I assembly the kit and change R2 to 91K and R33 to 22K so I obtain a range from 17.5°C to 52,8°C.
I set the temperature to 37°C and the hysteresis to the minimum value.
Normally all OK but sometime, rarely, the system don’t stop the heating when the temperature reach that setted and so continue to heath alltime.
I test the system and the two parts of the relay’s contact aren’t solded together meantime the relay’s coil is in the state to heat.
What the possible cause af this incorrect functioning?