Leaky Fire Sprinkler

I have a leaking fire suppression sprinkler head (the "drop down" type that have a flush plate at the ceiling) in one of my bedrooms. The leak is small. It is filling a 3 gallon bucket underneath it in about 2 or 3 days.

After turning the water off, I tried using adjustable wrench and big pliers to remove the sprinkler head, but to no avail. I've been trying for the last several days to remove it, but no matter the amount of force I apply to loosen the stuck sprinkler head, still nothing. I also used some W40 but it just won't come unscrewed. what should I do.

tx
ed

I know I am a million years to late and don't know how I missed this one but two pipe wrenches works every time. sometimes you need to get the large ones out but it should be an easy job. just remember to drain the lines first or there will be a huge mess.

I'm pretty sure there will be a huge mess anyways.

Good Luck!