DanFL
Member
I'm installing this Kingston Brass wall mounted tub filler in my master bathroom renovation.
https://media.kingstonbrass.com/pdf/technical/install/kingston-brass-AE8157DL-install.pdf
Their instructions (step 4) assume that I will have access to the back side of the wall to connect standard flexible faucet supply hose. This is not the case (and as I understand, not code to bury the flex supply hose in the wall anyway). I was going to rough-in the hot/cold supplies with 2 standard 1/2" NPT brass drop elbows (right...?), and then use a brass nipple to make the final connection to the tub filler after the wall is finished. The nipples provided with the faucet are 1/2" NPS (straight thread, not tapered) on both ends. The female threads on the swing arm elbows (or dog legs, or whatever you call 'em) that connect to those nipples are also straight threaded. My research says NPS and NPT are not compatible and prone to leak.
So.. #1). What is the right way to do this? Can I use an NPT nipple on those straight female threads on the swing arm? #2). I'm also concerned about the "temporary" pressure test stub out from the drop elbow rough-in in the wall. I'd prefer to make that connection permanent since it's always under pressure (unlike a shower arm drop elbow which is past the shower valve) and not disturb that connection after the wall is finished since I would not be able to see if its leaking afterwards. Is it a bad idea to try to approximate the correct nipple size and only have to remove the cap after the wall is in? Any advice is appreciated.
https://media.kingstonbrass.com/pdf/technical/install/kingston-brass-AE8157DL-install.pdf
Their instructions (step 4) assume that I will have access to the back side of the wall to connect standard flexible faucet supply hose. This is not the case (and as I understand, not code to bury the flex supply hose in the wall anyway). I was going to rough-in the hot/cold supplies with 2 standard 1/2" NPT brass drop elbows (right...?), and then use a brass nipple to make the final connection to the tub filler after the wall is finished. The nipples provided with the faucet are 1/2" NPS (straight thread, not tapered) on both ends. The female threads on the swing arm elbows (or dog legs, or whatever you call 'em) that connect to those nipples are also straight threaded. My research says NPS and NPT are not compatible and prone to leak.
So.. #1). What is the right way to do this? Can I use an NPT nipple on those straight female threads on the swing arm? #2). I'm also concerned about the "temporary" pressure test stub out from the drop elbow rough-in in the wall. I'd prefer to make that connection permanent since it's always under pressure (unlike a shower arm drop elbow which is past the shower valve) and not disturb that connection after the wall is finished since I would not be able to see if its leaking afterwards. Is it a bad idea to try to approximate the correct nipple size and only have to remove the cap after the wall is in? Any advice is appreciated.