Cast-In Heaters www.tempco.com | (800) 323-6859 | email: [email protected] 3-70 Installation Recommendations for Cast-In Thermal Components Installation 1. Allow sufficient space for thermal expansion. The amount of space required depends upon the Cast-In Heater size, operating temperature and alloy. 2. Surface being heated must be free of any foreign materials and have a smooth finish. 3. Make sure that the casting is properly seated. The clamping devices used should be tightened down to the correct recommended torque. After initial heat- up, retighten fasteners to the correct recommended torque. Recommended Torque: 10 ft-lb for 1/4–5/16 bolts, 20 ft-lb for 7/16–5/8 bolts 5. Thermal insulation can be used to reduce heat losses. 6. Avoid mounting heaters in an atmosphere containing combustible gases and vapors unless specifically manufactured for use in such conditions. 7. Liquid Cooled Cast-In Heater fittings must be securely tightened to prevent leaks. 8. To prevent overheating and heater failure, adequate temperature controls should be installed. For assistance in selecting temperature controls and thermocouples, see Tempco’s (in-stock) complete line of Plug-In type Proportional Temperature Controls for heating and cooling applications in Section 13. Also see the listing on standard and hot melt thermocouples in Section 14. Wiring 1. For connections at the heater terminals, use high temperature nickel conductor or nickel clad copper lead wire or alloy bus bar. Keep all electrical connections properly protected to eliminate electric shock to machine operators. 2. Heaters of equal wattage and voltage can be connected in series for higher voltage. 3. Heater installations must be properly grounded to eliminate electric shock hazard, and wiring must comply with electrical codes. 4. Always have a qualified electrician perform all wiring and connection of heaters and control compo- nents. Terminals must be tightened to the correct torque (2.5 ft/lb for terminal connections). CAUTION: Castings are not designed to be lifted or carried by the terminations or leads. Operation 1. It is recommended to slow start the process during first use. 2. Do not operate above rated voltage. Excess voltage will result in heater failure. 3. Do not operate Cast-In Heaters above recommended temperatures. Heater temperature must be monitored and controlled. Use of over-temperature T/C is strongly recommended for higher temperature applications. Excess temperatures will result in heater failure and/or melting. 4. Electrical terminals must be kept free of contaminants, as spillage of plastic, water, oils, and their vapors can cause electric shorts, resulting in heater failure. 5. Liquid Cooled Cast-In Heaters must not be cycled to operate simultaneously. Thermal stresses may result in shorter heater life. 6. The water used on Liquid Cooled Cast-In Heaters must be properly treated. Hard water contains corrosive media that will contaminate the tubing, producing stress corrosion cracks and resulting in shorter heater life. Presence of minerals in water can cause clogged tubes that can result in poor heat transfer and eventually heater failure. Maintenance 1. Never perform any type of service on heaters prior to disconnecting all electrical power. 2. To ensure good surface contact, periodically check clamping. Retighten clamping to the correct torque when required. 3. Repeat cycling of temperature controls can indicate poor surface contact or a burned-out heater. 4. Heater terminals must be kept free of plastics, oil, water, and any other foreign matter. As these materials carbonize, they create electrical shorts. 5. Heater terminal electrical connections must be kept tight. Loose connections can overheat and eventual destroy the connection or the heater terminal. 6. Water lines must be periodically checked for leaks. Water on heater terminals can be detrimental to the entire heating system. 7. Thermocouples must be kept free of contaminants and be checked for good response to temperature changes. Our recommendation is to change them periodically, as a bad thermocouple can be the cause of destroying an entire heating zone. Tempco Cast-In Heaters will provide long life and dependable, trouble-free service if properly installed, operated, and maintained as per the following recommendations: Exposed electrical wiring on cast-in heater installations is a violation of Electrical Safety Codes including O.S.H.A. Complete Your Installation With Accessories Available From Stock Accessory Catalog Section ✴ Stainless Steel Tubing and Fittings For Cooling Lines 3 ✴ Pressure Transducers and Rupture Disks 12 ✴ Temperature Controllers 13 ✴ Temperature Sensors, Thermocouple Wire, Jacks & Plugs 14 ✴ High Temperature Lead Wire & Fiberglass Tape, Ceramic Terminal Covers and Electric Plugs 15 ▼▼▼▼ ▼▼▼▼ ▼▼▼ ▼▼▼▼ ▼▼▼▼ ▼▼▼ Note: See page 16-11 for Wiring Diagrams and page 15-2 for lead wire selection
