Stuck gate valve... if I take channel locks to it could I cause a massive leak?

I just purchased a foreclosed condo unit and the place has been winterized for the last 4 months. After de-winterizing, the unit's main valve (gate valve) only opens a quarter turn and stops. It allows some water through, but not enough.

In order to replace the valve, I have to go through hoops to get the water shutoff since it's a condo association. Before doing so, can I attempt to free this valve?

I was going to soak the valve in PB blaster and take channel locks to it, very slowly inching it along. I don't care if it breaks and it's stuck open in any fashion, as then I'd have to replace it regardless. Yet is there a high risk of it breaking and shooting water everywhere, etc?

It probably WILL break, but it is stuck INSIDE the valve where PB Blaster, or anything else, CANNOT do any good. You will not cause a flood, but you will also not likely improve the flow before it strips.

I'm surprised the condo association even agreed to let you DIY this, and I suggest you maybe should rethink the wisdom of attempting it anyway. You're messing with the potential of damaging other condo units which will put you in a bad position. Other than snugging a packing nut, there is no way I would attempt to use a leverage tool to twist or force a valve on a "live" water line, especially where turning off the supply would be difficult and probably time consuming. It seems to me that this would be a case when Murphy's Law would come into play.

From what I've read (and not experienced), when a gate valve typically fails, the shaft breaks, disconnecting it from the gate itself and the handle just spins without moving the gate. It's unlikely anything you could apply from the surface would free up the bits further in. A pro would have better experience with this.

Thank you all. Got it, so it's inside that's all stuck. I brought in my friend who is a licensed plumber. He said you could attempt to spin it, and if it breaks it would likely just be stuck on. Yet worst case it snaps in an odd way and water spews. I was just curious how likely that would be, as I don't mind attempting to spin it free slowy before scheduling to get a water shut off, etc.

I own the unit, I can do what I would like to my plumbing. Obviously I wouldn't take a huge risk if it was going to flood the place. Hence my question regarding what would happen when a seized gate valve fails from turning with too much force.

Very unlikely water will spew. The stem will strip and it will be just like it is now except the handle will spin. Jump through the association hoops, put in a ball valve and move on. (There may be a plumbing emergency somewhere in the future where a functional shut-off would be a good thing to have.)

It depends on the local codes and the specific condo association bylaws, but in many places, you are NOT allowed to do plumbing in a multiple family dwelling unless you have a license. It is this way in the condominium where I live, and in the entire state. This is a common situation in many parts of the country, and I'd be surprised if it was not true in Chicago, where they have some pretty restrictive plumbing codes.

The issue is, should you install something incorrectly, you could affect the health and property of other owners - a professional is supposed to understand and perform the work correctly to prevent this or risk losing his license and fines.

Got it, thank you all so much. Very informative. I shall go ahead and schedule the plumber/shut off.

quote; if it breaks it would likely just be stuck on.

It will be "stuck" in whichever position it was when you started, usually closed.