bd,

Take off the drain and add it there. What is the drain for? If you want put extend the manifold out of the current box into a smaller new place along side to house the new valve and relocated drain. Done deal. JMHO Aloha

I am not sure what that might do to the water pressure if I take off the drain and add it there. The drain is threaded via a 1/2 in connection while the main line is 1 in. If I did that, the input line would go from a 1" down to a 1/2" and back to a 1" for the new valves. I Suspect the drain was installed to completely drain the manifold over winter.

As I see it, there is no way to cut the elbow to extend a stretch of pipe to a new box, which is what I would like to do.

I popped into an irrigation shop down in Denver and they concurred that a manifold rebuild was the right way to do it. Bummer for me and my back with all the digging to splice the current lines and reinstall a new manifold, but at least I get to learn something new with this little project.

Thanks for the response.

bd,

Do what you gotta do. You can do what I said. The manifold doesn't have to be in a straight line and there is no problem going from a 1/2" back to 3/4" or a 1" nipple and valve. It does not restrict the flow but only increases the velocity of the water through a very short distance.All you have to do is removed the valve box cut a hole for the last valve line to go through the valve box wall and into a second smaller valve box. The last valve can be a 3/4 or 1" valve with a drain valve attached as before and even using the existing valve. That is the easiest(on your back) and least expensive way to go. I have no motivation to sell you anything. Good luck. GL. Aloha

Thanks for your input. I agree and thought about the incentive for an irrigation shop to sell me something...albeit the added cost for a manifold T is only $5 bucks x 4.

I am not at all worried about everything being in a straight line. I am mildly concerned about the flow through the constriction. It sounds like you would not be at all concerned about it, so that is definitely something for me to consider. I would like to install a new valve box anyhow, so I could try another elbow where the drain is, run pipe out to a new box and connect the new valves. If it didn't seem right due to poor flow (which to me would be the only concern with doing it that way) then I could build a new manifold if needed in the existing box.

Again, thanks for your input.
Dan

bd,

It is not enough of a constriction to worry about. It may be slightly noisier because the velocity increases through that segment and their may be a very minor pressure loss but nothing to worry about with what you are proposing to do with that zone. You will need to bring your system pressure done to 20 psi for the drip zone with a pressure regulator. The pressure regulator itself is a constriction that is small enough to reduce pressure much smaller that a 1/2" line to reduce the pressure to 20 psi. You might want to put that pressure regulator before your last auto valve and existing gate valve. Have fun. aloha