Until about a decade ago, all refrigeration pressure measurements were taken with reliable analog measuring gauges. Then, like so many other gadgets, digital refrigeration pressure measurement gear and their related apps were introduced. The initial sets of these digital gauges hit equipment stores for around $1500 making them only obtainable by the most enthusiastic gadget fanatics.
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Now though, similar kits can be found for around $275. Even the most advanced brand name systems sell for under $500.
What are the advantages of these devices, and is the investment worth your hard-earned cash? Let's take a closer look at one of the most popular complete digital sensor kits – the Testo Smart Probe AC and refrigeration test kit (seen above). This $275 kit includes a carrying case, dual temperature sensor probes, and two high-pressure sensors.
Connecting to the Bluetooth enabled sensors is entirely app-based. This brings us to the biggest disadvantage of these systems – unlike “old fashioned” pressure gauges, you can't just plug and play. All measurements are made using your smartphone, so climbing up on the roof to get readings and forgetting your phone means climbing back down to your van. Additionally, forgetting to carry spare batteries for the sensors or not charging your phone, well, you get the idea…
There are not many other disadvantages though, and in this connected world, the app-only lifestyle might not be that much of an issue.
Advantages of systems like this are the lack of bulky hoses (which also means less refrigerant loss), the ability to capture data over a longer time frame, support for multiple refrigerants and the ability to connect more than just the included sensors. Collected data can usually be stored, emailed, exported and printed which is especially helpful if the problem needs to be documented. With captured data, it is also easy to calculate superheat and subcooling.
One other advantage often not mentioned by the manufacturer is that the longer range of the newest Bluetooth systems allows technicians to retreat off a hot roof while the sensors capture data. Newer sensors can even save a limited amount of measurements locally, so if your Bluetooth connection drops, reconnecting to the sensors will transfer the readings to the app without any loss of data.
Wireless measurement equipment is made by a variety of companies, but the largest and most well known come from Fieldpiece, Sporlan, and Testo. Once you invest in a system, keep in mind that sensors from one brand won't be compatible with those from another – so if you break or lose a sensor, you'll need to replace it with one from your original brand. With some cheaper brands, there is no guarantee that they will always be around, so one defective or lost sensor means replacing the entire system.
The most advanced configurations can be expanded with more than just pressure and temperature sensors, allowing for upgrades with psychrometer probes, anemometers, replacement temperature probes, hygrometers, and even wireless refrigerant scales – all reporting to a single app!
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