Pressure testing soldered joint

[Djarchow]

I had to solder up a Delta shower valve and a couple 6 port manifolds to add bronze Pex-A connectors. The new lead free fittings, especially the valve, were tough to get as good a joint as I get with regular copper even after watching the videos recommended here and practicing with some scrap fittings.

So before I hook up the water and cover the valve with sheetrock I wanted to test the valve and manifolds for leaks. I made up a test fitting with a pressure gauge and a schrader valve on it with a MIP to pex-a fitting. I have tried multiple times to get the MIP fitting to stop leaking air including using both tape and pipe dope. I used 12" wrenches and monkey arm strength to tighten them. This is the third of these gauges I have tried. All of them either the gauge didn't work, or they leaked somewhere; either at the FIP fitting, or the schrader valve. The current one, the best I can get is a loss of about 5 psi every two hours at the MIP fitting.

I have put the shower valve and my manifolds in a sink full of water and watched them for 30 minutes at 60 psi and had no bubbles from the any of my soldered joints.

Is this good enough to hook them up and turn on the water? Sheetrock is months out so I can still catch any slow leaks?

Thanks for any help!

 

[hj]

The way to test them is to "hook them up and turn on the water". That will show a leak very quickly.

 

[Sponsor]

 

[Djarchow]

HJ, Thanks for the reply. I appreciate it.

Yep that is a good way to test them. However I was hoping for something a bit less "squirty" since the manifolds are aimed at the blower on my water heater. I am going to assume that since at 60 psi I saw no bubbles from the soldered joints even after 30 minutes in water that if there are any leaks they won't be gushers .

 

[Cjlambert]

Turning on the water is not an adequate test. The reason for this is that there can occasionally be a surge in city water pressure.

Here in Canada, our water distribution systems must be capable of withstanding an air pressure of at least 1000 kPa for at least 1 hour with no loss of pressure, or a water pressure of 700 kPa for 2 hours with no loss of pressure, and our jobs will not pass inspection unless the inspector sees the gauge with their own eyes.

If you want to do it by the books, you need to find a way to get your test connection to stop leaking.

Wrap your teflon tape around the threads 4 times, tightly, in the direction of the threads. (So hold the piece with the male thread in your left hand horizontally, with the threads facing right, then using your right hand, roll the tape onto the threads clockwise/away from you, over the top (using your left thumb to hold the beginning of the tape). Then use your fingernail or the edge of the teflon tape roll to press the tape into the threads, before threading it into the fitting. (Stick you fingernail in the threads at the face, and rotate until your fingernail winds up at the end of the threads). This will prevent the tape from slipping while tightening, which is likely the reason for your leaking threaded joints. I can't imagine anything else being the culprit.

FYI - pipe dope is not acceptable for use on a potable water system.
**This may be false - I'm still looking into it. That being said, I've never had to use dope to seal a threaded joint. Teflon tape alone has always done the trick.

 

[SteveW]

Following is from Blue Monster description on a "big box" website - had not heard before that pipe dope/sealant can't be used on a potable water system:

• Seals threads on all metals, PVC, CPVC, ABS and nylon pipe
• Heavy-duty, industrial grade
• Safe for use on potable water
• Adheres to oily threads
• Non-hardening, soft setting
• Formulated for production line use
• NSF 14 and 61 approvals
  
  
  

 

[hj]

WOW! After 65 years, NOW you tell me I cannot use "pipe dope" on potable water systems. That must be something a TPFE tape manufacturer published.

 

[Cjlambert]

Ontario Building Code
7.3.2.3 Screwed Joints (Sentence 2) No pipe-joint cement or paint shall be applied to the internal threads.

Looks as though I’ve made a mistake. The code says internal threads, meaning you can’t dope a fitting. But it doesn’t say you can’t use it on external threads. Now I have to do more research on the topic.

As an apprentice I was taught to never use pipe dope on a potable water system, and I would swear up and down I read it on the can myself, years ago. But checking the can I have right now of Master's Pro-Dope, it doesn’t say anything about not using it for potable water.

 

[Reach4]

Ontario Building Code
7.3.2.3 Screwed Joints (Sentence 2) No pipe-joint cement or paint shall be applied to the internal threads.

But on the other hand, in Ontario, you can put the trap for a washing machine standpipe below the floor. Right?

 

[Cjlambert]

But on the other hand, in Ontario, you can put the trap for a washing machine standpipe below the floor. Right?

Yes.