** From the above graph, it can be observed that if air is made to flow through the 200v-1.5kw CLH heater with a flow rate of 39.62 gal/min (150L/min), the temperature of the heating element exceeds 2012ºF (1100ºC) at 240 V and this temperature range has an adverse impact on the service life of the unit.
Even then, the hot air temperature is approximately 896ºF (480°C). In other words, the maximum hot air temperature when 39.62 gal/min (150 L/min) of air flows through this heater is 932ºF (500°C).
If the air flow rate is reduced to 18.49 gal/min (70 L/min), hot air of about 1202ºF (650°C) can be obtained at 200 V. The heating element temperature is approximately 1922ºF (1050ºC), and a long service life can be expected.
In other words, if the flow rate of air flowing through this heater is about 18.49 gal/min (70 L/min), then a hot air temperature of 600°C or more can be obtained with stability. Since the heating element and the fluid do not come in direct contact with each other in CLH heaters, the hot air temperature does not rise proportionally by increasing the heating element temperature using higher flow rates.
However, if the air flow rate is lowered, sufficient heat exchange take places and air of considerably high temperature can also be obtained.
The temperature of a part of the sensor wire (thermocouple) rises to almost the same temperature as the heating element due to the CLH heater structure. This increase in temperature might reduce the service life of the temperature sensor.
Typically, in this model, K thermocouple of ∅0.062 in (1.6 mm) is used in the sensor, which is of sufficient thickness and long service life can be expected with normal usage.
When using heating element at high temperatures, it is safer to use external temperature sensors or R thermocouple (option) for built-in sensors.