A day after our first beer went into the fermenter we realized that there was another problem with our glycol system. Originally, we thought the only problem was that we couldn’t get our tanks below 38 – 40 degrees in any reasonable amount of time. However, we also found out that once we set our temperature control to the desired temperature it would continue to cool pass the point.
The way the system works is that once the temperature inside the tank reaches the set point programmed into the controller it should close, therefore preventing cold glycol from entering the tanks. Once the temperature begins to rise, the valve will open again and allow glycol in to cool the contents of the tank.
We had our first fermenter set at 64 degrees. Once it got down to that temperature we assumed the valve would shut and cooling would stop. When we came in the next morning our unfermented beer was sitting at 55 degrees. For some reason the tanks continued to cool past the set point.
We called some of the people that had been helping us with this problem. They told us the most likely reason was that there was glycol getting past the solenoid valve. They said it was possible that the valve was damaged during installation so we took it apart and check the condition. What we found out was that the plumber, who had been causing all these problems for us already, installed the valve backwards.
It’s easy to tell because anyone who understands how this system works knows that the glycol comes into the valve from the top and out through the bottom. As you can see in the picture the “out” is on top and the “in” is on the bottom. We checked and sure enough all the tanks were piped this way.
We got someone in the next day to rebuild and reinstall all the valves properly and the problem was corrected. Fortunately, we were able to warm up the tank back up to 64 and fermentation kicked in with in a few hours. Since the other two tanks were still empty we didn’t have to worry them.
Unfortunately, that didn’t solve the problem of getting the tank down below 38, but at least we fixed one of the major issues.