What happens when I turn my gas detector on?
Almost all gas detectors perform an automatic self-test at instrument turn on. Self-tests generally check the electronic circuit and that sensors are present.
They also typically light the display and sound the alarms and vibration mode so they can be verified by the user.
Self-tests do not confirm gas entries are free from any blockages or that the sensor or sensors are responding to gas.
This is why you need regular bump tests.