Bob.G

Hi all. First time here and looking for help please. We had a power spike and blackout for about 15 minutes three days ago and since then one of our two interconnected EI151 detectors have been beeping, and the other just 'chirps'. I had a look online for help and found this site - I've read all the posts and done as suggested above to no avail. With the power to the units off I removed the head that was chirping and noted that the four wires (blue, blue, red, yellow) were not on a plug but soldered into position with an insulating sleeve. I assume that the other one will be the same. Note that the units do not carry a date but are believed to be about 20 years old. Query 1: Do the replacement units come with a plug that accepts cable terminations to enable me to replace the unit, or will I need to resolder the connections ? Query 2: How do I determine which of the two blue cores to connect to the 'battery' terminal (I'm assuming that red = live and yellow = 'interconnect').