I have a number of FireAngel smoke alarms fitted and am having trouble with one of them. There is a protrusion on the base plate which causes a small spring on the alarm to depress. I assume to allow it to connect. However what appears to be happening is that the spring is causing the alarm to be pushed away from the base plate hence not engaging. Apologies for the clumsy description but has any body any ideas? Thanks in anticipation.

You do not say if this is a new smoke alarm?

I wonder is the baseplate fitted securely to the ceiling, not only secure, but level. If one or more fixing screws is pulling too much it could be causing the base to twist slightly.

You could even take the base and detector down (Temporarily) mount them on a known flat surface to see does the same problem occur.