A Navien NPE tankless unit installed in a cold climate shows freeze damage to the cold water inlet. The built-in freeze protection did not prevent it. What is the most likely reason?
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A
The freeze protection only works when the unit has power and is not tripped off
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B
The inlet water pressure was too low to activate protection
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C
The freeze protection thermostat setpoint was too high
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D
The gas valve was open during freezing temperatures