Corrosive condensation can form within heaters when they are run with water below 70F degrees.
Some heaters use a unitherm governor. A unitherm governor blocks water from exiting the heat exchanger until the water warms up in the exchanger.
It's similar to the thermostat in a car that regulates the coolant circulating through the engine. This prevents cold water from circulating through the heat exchanger.
Cold water circulating through the heat exchanger creates condensation that can drip off of the exchanger and onto the burner tray. So, you can get condensation any time that the conditions are conducive to condensation.
If you have ever seen condensation on your plumbing and system equipment, then you probably have had condensation in the heater.
The [Pentair MasterTemp Heaters][1] say:
- Operating this heater continuously at water temperatures below 68° F. (20° C) will cause harmful condensation and will damage the heater and void the warranty.
- When starting the heater for the swimming season with a water temperature below 50° F (10° C), the heater may be used to heat the water; however, make sure that the heater operates continuously until the water temperature reaches the heater’s minimum setting of 68° F (20° C).
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