Analog manifold gauge sets have long been the standard for HVAC
AC and Refrigeration Service Technicians to check pressures of heating or
refrigeration systems. Using this pressure reading, the technician would
convert that to temperature using a chart to start the process of calculating
superheat and sub-cooling to aid in troubleshooting of issues that were
affecting efficiency of either system.
Analog gauges work great but they have a large limitation in the number of refrigerants you could design them for, as there was no physical space for many refrigerant on the gauge scale. Most analog gauge sets work for up to 3 specific refrigerants. This eventually led to technicians having to keep multiple sets of gauges depending on what refrigerants they were using. Also, any time new freons came to market and were being utilized, a technician would have to buy a new set of gauges.
A few years back, a new style of gauges was created to fix this flaw – digital ac manifold gauges. From the onset, they seemed to be better and more accurate; however, techs were not utilizing them due to overcoming a learning curve, paying more for a set, and their analog gauges still working. Digital gauges have now all but replaced analog gauges, so let us focus on their advantages in order to provide more clarity for those who have been thinking of buying new gauge sets.
- Digital gauges are more accurate, as data processing is based on circuit board and processing chip intelligence, not only physical measurement.
- They come with a broad selection of refrigerants (typically 50+), so techs can test scores of coolants with one gauge.
- Many come with wireless communication allowing for data streaming to mobile devices.
- No more conversion tables, which were used with analog meters.
- Simultaneous display of temperatures, pressures, superheat and subcool values.
- Many include the option to plug a vacuum gauge right into the manifold.
- Some manufacturers offer diagnostic software, as a part of the set to further facilitate troubleshooting and interpretation of readings.
- Lower overall long term investment, as only one tool is required.
Figure 3 - The Testo 550 Manifold Kit and the Yellow Jacket P51-870 Manifold Kit
The most popular models are: Fieldpiece SMAN360
and SMAN460, Testo 549, 550 and 557, UEi AK940,
and Yellow Jacket newest product P51-870 and P51-860.