
Zeus isn’t here to sell you tools - already too many salesmen, using too much oxygen in this world as it is, kinda like lawyers- IMO. Zeus has no financial interests in any of the orginizations, companies or OEM’s represented or recommended here. Zeus bases these recommendations on experience with service, quality, integrity, honesty and value comparative to the instrument and it’s versatility in application and capabilities.
At this time Zeus recognizes and recommends a single source for advanced diagnostics instruments - TRUTech Tools - the reason for that is simple, as many of Zeus’ readers have discovered for themselves - service, quality and integrity. Totally professional.
Zeus hands out the Best Value Seal sparingly - it will rarely if ever be seen again aside from this article. It is not something that is taken lightly nor is it based on unsubstansiated claims and promises.
TRUTech Tools has requisitioned the final remaining handful of the Authentic first Generation Testo 523 RSA’s. Still boxed, fully supported and with full warranty at a fraction of their original cost. Available either without - Testo Package 1($349.00) or with - Testo Package 2 ($425.00), data logging interface software and cable. For a little more than the cost of a high quality analog manifold rig you can purchase an advanced diagnostics instrument with 10 fold the capabilities, reliability and accuracy of the analog set you are using now. So if you’re sitting on the fence, get off your ass and get over there - because when these are gone - they are gone.
For those of you that might need a refresher course, or for the ones who have not been paying attention in class, I’m including a brief spec review of the original 523 below, or better yet call Big Jim at (330) 696-6361 and experience what it’s like to deal with a man that know’s about the tools and instruments we use because he has used them - not because he’s read the latest edition of the catalog.

These are simply overstock. These were a great buy even at the $700+ list. We need to clear them out to make way for new stock.
The Testo line of refrigeration system analyzers is changing the way the HVAC/R world troubleshoots, commissions and services AC & refrigeration systems. With its graphic capabilities and superior accuracy, no other product made can compete at this level.
After rigorous testing in the lab and the field, the digital manifold has been proven to deliver laboratory accuracy results in demanding field service. The multi-functionality, reliability, repeatability, and unique features (eg. temperature compensated pressure testing) sets the Testo products apart from similar products.
Technicians will appreciate the ease of use, the wide range of applications, and the ability to upgrade to new refrigerants along with the data logging capabilities. Small features like a protective boot and a liquid sight glass have not been overlooked. The pressure-temperature chart is a thing of the past, and commissioning equipment to anything less than the manufacturer’s standard will become uncommon for all Testo users. Technicians can get more done with higher accuracy and quicker results than ever possible. Field documentation can be done with little effort, providing any interested party with the information needed to evaluate system operation in the field or the office.
Testo has taken a quantum leap forward in AC/R measurements allowing anyone from the lab technician to the service technician to deliver consistently accurate results to owners, manufacturers and end users of air conditioning and refrigeration equipment
The Testo 523/560 digital refrigeration/air conditioning system analyzer is a multipurpose tool designed to replace a gauge manifold, superheat or subcooling thermometers, Pressure-Temperature charts, etc.. with a rugged hand held versatile tool.
Unlike traditional gauge sets, the Testo 523 has dual pressure sensors that are accurate over the full range of working pressure and temperature measurements. From –14.7 to 725 psi, the sensors display with 0.1 psi resolution. The high and low side sensors are identical, allowing accurate pressure measurement over the full range on either side. The 35 onboard temperature pressure charts (can hold three additional user variable charts) provide unparalleled detail and accuracy. Unlike traditional charts no interpolation of the temperature-pressure relationship is required. It is now possible to measure and set superheat and subcooling with laboratory accuracy in the field as the Testo 523 reads pressures and temperatures to the tenth of a psi and tenth of a degree and automatically calculates real-time superheat and subcooling. Using absolute sensors, changes in altitude do not affect the zeroing of the instrument’s sensors unlike bourdon tube gauges. Shocks from normal handling (eg. dropping from its hanging hook in the back of a service vehicle) do not affect the sensor calibration. No field re-zeroing is ever needed. The platinum based spring loaded sensor (Pt-100) has a very low mass (yielding a fast response) and is not affected by any stray voltages which may be present on the equipment (unlike traditional K-type thermocouples). The sensor is available in lengths up to 40 feet. The Velcro-elastic strap provides insulation from ambient air along with positive contact to the refrigeration line from ¼” to 3” in diameter. Air and immersion probes are also available to further enhance your testing applications.
Also incorporated into the system analyzer is a new dimension: Time. Testo was first-to-market with a complete line of refrigeration system analyzers that incorporate data logging. This allows the service technician and/or system analyst to evaluate system performance over a period of time from a snapshot to 45 days. In addition, no laptop is required to review the logged readings.
The most significant advantages come when data from a Testo 523 is read, analyzed and managed in the Testo PC Software. (Optional) It is now possible for the technician designer, engineer, service manager, or a lead technician to spot trends, benchmark systems, verify proper/design operation, provide real-time system operation to a manufacturer or other interested party in an tamperproof data format that can be graphed to provide a “digital window” into the refrigeration/air conditioning system. System high and low side pressures, saturation pressures, measured temperatures, along with superheat and subcooling can be viewed on an auto-scaling graph. All measurements or each individual measurement can be viewed at once. Sections of the graph can be zoomed in on by dragging a box over the suspect area for further investigation when warranted.
Testo has not overlooked small, but important details that make the products well suited for field use. Owners of Testo products have come to expect such features as a display backlight, user selectable units, a sight glass, and battery life indicator to provide flexibility and reliability in their work.
• Real-time superheat and subcooling readings
• Confidently charge at outdoor temperature down to 55°F
• 35 “P/T charts” built-in, plus more FREE at www.testo.com
• Digital readout of temperatures and pressures
• One button MIN/MAX/HOLD/AVG
• Easy line temperature readings
• Built-in, 2-way manifold with sight glass
• Powerful PC analysis software
• Read up to 725 PSI high and low sides (psia or psig)
• Pressure leak test mode built-in
Refrigerant pressure range: 725 PSI (50 Bar)
Pressure resolution: 0.1 PSI
Pressure overload: 1087 PSI (75 bar)
External temperature input: 1, Pt 100
Temperature measurement range: -148 to 300°F
Memory locations: 1000
Data interface: RS-232 to PC
Pre-loaded refrigerants: 35
User variable refrigerants: 3
Weight (approx.): 2.4
| Dimensions: Watertight housing: Pressure accuracy: Ambient temperature compensation: Battery: Battery life: Extended battery life: System connection: Sensor diaphragm: Operating/storage temp.: Compatible with:Measuring units: |
7.75” x 4.5” x 1.75” NEMA 13 (IP 65) 0.5% Full scale 1 digit from 14 to 122°F 9 Volt 40 hours (continuous, backlight off) Sleep mode during extended datalogging 7/16″ UNF 316L Stainless Steel -4 to 140°F any refrigerant; Nitrogen, Water, Glycol (or secondary loop coolants) except Ammonia* Easily switch from English to Metric (SI) |
Includes: 523 RSA, Temperature Probe, Hard case, Quick start guide, and Testo Applications Guide




















