Removing Water From Your Heat Transfer System

Alright, you have confirmed the presence of water in your heat transfer system. So now what do you do to fix that? We have a few recommendations for you.

  1. If you suspect that any heat transfer fluid held in a container may contain some water, check to see if the distinct fluid layers can be decanted. A distinctive layer is only visible with significant amounts of water in your heat transfer fluid. A few parts per million will not be easily noticeable or decantable. This is also not a full-proof removal method and additional water removal may be required.
  2. The most popular and effective water removal method is the ‘Boiling/Flash Off Method’. This involves raising the system temperature to 105°C/220°F and allowing steam to flash out from the system through the vent on the expansion tank. It is important to maintain the tank temperature above 100°C/212°F to prevent a condensation of the exiting vapors back into tank. In cases where there in no warm-up line, an insulated line with a valve can be connected from the heater outlet to the vent on the expansion tank. When the temperature at the pump suction exceeds 105°C/220°F and the pump pressure gauge stabilizes, you can terminate the boil off. At this point, all or most of the steam must have been evacuated. However, you should still check the bottom of the expansion tank for any residual water left behind.
  3. If severe water contamination has occurred to the point where a high percentage of the heat transfer loop is filled with water, you should flush the entire fluid and replace with virgin fluid.
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