We have a church insured under the ISO CP 00 10 form with special causes of loss form CP 10 30. Air conditioning units were damaged by freezing. The insurer-appointed engineer stated there were two causes of loss: (1) failure of the “pump-down solenoid,” which allowed the compressors to run during freezing conditions, eventually resulting in the freezing of the circulating chilled water system and the destruction of the system; and (2) a control rod did not close on the louver vent “economizer” system, which allowed the very cold outside air into the church. The engineer concludes that the failure of the system was due to the mechanical failure of these devices.

The insurer is denying the entire loss based upon the mechanical breakdown exclusion, stating that the concurrent causation language in the policy precludes coverage for any damage resulting from mechanical breakdown. This is not my understanding of the exclusion's effect.

Please comment.