HB Products: Quick Guide to Liquid and Oil Level Switches
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Standard Switches Available from HB Products
Liquid Switches
| Supply voltage, recommended liquid temperature and IP class | Liquid Type | Electronic part design | Settings | Mechanical part design |
| 24 V AC/DC - dry conditions -40-50 °C (-40-122 °F) IP54 | R744 CO2, R600 Butane, R600a Isobutane, R290 Propane, R507, R410a, R407c R404a, R22, R32, R134a, R1234yf, R1234ze Other HFC/HFO | HBSC2, HBSR-HFC, HBSR, HBOR | NO/NC, NPN/PNP, EX version | V-track connection |
| 24 V AC/DC - elevated temp. 50-80°C (122-176 °F) IP54 | R744 CO2, R600 Butane, R600a Isobutane, R290 Propane, R507, R410a, R407c R404a, R22, R32, R134a, R1234yf, R1234ze Other HFC/HFO | HBSC2, HBSR-HFC, HBSR-HP, HBSR | NO/NC, NPN/PNP, EX version | V-track connection |
| 24 V AC/DC - for wet and condensing applications IP66 | R744 CO2, R600 Butane, R600a Isobutane, R290 Propane, R507, R410a, R407c R404a, R22, R32, R134a, R1234yf, R1234ze Other HFC/HFO | HBSC2-U, HBSR-HFC-U, HBSR-U, HBSR-U | NO/NC, NPN/PNP, EX version | Threaded union |
| 90-240 V AC - normal temp -55-80 °C (-67-86 °F) IP54 | R744 CO2, R600 Butane, R600a Isobutane, R290 Propane, R507, R410a, R407c R404a, R22, R32, R134a, R1234yf, R1234ze Other HFC/HFO | HBSC2-SSR-2, HBSC-HFC-SSR-2, HBSC-HFC-SSR-2, HBSR-SSR-2 | Preset, Relay output | |
| 24 V AC/DC low ambient temp -55-30 °C (-67-86 °F) IP66 | R744 CO2, R600 Butane, R600a Isobutane, R290 Propane, R507, R410a, R407c R404a, R22, R32, R134a, R1234yf, R1234ze Other HFC/HFO | HBSC2-SSR-1/IP, HBSR-HFC-SSR-1/IP, HBSR-SSR-1/IP, HBSR-SSR-1/IP | Preset, Relay output, EX version |
Mechanical Part Design: Switches are available with either a V-track connection or a threaded union. An EX version with a different electronic unit is also available.
Oil Switches
| Supply voltage and recommended oil temperature | Allowed temperature is typically higher | Oil Type | Application | Design | Settings (NO/NC, NPN/PNP) |
| 24 V AC/DC low temp -30-40 °C (-22-104 °F) | PAO, Mineral, POE, PAG | HBSO1, HBSO2 | Refrigeration | Preset | |
| 90-240 V AC - low temp -30-40 °C (-22-104 °F) | PAO, Mineral, POE, PAG | HBSO1-SSR-2, HBSO2-SSR-2 | Refrigeration | Preset, Relay output | |
| 24 V AC/DC - normal temp 0-60 °C (32-140 °F) | PAO, Mineral, POE, PAG | HBS01-MT, HBSO2-MT | Heat pump | Preset | |
| 90-240 V AC - normal temp 0-60 °C (32-140 °F) | PAO, Mineral, POE, PAG | Preset, Relay output | |||
| 24 V AC/DC - medium temp 40-100°C (104-212 °F) | PAO, Mineral, POE, PAG | Oil separator or universal | Can be changed, EX version | ||
| 24 V AC/DC high or all temp 90-145 °C (194-293 °F) | 0-145 °C (32-293 °F) changed settings | PAO, Mineral, POE, PAG | Preset | ||
| 24 V AC/DC - Oil return switch -30-80 °C (-22-176 °F) | PAO, Mineral, POE, PAG | HBOR | Oil return system NH3 | Preset |
Quick Guide: All Liquid Level Switches with Circular Electronic Unit HBSC2, HBSR, HBOR & HBSO
Functionality and Labelling
The switches are designed for detecting liquid in gas or air. The HBOR model specifically detects oil in liquid ammonia. Mechanical elements differ to optimize performance with various liquids. The switches utilize a capacitive measuring principle, reacting to differences in dielectric constant between liquid and gas. While calibration and parameter settings are handled by the electronic unit, the unit itself is standardized. Settings are fixed and must match the mechanical part. Switches manufactured after September 2020 include a built-in heater that activates below 5°C to maintain sensor dryness.
Switches are supplied with NO/NC and NPN/PNP connections. The specific settings are indicated on a small silver label on the switch, which also displays the type code, a combined version number, manufacturing date, and a unique production number.
LED Indication
Four red LEDs indicate liquid or oil detection. Four green LEDs flashing indicate that the sensor is active but no liquid is detected. Four red flashing LEDs signal a lack of connection to the mechanical unit. Regardless of the output function (NO/NC), the LEDs activate when liquid is detected.
Electrical Connection
Each switch is pre-defined as either Normally Open (NO) or Normally Closed (NC) for its contact behavior in a dry state. The switch type is either PNP or NPN, and connections must follow the provided diagrams. While switches can be supplied with AC, the output signal is DC.
Connection Diagrams:
Source / PNP: Shows connections for +24 V AC/DC, Digital ON/OFF signal, PNP current flow, external relay max 50 mA, and 0V common/ground.
Sink / NPN: Shows connections for +24 V AC/DC, Digital ON/OFF signal, NPN current flow, external relay max 50 mA, and 0V common/ground.
Mechanical Installation
For switches with NPT threads, installation in a vessel or compressor should use Teflon tape or liquid sealant. In cold conditions where liquid viscosity is high, ensure the switch is installed with a downward slope of approximately 5 degrees to facilitate liquid drainage. Long weld adapters should be avoided as they can create gas pockets that interfere with measurement. Similarly, switches installed pointing upwards may collect liquid, affecting measurement accuracy.
Mounting the Electronic Unit
The electronic unit is mounted using either a threaded union or two set screws in a V-track. The threaded union is typically preferred for switches operating in cold conditions. Set screws should be tightened to a torque of 5 Nm, and the threaded union should be secured firmly by hand or with pliers to ensure a good electrical connection. For installations prone to condensation, the threaded union is recommended to prevent poor contact between the mechanical and electrical units.
Switching
All switches, except the HBOR model, activate when liquid is detected. This means a NO switch closes its contact, and an NC switch opens its contact when liquid is present. The HBOR switch operates differently; it switches off when oil is detected.
Switching Behavior Diagrams:
All switches except HBOR:
- NO: Contact is normally open and closes when liquid is detected.
- NC: Contact is normally closed and opens when liquid is detected.
HBOR only:
- NO: Contact is normally open when HBOR detects oil and closes when no oil is detected.
- NC: Contact is normally closed when HBOR detects oil and closes when no oil is detected.
Electrical Specifications
- Connector: DIN 43650/ISO4400
- Relay current: max 50 mA
- Supply: AC/DC 24V ± 10 %
More Information
For more detailed information, please download the instruction manual from the HB Products homepage: www.hbproducts.dk.
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