Troubleshooting My Philips Air Purifier accidentally powers off If your Philips Air Purifier powers off unexpectedly, there might be a simple solution. Find out how to solve it yourself here. The air purifier is restarting When the power resumes, your Philips Air Purifier restarts automatically and goes to the previous mode. The purifier was set to shut down If your purifier comes with the option to pre-set it to shut down, then this might have been set. The filter alert has been on for more than two weeks If your purifier has been showing a filter replacement alert for more than two weeks but the filter was not replaced, it will be locked and shut down. If this is the case, please replace the filter.