SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

jusme,

First some terminology. Several places on your drawings refer to "nipples". From what I understand, nipples usually refer to short pieces of female x female threaded pipes. But based on where some of your "nipples" are located, it looks like some of your nipples would be more appropriately be short pieces of standard sch 40 used to glue two fittings together.

As you say, Rainbird seems to like female threads on their valves, and if your getting stuff from one of the big-box retailers, that's all that is available. But if you are going to someplace where you can order the type of valve you can get, I would suggest getting valves with Slip x Slip (glue) connections. The reason I say this is because if you every have to replace the entire valve, you have a better shot at getting the geometry to match up at the unions. Like I stated before, base on my (limited) experience, if you have any bending forces on the pipe at the union, it's going to leadk, so the geometry has to be perfect. In this case, that means you've got to have two pipes that are perfectly lined up (not much of an issue there) AND the exact distance between the pipes has to stay the same. Because both of these have to match, using threaded connections puts you at the mercy of how the threads were cut. Obviously you have to have the pipes screwed in so that they point down, but the question is once you've done that, is the distance between the two pipes (legs of the upside-down U) a specific distance apart. When it comes to trying to increase or decrease that distance, you are limited to +/- the distance between threads. Now if you are using Slip X Slip connections, the thing that you can do at the time of replacement is to rebuild and reglue everything with the unions already in place except for the final short piece of pipe that will connect the valve and the elbow on the lateral side. You can cut that piece of pipe just a hair too short, and glue this final joint with everything in place. Since you're talking about a pipe that is not under constant pressure (and Sch. 40 to boot), things will be ok if a 1" pipe is 1/8" or 1/4" short of being FULLY seated in the valve fitting.

BTW, I also suggest Slip x Slip valves because I've have problems with threaded connections leaking (even though I've followed what appear to be leading suggestions on how to properly assemble leak-free threaded connections). Glued connections are SOO much easier to make leak-free.

Your final drawing is very close to what I eventually used, except that I used nipples to connect the female threaded elbow to the female threaded valve. I then just used a short piece of regular sch40 to glue the Slip side of the elbow to the slip connection of the union (you show a nipple at this location, and I consider that to be a double threaded female pipe, and I didn't have access to any unions that had female threaded connections.

So let me try to restate my design (which still has the shortcoming of getting the geometry perfect if I ever have to replace the entire valve)... Here's the pieces I used described as the water would travel:

Slip x Slip x Slip TEE at the manifold
short piece of sch40
Slip x Slip Union
short piece of sch40
Slip x Female elbow
1" sch80 nipple (no such thing as a sch40 nipple)
Female x female valve
1" sch 80 nipple
Female x Slip elbow
short piece of sch40
Slip x Slip Union
short piece of sch 40
Slip x Slip elbow (turning out of the upside down "U" to lead out into the yard)

The last comment is that just like a mentioned I had to do things to make sure the distance from elbow to valve to elbow was short enough to fit inside the box, you also have to make sure that the vertical legs of the up-side-down U will also fit inside the box. At a minimum, the bottom of the unions must be above ground level inside the box, while still allowing the entire valve to still fit under the cover of the box. If your drawing were to scale, that extra long leg from the manifold to the union would cause me to hav

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by jusme</i>
...I'm curious why you don't just use a male x male valve straight into the slip x female ell? That would save you even more room by doing away with the nipples on either end...<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

I used Rainbird valves available from the local big box retailer. The only thing they sell is female x female valves.

Of course another alternate would be to use male x slip ells on either side of the female x female valve. But if you've got the choice, I'd still suggest replacing he female x female valve and female x slip ells with all slip connections. If so, I'd suggest that you turn on of the unions around. That way the entire secion above the union can be completely rebuilt, in needed, with only one union.

Otherwise, you've pretty much diagramed what I installed.

Do all those manifold pieces screw together line unions or like male x female and add tape to stop leaks.

If tape is needed, I wouldn't want to go that way. Too many threaded connections to make. I don't know why, but I've had a VERY difficult time at getting threaded connections perfectly leak free. A weeping leak might be ok on latteral lines, but on mainlines, I don't want even the smallest of leaks. Yet for some reason, I've had lots of trouble keeping things leak free.

About the only place I did pretty well at preventing leaks was at the nipple to valve connection using the "pink" thick tape rather than the typical white tape.

Otherwise, the little trick I have found to help get leak free connections is to wrap your tape on the male threads (about 7 times) and then "screw the male fitting to a rag"... basically, run a rag around the tape to help pre-press (or seat) the tape in the male threads before screwing it to the female fitting.

Do all those manifold pieces screw together line unions or like male x female and add tape to stop leaks.

If tape is needed, I wouldn't want to go that way. Too many threaded connections to make. I don't know why, but I've had a VERY difficult time at getting threaded connections perfectly leak free. A weeping leak might be ok on latteral lines, but on mainlines, I don't want even the smallest of leaks. Yet for some reason, I've had lots of trouble keeping things leak free.

About the only place I did pretty well at preventing leaks was at the nipple to valve connection using the "pink" thick tape rather than the typical white tape.

Otherwise, the little trick I have found to help get leak free connections is to wrap your tape on the male threads (about 7 times) and then "screw the male fitting to a rag"... basically, run a rag around the tape to help pre-press (or seat) the tape in the male threads before screwing it to the female fitting.