Hard wired smoke alarm which keeps beeping- please advise?

Usually, this indicates that the backup battery in the smoke alarm is low.

If your alarms are connected to each other (usually indicated by a third wire connected to the alarm), it can be tricky to re-integrate one once you disconnect it. It seems that when connected for the first time, the alarm trips all the other alarms connected to it. To re-integrate an alarm properly, you need to disconnect power to all units (usually via the main circuit breaker) add the new unit, and then reconnect power to all units simultaneously (just turn the switch back on again).

If you can replace the battery without disconnecting the alarm from its hardwired connection, that would save you a lot of headache. Sometimes the wires aren't very long which makes it challenging to replace batteries. If several alarms are beeping, it may be easier to disconnect them anyway.

so basically, in other Words.....it means you need a new smoke alarm...duhh ahahah