Mini Float Switch V4A Changeover Contact

The mini float switch made of V4A stainless steel with changeover contact: robust level monitoring from 4 cm, also for salt water and chlorine-containing media

The Schabus Mini Float Switch SHT 5016 monitors liquid levels in tanks, shafts, containers and systems. Its design made entirely of V4A stainless steel is intended for applications with higher requirements for corrosion resistance, for example with salt- or chlorine-containing media such as pool water. The shaft is turned and milled from solid material; the switch is handmade.

A ring magnet is located in the movable float. It actuates a changeover contact (SPDT) potted in the shaft: depending on the float position, the switch connects the common contact to one of the two other contacts. In this way you select the desired normally-open or normally-closed function solely via the appropriate contact combination. Thanks to the compact design, the SHT 5016 switches from a level of approximately 4 cm. It is intended as an accessory for the Schabus water detectors SHT 5000, SHT 5001 and SHT 5002.

Reliable switching, even in demanding media

What is included in the box

The SHT 5016 has no options and no additional variants. Connection material or water detectors are not included.

• Mini float switch SHT 5016, V4A stainless steel, changeover contact
• Permanently potted to 2.5 m LIYY control cable with three cores
• Operating instructions

How the SHT 5016 is constructed

The SHT 5016 consists of a few robust parts: the shaft with contact and cable, and the movable float with magnet. Potted components must not be opened.

Correct installation and connection

The shaft must stand vertically and the float must remain free to move. The mounting position determines the switching height.

Installation

1. Fix the shaft vertically; a maximum deviation of 30° is permissible.
2. Determine the switching height: the mounting position determines the switching height. Choose it so that the desired signal is given in good time.
3. Ensure free movement of the float over the entire travel. It must not catch on the container wall, pipes or deposits.
4. Carry out sealing and fastening to suit the installation situation, for example with the matching mounting bracket.
5. Check the connection assignment on the label of the specific variant.
6. After installation and connection, carry out the complete function test.

Connection

• Suitable devices: Water detectors SHT 5000, SHT 5001 and SHT 5002 (available separately). Observe the instructions of the connected device and check its type and version
• Cable: Use thin, unshielded LIYY cable with three cores. The cable must never be run parallel to 230 V mains cables. Protect it against crushing, tension and sharp edges and protect connections against moisture
• Extension: The cable can be extended to a total length of 50 m, using 3 × 0.14 mm² LIYY. When several sensors are connected in parallel, the cable lengths are added together. For the Schabus water detectors a maximum of 50 m per detection line is provided
• Contact combination: Use the common contact and the second contact provided for the desired normally-open or normally-closed function
• Unused core: When only one contact combination is used, the third core remains unused. Insulate it individually and protect the cable end against moisture. Unused cores must not be connected together arbitrarily

Protecting the reed contact

Incorrect electrical connection can destroy the sensitive reed contact and lead to malfunctions of the system. The float switches are not universal load switches. Therefore observe the following:

• No direct operation on circuits with inductive load, for example relays or solenoid valves
• No direct operation on circuits with capacitive load, for example PLC or PLS
• No cable lengths over 50 m
• Do not exceed the permissible switching capacity
• With inductive loads, protect the reed contact with an RC network or a freewheeling diode. Different solutions are required for DC and AC, matching the load and switching voltage
• The protective circuit does not increase the permissible switching values; all limit values of the model must be observed

Understanding normally open, normally closed and changeover

A changeover has a common contact (COM) and two switching paths. Depending on the float position, the common contact is connected to one or the other contact: when switching, one contact path opens while the other closes. The two contact paths have a common connection and are not independently switching contacts.

The float body of the SHT 5016 is not inverted for function selection; that is only possible with suitable mini float switches that have a reversible normally-open/normally-closed function, not with changeovers.

Check, clean, find faults

Function test

1. Visual inspection: Check fastenings, cables and seals. Is the float free to move?
2. Trigger detection: Raise the liquid level slowly and in a controlled manner past the switching point.
3. Observe reaction: Check the signal and the intended subsequent function. Test a connected pump or valve in a controlled manner.
4. Restore normal state: Lower the level again. Check the return switching and any acknowledgement that may be required on the water detector.

Cleaning and care

• Clean with a soft, damp cloth
• Do not use solvent-based agents
• Carefully remove deposits and residues and check the free movement of the float
• Repeat the function test after cleaning or modification
• The LIYY cable is only briefly waterproof and is not intended for permanent immersion
• Do not continue to use damaged cables, housings or seals; do not open potted components

Troubleshooting

• No reaction? Check model, connection and input. Has the float moved?
• Signal remains? Check residual water, deposits, a blocked float or acknowledgement on the water detector
• Unexpected signal? Check moist connections, the cable routing and the selected contact function
• If the fault persists, put the system into a safe state and contact Schabus Support

Matching accessories (available separately)

The SHT 5016 itself has no options. The following separate articles complement it for mounting and extension.

• Mounting bracket (Art. No. 300787): For precise, vertical fastening to a side wall of a tank or shaft. The bracket is made of V2A stainless steel and must be aligned so that the shaft stands vertically. It prevents tilting
• Dirt trap basket with mounting bracket (Art. No. 300320): Reduces the ingress of coarse foreign bodies such as leaves, sediment or small branches and protects against small animals; ideal for shafts, outdoor areas and rainwater systems. It does not replace cleaning and function testing. According to the manufacturer it is not suitable for chlorine- or salt-containing media; the suitability of the accessory must be checked separately
• LIYY control cable 3 × 0.14 mm² (sold by the metre): For proper extensions up to a maximum total cable length of 50 m per detection line. Use only thin, unshielded LIYY cables; larger cross-sections can cause malfunctions

What the float switch is not

• It is not a water sensor for conductive water at contacts, but monitors a liquid level
• It is not a universal load switch and must not switch pumps or solenoid valves directly
• It is a low-voltage switch and must not be connected to mains voltage
• The liquid must have a density of at least 0.7 g/cm³ and operation must be pressureless
• V4A does not replace checking compatibility with the specific medium
• The float must not be inverted; the function is selected via the contact combination
• The cable is only briefly waterproof and is not intended for permanent immersion

Manufacturer’s notes

• Before installation, read the pages of the operating instructions belonging to your model as well as the instructions of the connected evaluation device and keep both
• Work on mains voltage may only be carried out by qualified electricians. Isolate and verify absence of voltage before work. Never connect low-voltage models to mains voltage
• Before installation, check the medium, temperature, installation position and the permissible electrical limit values of the specific model
• Housing and connection cable must be suitable for the place of use
• Do not continue to use damaged products; do not open potted components
• Packaging material does not belong in children’s hands
• After installation, connection or modification always carry out the complete function test
• The declaration of conformity is available for download on the manufacturer’s website

Warranty, guarantee and disposal

The SHT 5016 is covered by the statutory warranty of at least 2 years in the EU. The manufacturer Elektrotechnik Schabus additionally offers a 5-year guarantee that can be registered online. Repairs and spare parts are available directly from the manufacturer, even beyond the statutory warranty. Repairs and maintenance may only be carried out by the manufacturer or authorised specialist personnel.

The SHT 5016 does not belong in household waste. In accordance with the European Directive 2012/19/EU on waste electrical and electronic equipment (WEEE), it must be collected separately at the end of its service life and subjected to environmentally sound recovery (WEEE Reg. No. DE91394868). Hand it in at a municipal collection point; further information is available from your city or municipality. Also dispose of the packaging material in an environmentally sound manner and recycle it if possible.

Why the SHT 5016 is suitable

Areas of application

• Tanks and cisterns
• Wells, shafts and pump sumps
• Containers and systems
• Pools and pool technology
• Salt-water systems
• Water treatment
• Food industry
• Chemical plants and cooling technology
• Overflow warning and level monitoring
• Applications with permanently humid environments

The Schabus SHT 5016: robust, corrosion-resistant, reliable in level monitoring.

Frequently asked questions