Beside lightning and damaged (shorted or grounded control) wires what could cause a failure on a control transformer?
The unit is a split 10T HP with heat strips. Twice this unit's has control transformer and heat strip contractor coils have burned out? The unit is a 3P 240 HP. There are a total of four units at this facility and this is the only one that is blowing the control transformer? The transformer is a 75VA. The thermostat is located around 30 feet away. The 24 volt circuit is fused correctly.
Any probable causes would be welcomed.