08/08/2026
When is Compressed air quality performance not critical?
Compressed air dryer dewpoint performance is a serious matter. The majority of plants have compressed air dryers fitted as a standalone unit and as inbuilt units within the compressor. However, less than 5% have a dew point performance monitoring system fitted.
A standard refrigeration air dryer is fitted with a thermal probe that measures the physical temperature of the compressed air and not the actual moisture content in ppm or °C Td of the c/air leaving the air dryer.
These probes are basic fitments to most air dryers. They normally measure the actual physical temperature in the compressed air/Freon heat exchanger – the coldest part of the dryer. It does not reflect the actual pressure dew point of the compressed air being introduced into the factory. The dew point (compressed air dryness) of your compressor system can fluctuate wildly for a number of reasons.
Causes of dew point variation can be the result of many factors. These are summarised as:
• Compressed air volume overloading, thus exceeding the dryer capacity and elevating dew points.
• Low inlet compressed air pressures; normally when < 7 bar G.
• A jammed condensate drain valve. Condensates are formed but are not drained!
• High inlet air temperatures and high compressor room temperatures, e.g. above the dryer’s standard selection criteria.
• Poor setting of gas expansion and/or a hot gas bypass valve.
• A bypass valve left open!
• Poorly designed inlet/outlet air piping to the dryer.
• The air dryer’s refrigeration compressor is tripped on internal overload. Rarely is it ever reflected on a dryer’s fascia display.
• An Eskom mains failure, with no auto restart system on the air dryer.
These faults can dramatically affect an air dryer’s performance.
Most operators doing their daily walk through will rarely spot the problem. And the majority will struggle to identify the cause of the fault. If one analyses the effect of any of the problems above, the results are a high-pressure dew point.
Solution - The fitment of an independent dewpoint monitor on the air line, after the air dryer, will highlight the high dew point problem. The S305 Suto Dew Point Monitor will sound a warning horn and flash large warning LED lights in the compressor room/area. The operator screen flashes its red backlight and the 4 … 20 mA output can be used to connect the dew point monitor to a PLC or a SCADA system. The S305 unit has volt free contacts.
Every compressed air dryer should have one! The investment cost is very affordable especially when compared to the cost of contamination to the compressed air system. We also offer a system to monitor compressor oil vapour carry over to your plant. The S120 is for oil vapour and the S130 is a particle counter system. The S132 is an air quality system that contains everything you will ever need!
Option 1 is available from minus -60 to +20 °C Td dew points.
Option 2 is available from minus -20 to +50 °C Td dew points.
Artic Driers International, founded in 1991, is the trusted supplier for all compressed air treatment equipment that you could require. We import from around the world and now manufacture in the RSA.
Our product range is vast, stock loads are comprehensive, and we have short lead times on local builds.
We offer air leak detection, on site mobile air quality, pressure, volumes etc. and also air dryer refurbishment, air dryer servicing, air dryer hire, as well as special air dryer skid packages.
Why wait? Visit us on articdriers.co.za or call on +27 (0)11 420 0274.
We have the answers and solutions to your challenges! Not bigger… Just better…
https://articdriers.co.za/
https://articdriers.co.za/compressed-air-dryers/
