Using an Air Heater

If used properly, heater life of 5000 hours or greater can be expected. To ensure long heater life and safe operation, follow these guidelines. Also read and understand your heater Operating Manual before use. Failure to follow these guidelines can result in heater damage, failure, or personal injury.

Air Sources

Compressed air and air from regenerative blowers may be used to supply Osram Sylvania air heaters. Your air source should be clean and dry. Dirt, grease, oil, oil vapors, or corrosive/reactive gases will damage an air heater. Use air or inert gas only — never volatile or combustible gases.

Regenerative Blowers

Regenerative blowers are compact and inexpensive clean‑air sources. They provide large amounts of low‑pressure air. Blower size is based on maximum airflow without restrictions. When a heater or piping is attached, flow decreases. Severe restriction can overheat and damage the blower motor.

Minimize restrictions and select a blower capable of overcoming heater backpressure. Because of their small size, the Series, Hot Air Tool, and Serpentine II heaters should not be used with regenerative blowers.

Compressed Air

Compressed air is commonly available in factories. It is high‑pressure regulated air (typically 100 psi) and often contains oil for pneumatic equipment. This oil must be filtered to prevent fouling and damage to heater elements.

When measuring compressed air flow, be sure you are measuring Standard CFM or Standard LPM. “Standard” means measured at standard temperature and pressure. Many flow meters labeled SCFM are incorrect at high pressure. Consult your meter manual for proper conversion.

Controls

A good control system is critical for long heater life. Always establish sufficient airflow before applying power. Only qualified individuals should install heaters and controls.

Open‑Loop (Manual) Control

Uses a manually operated power controller to apply fixed voltage. If airflow is interrupted, the element may fail. Generally used with Series heaters.

Closed‑Loop (Feedback) Control

Uses a power controller, temperature controller, and thermocouple to maintain constant output temperature. Provides a convenient temperature display.

Power Controller

Phase‑angle fired SCR controls provide the smoothest regulation. Other controls may be suitable; consult Osram Sylvania.

Temperature Controller

Use digital controls with type‑K thermocouple inputs. Output must match power control input. PID with wide proportional band minimizes overshoot. Auto‑tune only at safe temperatures.

When using SSR power control, set cycle time to 100 ms or less.

Thermocouple

Use fine‑wire (.030" max), exposed‑junction type‑K thermocouple placed within 1 inch of heater exit. Other styles or distances cause measurement errors or heater failure.