Why can't I use fan automation below -7 C (19 F) ambient air temperature on my OPI Blue System?

OPIsystems Inc. strongly advises against freezing the grain mass inside the bin so the ability to run the fans in automation mode is restricted.

OPIsystems Inc. fan automation restricts the fans from turning on and running with an ambient air temperature below -7 Celsius (19 Fahrenheit). This is because we as a company know that freezing the grain mass carries a lot of risk and will damage the grain, therefore we have built restrictions into the fan automation to prevent the fans from running. You can still run your fans in manual mode if you want to freeze the grain mass, however we strongly advise against doing so.

What are the risks?

There are two main risks that come with freezing your grain mass:

  1. Freezing the mass will damage the grain: When you freeze the grain, depending on the grain type you can damage it and reduce the quality of the grain. This damage will lead to an inferior product going to market, effectively reducing your return on investment. 
  2. Condensation and hot spots will be far more likely: When you freeze the grain, you will need to thaw it before you take it to market. When you run the fans in the spring/summer to thaw the grain mass, you are introducing a warm and potentially moist air mass into a cold grain mass. This warm moist air clashes with the cold dry grain mass (similar to a warm weather front and a cold weather front meeting), causing the moisture in the air to condense into liquid water that settles on the grain. This moisture will increase the risk of a hot spot developing and spoiling the grain. Furthermore, if you stop thawing the grain mass midway, a crusty hard layer of grain will form where the condensation settles between the frozen and thawed mass. This layer prevents further drying by making it harder to push air through it into the rest of the grain mass, trapping any hotspots that develop.