Thermal Solutions of Texas offers our repair/evaluation program which allows us to help you understand why your electric heater, temperature controller, power switching device or thermal system has failed.
Electric heaters are the most cost effective product when it comes to repair. There are four basic components that make up an electric heater: Resistance Element, Insulation, Sheath and Termination. All four components must be thoroughly evaluated to determine what has caused your failure.
Services we can provide are as follows:
- Insulation resistance (Megohm) testing
- Bake out Insulation and Re-Seal the heater elements
- Repair/replace buss bar, terminals, and hardware
- Repair/replace cold pins where required
- Replace cover O-ring and Gaskets
- Epoxy seal when applicable to prevent moisture infiltration
- Replace individual elements or zones of elements in bundle
- Repair/replace process and hi-limit sensors
- Repair Distribution Block
- Stock replacement parts
The resistance element is typically in the form of a small diameter metal alloy wire or a thin flat ribbon. One of the most common resistance wires used in electric heaters today is referred to as Nichrome (80% Nickel, 20% Chromium). Nichrome wire is frequently used due to its ability to operate at high temperatures (1600F) for extended periods of time. All heaters eventually fail or burn out. Some common causes of resistance wire failure are physical damage, contamination and oxidation. The oxidation of a resistance element can be accelerated by constant thermal cycling (heating up and cooling down) of the heaters. Selecting a heater with a lower watt density and operating at lower and constant temperatures with the proper power switching device can greatly extend the life of your heater.
The insulation in an electric heater is used to electrically insulate the resistance element from the outer metal sheath of the heater. It prevents the electric current in the resistance element from arcing to the sheath and causing a short or electric shock. The two most common types of insulation used in our electric heaters are: Mica and Magnesium Oxide (MgO). When used with Nichrome resistance wire, Mica has a maximum operating temperature limit of around 1100F (600C) and Magnesium Oxide has a maximum operating temperature limit of around 1600F (870C). One disadvantage of Magnesium Oxide is that it is hygroscopic which means that it absorbs any humidity or moisture. To prevent the insulation from absorbing moisture, it should be stored in a cool, dry area and/or baked out to evaporate any moisture.
The sheath of an electric heater serves multiple purposes including providing strength, good thermal conductivity and protection against contamination, corrosion and mechanical damage. The sheath allows the heater to be packaged and formed into various different shapes and sizes. In certain types of heaters, the sheath can serve as both a protective covering and insulation in one. When a heater is bad, the sheath must be inspected for any signs of corrosion or other physical damage.
The terminations are the part of the heater which allows for connections to an electric power supply. There are many termination options commonly found on an electric heater including: flexible lead wire, screw studs, pins, metal strips, etc. These terminations are connected to the resistance wire inside the heater which allows the electric current to flow causing the resistance wire to heat. The terminations of an electric heater must also be thoroughly evaluated for damage.
Please call us to schedule a free evaluation.