LP, CO and smoke alarms

Alarms that chirp or go off are a top service complaint. Never assume it's a false alarm until you've checked.

The short version

Treat a real alarm as real: get people out, shut off LP at the tank, ventilate, and don't flip switches or light anything until you find the source.
Chirping is often low battery or low 12V supply. Many LP detectors are hardwired to 12V.
Detectors expire. Most have a date on the back and an end-of-life chirp. Replace them when they're past it.
Aerosols, cleaning products and cooking can set off LP detectors. Ask what was going on.

LP alarm: cylinders off, ventilate, no switches. Then leak test. Then check the detector's date and 12V.
Safe-T-Alert: green normal, flashing red + tone alarm, red/green alternating + two beeps every 15 s = malfunction, flashing yellow = warm-up.
Chirp every 30 to 60 s on CO or smoke: battery or end of life. Replace the battery, then the unit if it keeps chirping.
CO alarm: everyone out, fresh air, generator and gas appliances off, find the source with a meter.

Check the date on every detector during service. Expired detectors are a liability.