If your vent loses connection with the Hub there are a few steps you can try:
Power Cycle the Sensor: Unplug that room's Sensor from the wall for 10 seconds and plug it back in
Power Cycle the vent:Remove the battery pack from the ventTake care to NOT press the "reset" button on the vent, as doing so will require you to re-add the vent in the roomWait approximately 5 seconds and Re-insert the battery pack into the vent. When reinserting the batteries look for the LED next to the Serial number sticker:If LED flashes once: you should be all set, wait for the message to clearIf LED does not flash: Try a new set of batteries and check againIf LED continues flashing: This device has accidentally been reset and will need to be deleted from the app and added to the room again - you can check these instructions here for help
If you're still seeing communication issues please contact support@ecoventsystems.com we'll figure out what's going on.