WIKA A52 Bimetal Thermometer, Back Mount, Stainless Steel Case

Overview

The WIKA A52 is a back mount (axial) bimetal thermometer designed as a cost-effective solution for standard applications in industry and building services. Built to EN 13190, it already provides a robust stainless steel case, ring, stem and process connection in the entry-level class, and reaches accuracy class 1 from nominal size 63 mm. It is offered in eight dial sizes, 25, 33, 40, 50, 63, 80, 100 and 160 mm, with scale ranges from -30 to +500 °C and a large choice of stem lengths and threads.

Seven Star LLC supplies the WIKA A52 to MEP contractors, HVAC equipment manufacturers, panel and skid builders and facility management companies across Oman and the GCC, with engineering support in Muscat. For projects that need a dependable thermometer supplier in Oman for chilled water, ventilation and machinery, it covers most building services temperature points at a sensible cost.

Measuring Principle

Inside the stem of the WIKA A52, a bimetal coil made of two bonded metals with different thermal expansion coefficients twists as the temperature changes. Because the coil is fixed at one end, the twist turns a shaft that drives the pointer directly over the dial. The system is purely mechanical and maintenance-free, needing no power supply, batteries or wiring, which is why bimetal thermometers remain the standard local indicator on pipework and equipment.

EN 13190 distinguishes between the scale range printed on the dial and the narrower measuring range within it. The WIKA A52 may be loaded continuously for up to one year within the measuring range and for short periods of up to 24 hours across the full scale range. The printed accuracy class, class 1 for NS 63 and larger, class 2 for NS 40 and 50, and ±5 % of scale range for NS 25 and 33, is guaranteed only within the measuring range. When choosing a range, the normal operating temperature should therefore sit inside the measuring range: a chilled water line running at 6 to 12 °C, for example, falls inside the -20 to +40 °C measuring range of the -30 to +50 °C scale, but below the 10 to 50 °C measuring range of a 0 to 60 °C scale.

Engineering Design of the WIKA A52

On the WIKA A52, housing, ring, stem, process connection and spacer are all stainless steel, while the dial and pointer are aluminium. The window is instrument glass, or shatterproof polycarbonate on NS 33. Stem diameters are 4, 6 or 8 mm, and process connections include a plain stem, G 1/2, G 3/4, G 1/2 B, G 1/4 B, G 1/8 B, 1/2 NPT, M8 x 1.25, M18 x 1.5, M20 x 1.5 and M24 x 1.5 female. Connection designs cover the standard male thread, male nut, union nut and compression fitting sliding on the stem, with the latter three available from NS 63. The miniature NS 25 and 33 versions use a 4 mm stem with M8 x 1.25, G 1/8 B or G 1/4 B threads, which suits compact equipment where there is little room for an indicator.

Maximum operating pressure at the stem is 6 bar static for NS 25 to 40 and 25 bar static for NS 50 to 160. Ambient temperature at the case is -20 to +60 °C, and ingress protection is IP54 for the small sizes and IP43 for NS 50 and above. For higher process loads, or where the instrument must be replaced during operation, WIKA recommends a thermowell such as models TW45, TW50 or SWT52.

Key Features

The WIKA A52 offers a durable stainless steel thermometer at an entry-level cost:

• Robust stainless steel case, stem and process connection for industrial environments.
• Eight nominal sizes from 25 to 160 mm for very different mounting situations.
• Scale ranges from -30 to +500 °C, single °C or dual °C/°F scales.
• Accuracy class 1 per EN 13190 from NS 63 upwards.
• Back (axial) connection; the R52 lower mount version is available from NS 63.
• Stem diameters of 4, 6 and 8 mm and a wide range of metric, BSP and NPT threads.
• Maintenance-free bimetal measuring system with no power required.
• Optional 2.2 test report and CRN registration.

Industrial Applications

In HVAC and building services across Muscat and the wider GCC, the WIKA A52 is installed on chilled water and condenser water pipework, air handling unit coils, heat exchangers, fan coil headers and energy transfer stations, where engineers read supply and return temperatures to check delta-T and unit performance. Its stainless steel case resists the humid conditions of plant rooms and roof-mounted equipment, and the back mount format suits panels and equipment faces where the dial must face forward.

Machine builders use the WIKA A52 on hydraulic power packs, compressors and cooling circuits, and equipment and laboratory manufacturers fit the miniature sizes to test benches, ovens and technical equipment. Seven Star LLC supplies the thermometer in the size, range, stem length and connection required, together with the WIKA data sheet, and can propose a heavier process-grade model where conditions call for it.

For process industry duty, see the WIKA Model 55 stainless steel bimetal thermometer.

Technical Specifications

Specifications for the WIKA A52 are taken from WIKA data sheet TM 52.01 (11/2025):

How to Order

To get a quotation for the WIKA A52, share the dial size, scale range, stem length and diameter, process thread and the number of thermometers per range with Seven Star LLC. Our Muscat team will confirm the configuration and thermowell needs, advise on supply to sites in Oman and the GCC, and include the WIKA data sheet. Related temperature and energy products on our site include the WIKA TR10 RTD sensor, the Isotech milliK precision thermometer for calibration and the pFlow E3E ultrasonic BTU meter.