Danfoss AKS 4100 Liquid Level Sensors
The Danfoss AKS 4100 is a liquid level sensor for precise, continuous level measurement in industrial refrigeration vessels — receivers, separators, condensers and accumulators. It uses proven time domain reflectometry (TDR), also known as guided-wave technology: a 2-wire loop-powered 4–20 mA output signal proportional to the refrigerant level.
Measurement is unaffected by dust, foam, turbulent or boiling liquid surfaces, liquid density changes or dielectric-constant (εr) changes. Oil accumulating at the bottom of the standpipe does not interfere with the level signal — no need to remove the sensor for cleaning after draining oil.
Wenzhou Phonetoo Electromechanical Co., Ltd. is an authorized Danfoss distributor in China. All AKS 4100 sensors supplied are genuine, factory-new, with full Danfoss warranty.
Two versions
| Version | Probe | Refrigerants | Installation |
|---|---|---|---|
| Cable version | Adjustable 800 – 5000 mm | R717 (ammonia), HCFC, non-flammable HFC (εr > 5.6) | Must be installed in a standpipe. Not for CO2 or marine applications. |
| Coaxial version | Fixed lengths: 280 – 2200 mm (G1) / 11 – 85 in. (¾ in. NPT) | R744 (CO2, εr > 1.3), R717, HCFC, HFC | Standpipe or directly in the vessel. Required for marine applications. |
Technical data
| Parameter | Value |
|---|---|
| Measuring principle | Time domain reflectometry (TDR) / guided wave |
| Output signal | 4–20 mA, 2-wire loop powered |
| Refrigerant temperature | –60 – +100 °C |
| Ambient temperature | –40 – +80 °C (HMI: –20 – +60 °C) |
| Operating pressure | –1 – 100 bar |
| Supply voltage | 14–30 V DC (powered directly by EKE 347 level controller) |
| HMI | Optional multilingual display (EN/DE/FR/ES or EN/CN/JP/RU); level readout in mm, cm, m (ft, in) |
Approved refrigerants
| Refrigerant | Temperature range |
|---|---|
| R717 / NH3 | –40 / +50 °C |
| R744 / CO2 | –50 / +15 °C (coaxial version) |
| R22 | –50 / +48 °C |
| R404A | –50 / +15 °C |
| R410A | –50 / +15 °C |
| R134a | –40 / +50 °C |
Models & pricing
| Model (code no.) | Version | Price (USD) | Availability |
|---|---|---|---|
| Cable versions | |||
| 084H4500 | Cable version, HMI not included | $2,759 | Contact us |
| 084H4501 | Cable version, with HMI display unit | $3,099 | Contact us |
| 084H4550 | Cable version, with HMI display unit | $3,099 | Contact us |
| 084H4520 | AKS 4100U cable version, HMI not included | $2,759 | Contact us |
| 084H4521 | AKS 4100U cable version, with HMI display unit | $3,099 | Contact us |
| 084H4571 | AKS 4100U cable version, with HMI display unit | $3,099 | Contact us |
| Coaxial kits, with HMI display unit | |||
| 084H4510 | Coaxial kit, 1 tube, with HMI | $3,949 | Contact us |
| 084H4560 | Coaxial kit, 1 tube, with HMI | $3,949 | Contact us |
| 084H4511 | Coaxial kit, 2 tubes, with HMI | $4,119 | Contact us |
| 084H4561 | Coaxial kit, 2 tubes, with HMI | $4,119 | Contact us |
| 084H4512 | Coaxial kit, 2 tubes, with HMI | $4,119 | Contact us |
| 084H4562 | Coaxial kit, 2 tubes, with HMI | $4,119 | Contact us |
| 084H4513 | Coaxial kit, 2 tubes, with HMI | $4,119 | Contact us |
| 084H4563 | Coaxial kit, 2 tubes, with HMI | $4,119 | Contact us |
| 084H4514 | Coaxial kit, 3 tubes, with HMI | $4,279 | Contact us |
| 084H4564 | Coaxial kit, 3 tubes, with HMI | $4,279 | Contact us |
| 084H4515 | Coaxial kit, 3 tubes, with HMI | $4,279 | Contact us |
| 084H4565 | Coaxial kit, 3 tubes, with HMI | $4,279 | Contact us |
| 084H4530 | AKS 4100U coaxial kit, 1 tube, with HMI | $3,949 | Contact us |
| 084H4580 | AKS 4100U coaxial kit, 1 tube, with HMI | $3,949 | Contact us |
| 084H4531 | AKS 4100U coaxial kit, 2 tubes, with HMI | $4,119 | Contact us |
| 084H4581 | AKS 4100U coaxial kit, 2 tubes, with HMI | $4,119 | Contact us |
| 084H4532 | AKS 4100U coaxial kit, 2 tubes, with HMI | $4,119 | Contact us |
| 084H4582 | AKS 4100U coaxial kit, 2 tubes, with HMI | $4,119 | Contact us |
| 084H4533 | AKS 4100U coaxial kit, 3 tubes, with HMI | $4,279 | Contact us |
| 084H4583 | AKS 4100U coaxial kit, 3 tubes, with HMI | $4,279 | Contact us |
| 084H4534 | AKS 4100U coaxial kit, 3 tubes, with HMI | $4,279 | Contact us |
| 084H4584 | AKS 4100U coaxial kit, 3 tubes, with HMI | $4,279 | Contact us |
| 084H4535 | AKS 4100U coaxial kit, 4 tubes, with HMI | $4,449 | Contact us |
| 084H4585 | AKS 4100U coaxial kit, 4 tubes, with HMI | $4,449 | Contact us |
| Coaxial kits, HMI not included | |||
| 084H4503 | Coaxial kit, 1 tube, HMI not included | $3,499 | Contact us |
| 084H4504 | Coaxial kit, 2 tubes, HMI not included | $3,669 | Contact us |
| 084H4505 | Coaxial kit, 2 tubes, HMI not included | $3,669 | Contact us |
| 084H4506 | Coaxial kit, 2 tubes, HMI not included | $3,669 | Contact us |
| 084H4507 | Coaxial kit, 3 tubes, HMI not included | $3,829 | Contact us |
| 084H4508 | Coaxial kit, 3 tubes, HMI not included | $3,829 | Contact us |
| 084H4524 | AKS 4100U coaxial kit, 1 tube, HMI not included | $3,499 | Contact us |
| 084H4525 | AKS 4100U coaxial kit, 2 tubes, HMI not included | $3,669 | Contact us |
| 084H4526 | AKS 4100U coaxial kit, 2 tubes, HMI not included | $3,669 | Contact us |
| 084H4527 | AKS 4100U coaxial kit, 3 tubes, HMI not included | $3,829 | Contact us |
| 084H4528 | AKS 4100U coaxial kit, 3 tubes, HMI not included | $3,829 | Contact us |
| 084H4529 | AKS 4100U coaxial kit, 4 tubes, HMI not included | $3,999 | Contact us |
How we supply coaxial versions: coaxial versions are not stocked as complete factory units. We supply the cable-version sensor plus coaxial tube(s) and mounting parts — functionally identical to the factory coaxial unit, only the order code differs. Each coaxial tube is 680 mm; the number of tubes matches the ordered probe length. Ships from China. Send an RFQ with your refrigerant, vessel dimensions and operating conditions and we will confirm the exact configuration and code number.
Typical applications
- Level control in high/low-pressure receivers and liquid separators (with EKE 347)
- Condenser and surge-drum level monitoring
- Alarm and interlock signals for pumps and compressor protection
Datasheet downloads
Frequently asked questions
What is the difference between 084H4500 and 084H4501?
Both are the cable version of the AKS 4100 for ammonia, R134A, R404A, R410A and R22. The only difference is the HMI: 084H4501 ships with the HMI display/service unit for commissioning and on-site setup, while 084H4500 is supplied without it. An HMI can also be ordered separately (084H4540/084H4590), and one HMI can program any number of sensors.
What power supply does the AKS 4100 need?
It is a 2-wire loop-powered transmitter with a 4–20 mA output, so no separate transformer is required. Supply voltage is 14–30 V DC (16–30 V DC at ambient temperatures from −40 to +80 °C). It can also be powered directly through a Danfoss EKE 347 level controller.
Which refrigerants can the AKS 4100 measure? Can it be used with ammonia and CO₂?
The cable version covers HCFC, non-flammable HFC and R717 (ammonia). For R744 (CO₂) or marine applications the coaxial version must be used — the cable version is not approved for CO₂ or marine use. The coaxial version additionally covers ammonia, HCFC and HFC.
What is the HMI display unit for? Do I need one?
The HMI is a detachable display and service tool used to commission the sensor and adjust settings on site. Level and settings are shown in mm/cm/m (or ft/in) with multi-language support. Note: every AKS 4100 must be programmed via an HMI, but a single HMI unit can program any number of sensors, so one unit per site is enough.
What probe lengths are available?
The cable probe is field-adjustable from 800 to 5000 mm. The coaxial version comes in fixed lengths: D14 from 500 to 2200 mm, D22 in 280 mm (metric); imperial (U) versions with NPT threads are also available.
What is the output signal?
4–20 mA (or 3.8–20.5 mA per NAMUR NE 43), 2-wire loop-powered, proportional to the refrigerant level.
Is this a genuine Danfoss product?
Yes. We are an authorized Danfoss industrial refrigeration distributor in China, listed in Danfoss China's official authorized dealer directory. All units are brand-new, genuine stock with valid warranty.
Where do you ship from, and how long does delivery take?
We ship from China. Express delivery takes about 1–2 weeks to most destinations worldwide; sea freight is available on request — contact us for a quote.
How do I select the coaxial version of the level sensor?
Selecting the coaxial version involves four steps: 1) choose AKS 4100 (G1 thread) or AKS 4100U (NPT 3/4 thread); 2) determine the coaxial tube length; 3) choose the language; 4) decide whether an HMI is needed. Example: for a 1200 mm English-language coaxial AKS 4100 with HMI — option 1: select 084H4513 or 084H5663 directly from the selection table, but factory coaxial versions have limited stock and longer lead times. Option 2: use a cable-version sensor plus coaxial tubes and end fittings instead. Standard coaxial tubes are 680 mm long, so 1200 ÷ 680 = 1.76 — use 2 tubes; e.g. 084H4501, or 084H4550 + 2 × 084H4543 (coaxial tube) + 084H4549. We can supply standard-length tubes or cut them to your required length.