I'm thinking the problem may be with the IRP2+ or the power supply. I have installed many of these, with many different components, and not had this problem. This doesn't mean it can't happen, as I have had unfavorable results with Audioplex's Plasma Proof system. Anyway, I'm thinking that if the IR works with the remote close to the sensor, that would explain a weak power supply or defective IRP2+. If possible, I would exchange the entire system (sensor, flashers, and IRP2+) and see if the problem is resolved. It seems as though you've exhausted all other options.