Trying to put in a new main shutoff

I live in a townhouse condo, about 10 units in this building. We're having some work done late this week on our aux pump (we're up on a hill - this is used to give us adequate pressure and it boosts it more if a fire hydrant is opened) and they will be shutting off the water for probably a short time. The current main shutoff in my unit leaks...I've wanted to replace it for awhile, but it is a pain getting everyone to agree on a time to shut off the water. Each unit has an individual shutoff, but the building one is acttually in the end unit. Trying to get them to let you in is a problem, too.

SO, I'd like to replace the valve with a nice ball valve. Problem as I see it is that where that valve is is in the basement (3/4") but it taps off of a 2" line that feeds all of the other units in the building. What I'm afraid of is that even with the main water shut off, with all of the other users and that large line, it may not drain enough before they get ready to turn it back on to get the line dry enough to actuall solder on the new valve.

I could cut out the existing valve in a couple of minutes, but will the water likely drain for minutes, hours, ?

I'm not sure the old bread trick will work - there is two stories of tub, toilets, etc above me and somebody is going to open a tap, letting air in the system from somewhere allowing it to drain. Are there other things that are readily available that would likely give me enough time to get the supply end soldered on? I can get the inside stuff at my leisure. I prefer to solder it, but is there a compression fitting that would be reliable in this situation? Then I don't have to worry about the drip/flow. Or, am I worrying too much, and the flow will stop?

Thoughts? How would you approach this?

Would you feel comfortable using one of these? Am I likely to find one at the local plumbing supply?

water

You can buy, or maybe rent, an expansion plug to stop the water until the valve is installed. Then, assuming you use a full port ball valve, the plug is loosened and pulled out of the pipe before turning off the valve. Compression valves are only good for real emergency situations.

I found this plug by Petersen. Not sure if I can get one locally in stock, would rather rent one, since I don't expect to need one again! For the cost, I guess it might just be cost effective to have somebody do it. I'll check the rental agencies. ANyone ever seen one of these in a rental place?

Interesting that a main valve for your unit is inside someone elses unit. In any event, the management company should coordinate needed work that afects multiple units, as they apparently are doing for the pump job. You should be able to get them to keep the main tagged off until you can finish your job.


A compression valve would not be recommended for a main valve, although probably allowed by the inspector if it is in an accessible location. If I were the owner whose unit the valve was IN, I would insist on a more robust valve. I would also insist on the work being done by a licensed plumber.

Anyway, you are correct in thinking that the drain down for a 2" line to 10 units may take awhile. Are the 3/4" shutoffs for the other 9 units in the same location? That would help with that problem. And the JetSweat plug set already mentioned would seal the deal.

Each unit has an individual shutoff. The building shutoff is in the end unit. The complex consists of 7 buildings, and they are shutting the water off at the facility entrace to work on the pumps, so everyones water will be off for a bit. I'll check things out and let you know. It is just annoying to have the thing leak (it doesn't completely shut off), so when you do need to do something, you have to play around to actually get the pipes dry to work on something. The shutoff I'm talking about is in my unit.