Why is my ESL 521BXT 2-Wire smoke detector chirping?

Hello, Nancy -

Without knowing the manufacturer and model of the smoke detectors you have it is a challenge to provide you with the right advice.

One of our smoke detectors needs to be completely replaced when it starts chirping.

My husband takes the main part off that smoke detector and takes it with him to the hardware store to make sure he purchased the right replacement.

Perhaps the information here will prove instructive:
http://www.wirechiefelectric.com/blog/resources/what-to-do-when-smoke-alarm-keeps-beeping
Be sure to read through all the information on that web page.

Best wishes.

Hello, Julie -

1. Try removing and resetting the new battery in the smoke detector.

2. If the smoke detector still chirps, I suggest just purchasing a replacement smoke detector unit.

We have a "main" smoke detector (along with others inside bedrooms and in corridors.) When the "main" smoke detector chirps, we have found we have to replace it, with a fresh battery, entirely. To make sure we purchase the right unit, we remove the entire thing from the ceiling mount and take it to the hardware store.

Best wishes.

The chirping must be coming from some physical object. Sometimes it can be difficult to locate a chirp. Maybe there is a CO detector nearby. Those chirp also.

A chirping smoke detector indicates low battery! Change battery or replace smoke detector!

Look at the detector you removed, and all others that may still be wired in.
They all have battery backup. Although the detectors are hardwired, the chirping is coming from one of the detectors to let you know to change the battery.

http://www.smarthome.com/manuals/7309.pdf

Not sure what you mean; can you be more specific about the problem?

Yes it is. See link. (pdf)

http://www.sdilink.com/pdf/ESL/CompatIndex_Oct04.pdf

Battery low,must change,Must check for battery power every 3 months.

you may need to clean the chamber.