Hydac HFS 2156-1W-0020-0060-7-B-1-000 Flow Switch, 60 L/min

A larger oil flow switch with an M12 plug and a change-over contact

The Hydac HFS 2156-1W-0020-0060-7-B-1-000 (HYDAC part number 925574) is the higher-flow, M12 version of the HFS 2100 oil flow switch. It uses the same float and reed-contact principle as its smaller sibling, but this code covers 20 to 60 L/min on a G1 body, and it has one change-over contact rather than a simple normally open one. That lets a controller read both a flow-present and a no-flow signal on one device.

The 6 in the code marks the 4-pole M12x1 plug, which suits compact industrial wiring, with the mating connector ordered separately.

Technical specifications

How this code differs from the smaller switch

HFS 2156-1W-0020-0060-7-B-1-000: the third digit 5 selects the 1 inch connection and the fourth digit 6 the M12x1 four-pole plug. 1W means one change-over contact, 0020-0060 the 20 to 60 L/min range, 7 the 10 % accuracy class, B the brass body, 1 the mechanical indicator and 000 the standard modification. The M12 version has a lower fluid temperature limit (85 °C) than the DIN plug version (120 °C), and the size 2 change-over contact is rated max. 250 V / 1.5 A / 50 VA, so check the load of your input card against that rating.

Installation notes

The oil must be free of solid particles and a contamination strainer is recommended. The switch works in any mounting position but strong external magnetic fields, such as those from motors, can disturb the contact, so keep it clear of them. Its contact opens or switches when the flow drops below the preset switching point. Use the pin table in the datasheet, which lists the centre pin, N/C on pin 2 and N/O on pin 4, when wiring a PLC input.

Place the switch on a vertical or horizontal run with enough straight pipe before it to settle the flow, and take the viscosity of your oil into account when you choose the switching point. The datasheet states a calibration to a particular viscosity can bring the accuracy to 3 percent, so mention your oil grade in the enquiry.

The datasheet also offers a stainless steel housing and an ATEX version for potentially explosive areas, so mention any hazardous-area requirement when you ask for a quotation. Choose the switching point with margin, because accuracy is within 10 percent of full scale and the switch point can shift with oil viscosity.

Documents and quotation

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

How the HFS 2156-1W-0020-0060-7-B-1-000 works

Like every HFS 2100 switch, this model uses a variable-area float. A spring-loaded float with a built-in magnet is pushed along the flow path by the oil, and its position depends on the flow rate. A reed contact mounted outside the housing switches when the magnet reaches the preset position, so the electrical part never touches the oil. The switch casing can be moved steplessly to set the switching point anywhere in the 20 to 60 L/min range.

On the HFS 2156-1W-0020-0060-7-B-1-000 the change-over (1W) contact gives both an N/O and an N/C output. HYDAC states that the contact opens or switches when the flow falls below the preset switching point, and that the instrument compensates for viscosity changes between 30 and 600 cSt and works in any mounting position.

Datasheet values for HFS 2100 size 2

Selection & ordering guide

• Range: for 20–60 L/min the datasheet lists the 1 inch connection; neighbouring ranges are 15–45 and 30–90 L/min.
• Plug: 6 = M12x1 4-pole (connector not supplied); 5 = EN175301-803 (DIN 43650) with connector and a higher fluid temperature limit.
• Contacts: 1S, 2S, 1W or 2W. A second contact is fitted at 90° to the first.
• Housing: B = nickel-plated brass, S = stainless steel 1.4571 with a higher pressure rating.
• Indicator: 1 = with mechanical indicator, 0 = without.

Our team can help confirm the correct ordering code for the HFS 2156-1W-0020-0060-7-B-1-000, a matching M12 cable, or a version with a stainless steel housing or ATEX approval.

Installation & maintenance

• Fit a contamination strainer upstream; HYDAC states the medium must not contain solid particles.
• Keep a sufficient distance from magnetic fields, for example from electric motors.
• Wire the M12 plug as per the datasheet pin table and confirm the PLC input load is above the 3 VA minimum for the change-over contact or use a suitable relay.
• Set the switching point at normal operating temperature and viscosity.
• During maintenance, check the switching point and clean the strainer, since debris on the float can affect switching.

Typical applications in Oman & the GCC

The datasheet names central and circulating lubrication systems, transformers, cooling circuits, hydraulic systems, pumps, welding and laser systems and the chemical industry. In Oman and the GCC the HFS 2156-1W-0020-0060-7-B-1-000 suits lube-oil return monitoring on large gearboxes, compressors and turbines, oil cooling loops and hydraulic power units where a flow-loss trip is required.

Why source the HFS 2156-1W-0020-0060-7-B-1-000 from Seven Star LLC

Seven Star LLC supplies HYDAC flow switches across Oman and the GCC. Send the model code, oil grade, switching point and plug type to request a quote, and our team can help confirm the correct ordering code.