Well, did you do a fire test when you took over the aircraft? The only case when only one loop will trigger an overheat or fire warning is when the other one is detected to be failed (loss of gas pressure or power failure). Were you directed by an engineer to do these steps? I would have done a bit of troubleshooting myself as well to get her going, so I don't want to question your course of action, but a recurring overheat warning is a little bit too serious for my taste - especially because having normal engine indications otherwise are no guarantee of not having an abnormal situation (you could have a had a bleed leak, or worse...)