3/8" supply needed from 5/8" polybutylene line


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Old 09-12-05, 06:45 PM
mrusnak
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3/8" supply needed from 5/8" polybutylene line

I'm about to install a water purifier under my kitchen sink, and I'm not sure what is the best way to go about it. A family member said she used a self-tapping saddle valve that came with her unit (same brand, but I have the countertop version) -- but she had copper pipes and I have polybutylene. We're switching countertop/under-sink kits, but the saddle valve is still in the house she just sold.

Under my sink, the supply from the basement is 5/8" polybutylene, then there is a valve, then 3/8" polybutylene running up to the faucet. The water purifier has a 3/8" supply line.

I'm not sure if I can use a self-tapping saddle valve on the 5/8" polybutylene line to begin with, and I've seen on these forums that some people say saddle valves often leak.. plus, the only saddle valve I could find at Home Depot only has a 1/4" connector. Other than shopping somewhere other than Home Depot, does anyone have any suggestions?

Also, I'm not too familiar with compression fittings, but the purifier's line seems slightly loose in a 3/8" fitting. I didn't tighten it down all the way, but after finger-tightening, the tubing can come out with a light tug. Is that ok?
 
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Old 09-12-05, 07:23 PM
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What kind of valve is under your sink?
 
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Old 09-12-05, 07:44 PM
mrusnak
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The valve under the sink is just a shutoff valve with two different size ends -- the 5/8" polybutylene supply going in one end, and the 3/8" polybutylene line to the faucet going out the other.

There are hex nuts on both ends -- I'm guessing they're just compression fittings, but I haven't tried taking them apart.
 
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Old 09-13-05, 07:13 AM
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You can buy little stop valves, just as you described, with 2 3/8" outlets. Any plumbing supply house has them. You might try a big box store or large hardware store.

You will see them all the time on the hot water supply to the kitchen sink for the sink and dish washer.

Please, forget the saddle valve. They are bad news on copper and your using plastic which is even worse news.

As for the compression connection, you need an insert. This is a little piece of copper tubing, slightly flared, and it holds the plastic pipe in place as the ferral makes the seal when you are compressing it. Buy one while you buy the vlave, the salesperson will know what you need when you tell him/her what you are doing.

Hope this helps and good luck with your project...
 
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Old 09-13-05, 09:58 AM
mrusnak
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I'll take a look at another store, because I don't remember seeing any small valves with more than one outlet at my local Home Depot -- it would be great if I could just replace the valve with another one with two outlets. I don't want to get into cutting the pipes in case I screw up -- I need water in my kitchen. (At Home Depot, they had plenty of tee connectors, elbows, and other things of various sizes but very few valves!)

With the compression fitting I was using for testing, there was a copper insert in it as you described, but the connection just didn't feel tight. I didn't tighten it all the way though -- could that be it, or should it feel reasonably secure just from finger tightening?

Thanks for your help!
 
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Old 09-13-05, 04:09 PM
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Finger tight will blow apart. You need to use tools to tighten it down.

Good luck...
 
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Old 09-13-05, 05:14 PM
mrusnak
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Right, I just mean that if I only finger-tighten it, it barely grips at all.. so I was wondering if my tubing was really the right size, or if the water purifier used some off-standard junk so you'd have to buy factory replacement parts.

But I got a scrap piece of tubing I know to be the right size, and it's the same, and tightening it with wrenches does the trick. Thanks again!
 
 

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