It is advisable to investigate why a freeze alarm went off in a glycol system chiller before you reset that alarm. Such an investigation will prevent any further damage that would have occurred if the cause of the alarm wasn't fixed. This article discusses some of the possible reasons why the freeze alarm can go off.
Insufficient Glycol Solution
You should ensure that the quantity of the glycol (the glycol percentage) in the glycol solution is what the manufacturer recommends. Anything less than that can cause the freeze alarm to go off. Compressors and other components can also fail if you continue to use the chiller when it is low on glycol. The glycol solution should also be at the level recommended by the manufacturer before you reset the freeze alarm.
Incorrect Pump Rotation
Some pumps, such as centrifugal pumps, can still work at reduced capacity if their rotation is reversed. Others stop completely. This can cause the system to freeze up due to the reduced temperature in the evaporator. Pumps usually have a rotation indicator that shows you in which direction the motor should rotate. Change the motor leads in case you find that the motor was rotating in the wrong way.
An obstruction in the piping can cause the freeze alarm to go off. For instance, you may have overloaded the chiller. The alarm can also go off if a valve in the system remains closed at a time when it should be open. The pump can also cause a flow restriction when it fails. You should therefore check all these components so that you rule out each of them until you discover the cause of the restriction. Fix that problem before you reset the alarm.
The reduction of the refrigerant in your glycol system chiller can also cause the freeze alarm to go off. Such a reduction may be due to a leak in the system. You can be certain that your chiller is low in refrigerant in case you see bubbles long after you restarted the system. The bubbles can be viewed through the liquid line sight-glass on your chiller. Recharge the refrigerant or ask a technician to fix any leaks in case you observe signs, such as oil stains outside copper piping, of a refrigerant leak.
As you can see, you can reduce the cost of maintaining your glycol system chiller by fixing some of the problems above on your own. However, you will still need a professional to inspect and service the entire system periodically so that it keeps performing at peak levels.