Process Air Heaters

Secomak 688 Process Air Heater

Model 688 Process Heater (24-36kW)

The Model 688 Heater consists of element assemblies mounted inside a stainless steel tube which is enclosed in an insulated jacket. The jacket allows maximum heat transfer to the air stream while maintaining a low surface temperature. This makes the model 688 ideal for mounting in vulnerable areas or in enclosures containing other equipment.

The inlet of the 688 is flanged and the outlet is either flanged or provided with a duct/hose adapter.The terminal box is manufactured from aluminium and is protected to IP65. Connection is made to each element using DIN rail termination for ease of wiring. 

The Model 688 will give an outlet temperature up to 300°C and is available in loadings from 24 to 36kW. The inlet can be fitted with a thermal cut-out to protect the element in the event of the airflow becoming restricted. 

A variety of temperature controls are available, ranging from switching devices to provide fixed loadings through to systems to monitor and regulate the output temperature. A range of adapters are available to couple the Model 688 with a variety of Secomak fans.





200 ft²/min 0.22" w.g.
800 ft²/min 3.50" w.g.
1400 ft²/min 10.80" w.g.

Voltage* Supply
415V Three-phase
380V Three-phase
240V Single-phase
220V Single-phase

*Other voltages are available with
limited loading

Heat Transfer Curve

The following heat transfer curve can be used to specify the appropriate heater size. First, determine the required flow rate and heater outlet temperature, then read across the axes to find the recommended size. Please note, when using the heat transfer curves allowances should be made for losses which will depend on the distance from the heater outer and the degree of insulation.The Model 688 Heater is only available in sizes 24-36kW, please click here to view the heat transfer curves for smaller loadings.

Product Drawings

Click on the drawings to enlarge. 

Secomak Model 688 Process Air Heater Line Drawing