Can we use ATS22 or ATS48 for heater?
Operation of ATS for heater application is not validated. There is almost no risk of ATS damage, only the functionality cannot be guaranteed.
First, ATS requires more inductive load (cos phi of induction motor is around 0.8).
Seconds, the rise of the current when thyristors gets conductive is normally limited by motor inductance. Here in case of heater the rise of the current di/dt is much higher (especially during the "starting") and it is unpleasant for thyristor operation. The limit rise di/dt is characterisitc of thyristor and depends on the voltage and the load inductance and resistance. If di/dt exceeds critical value thyristor can be damaged.
Third, ATS funcionality regarding acceleration, torque control, end of starting can fail or give incorrect signalization. Controlled stop does not make sense as well.
Conclusion: ATS use for heaters is fully under customer responsibility.