Forum Title: Preferred outlet connection on stop valves?
Couple of the stop/shutoff valves in my house have started leaking thru the stem. Some valves (not all) have an integral metal flex-bellows to the fixture, and inside the flex metal it's green & corroded looking. House is 30 yr old & I am original owner. I'm going to replace all the stop valves to avoid risk of a flood disaster. Planning to use Brasscraft "KT" series angle stops & new Brasscraft flex lines, to all faucets & 3 toilets. Finally, my question -- the commonly available KT stop valve outlets can be either: A) 3/8" compression, used with flex line having 3/8 comp to faucets (1/2 FIP) or toilets (7/8 ballcock). OR B) 1/2" slip-joint, which appears to mate with flex line having 1/2 FIP to faucets or toilets. Parts for both #A or #B are readily available in my region (Calif).Any reason to favor one over the other, eg for long-term reliability? Is one more popular for new construction or remodels? Personally, I'm leaning slightly toward #2 because I need only fumble with 1 wrench size underneath sinks, and FIP has a larger & more substantial seal/gasket. But I'd like to hear opinions. edit: appears I incorrectly put this post into "shower & tub" sub forum. Will ask moderator to move it to "general" .
Category: Plumber Post By: EVERETT CORTEZ (Walnut Creek, CA), 05/16/2016

Quote: Originally Posted by SHR Always: A) 3/8 compression, used with flex line having 3/8 comp to faucets (1/2 FIP) or toilets (7/8 ballcock). Never, ever slip-joint on supply lines. Mmm, but it's not actually a slip joint being fabricated, even though the outlet of the valve is slip-joint. Valve outlet would mate to a flex line with a 1/2 FIP end , rubber gasket, and metal nut. It physically cannot ever come apart. The house actually had that style of interconnect on 2 of 3 toilets. I'm original owner & house came that way. Regardless -- seems you're saying a 3/8 compr valve outlet is now standard practice, so I should stick with that to not confuse future homeowners or plumbers.

- SEAN ORTIZ (Bristol, CT), 09/06/2017

if you are talking about using a cone washer and friction ring , DONT,

- DOROTHY WILSON (Coppell, TX), 09/09/2017

Always: A) 3/8 compression, used with flex line having 3/8 comp to faucets (1/2 FIP) or toilets (7/8 ballcock). Never, ever slip-joint on supply lines.

- ZACHARY SANDOVAL (Cambridge, MA), 10/05/2017

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