I have two (hopefully small) repairs that I need to do for my system. Luckily most of it is in a control box, so it is easy to get at. Here's the setup:
At the top was a valve that was broken, and at the bottom was (what the guy Lowe's said was) a backflow preventer:
Last relevant picture, is just outside of the control box on the left side:
It's still a little covered, but you can see that there is a T joint close to the box.
Replacing the valve
The valve that was in place had male connectors, but the store only had valves with female connectors. I bought one of those valves and two adapters, but there isn't quite enough room - the valve plus the two adapters is about 2cm too wide to fit. These are 1" pipes. The two parts to connect to are swivel connectors somewhat like this.
What are my options here? I thought of three possibilities, and would like to know which one would work best as a long-term fix and if there is a better option that I haven't considered.
Cut off about 1 cm from each of the two adapters until the valve+adapters fits snuggly in there. This should leave a little more than 1 cm exposed on each side. I'm concerned that this wouldn't leave enough to screw onto to get a good seal. I also don't trust my ability to cut the adapters cleanly enough to have it be absolutely flat against the other parts of the pipe.
Cut off one of the swivel connectors and put a new one on. I could cut off enough pipe to get a fit as snug as I need and also get slightly longer adapters to make sure that the fit isn't too loose.
Cut out a section of pipe and get a connector to rejoin the two new ends, effectively shortening the pipe.
General question - how tight does the fit need to be? Will it leak if there is even a small gap between the adapter and the pipe inside of the swivel connector?
Replacing the backflow preventer
As you can see in the pictures, there was an adapter at the end of the pipe coming into the box, but it was cracked and the threaded part came off with the backflow preventer (which was also cracked, hence why I needed to replace it). After I cut off that broken adapter there will still be 1" of pipe coming out of the T joint. There will be 6" of space from there to the threading of the valve that's still in there. Here I'm working with 3/4" pipe. I already have a new backflow preventer with female connectors on both ends, and it's not quite 5" long.
How do I replace this? There's not enough room in there for an extendable repair piece. I figure that I should put the new backflow preventer in first, and that will leave about 1.5-2" of space and then 1" of pipe to connect to. What parts should I get and how to I get them all in there?