Aluminum Furnace Maintenance Tips

 Working with Thermocouples

A thermocouple is the most basic kind of temperature sensor, and essential to the operation of  heat processing equipment.  We suggest that users perform instrument maintenance and calibration as recommended by the manufacturer's manual. Many customers have found that having a maintenance contract with the instrument manufacturer is the best preventative maintenance strategy.  The following are best practices for keeping thermocouples in service:

• Always use proper type extension wire for each thermocouple.  The chart below lists the most common thermocouple types, leadwire, and color identification.
• Install thermocouple leadwire in grounded metal conduit separate from all other wiring. Do not run across or parallel to AC wiring within 1 foot.
• Never splice thermocouple leadwire.  Run wire in continuous runs from the thermocouple to the instrument.
• Be very careful to avoid thermocouple reversals.  Connect positive to positive and negative to negative in the thermocouple head and the instrument.
• Check thermocouples regularly. In most applications, once a month is reasonable.
• Check thermocouples by comparison, or by inserting in a test oven.
• If you remove the thermocouple for checking, be certain to insert to the same depth.
• Replace burned out protection tubes immediately to avoid damage to thermocouples.
• Do not contaminate thermocouples with oil, grease, or solvents.

The latest design, materials and equipment specifications should be obtained from the company before any reliance is placed on the enclosed since changes may occur due to product improvement.