Kidde Model 1276 Smoke Alarm My Newly Installed Hardwired Kidde Smoke Detectors Beep. Any Suggestions Beyond The Battery?

My newly installed hardwired Kidde smoke detectors beep. Any suggestions beyond the battery? - kidde model 1276 smoke alarm

I Set the switch after installation, the units have fresh batteries, the green LED lights and power units (tested), the LED flashes red every ~ 40 sec. These were installed on the existing hard iron, no sound earlier detectors, new 9V batteries 9V during the test. I have stressed several combinations of tests and silence. Drive is a Kidde Model 1276th A former model in 1276 are also integrated into the system beeps.