Gotchas replacing outdoor water valve
A bit of plumbing heading my way. Client has a sprinkler system, and the main shutoff valve, right next to the meter box, is not working. The shaft for the handle is just 1/4″ high and has been rounded with pliers, so there’s no way to grab and turn it. The pipe appears to be 1 inch galvanized, and has been in the dirt for years, so I’m not too optimistic about unscrewing it. Besides, there are no unions close by, so cutting the pipe appears to be my only option. I had thought about unscrewing the top of the valve and trying to find parts to rebuild it but HD certainly didn’t have anything that would fit, and with something that old, it seems like a real long shot.
My plan is to cut the pipe with sawzall at either side of the valve, use a pipe threader die to rethread the cut ends, and then put in a new valve with a close nipple and union. The die and handle rent for just 6.00/day, much cheaper than buying die and handle for about 65.00 each at HD.
My concerns are that the old pipe may or may not cooperate with the die — it does have some surface dirt and corrosion. And my other concern is that the valve I got was “compact” which means it only has threads for about 1/2″ on either side, and my connections may bottom out before they get tight.
Any helpful hints or things I should be watching out for?
Geoff in Seattle
Replies
Your plan to cut, re-thread and re-pipe with valvle, nipple and union will probably work.
Make sure your client understands "probably".
Tips:
Give yourself plenty of working room by digging out around the work area.
Thoroughly scrape off the dirt and corrosion adhering to the old pipe. Surface pits on the pipe will not likely be deep enough to remain after threading.
Be sure to "back" the existing pipe with a pipe wrench when using the threader so that you don't disturb other old connections and start a leak.
Use a combination of teflon tape and dope to seal threads.
EDIT: It appears to me from your picture that the pipe size is 3/4" nominal, which means the outside diameter is a little more than 1".
I'm confused. How are you going to work on this when water begins gushing out. You said it was the main shutoff.
Aaaaa just stuff some bread in there, it'll be fine ;)
I took it to mean the main
I took it to mean the main shutoff for the sprinkler system.
The true main shutoff for the entire service would probably be located in the meter box, and that shutoff is usually the responsibilty of the water purveyor.
Steel in dirt
is only a temporay installation. I take it that this is only for the sprinkler system and THE main.
IF it were my sprinkler system, I would put in a valve vault for protection and accessibility. Replace the valve and immediate pipe with something alittle more resistant to corrossion resistant, like PVC or polypropylene. The PP can be slipped over the cut ends of the steel pipe and secured with stainless steel host clamps. Match the PP ID to the steel OD.
>>>And my other concern is
>>>And my other concern is that the valve I got was "compact" which means it only has threads for about 1/2" on either side, and my connections may bottom out before they get tight.
Ok, so you could screw nipples into the valve then use unions to join up with the existing pipe.
Don't you just love the way people like to operate valves with pliers?