Weicon Smoke Detector Test Spray The Smoke Detector Test Spray can quickly and reliably test the given capacity of optical and photoelectric smoke detectors without an additional tester. WEICON Smoke Detector Test Spray does not contaminate detectors as it evaporates without residue. WEICON Smoke Detector Test Spray can be used in all applications involving photoelectric fire detectors – in written, elevated facilities, public facilities or private residences.