sensor temp kits, some are using fieldpiece, one kid even showed me where he tucked the tip of his pocket digital thermometer under the suction piping insulation. Add to that the inaccuracy inherent in analogs and we can all see that is time for a change.

Field Applications

Hello everyone – today was the third time i have used the 556. today’s patient was a 80 ton Trane water cooled VAV unit with four compressors, each with single circuit. Age of unit is appx 20 years old. Several of these units have developed leaks and I havn’t found them all yet. I’ve used electronic leak detectors, Halide torches, bubbles and dye. As this is typical of the type of service work most of us encounter I thought it would be a good trial for the 556.

The 556 is rugged and appears well suited to field use. It is very easy and intuitive to use and dare I say fun. What a pleasure it is to watch s/h & s/c readings in real time. Here is a picture of the setup I used before the TESTO arrived.

 I underestimated the time saved and ease of gauging up to equipment.. I attached wired probe to LL line and wireless probe to suction line. I left radio handle inside unit and it broadcasted temp signal to 556 flawlessly. Yesterday I could not get it to read s/h & s/c values. Then I realized that I forgot to enter refrigerant type. After that okay. Here is a picture of both the old way and the new way of checking charge. I like the new way better.

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