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  • Passive temperature sensor | NTC3kΩ | 1m | -20-60°C | stainless steel probe | Sentera Controls | FLTSN-N3K3A1-100

    Code: FLTSN-N3K3A1-100
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  • Product description

    Passive temperature sensor | NTC3kΩ | 1m | -20-60°C | stainless steel probe | Sentera Controls | FLTSN-N3K3A1-100

    FLTSN-N3K3A1-100 – a Sentera Controls passive NTC thermistor temperature sensor: resin-insulated element in a stainless steel tube with 1 m wires. Nominal resistance 3 kΩ at 25 °C, intended for measuring and maintaining temperature in HVAC systems.

    Key idea:
    The NTC sensor offers high sensitivity where the controller has a dedicated NTC 3 kΩ input – especially when replacing existing sensors of the same type.
    Sensing element
    NTC 3 kΩ (at 25 °C)
    Tolerance
    ±0.1 °C (0…+70 °C)
    Operating temperature
    -20…+60 °C
    Wire length
    1 m

    Operating principle

    The NTC thermistor is resin-sealed and housed in a stainless steel tube with 1 m 0.5 mm² leads; leads with lead content reduce heat conduction from the leads to the element. The probe is installed in a thermowell or on a surface, the leads are connected to the controller's NTC 3 kΩ input, and a shielded cable is used for extension.

    The NTC has a negative temperature coefficient (4.39 %/°C at 25 °C): resistance decreases as temperature rises – 9795 Ω at 0 °C, 3000 Ω at 25 °C, 1080 Ω at 50 °C. The characteristic is nonlinear, so the controller must be set specifically for this NTC type.

    Result – fast response (< 1 s in liquids) and ±0.1 °C (0…+70 °C) tolerance. NTC characteristics differ between manufacturers, so before replacing a sensor compare the resistance table with the controller data; the sensor will not work with a PT100 / PT500 / PT1000 input.

    Benefits FLTSN-N3K3A1-100?
    High sensitivity and fast response in liquids (< 1 s) in a compact stainless steel probe.

    Technical specifications

    Product type Passive temperature sensor with wires (NTC thermistor)
    Manufacturer / code Sentera Controls / FLTSN-N3K3A1-100
    Series FLTSN-N (NTC)
    Sensing element NTC, nominal resistance 3 kΩ at 25 °C
    Temperature coefficient Negative (resistance decreases as temperature rises)
    Temperature coefficient of resistance (25 °C) 4.39 %/°C
    Resistance vs. temperature 9795 Ω (0 °C), 3000 Ω (25 °C), 1080 Ω (50 °C)
    Tolerance ±0.1 °C (0…+70 °C)
    Dispersion stability 0.75 mW/°C (still air, 25 °C)
    Response time < 1 s in liquids
    Probe Stainless steel, resin-insulated element
    Wires 1 m, 0.5 mm²; use shielded cable for extension
    Operating environment -20…+60 °C, < 95 % rH non-condensing
    Weight 0.032 kg (net, 1 pc.)
    Compliance WEEE 2012/19/EU, RoHS 2011/65/EU

    Manufacturer documentation

    ✔ Recommended by Elektrotechnikos sprendimai

    Original manufacturer documentation – technical data, wiring diagrams and installation instructions.

    Main functions

    • NTC 3 kΩ thermistor – high sensitivity to temperature changes (4.39 %/°C at 25 °C).
    • Fast response – < 1 s in liquids.
    • Stainless steel probe – suitable for a thermowell and a surface.
    • Resin-insulated element – protected against mechanical impact.
    • Wires with lead content – less heat leakage from the leads to the element.
    • Tolerance ±0.1 °C (0…+70 °C) – accurate measurement in the HVAC range.
    • 1 m wires – can be extended with a shielded cable.

    Where is it used?

    • Heating and cooling pipework up to +60 °C (with thermowell)
    • Hot water tanks and heat substations up to +60 °C
    • Air handling unit ducts and chambers
    • Control cabinets and technical rooms
    • BMS temperature monitoring
    • Replacing existing NTC 3 kΩ sensors in equipment

    On-demand operation

    For service engineers.
    The NTC 3 kΩ probe replaces a faulty sensor when the resistance table (9795 Ω at 0 °C, 3000 Ω at 25 °C) matches that of the controller.
    For heating equipment installers.
    Fast response in liquids (< 1 s) – suitable for supply water temperature in a thermowell.
    For ventilation unit manufacturers.
    A compact NTC 3 kΩ probe with 1 m leads for a controller with an NTC input.

    Practical application

    If a unit controller uses an NTC 3 kΩ sensor (3000 Ω at 25 °C) and the old one has failed, then the FLTSN-N3K3A1-100 is connected to the same terminals, after first checking that the controller's table shows about 9795 Ω at 0 °C.

    Application guide: how it is used in practice

    FLTSN-N3K3A1-100 is a universal probe with cable; it can be placed in a thermowell, fixed in a duct or in a room:

    Site What is connected Result Installer's note
    Heating substation, tank FLTSN-N3K3A1-100 in a thermowell → controller NTC 3 kΩ input The controller regulates according to water temperature Use thermally conductive paste in the thermowell
    Air handling unit chamber FLTSN-N3K3A1-100 in the airflow → controller Supply or outdoor air temperature measurement Secure the wire so that it is not strained
    Heating circuit FLTSN-N3K3A1-100 on the pipe surface → controller Return water temperature control Insulate the sensor location so that the readings are not reduced
    BMS modernization The existing NTC 3 kΩ probe is replaced with FLTSN-N3K3A1-100 Same characteristic – no need to change settings Check the controller's input type

    How to choose a sensing element and cable length

    Sensing element / probe / cable Recommended model
    PT100, stainless steel probe, 1 m FLTSN-P100-100 (PT100, 1 m)
    PT500, stainless steel probe, 1 m FLTSN-P500-100 (PT500, 1 m)
    PT500, stainless steel probe, 4 m FLTSN-P500-400 (PT500, 4 m)
    PT1000, stainless steel probe, 1 m FLTSN-P1K0-100 (PT1000, 1 m)
    PT1000, stainless steel probe, 4 m FLTSN-P1K0-400 (PT1000, 4 m)
    PT500, ABS probe, IP65, 1 m FLTSN-P500P100 (PT500, 1 m)
    PT500, ABS probe, IP65, 4 m FLTSN-P500P400 (PT500, 4 m)
    PT500, ABS probe, IP65, 8 m FLTSN-P500P800 (PT500, 8 m)
    PT500, ABS probe, IP65, 16 m FLTSN-P500P1K6 (PT500, 16 m)
    PT1000, ABS probe, IP65, 1 m FLTSN-P1K0P100 (PT1000, 1 m)
    NTC 3 kΩ (25 °C), 1 m FLTSN-N3K3A1-100 (NTC, 1 m) ← this model
    NTC 10 kΩ (25 °C), 1 m FLTSN-N1K4A1-100 (NTC, 1 m)
    Rule: the sensing element (PT100 / PT500 / PT1000 / NTC) must match the controller input, and for NTC – also its resistance characteristic. Choose a cable length that avoids splices; for extension use only a shielded cable.
    When to choose another solution: for a room – ROTSN series (wall-mounted housing); for a duct – TUTSN series (150 / 250 mm); when the controller accepts only Modbus RTU – DTS-M (duct) or DTP-M (strap-on).

    Pros

    • No power supply or settings needed
    • NTC 3 kΩ – high sensitivity
    • Fast response < 1 s in liquids
    • Compact stainless steel probe
    • Tolerance ±0.1 °C (0…+70 °C)

    Cons / limitations

    • No 0-10 VDC or Modbus output – a controller with a NTC 3 kΩ input is required; for a Modbus pipe sensor choose DTP-M
    • Operating range -20…+60 °C – not suitable for hotter media
    • The thermowell is not included in the kit
    • Nonlinear characteristic – the controller must be matched to this NTC type, and a PT input requires the FLTSN-P series
    • IP rating not specified in the datasheet

    Safety and installation notes

    • Installation and connection are to be carried out by a qualified installer.
    • For extension use only a shielded cable, routed separately from 230 V lines.
    • Do not exceed the operating temperature of -20…+60 °C and < 95 % rH non-condensing.

    Quick selection guide

    NTC 3 kΩ
    1 m
    NTC
    Stainless steel
    -20…+60 °C
    Suitable when you need:
    • to measure temperature for a controller with an NTC 3 kΩ input;
    • to install a sensor in a thermowell, duct or on a surface;
    • to replace an old probe of the same type.
    Check before use:
    • the controller input type (NTC 3 kΩ);
    • the required cable length;
    • the medium temperature – whether it does not exceed +60 °C.
    Important reminder: FLTSN-N3K3A1-100 is a passive sensor; it works only with a controller that has a NTC 3 kΩ input.

    FAQ

    Is a power supply needed?
    No, it is a passive resistive sensor, and the measuring current is supplied by the controller.
    What is the nominal resistance?
    The nominal resistance is 3000 Ω at 25 °C and 9795 Ω at 0 °C.
    Can the wires be extended?
    Yes, extend the standard 1 m leads with a shielded cable.
    What is the operating temperature range?
    The sensor operates within -20…+60 °C.
    Is it suitable for a controller with a PT1000 input?
    No, the NTC characteristic is completely different, so a controller with a matching NTC input is required.
    Will another manufacturer's NTC work instead?
    Suitable only when the resistance table matches the characteristic set in the controller.

    Passive temperature sensor | NTC3kΩ | 1m | -20-60°C | stainless steel probe | Sentera Controls | FLTSN-N3K3A1-100

    Sentera FLTSN-N3K3A1-100 – passive NTC 3 kΩ temperature sensor with a stainless steel probe and 1 m leads, fast response in liquids and ±0.1 °C tolerance (0…+70 °C).

    Illustrative image may have been created using AI. The appearance of the product may differ slightly from the image shown. Please refer to the technical specification.

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