Lat night at 4:00 a.m., the fire alrm when off. It would go off for abut 10 seconds then get quiet and then after ~5 minutes do it again. I disconnected it. This morning I reconected it and changed the battery (9 Volt). When I checked the old battery, it indicated it was good on the battery tester. I did notice that the light on the detector was off but every once in a while it would blink red. The other alarms in the house that are connected have the green ligh stay on. Is this a hard wire derect, a detector defect or a batter issue? Thabnks for any advice you can give me! Gary