MAKING MODERN LIVING POSSIBLE
© Danfoss A/S (AC-MCI/MWA), 2012-05  DKRCI.PD.SC0.C3.02 / 520H5687 1
Technical brochure
Liquid Level Sensor
AKS 4100/4100U
The AKS 4100/4100U  liquid level sensor is designed 
specically to measure liquid levels in awide range of 
refrigeration applications. 
The AKS 4100/4100U liquid level sensor is based 
on a proven techhology called Time Domain 
Reectometry (TDR) or Guided Micro Wave.
AKS 4100/4100U liquid level sensor can be used to 
measure the liquid level of many dierent refrigerants 
in vessels, accumulators, receivers, standpipes, etc.
The electrical output is a 2-wired, loop powered 
4-20 mA output signal, which is proportional to the 
refrigerant liquid level.
AKS 4100/4100U in a cable version is suitable 
for most commonly used refrigerants, including 
R717(ammonia), HCFC, HFC and non corrosive gases/
liquids except CO
2
, and diering lengths from 800 
mm(31.5 in.) and up to 5000 mm (197 in.).
The coaxial version of AKS 4100/4100U is designed for 
use with CO
2
. It can also be used for all other appoved 
commonly used refrigerants.
The AKS 4100/4100U coaxial version should always 
be used for marine applications for all refrigerant 
types.
The AKS 4100/4100U cable version should NOT be 
used for CO
2
 or marine applications.
Dust, foam, vapour, agitated surfaces, boiling 
surfaces, changes in density or in the dielectric 
constant , εr, for the liquid have no inuence on the 
AKS 4100/4100U performance.
Oil accumulated in the bottom of a standpipe will not 
disturb the liquid level signal and it is not necessary 
to remove AKS 4100/4100U for cleaning after oil has 
been drained out of the standpipe.  
AKS 4100/4100U - Coaxial VersionAKS 4100/4100U - Cable Version
Features Approved and qualied by Danfoss for 
refrigeration applications
One product covering several probe lengths 
(cable version)
A single product for  all commonly used 
refrigerants (cable version)
Cable version requires less top-end clearance 
for installation and service
Proven operation with all refrigerants in 
combination with oil.
No need to clean cable version when fully 
covered by oil.
The cable version is very compact and easy 
to handle, ship, install and use with dierent 
lengths and refrigerants
Changes of the liquid dielectric constant (εr) 
do not aect operation.
5000 mm (197 in.) probe length with cable 
version
2-wire loop powered; no separate transformer 
needed. 
 
Please Note: 
If used together with Danfoss EKC 347 Level 
Controller, a 14-30 V d.c supply is required.
Multi language HMI.  
Level and setting readout in mm,cm,m( ft, in.)
For further details regarding mechanical and electrical installation please refer to the product 
instructions PI.SC0.D (CABLE version) and PI.SC0.E (COAXIAL version).