The WIKA A52 / R52 Bimetallic Thermometer is a mechanical dial thermometer designed for cost-effective temperature monitoring in industrial and building services applications. It uses a bimetallic measuring element to convert temperature changes into pointer movement, providing a direct reading without requiring an external electrical power supply.

The two model variants accommodate different installation requirements. The A52 features a back-mounted (axial) connection, while the R52 features a lower-mounted (radial) connection. Both models offer stainless steel construction, a choice of dial sizes and multiple stem lengths to suit different equipment layouts.

Manufactured in accordance with EN 13190, the A52 / R52 is a practical choice for standard industrial temperature measurement where straightforward operation, durable construction and flexible mounting are important.

Key Features

• Mechanical bimetal measurement: Provides direct temperature indication without an external power supply.
• Stainless steel construction: The case and stem are made of stainless steel for industrial use.
• Wide temperature scale selection: Available scale ranges extend from -30°C to +500°C, depending on configuration.
• Multiple dial sizes: Nominal sizes range from 25 mm to 160 mm.
• Two mounting orientations: A52 offers back mounting, while R52 offers lower mounting.
• Flexible process connections: Five standard connection designs are available, with additional designs available on request.
• Maintenance-friendly design: Proven bimetal technology supports straightforward operation without electrical components.
• Industrial standard compliance: Manufactured in accordance with EN 13190.
• Cost-effective temperature monitoring: Suitable for standard industrial applications and building services.

Suitable Applications

1. Machine Building and Industrial Equipment

The A52 / R52 is suitable for temperature monitoring in industrial machinery and equipment where operators need clear, direct readings.

• Monitor operating temperatures in machinery.
• Check temperatures at accessible measurement points.
• Select an appropriate dial size and stem length for the installation.

2. Hydraulic Systems and Compressors

Temperature monitoring helps operators assess the operating condition of hydraulic power units and compressors.

• Monitor temperatures in hydraulic systems.
• Check operating conditions in compressor equipment.
• Support routine inspection and maintenance activities.

3. HVAC and Building Services

The thermometer can be used in heating, ventilation and air-conditioning installations to monitor heating and cooling processes.

• Monitor temperatures in heating systems.
• Check operating temperatures in cooling circuits.
• Support temperature monitoring in ventilation systems and heat exchangers.
• Select a suitable mounting design for the available installation space.

4. Vessels, Piping and Process Equipment

The A52 / R52 can be installed in compatible industrial vessels, pipelines and equipment to provide local temperature indication.

• Monitor process temperatures at selected measurement points.
• Choose a suitable process connection for the installation.
• Verify whether a thermowell or other protective accessory is required.

5. Test Benches and Laboratory Equipment

The thermometer can support temperature indication in test benches and technical equipment where a mechanical display is appropriate.

• Provide direct visual temperature readings.
• Support routine equipment testing.
• Select a measuring range appropriate for the test conditions.

6. Mobile Heating Equipment

The A52 / R52 can also be used in compatible mobile heating systems where a simple mechanical temperature display is preferred.

• Check operating temperatures during equipment use.
• Select a suitable dial size for visibility.
• Verify mounting, vibration and operating conditions before installation.

Technical Highlights & Selection Considerations

Before ordering the WIKA A52 / R52, confirm the following requirements to select the correct model and configuration.

1. Model Selection: A52 or R52

The primary difference is the connection location:

• A52 — Back Mount: The connection is located at the rear of the dial, making it suitable for installations where the thermometer is mounted facing forward from a panel or equipment surface.
• R52 — Lower Mount: The connection is located below the dial, making it suitable for installations where the sensing stem enters the process from beneath the display.

Choose the mounting orientation according to the available space and required viewing angle.

2. Temperature Measuring Range

Select a scale range that covers the normal operating temperature and any expected temperature variations. Available ranges depend on the selected configuration.

Avoid choosing a range solely based on the maximum process temperature. Consider the normal operating temperature and the readability required for routine monitoring.

3. Dial Size

The A52 / R52 is available in nominal sizes from 25 mm to 160 mm.

• Smaller dial sizes: Suitable for compact equipment and restricted installation spaces.
• Larger dial sizes: Provide a larger display for easier reading where space permits.

Confirm the required dial diameter before ordering or replacing an existing instrument.

4. Stem Length and Insertion Depth

Choose a stem length appropriate for the measurement point and installation geometry. The sensing element must be positioned appropriately within the process to obtain a representative temperature reading.

Check the equipment dimensions and confirm whether a protective thermowell is required.

5. Process Connection

The product family offers multiple connection designs, including plain stems and threaded connection options, depending on configuration.

Confirm the thread size, connection standard, mounting arrangement and any required protective accessories before placing an order.

6. Accuracy Requirements

The manufacturer specifies accuracy class 1 according to EN 13190 for nominal sizes greater than 60 mm. Accuracy requirements for other dial sizes and configurations should be verified against the relevant technical datasheet.

If the application requires a specific measurement tolerance, confirm the applicable accuracy class before purchase.

7. Environmental and Operating Conditions

Consider ambient temperature, process temperature, vibration and the compatibility of the wetted materials with the process medium. For applications involving strong vibration, pressure fluctuations or corrosive media, verify suitability with the manufacturer before installation.

8. Replacement and Procurement

For replacement orders, provide the full model or part number, dial size, temperature range, mounting orientation, stem length and process connection. A photograph of the existing instrument or its nameplate can help identify the correct configuration.

Frequently Asked Questions (FAQ)

Q1: What is the WIKA A52 / R52 Bimetallic Thermometer?

The A52 / R52 is a mechanical dial thermometer designed for industrial temperature measurement. It uses a bimetallic measuring element to provide direct temperature indication without requiring an external electrical power supply.

Q2: What is the difference between the A52 and R52?

The A52 has a back-mounted (axial) connection, while the R52 has a lower-mounted (radial) connection. The appropriate model depends on the equipment layout and installation requirements.

Q3: What temperature ranges are available?

The product family offers scale ranges extending from -30°C to +500°C. The actual range available depends on the selected model and configuration.

Q4: What dial sizes are available?

Nominal dial sizes range from 25 mm to 160 mm. Confirm the required size when selecting a new instrument or replacing an existing thermometer.

Q5: Does the A52 / R52 require an electrical power supply?

No. The thermometer uses mechanical bimetal technology and does not require an external electrical power supply for temperature indication.

Q6: What industries commonly use the A52 / R52?

Typical applications include machine building, hydraulic systems, compressors, HVAC installations, heating systems, vessels, piping and equipment manufacturing.

Q7: What information should I provide when requesting a quotation?

Provide the model number, measuring range, dial size, mounting orientation, stem length, process connection and any accessory requirements. If replacing an existing instrument, a photograph of the nameplate is also helpful.