Danfoss LLS 4000, LLS 4000U Data sheet

Data Sheet

Liquid level switch Type LLS 4000 and LLS 4000U

Compact, cost-ecient, and reliable switch for liquid level measurements

The LLS 4000/4000U liquid level switch is designed to detect the state (gas or liquid) of the refrigerant in front of the sensing head, while installed in a wide range of refrigeration applications.

The LLS level switch comes in 2 variants, LLS 4000 and LLS 4000U. They are identical except for the connector thread interface to the system. The LLS 4000 is provided with G thread, while the LLS 4000U is provided with

NPT

⁄4” thread.

⁄4”

The LLS 4000/4000U liquid level switch is based on the proven reectometry measuring technology (microwave level measurement) adapted specically for the new LLS 4000/4000U switch.

LLS 4000/4000U liquid level switches can be used to control the liquid level of many dierent refrigerants in vessels, accumulators, receivers, standpipes, etc. The switches are normally installed in a pair of two, controlling the upper liquid level and the lower liquid level.

The level switch includes a relay that switches by change in refrigerant state. The on site conguration of the LLS allows the normally open/closed relay setting depending on the desired correlation.

For SIL applications a SIL2 version is available with blocked conguration (not congurable).

All conguration and readings from the LLS switch are performed through Bluetooth and a downloadable special Danfoss app.

AI323832972563en-000401

Liquid level switch, type LLS 4000 and LLS 4000U

Features

• Plug and play liquid level switch

• Easy installation and minimum or no need for conguration

• SIL design with redundancy on microprocessor and relay

• Convenient communication with all units via Bluetooth and a Danfoss app

• SIL2 compliant version

• Two commonly used connection variants

• Maintenance free

• Replacement of electronic part without removing mechanical part (not applicable for SIL2 devices)

• Applicable for ammonia and commonly used H(C)FCs

• Applicable for R1234ze(E) with POE oils (miscible) or oil free systems

• Applicable for refrigerant oils in Ammonia and H(C)FC systems with a refrigerant gas temperature up to max. 80 °C

• For other medias and mixed medias, please contact Danfoss

• Well proven reectometry measuring principle

• Conforms to: Telecommunications Directive RED 2014/53 EU. Low voltage directive 2014/35/EU. EMC directive 2014/30/EU. ROHS 2011/65/EU

• Approvals: SIL2, FCC, IC, EAC, UA, CMIIT, ANATEL, NBTC CRN

Liquid level switch, type LLS 4000 and LLS 4000U

Applications

To control if a liquid level is within predened allowed limits, two LLS 4000 are installed in an upper and a lower limit position respectively. By this setup the liquid level is between the two level switches and the lower switch will sense liquid, while the upper will sense gas.

In case the liquid level moves outside the limits, one of the switches will sense opposite and switch the built-in relay. This relay switch function should be used for alarm settings. This is made easy when connected to the system PLC.

Figure 1: LLS locations



NOTE:

The LLS can be used wherever liquid levels of selected refrigerants and refrigerant oils must be controlled.

ABC

Upper LLS 4000/U

Lower LLS 4000/U

Liq. Level

A B

Danfoss

60L9031

ABWith liquid

Without liquid

Liquid level switch, type LLS 4000 and LLS 4000U

Figure 2: LLS orientation

 NOTE:

Horizontal installation recommended. Vertical or inclined installation not recommended: * Risk of Gas Pockets

The LLS comes in two versions:

• A standard version, which is applicable for most refrigeration or processing plants, and is fully congurable regarding type of liquid and relay setting.

• A SIL2 version applicable for SIL compliant process plants. This version is non-congurable regarding relay setting (see Congurable parameters) and is intended specic as the upper level switch.

Measuring principle

The measurement principle of the LLS is based on reectometry with a 4.8 GHz to 6.4 GHz linear sweep (Microwave switch technology). The reected signal is characterized by a resonance frequency.

The resonance frequency in air is taken as a reference (f the resonance frequency is shifting to a lower frequency. This is due to the change of the dielectric constant of the medium.

The point level switch monitors the resonance frequency and indicates whether the sensing element is surrounded by liquid or gas. The gure below shows the reference frequency with air (dielectric constant εr=1) in front of the sensing element and with a liquid dielectric constant εr>1.35.

Figure 3: Reference frequency

). When the sensing element is in contact with the liquid,

ref

Media

Saturation temperature range

Ammonia and listed H(C)FCs and HFOs.

NOTE: For other medias and mixed medias, please contact

Danfoss.

R717 (Ammonia)

-50 °C – +105 °C (-58 °F – +221 °F)

R22 (HCFC)

-50 °C – +86 °C (-58 °F – +187 °F)

R507A (HCFC)

-50 °C – +60 °C (-58 °F – +140 °F)

R134a (HFC)

-50 °C – +91 °C (-58 °F – +196 °F)

R404A (HFC)

-50 °C – +63 °C (-58 °F – +145 °F)

R407A (HFC)

-50 °C – +72 °C (-58 °F – +162 °F)

R410A (HFC)

-50 °C – +61 °C (-58 °F – +142 °F)

R513A (HFC)

-50 °C – +83 °C (-58 °F – +181 °F)

R1234ze(E) (HFO)

(1)

-50 °C – +85 °C (-58 °F – +185 °F)

PAO (Oil)

(2)

Max 5000 cP and +120 °C (Max 5000 cP and +248 °F)

POE (Oil)

(2)

Max 5000 cP and +120 °C (Max 5000 cP and +248 °F)

Mineral (Oil)

(2)

Max 5000 cP and +120 °C (Max 5000 cP and +248 °F)

Liquid level switch, type LLS 4000 and LLS 4000U

Media

Refrigerants

Table 1: Approved media

(1)

R1234ze(E) with POE oils (miscible)

(2)

When detecting oils in Ammonia, H(C)FC and HFO systems, the refrigerant gas temperature above the oil must be lower than 80 °C

New refrigerants

Danfoss products are continually evaluated for use with new refrigerants depending on market requirements.

When a refrigerant is approved for use by Danfoss, it is added to the relevant portfolio, and the R number of the refrigerant (e.g. R513A) will be added to the technical data of the code number. Therefore, products for specic refrigerants are best checked at store.danfoss.com/en/, or by contacting your local Danfoss representative.

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