Chromalox PG405-5 specifications Operation, Maintenance

OPERATION

FIRE/EXPOSION HAZARD. This heater is not intended for use in hazardous atmospheres where flammable vapors, gases, liquids or other com- bustible atmospheres are present as defined in the National Electrical Code. Failure to comply can result in personal injury or property damage.

Before energizing this heater:

1.Be sure all electrical connections are tightly made. Hold ter- minal with pliers when tightening screw.

2.Be sure that all conductors are properly insulated.

3.Be sure that all element assemblies have been properly replaced, and that secondary insulation bushings have not been omitted.

A.Controlling Radiant Intensity —

Standard Radiant Heaters are built to operate at approximately

40watts per sq. inch on the element sheath. When it is desired to reduce radiant intensity, one or more of the following meth- ods may be used.

1.INPUT CONTROLLERS. These motor-driven cycling devices can be used to vary heater output capacity from 4 to 100%. They are usually connected in holding coil circuit of magnetic contactors. See Chromalox Radiant Heater Manual for further information regarding Input Controllers and Contactors.

2.SOLID STATE THYRISTOR POWER CON- TROLLERS.

For best non-contact control of radiant heat, a Series #6 Chromalox Thyristor Power Controller with manual poten- tiometer setting is recommended. Truly proportional output of from 0-100% can be easily dialed-in to suit the particular product or process requirements. The Series #6 panels are pre-engineered, pre-packaged assemblies in an enclosure with circuit disconnect provided and ready for installation.

B.Maximum Ambient Temperatures —

CHROMALOX Radiant Heaters are not recommended for applications in ambient temperature exceeding 450˚F. Higher ambient temperatures mean shorter heater life.

Maximum work temperature in a given time depends on sever- al factors: Reflectivity of work, specific heat of work, mass of work, kW input and losses from oven, and time of exposure. As work temperature increases, the work loses heat by radiation and by convection to the surrounding ambient. Although it is a gen- eral principle of Radiant Heater application that work tempera- ture conventionally exceeds ambient temperature, in cases where extremely high work temperatures are desired, it is nec- essary to enclose the heaters in order to increase the ambient. If evaporation of a liquid is desired as a result of increasing work temperature, it is necessary to provide ventilation air in order to carry away the evaporated liquid. Under carefully engineered circumstances, a maximum work temperature of 600˚F may be attained.

MAINTENANCE

ELECTRIC SHOCK HAZARD. Disconnect all power before installing or servicing heater. Failure to do so could result in personal injury or property dam- age. Heater must be installed or serviced by a qual- ified person in accordance with the National Electrical Code, NFPA 70.

A. To Remove Heating Element —

1.Remove element assembly mounting nut and bolt 18 and 16 and element support clips (see Figure 8) and slide element assembly out of housing.

2.Disconnect heating element from electrical leads at both ends.

3.Remove screws from porcelain terminal blocks.

4.Remove element support clips and secondary insulating bushings.

5.Lift element out of heater.

B.To Install Element —

Observe instructions for removing element and proceed in reverse fashion. Be sure to replace secondary insulating bushings.

C.Care of Reflectors —

Reflectors should be cleaned periodically. A mild soap and water solution or fine cleaning powder is best although more drastic means may be required if reflectors are badly soiled by chemical or other deposits. The reflector is aluminum. DO NOT use alkali cleaners since alkalies will dull reflector. Mild non- alkaline cleaners, such as used for scouring kitchen sinks, may be used. Reflectors are replaceable and may be purchased from Chromalox.