How to interpret Astrel Easy Heater model numbers

The Astrel Easy heaters are available in several versions, depending on the power, the type of flow detection and the sensor model installed on it. All part numbers start with "PFEAT" or "PFEAR" (former references) and end with "00000" or "00001" (the last digit is not important). The three digits after the letters PFEAR provide the essential information on the heater configuration.

Power consumption
The first digit indicates the heater power:
1 = 3.6 kW
2 = 3.0 kW
3 = 2.0 kW

The resistance on Astrel heaters is welded in place, and cannot be replaced.

Flow detection
For safety reasons, all spa heaters require a flow sensor to shut off the heater if the water flow is insufficient. The second digit of the model number indicates the type of detection used. The types of flow sensors are:
0 = Lamella detector
1 = 2-in-1 sensor
2 = Pressure switch
3 = Hi-Limit sensor. A heater of this type can be replaced with one with a 2-in-1 sensor (as if there was the number 1 instead of 3).

Sensor type
The third digit indicates the type of sensor. There may be a link with the type of flow detection, if the sensor is also used as a flow sensor, but it is quite possible to have a heater equipped with a pressure switch AND a 2-in-1 sensor, for example.
0 = Hi-Limit sensor only
1 = 2-in-1 sensor

Since the 2-in-1 sensor incorporates the functions of the Hi-Limit sensor, you can replace a Hi-Limit with a 2-in-1, but not the other way around.