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testo 635-2 - Thermohygrometer

0563 6352
1
  • Versatile Measurement Capabilities – Supports temperature, humidity, material moisture, pressure dew point, and absolute pressure measurements.
  • Multi-Sensor Connectivity – Can connect to 2 plug-in sensors and up to 3 wireless sensors for flexible data collection.
  • Large Data Storage – Super-size memory for up to 10,000 readings, allowing long-term monitoring.
  • Seamless Data Transfer – Includes USB cable and PC software for easy logging, archiving, and analysis.
    • The testo 635-2 is a high-performance thermohygrometer designed for precise climate monitoring across multiple applications. With support for temperature, humidity, material moisture, and pressure dew point measurements, it features expandable sensor connectivity and a large memory for 10,000 readings. The included USB interface and PC software allow seamless data logging and analysis, making it an essential tool for HVAC professionals, facility managers, and quality control experts.
    The testo 635-2 Thermohygrometer is an advanced measurement tool for professionals in HVAC, environmental monitoring, and industrial applications. Designed to handle a wide range of temperature and humidity measurements, it supports optional sensors for monitoring material moisture, pressure dew point in compressed air systems, and absolute pressure.

    With two plug-in sensor ports and the ability to connect up to three additional wireless sensors, the testo 635-2 provides flexible and comprehensive data collection. Users can also benefit from the ability to calculate dew point differences, which helps analyse moisture levels on surfaces such as ceilings and walls, crucial for preventing mold and structural damage.

    Equipped with a super-size memory, the device can store up to 10,000 readings, making it ideal for long-term monitoring. The included USB cable and PC software enable easy data transfer and archiving, while the testo fast printer (optional) allows for instant printouts directly on-site.

    Designed for convenience, the testo 635-2 features a backlit display for easy readability in poor lighting conditions, an intuitive menu navigation system, and a robust protective casing to withstand demanding environments. Whether in climate control, building diagnostics, or industrial quality assurance, the testo 635-2 delivers reliable, high-precision measurements with user-friendly operation.

    testo 635-2 - Thermohygrometer, PC software and USB-cable incl. battery and calibration protocol

    Temperature - NTC

    Measuring range
    -40 to +150 °C
    Accuracy
    ±0.4 °C (-40 to -25.1 °C)
    ±0.4 °C (+75 to +99.9 °C)
    ±0.5 % of mv (Remaining Range)
    ±0.2 °C (-25 to +74.9 °C)
    Resolution
    0.1 °C

    Temperature - TC Type K (NiCr-Ni)

    Measuring range
    -200 to +1370 °C
    Accuracy
    ±(0.2 °C + 0.5 % of mv) (Remaining Range)
    ±0.3 °C (-60 to +60 °C)
    Resolution
    0.1 °C

    Humidity - Capacitive

    Measuring range
    0 to +100 %RH
    Accuracy
    See probe data
    Resolution
    0.1 %RH

    Air probes

  • Air probes
    Robuster Luftfühler, TE Typ K
    Robust air temperature probe (TC type K) – measuring range: -60 to +400 °C
      :
      0602 1793
      £ 65.00 £ 78.00
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      • Humidity probes

    • Humidity probes
      Dünner Feuchtefühler mit abgesetzter Elektronik
      Thin humidity probe (Ø 4 mm) for measuring material moisture via the equilibrium moisture content – can be used in small bore holes and recesses
        :
        0636 2135
        £ 472.00 £ 566.40
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      • Humidity probes
        Robust humidity probe for measuring the material equilibrium moisture content and humidity measurements at high temperatures
          :
          0636 2161
          £ 605.00 £ 726.00
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        • Humidity probes
          Streufeldsonde
          Scatter field probe for fast and damage-free material moisture measurement, with probe cable 1.2 m
            :
            0636 6160
            £ 384.00 £ 460.80
            1
          • Humidity probes
            Feuchte-/Temperaturfühler
            Humidity/temperature probe (Ø 12 mm) with humidity sensor that has long-term stability – measuring range: -20 to +70 °C
              :
              0636 9735
              £ 395.00 £ 474.00
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              • Radio handles and probe head

            • Radio handles and probe head
              Radio handle for plug-in probe heads
              Radio handle for plug-in probe heads, approval for the countries: DE, FR, UK, BE, NL, ES, IT, SE, AT, DK, FI, HU, CZ, PL, GR, CH, PT, SI, MT, CY, SK, LU, EE, LT, IE, LV, NO
                :
                0554 0189
                £ 118.00 £ 141.60
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              • Radio handles and probe head
                T/C probe head for surface measurement
                T/C probe head for surface measurement (T/C Type K)
                  :
                  0602 0394
                  £ 74.00 £ 88.80
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                • Radio handles and probe head
                  Compact professional humidity module
                  Compact professional humidity module for wireless humidity/temperature measurement
                    :
                    0636 9736
                    £ 235.00 £ 282.00
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                    • Surface probes

                  • Surface probes
                    Spare meas. head for pipe wrap probe, TC Type K
                    Spare measuring head for pipe wrap probes (TC type K) - Measuring range: -60 to +130°C
                      :
                      0602 0092
                      £ 55.00 £ 66.00
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                    • Surface probes
                      Fast-reaction paddle surface probe
                      Fast-reaction paddle surface probe (TC type K) - Measuring range: - 0 to +300°C
                        :
                        0602 0193
                        £ 132.00 £ 158.40
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                      • Surface probes
                        Fast-action surface probe with sprung thermocouple strip
                        Fast-action surface probe (TC type K) – measuring range -60 to +300 °C, short-term up to +500 °C
                          :
                          0602 0393
                          £ 129.00 £ 154.80
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                        • Surface probes
                          Efficient, waterproof surface probe with small measurement head
                          Efficient, waterproof surface probe with small measurement head for flat surfaces, T/C Type K
                            :
                            0602 0693
                            £ 115.00 £ 138.00
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                          • Surface probes
                            Fast-action surface probe with sprung thermocouple strip
                            Fast-action, angled surface temperature probe (TC type K) for flat and uneven surfaces – measuring range: -60 to +300 °C
                              :
                              0602 0993
                              £ 155.00 £ 186.00
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                            • Surface probes
                              Waterproof surface probe with widened measurement tip
                              Waterproof surface temperature probe with widened measuring tip (TC type K) for flat surfaces – measuring range -60 to +400 °C
                                :
                                0602 1993
                                £ 65.00 £ 78.00
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                              • Surface probes
                                Clamp probe for measurements on pipes
                                Clamp probe (TC type K) for temperature measurements on pipes with Ø 15-25 mm – Measuring range -50 to +100°C, briefly up to +130°C
                                  :
                                  0602 4692
                                  £ 75.00 £ 90.00
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                                • Surface probes
                                  Magnetic probe (TC type K) - for surface temperatures
                                  Surface temperature probe with magnet (TC type K), adhesive power 20 N – Measuring range -50 to +170°C
                                    :
                                    0602 4792
                                    £ 155.00 £ 186.00
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                                  • Surface probes
                                    Magnetfühler, Haftkraft ca. 10 N, mit Haft-Magneten
                                    Surface temperature probe with magnet (TC type K), adhesive power 10 N – Measuring range -50 to +400°C
                                      :
                                      0602 4892
                                      £ 175.00 £ 210.00
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                                    • Surface probes
                                      Temperature probe to determine U-value, triple sensor system
                                      Temperature probe to determine U-value, triple sensor system for measuring wall temperature, modelling clay included
                                        :
                                        0614 1635
                                        £ 252.00 £ 302.40
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                                      • Surface probes
                                        Pipe wrap probe with velcro strip
                                        Temperature probe with Velcro (TC Type K)
                                          :
                                          0628 0020
                                          £ 47.00 £ 56.40
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                                          • Thermocouples

                                        • Thermocouples
                                          Thermocouple with TC adapter, flexible, 800 mm long
                                          Flexible thermoelectric couple (TC type K, glass fibre) – Measuring range: -50 to +400°C
                                            :
                                            0602 0644
                                            £ 20.00 £ 24.00
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                                          • Thermocouples
                                            Thermocouple with TC adapter, flexible, length 1500 mm
                                            Flexible thermoelectric couple (TC type K, glass fibre) – measuring range -50 to +400°C
                                              :
                                              0602 0645
                                              £ 30.00 £ 36.00
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                                            • Thermocouples
                                              Thermocouple with TC adapter, flexible, 1500 mm long, PTFE
                                              Flexible thermoelectric couple (TC type K, PTFE) – measuring range -50 to +250°C
                                                :
                                                0602 0646
                                                £ 31.00 £ 37.20
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                                                • immersion/ penetration probes

                                              • immersion/ penetration probes
                                                Efficient and fast-action immersion probe, waterproof
                                                Flexible, fast-action immersion probe (TC type K) – measuring range: -60 to +1000 °C
                                                  :
                                                  0602 0593
                                                  £ 99.00 £ 118.80
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                                                • immersion/ penetration probes
                                                  Waterproof immersion/penetration probe, TC Type K
                                                  Waterproof immersion/penetration probe (TC type K) – measuring range -60 to +400 °C
                                                    :
                                                    0602 1293
                                                    £ 51.00 £ 61.20
                                                    1
                                                  • immersion/ penetration probes
                                                    Fast-action, waterproof immersion/penetration probe
                                                    Fast-action immersion/penetration probe (TC type K) – measuring range: -60 to +800 °C
                                                      :
                                                      0602 2693
                                                      £ 120.00 £ 144.00
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                                                    • immersion/ penetration probes
                                                      Tauch-Messspitze, biegsam, TE Typ K
                                                      Immersion measuring tip with TC plug type K - for fast temperature measurements
                                                        :
                                                        0602 5792
                                                        £ 30.00 £ 36.00
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                                                        • Cases

                                                      • Cases
                                                        testo 0516 1435 case
                                                        Service case for measuring instrument, probe and accessories, dimensions 518 x 398 x 155 mm
                                                          :
                                                          0516 1435
                                                        • Cases
                                                          testo 0516 1035 case
                                                          Service case for measuring instrument, probe and accessories, dimensions 454 x 319 x 135 mm
                                                            :
                                                            0516 1035
                                                            £ 99.00 £ 118.80
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                                                            • Further accessories measuring instrument/probes

                                                          • Further accessories measuring instrument/probes
                                                            Control and adjustment set for Testo humidity probes
                                                            Control and calibration kit for Testo humidity probes
                                                              :
                                                              0554 0660
                                                              £ 315.00 £ 378.00
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                                                              • Printer and accessories

                                                            • Printer and accessories
                                                              Plug-in Power supply
                                                              Plug-in mains adapter, 5 VDC 500 mA with European adapter, 100-250 VAC, 50-60 Hz
                                                                :
                                                                0554 0447
                                                                £ 34.00 £ 40.80
                                                                1
                                                              • Printer and accessories
                                                                External fast charger
                                                                External fast charger for 1-4 AA rech. batteries, incl. 4 Ni-MH rech. batteries with individual cell charging and charge control display, incl. impulse trickle charging, integrated discharge function, with built-in international mains plug, 100-240 V, 300 mA, 50/60 Hz
                                                                  :
                                                                  0554 0610
                                                                  £ 49.90 £ 59.88
                                                                • Printer and accessories
                                                                  Spare thermal paper
                                                                  Spare thermal paper for printer, permanent
                                                                    :
                                                                    0554 0568
                                                                    £ 30.00 £ 36.00
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                                                                  • Printer and accessories
                                                                    testo-Schnelldrucker IRDA mit kabelloser Infrarot-Schnittstelle
                                                                    testo fast printer IRDA
                                                                      :
                                                                      0554 0549
                                                                      £ 219.00 £ 262.80
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                                                                      • Radio handles and probe head for surface measurement

                                                                    • Radio handles and probe head for surface measurement
                                                                      Radio Module for measuring instrument
                                                                      Radio module for measuring instrument, 869.85 MHz, approval for the countries: DE, FR, UK, BE, NL, ES, IT, SE, AT, DK, FI, HU, CZ, PL, GR, CH, PT, SI, MT, CY, SK, LU, EE, LT, IE, LV, NO
                                                                        :
                                                                        0554 0188
                                                                        £ 46.00 £ 55.20
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                                                                        • Radio handles, seperate county variant

                                                                      • Radio handles, seperate county variant
                                                                        Radio handle for plug-in probe heads
                                                                        Radio handle for plug-in probe heads, approval for the countries: DE, FR, UK, BE, NL, ES, IT, SE, AT, DK, FI, HU, CZ, PL, GR, CH, PT, SI, MT, CY, SK, LU, EE, LT, IE, LV, NO
                                                                          :
                                                                          0554 0189
                                                                          £ 118.00 £ 141.60
                                                                          1

                                                                          • Localising mould

                                                                          Damp ceilings and walls may be a result of structural damage. In most cases, however, it is a sign of improper ventilation. Once the mould appears inside a house, the tenant assumes that moisture has come in from outside. Numerous disputes have erupted because of the issue of who is liable for the mould damage. However, it is difficult to find out who or what has caused the mould: the tenant or faulty structural design?

                                                                          Testo 635-2 is ideal for measuring moisture in ceilings and walls. Using the optional attachment temperature/moisture probe and optional surface temperature probe, the testo 635 automatically calculates the dew point distance. It provides initial information about whether mould is being caused by condensation, or from moisture ingress due to structural damage or faulty insulation.

                                                                          The supplied PC software can be used to document and analyse the measurement data.

                                                                          Measuring material moisture

                                                                          Monitoring the moisture in construction materials and different timber is an important part of everyday work in the most diverse areas. For many users, measuring the material moisture as quickly and as non-destructively as possible is crucial.

                                                                          Whether it is used to assess the screed drying process, further processing, or the combustibility of wood, our testo 635-2 hygrometer can be used to examine the moisture content in many different construction materials and types of wood.

                                                                          Monitoring drying processes

                                                                          Whether freshly laid screed, or monitored drying of moisture damage, timely determination of the required moisture level will save time and therefore money.

                                                                          Screeds are laid in the in interior works stage, generally after plastering. The flooring and painting and decorating then follow. The drying behaviour is therefore a significant factor in the works schedule, primarily because the laying of flooring depends on this.

                                                                          The moisture measurement establishes readiness for flooring; liability for the flooring is thus transferred to the respective trade installing the flooring. An important part of this work is therefore documentation and assurance in the testing for readiness for flooring.

                                                                          What is the extent of moisture damage and what consequences can be expected in terms of time and costs? These questions have to be answered in order to decide which auxiliary tools and materials are to be used to speed up the drying process.

                                                                          The t 635-2 and attachment scatter field probe can be used to measure the moisture in the construction material.

                                                                          Using a thin moisture probe combined with the testo 635-2 the moisture of construction materials can be determined by means of an equilibrium moisture measurement. To do this, the probe has to be inserted in a borehole in the material being measured and sealed. The relevant material characteristic can be manually entered into the device or via software. After several hours, equilibrium with the material has taken place and the testo 635-2 displays the material moisture.

                                                                          Monitoring production and storage conditions

                                                                          Our temperature/humidity measuring instruments are used around the world in production, storage and server rooms, museums, archives, cold storage warehouses, containers and sales counters.

                                                                          Manufacturers, carriers, or dealers of sensitive products must ensure that specified temperature or humidity values are observed during production and storage. The testo 635 offers the option of performing spot measurements in relevant places.

                                                                          The temperature/humidity measuring instrument testo 635-2 offers the user a wide range of humidity/moisture probes. It provides the option of measuring humidity, material moisture and U-value (for the thermal assessment of structural components). In addition to the standard probes, up to three radio probes can be connected to the device in parallel. Measurement results can be analysed, stored and documented using the supplied PC software.

                                                                          U-value measurement in old buildings

                                                                          When redeveloping or renovating old buildings, it is crucial to be able to determine quickly if heat is being lost through the windows and walls. Only then can energy costs be reduced and redevelopment measures carried out efficiently.

                                                                          When assessing thermal transmission, e.g. in old buildings in need of renovation, the U-value is one of the most important values. It enables thermal assessment and monitoring of the installed material.

                                                                          3 temperature values are required for calculating the U-value:

                                                                          • Outside temperature
                                                                          • Surface temperature of the internal wall
                                                                          • Indoor air temperature

                                                                           

                                                                          A radio probe is needed to determine the U-value; this is placed in position outside. It transmits the readings to the measuring instrument inside. To measure the surface temperature the three wires of the U-value probe are attached to the wall with plasticine. The air temperature is recorded by a sensor located on the probe plug. The measuring instrument testo 635-2 automatically calculates the U-value from the three values and shows this on the display. The advantage: there is no need for manual calculation; the result is quick and accurate.

                                                                          Measuring wood moisture quickly and non-destructively

                                                                          The testo 635-2 uses the optional attachment scatter field probe (item no.: 0636 6160) to quickly and non-destructively examine the material moisture in timber. Characteristic curves are available for measuring wood moisture in soft and hard woods, and chipboard. These characteristic curves were developed in cooperation with the LPI institute.

                                                                          The measurement results are calculated up to a depth of 5 cm and can be recorded at the touch of a button. The readings are displayed in percent by weight in comparison to the dry mass of the material.

                                                                          Measurement data can be stored and documented using PC software.