Hydac HFS 2145-1S-0001-0004-7-B-1-000 Flow Switch, 1 to 4 L/min

A reed-contact flow switch for oil and lubrication circuits

The Hydac HFS 2145-1S-0001-0004-7-B-1-000 (HYDAC part number 922052) is a variable-area float flow switch from the HFS 2100 series for oils and viscous fluids. The flowing oil pushes a spring-loaded float, and when the magnet in the float reaches the preset position, a reed contact outside the fluid path switches. Because the contact is separated from the oil, the switch is robust and keeps working when the viscosity changes between 30 and 600 cSt.

This version has a switching range of 1 to 4 L/min on a 3/4 inch connection in a nickel-plated brass body, with a mechanical indicator and a single normally open contact.

Technical specifications

Order code in plain words

HFS 2 1 4 5 – 1S – 0001-0004 – 7 – B – 1 – 000: 2 is the variable-area float principle, 1 the measurement of oils and viscous fluids, 4 the 3/4 inch connection digit in the generic key and 5 the male EN175301-803 plug, 1S one normally open contact, 0001-0004 the 1 to 4 L/min range, 7 the 10 % accuracy class, B the nickel-plated brass housing, 1 the mechanical indicator and 000 the standard modification. For the 1 to 4 L/min range the datasheet offers 1/4, 1/2, 3/4 and 1 inch connections; the 3/4 inch version has an installation length of 152 mm, so confirm the port size against your pipework before ordering.

Where flow switches are used

The datasheet names central lubrication, oil circuit lubrication, transformers, cooling circuits, hydraulic systems, pumps, welding machines and laser systems, the chemical industry and research as applications. The contact opens when flow falls below the preset point, so the switch can guard a lubrication line against a blocked pump or a closed valve. Keep the oil free from solid particles, fit a strainer upstream, and stay away from strong external magnetic fields, such as electric motors, which can influence the reed contact.

Fit the switch where the flow is steady and the pipe is full, and choose the switching point so that it sits comfortably inside the 1 to 4 L/min range rather than at its edge. Where a second contact is needed for an alarm, ask for the 2S or 2W version, which fits the extra contact on the side at 90 degrees to the first.

Documents and quotation

The HFS 2100 datasheet is attached. Please state the oil, the switching point and the voltage. See also our flow indicators and switches range.

How the HFS 2145-1S-0001-0004-7-B-1-000 works

The HFS 2100 series uses the variable-area float principle. Inside the housing a spring-loaded float carries a permanent magnet. As oil flows through the switch, it pushes the float in the direction of flow against the spring, and the float position depends on the flow rate. A reed contact sits on the outside of the housing, separate from the fluid. When the magnet reaches the preset position, the reed contact switches. The switch casing can be moved steplessly along the housing, so the user can set the switching point anywhere inside the 1 to 4 L/min range.

On the HFS 2145-1S-0001-0004-7-B-1-000 the single normally open contact opens when the flow falls below the set point. This fail-safe behaviour means a broken wire or a lost flow both give the same alarm state in the controller. HYDAC states that the switch compensates for viscosity between 30 and 600 cSt and can be mounted in any position.

Datasheet values for HFS 2100 size 2

Selection & ordering guide

• Range: size 2 ranges for oil run from 0.5–1.5 L/min up to 35–110 L/min. Choose a range where your alarm point sits near the middle.
• Connection: the third digit sets the thread (1 = 1/4″, 2 = 3/8″, 3 = 1/2″, 4 = 3/4″, 5 = 1″); options depend on the range.
• Plug: 5 = EN175301-803 (DIN 43650) with connector supplied, 6 = M12x1 4-pole without connector.
• Contacts: 1S, 2S, 1W or 2W. With two contacts the second is fitted at 90° to the first.
• Housing: B = nickel-plated brass, S = stainless steel 1.4571.
• Indicator: 0 = without, 1 = with mechanical indicator.

An ATEX version is also listed for potentially explosive areas. Our team can help confirm the correct ordering code for the HFS 2145-1S-0001-0004-7-B-1-000 or a variant with a different range, plug or housing.

Installation & maintenance

• The oil must not contain solid particles; HYDAC recommends a contamination strainer upstream.
• Keep the switch away from external magnetic fields such as electric motors, which can affect the reed contact.
• Observe the flow direction marked on the housing and use thread sealing suited to the oil.
• Set the switching point with the system running at the real oil temperature, then lock the casing.
• Check the switch point during routine maintenance and clean the strainer, because dirt on the float can change the switching behaviour.

Typical applications in Oman & the GCC

HYDAC lists central lubrication, oil circulation lubrication, transformers, cooling circuits, hydraulic systems, pumps, welding and laser systems, chemical plants and R&D. In Oman and the GCC the HFS 2145-1S-0001-0004-7-B-1-000 fits low-flow lube lines on compressors, gearboxes and turbines, transformer oil circuits and test rigs, where a simple and reliable no-flow alarm is needed.

Why source the HFS 2145-1S-0001-0004-7-B-1-000 from Seven Star LLC

Seven Star LLC supplies HYDAC flow switches and sensors across Oman and the GCC. Send us the model code, oil type, flow range and supply voltage to request a quote, and our team can help confirm the correct ordering code.