[rjniles]

I am installing a new vanity and I wanted to replace the multi turn stops with quarter turn stops. Since the pipe out of the wall is PEX, i planned on cutting off the old stop (I have length to play with) and installing a Sharkbite stop. As it happens the supply house was out of the Sharkbites and I did not want to drive 20 miles to Home D. The counter man suggested I use a regular compression stop with a plastic ferrule and PEX tube insert.
I bought the stops but am having second thoughts. Is the compression stop a valid connection to PEX? I have the project on hold. Thanks for any insight.

 

[WhatRnsdownhill]

I wouldnt trust it, especially on the hot side where the pex will get soft, the shark bit grips with little teeth and does not use the compressive nature to hold it on, I have had many failures in the past with plastic water supplies slipping out of a compression fitting both hot and cold...if it lets go when your away or at night..it could be a disaster..even with the stiffener in the pipe, and that should be brass or stainless..not plastic..the ferrel should be plastic..

 

[ben's plumbing]

agree with whatsrns....don't trust it..:vs_no_no_no:.its not worth it..drive the 20 miles...:

 

[gregzoll]

RJNiles, if you order the parts off of Amazon you can get it by Tuesday. Supply house would be $5.99 S&H ground. Twice as much for the cost of the part, to get it next or 2nd day.

 

[joecaption]

I agree just not worth the risk.

 

[TheEplumber]

Some plumbers here use these all the time. I haven't heard of any problems

 

[rjniles]

Well it seems we have a disagreement . 2 say no, 2 say OK ( I am counting the supply house counter man). I am twixt and tween.

 

[WhatRnsdownhill]

Some plumbers here use these all the time. I haven't heard of any problems

on pex or on copper pipe? on copper pipe, no problem they will hold...

 

[WhatRnsdownhill]

Well it seems we have a disagreement . 2 say no, 2 say OK ( I am counting the supply house counter man). I am twixt and tween.

its only 1 for..unless your counting yourself as 2..LOL:smile:

 

[TheEplumber]

on pex or on copper pipe? on copper pipe, no problem they will hold...

On pex of course. Think pac joint. Stiffener goes in the poly pipe, then a compression ring and fitting on the outside.
Pex is softer than the ferul so it will dig in- same as brass ferul on copper.

Granted, I only see a couple guys use them regularly.

 

[rjniles]

I wouldnt trust it, especially on the hot side where the pex will get soft, the shark bit grips with little teeth and does not use the compressive nature to hold it on, I have had many failures in the past with plastic water supplies slipping out of a compression fitting both hot and cold...if it lets go when your away or at night..it could be a disaster..even with the stiffener in the pipe, and that should be brass or stainless..not plastic..the ferrel should be plastic..

A question for those who think the stop will blow off the PEX. How is this any different than using a 3/8 PEX riser pipe to connect from the stop to the faucet? That is also a compression fitting with a plastic ferrule.

 

[WhatRnsdownhill]

A question for those who think the stop will blow off the PEX. How is this any different than using a 3/8 PEX riser pipe to connect from the stop to the faucet? That is also a compression fitting with a plastic ferrule.

I have had the hot side blow out on pex water supplies like the one you posted..all I use now are real chrome or copper and braided supplies...and no plastic nuts up by the faucet..the plastic seems to loosen with the constant hot cold cycles...for the few bucks for non pex connectors, it will cost less than a return call or insurance claim for water damage..

 

[rjniles]

Tried a little test. Connected a compression valve to a piece of PEX using a plastic ferrule. Did not use a tube insert as I didn't have an extra one. Hung it up with a full 20 pound propane tank hanging off the valve. It has been hanging there about 3 hours when I took this photo. I am going to leave it over night and see what happens.

 

[WhatRnsdownhill]

Tried a little test. Connected a compression valve to a piece of PEX using a plastic ferrule. Did not use a tube insert as I didn't have an extra one. Hung it up with a full 20 pound propane tank hanging off the valve. It has been hanging there about 3 hours when I took this photo. I am going to leave it over night and see what happens.

get out a hair dryer and heat the pex up, like hot water would be running through it and see what happens..

 

[rjniles]

get out a hair dryer and heat the pex up, like hot water would be running through it and see what happens..

I am going to let it hang overnight and I will try the hair dryer in the morning and report back.

 

[WhatRnsdownhill]

whats the total weight of the propane canister?

 

[rjniles]

whats the total weight of the propane canister?

Total weight is 37 pounds. I weighed before I hung it.

BTW I am not trying to justify using the compression valves. The supply house will have the Sharkbite valves in this week and I am going to use those.

 

[WhatRnsdownhill]

Total weight is 37 pounds. I weighed before I hung it.

BTW I am not trying to justify using the compression valves. The supply house will have the Sharkbite valves in this week and I am going to use those.

not a problem, im curious what the outcome will be, heres a question, average water pressure is around 60 lbs, so the weight on the valve should be about the same, if figuring is correct, then you have to add the shock load on, every time you open and close the water its banging into that valve..does that make sense?

 

[rjniles]

not a problem, im curious what the outcome will be, heres a question, average water pressure is around 60 lbs, so the weight on the valve should be about the same, if figuring is correct, then you have to add the shock load on, every time you open and close the water its banging into that valve..does that make sense?

Doing a little math; the ID of 1/2' PEX is .485 inches
Using Area = Pi times radius squared = approx. 0.2 square inches

At 37 pounds for the propane tank, I applying a force of about 185 PSI to the valve.

60 psi water pressure applied to the same 0.2 sq in would only apply 12 PIS to the valve.

 

[WhatRnsdownhill]

Doing a little math; the ID of 1/2' PEX is .485 inches
Using Area = Pi times radius squared = approx. 0.2 square inches

At 37 pounds for the propane tank, I applying a force of about 185 PSI to the valve.

60 psi water pressure applied to the same 0.2 sq in would only apply 12 PIS to the valve.

but wouldnt it be fluid mechanics to figure that out? since dealing with properties of water, not a dead weight situation? something in there about hydraulic effect on pipe or tubing...? that stuff makes my head hurt thinking about it..lol