As a general rule, there is not likely to be subrogation without evidence.  However, in some cases subrogation will exist.  
Example:  if a major department store sells and installs a product, such as a dishwasher or refrigerator, and the product fails, causing water damage, the store service unit may respond to the insured’s home and replace a part, and keeping the part. You will have good subrogation for either products liability or negligent installation.
Example: where a contractor or subcontractor is working on the insured’s home, and causes a loss, whether fire or more likely, water. If the contractor repairs the part, but not the damage, and takes the faulty part, there will be subrogation.
The lesson to be learned is to go the extra step and identify what happened to the part after the loss, and determine who last had possession of it, who removed it, and what happened to the part thereafter.