The AKS 4100 / AKS 4100U liquid level sensor is designed specifically to measure refrigerant liquid levels in a wide range of refrigeration applications, in vessels, accumulators, receivers, standpipes, etc. The AKS 4100 / AKS 4100U liquid level sensor is based on a proven technology called Time Domain Reflectometry (TDR) or Guided Micro Wave. The electrical output is a 2-wired, loop powered 4-20 mA output signal, which is proportional to the refrigerant liquid level. AKS 4100 / AKS 4100U cable version is suitable for HCFC, non flammable HFC and R717 (Ammonia), and is available in lengths from 800 mm (31.5 in.) and up to 5000 mm (197 in.). The cable version should NOT be used for CO2 or marine applications. The coaxial version is designed for use with R744 (CO2), HCFC, non flammable HFC and R717 (Ammonia). The coaxial version should always be used for marine applications for all refrigerant types. Dust, foam, vapour, agitated surfaces, boiling surfaces, changes in density or in the dielectric constant for the liquid have no influence on the AKS 4100 / AKS 4100U performance. Oil accumulated in the bottom of a standpipe will not disturb the liquid level signal and it is not necessary to remove AKS 4100 / AKS 4100U for cleaning after oil has been drained out of the standpipe.