During fermenting beer, sometimes, there will be some unusual phenomenon as below.

1.Air leakage.
Air leakage is common phenomenon on fermenter operation. If fermenter leakage is confirmed not because welding line, it is usually due to loose connection of accessories. For example, on top of fermenter, where mounted safety valve, CIP cleaning pipe. On beer outlet and discharge port. Improper operation during beer goes into fermenter, fermenting and draining beer will has risk of air leakage.
Solution: Checking pressure gauge regularly; cleaning safety valve; changing seals timely

2.Beer freeze
Freezing point is refer to temp that beer will freeze. Freezing point of beer is depend on alcohol concentration and wort gravity. Its calculation formula is as below:
t=-(N1x0.42+N2x0.04+0.2)
T----Beer freezing point
N1----Alcohol concentration
N2----Original wort gravity
Beer freezing is usually result from 2 reasons. 1. Coolant temp is too low.  2. Improper design of cooling jacket.
Solution: Control coolant temp at -6~-4℃; Don’t put coolant inlet on low temp area of fermenter

3.Negative pressure of fermenter
Negative pressure is really dangerous on fermenter. It may results in tanks damaged or tank out of work. Normally, after beer is drained out of fermenter, there is still amount of CO2, if brewers cleaning tanks in this time via hot caustic, caustic will absorb CO2 immediately. And if brewers flush tank via cold water, the temp inside FV will reduce immediately. This two improper operation will cause vacuum on fermenter. However, if safety valve couldn’t receive enough air in this time, fermenter is high risk of out of shape.
Solution: Draining all of CO2 before cleaning tanks and sparging fermenter for 10-20mins via clean water first