main water valve vs. sprinkler valve shutoff

[gorphus]

Hi,
I have to swap out a leaky old manual sprinkler valve (galvanized steel) that connects to PVC. I want to put in a new master control valve (digital), likely with a brass ball valve before it (just in case I have to replace the master control valve down the line. The problem is the sprinkler shutoff valve is likely in the crawl space (need to confirm). Is there a risk shutting off the water main and swapping this piece out? Won't all the water higher than the valve I'm opening drain through the sprinkler valve when I loosen it? (I could open another hose bib to let the water drain to that point). I could check in the crawl space, but it is a small entry and I'm a little claustrophobic. . What are my risks for this <5 min swap out if I shut down the main water supply?

 

[bud16415]

Yes all water above the point you open will come out there unless you drain it some other way first.

Valves should be located in easily accessible locations not under the crawl space. maybe you should plan the new valve to a better spot.

As to risk that&#8217;s hard to guess.

 

[nealtw]

How bad can it be.
[ame]https://www.youtube.com/watch?v=_MT-IFCp4oE[/ame]

 

[slownsteady]

Risk is a relative word here. it makes it sound like a really bad situation. But if you have the main valve closed and drain the house as much as possible (open a valve high in the house and open one as low as possible), you shouldn't see too much water when you change the sprinkler shutoff.