Technicians need to verify superheat to ensure compressors are operating well. (See related article by John Tomczyk, "Understanding Superheat," in this issue.) Subcooling is also important to check, especially for newer refrigerants like R-410A, to verify that the condenser is performing as designed. Both superheat and subcooling usually require several measurements, PT tables, and math by the technician. There is potential for error.
At the same time, many faults may be difficult to detect with traditional tools. A thermostatic expansion valve that is hunting slowly and fluctuating over several psi is very difficult to isolate using a needle or purely digital pressure gauge.
One SolutionThe Digital Refrigeration System Analyzer (DRSA) from Digi-Cool Industries of Duncan, British Columbia, Canada. The instrument is designed to replace analog gauges on most service manifolds. It is said to show pressure symptoms clearly, facilitating more accurate diagnosis, according to the company.
The product displays small changes from the digital readings, with 1/4-psi resolution on the low side and 1-psi resolution on the high side. The company said the display reveals early warning signs for many faults.
Also, the analyzer automatically calculates saturation temperatures based on detected pressures for refrigerants stored internally, eliminating PT chart calculations. It also indicates vacuum in mercury (Hg) "for a rough reading during routine service."
Advanced FeaturesThe product can be used indoors and outdoors, the company said. The case is said to resist impacts, typical oils, acids, and sun exposure.
The DRSA-1100 comes with a pipe-mounted temperature probe. It performs superheat/subcooling calculations automatically for 22 refrigerants and can be upgraded for additional refrigerants, the company said. It also tracks pressure minimums and maximums, which can be used when setting pressure controls.
According to the company, this new model is an improvement upon the BTD-1000 released last year. The BTD-1000 remains available without the temperature probe and max/min pressure monitoring feature. It retains the bar graph for pressure dynamics and the claimed Â±0.5 percent accurate digital display. Bubble and dewpoints are shown for 16 common refrigerants.
Publication date: 06/07/2004