Dear Niwat, what exactly makes you sure, that the probe is not working. The position of LSA must not urgently 90%. And the level indication by differential pressure must not alwady be correct. In fact during CIP both sensors , if Cip pump is running at the recommended speed, must give signal. If signal during Cip comes up, the probe works and maybe the level indication is a bit too high. Level is only indication LSA and LSH probes are the important switches. So please during next CIP first check if there is signal reaction from both probes