WIKA TF41 Outdoor Thermometer, Miniature Case

WIKA TF41 outdoor thermometer in a miniature case

The WIKA TF41 is a very small outdoor temperature sensor in a UV-resistant plastic case, built for measuring air temperature on building walls, in cold rooms, in production and in storage areas. It is delivered with the element integrated in the case or, for a faster response, with an external probe sleeve, and a clip-on sun protector is offered as an accessory. WIKA states a temperature range of -40 … +100 °C and protection to IP65. Seven Star LLC supplies the TF41 in Oman and the GCC as an independent supplier in Muscat; the sections below explain the element choices and sun-exposure rules that matter in a hot climate.

TF41 technical specifications

Choosing the element

For outdoor air measurement, accuracy demands are usually low, so WIKA offers a 2-wire connection to hold down cost. The datasheet recommends a Pt1000, because the influence of lead resistance is about 0.04 °C per metre, ten times lower than with Pt100 at 0.42 °C per metre (0.22 mm² copper). If the controller wire is 0.5 mm², the influence drops below 0.04 °C/m for Pt100 and 0.004 °C/m for Pt1000. NTC elements are inexpensive and sensitive, but a lack of standardisation limits interchangeability between suppliers. Platinum elements add better long-term stability, behaviour under temperature cycling and a wider range.

Sun, wind and mounting position

The datasheet warns that strong sunlight can falsify the reading, so the thermometer is best mounted on the north side of a building, and the clip-on sun cover is available when the sun cannot be avoided. The case is deliberately tiny so it can be fixed where there is little room. Avoid positions near exhaust vents, window frames, dark walls or heat sources, and keep the sensor away from the wall’s thermal influence by using the external probe sleeve where the building surface is warm.

Measuring-range limits

The range is set by the case material and the element, and the case is designed for -40 … +100 °C. In the Gulf, wall surfaces in direct sun can exceed the air temperature greatly, so the sensor must never be installed against a hot, dark facade without the sun protector. Both Pt100 and Pt1000 are listed for the same -40 … +100 °C range.

Where the TF41 fits the WIKA range

The TF41 belongs to WIKA’s compact sensors for HVAC and building services, alongside probes such as the TF44 strap-on thermometer and the TR60 indoor/outdoor resistance thermometer. Use the TF41 for the simplest ambient reading and the TR60 when a larger case, a transmitter or an explosion-protected version is needed.

Installation notes

• Fix the case to the wall with the wall-mounting kit, with the cable gland facing down
• Use the M16 gland suitable for the cable and seal it correctly
• Form a drip loop so water does not run along the cable into the case
• Choose Pt1000 or NTC to limit the cable effect on long runs
• Fit the sun protector wherever direct radiation is possible

Applications in Oman and the GCC

WIKA lists combined heat and power plants, HVAC and refrigeration technology. In the region this includes outdoor air references for chillers and district-cooling plants, cold-room monitoring, air-handling units and storage facilities. The high summer temperatures and strong sun make the sun protector and shaded mounting particularly important to avoid reading too high.

TF41 ordering checklist

• Element type and resistance
• Integrated element or external probe sleeve
• Cable length and wire cross-section
• Sun protector and wall-mounting kit
• Controller input and expected temperature range

Practical points when specifying the TF41

The TF41 is a simple, low-cost sensor and the choices that matter are few. First, decide whether the element is integrated in the case or on an external probe sleeve: the sleeve gives a faster response and moves the sensing point away from the case, which is better on a warm wall. Second, match the element to the controller input, remembering that NTC elements of different makers are not interchangeable. Third, decide where it will be mounted, because radiation from the sun and from the wall can dominate the reading.

For long cable runs choose Pt1000 or NTC, whose lead influence is small. For a 2-wire Pt100 the datasheet’s figure of about 0.42 °C per metre of 0.22 mm² cable can easily exceed the accuracy you expect, and a thicker 0.5 mm² cable reduces it to below 0.04 °C per metre.

Information to send with an RFQ

Send the element type required by your controller, cable length, mounting location and quantity.

Documents and quotation

The WIKA data sheet TE 67.17 for the TF41 is attached on this page. Send us the specification and quantity for a quotation from Muscat as an independent supplier.