Thank you, no issues with electricity I know what to do ;) This ups is planed for my bedroom, and really do not want beeping sounds until i am slipping.

Can be some other small ups .. but must have AVR since sometimes a I have some voltage anomaly ( dont ask why long story ) also short power outages .. for 1 to 2 mins .. not every day but once per month happen ... And yes is nothing which is related to my el. Installation.

Funny, I did this 2 days ago as the beeping was driving me insane. It was a 1 minute procedure: opened the UPS (5 screws) and just pulled the speaker off of the board with some plyers.

can I remove the beep speaker from apc easy ups?

Just cover its hole with some sticker/duct tape, this can almost completely mute it.