I have woken up this morning at 5 am (smoke alarms always have their the problem seems early in the morning) one of my smoke signals makes three blasts, then silence occurs a few minutes, then make three signal sounds again, etc.
We have Kiddie KN-COSM-1B smoke detector. Of the last few months after the restoration of the foundation we have been slow to replace our old hardwired signals from the Kiddie models. Kiddie model CO/Smoke detector built in.
They don’t have to concern sick, get one with a digital read out and memory button, it should go to zero or have any questions, they don’t signalling to a certain amount will be achieved over time, just check peak every day, even if it goes to 20 I would start looking.