Replies

1. 
   BoJangles | Jan 20, 2009 05:06pm | #1

   I doubt that it is leaking with a pressure drop like that.  The exposed pex could stretch that much or the air temperature could have changed enough to cause that.  If it drops down a lot more than that over a few days, you have a leak.

   How are you testing it?  Are the connections permanent?

1. 
   westmich | Jan 20, 2009 05:14pm | #3

   I used an air compressor into a valve that threads into the manifold and came with it. I believe it is soldered onto the manifold. The pressure test piece has a shutoff lever valve as well.  

   It kept at 30 psi for about 6 hours then fell 1 psi over the next few and overnight  it fell another 1 psi.  That could just be the air making its way through the system? I would like that to be the case.  

1. 
   davidmeiland | Jan 20, 2009 07:41pm | #6

   Agree with Bo that it is probably not leaking with a small drop like that. Air temp changes, slight loss at the air fill valve, stretching of the tubing under pressure. A more stringent test would be 100 PSI hydrostatic test (meaning tubing is full of water and pressure is applied with a test pump). I tested a house full of PEX at 100 PSI and I could not get the pressure to stay at 100 until a few days had gone by. There was about 1600 feet of tubing, all exposed to view and easily inspected, pressure would drop a few pounds overnight. I checked all of it several times (crawl, crawl, crawl) and there was no leak. After a few recharges to 100 PSI it held, I attribute it to the tubing stretching slightly. A smarter man than I could calculate the exact amount of stretching required to drop from 100 to 98 PSI in 1600 feet of 1/2" tubing, it would be infintesimal.

2. 
   BoJangles | Jan 20, 2009 11:32pm | #10

   I would bump the pressure up to at least 60psi.  Remember that pex is not like copper...it stretches.

   You can easily see a 2 or 3 # drop in pressure just from temperature change.  Soap test the connections and let it sit for a few days and see if the pressure finally stabilizes.

   The number of feet of exposed pex makes a big difference too.

   That is a minor drop in pressure.  If it goes down 10# or so, you have pretty good leak somewhere.

2. 
   Clewless1 | Jan 20, 2009 05:12pm | #2

   I think even w/ a slow leak, the soap should show up right away. FYI I tested mine to around 100 psi. The BO required that if I recall. You could increase your pressure to emphasize the leak. Since your operating pressure should be roughly 20-40 psi, shouldn't you test it to a much higher level? That is my experience ... test to a much higher level than the working pressure (I'm sure there is a reason why).

   A fix for a leak ... not as catastrophic as you might think ... but no fun either. Yes chisel up the concrete ... e.g. 12 inch square and splice/repair it and pour back. Sounds easy, right? I took pics of my layout on my 6x6 WWF prior to pour. That helped me avoid problems with my fasteners in my bottom plate. I planned my layout well in advance to avoid the walls to begin with whenever possible.

   Finding the leak may be a bit trickier than repairing it.

   I'd start with higher test pressure (talk w/ the BO?). That should emphasize your problems and tell you if it is at your manifold. If you have continous tubing ... unless it was punctured, your problem should be at the manifold/other connections.

1. 
   westmich | Jan 20, 2009 05:18pm | #4

   I'll try a higher pressure.  I have 3 runs of about 180 feet each, if that matters at all.  I did the layout with the framing plan in hand to try to miss the walls.  According to the plans I laid it out about 10" from each wall and proposed wall.  I was paranoid about this very thing happening.  

3. 
   PedroTheMule | Jan 20, 2009 07:36pm | #5

   test at 30 psi for infloor heating?

   I had the opportunity to work with a friend installing his infloor pex heating. We tested at 200 psi. After two days it dropped to 196 psi, all air. We figured it was the pex settling in and bumped it back to 200 psi on the third day.

   The temps during that spring were pretty steady so we didn't have to be concerned about temp swings surrounding the worksite.

   He left it inplace and worked on some other items for the next two weeks. Not a single lb. drop in pressure the whole time.

   We let the pressure out, filled with water and pressured to 60 psi. Poured the slab and left it under pressure until months later when he was ready to connect the system.

   My friend, you DON'T want to proceed until you are certain you have "NO" leaks. Your belongings, time, comfort and sanity are at stake here.

   Pedro - hate getting my mule hooves wet

1. 
   westmich | Jan 20, 2009 07:56pm | #7

   Pedro, that is some good advice that I am happy to take.  Thanks.

1. 
   PeterJ | Jan 20, 2009 08:17pm | #8

   My inspection required 100 psi air in pex only, boiler was not designed for those pressures. Tested entire system @ 30 psi air prior to filling with water, mostly for my peace-of-mind.

   If you can isolate your pex runs, I'd think the higher pressure would be best, you sure don't want to find problems after filling if you can avoid. Easiest way is with a pressure tester like this

   http://www.grainger.com/Grainger/wwg/productIndex.shtml?from=Search&newSrch=yes&operator=keywordSearch&search_type=keyword&action=Go%21&QueryString=2hce8&submit.x=12&submit.y=7

   Adapt tester as needed and fill with compressor.

   You may want to ask inspector what they'd like to see. 

   Everything will be okay in the end.  If it's not okay, it's not the end. 

1. 
   westmich | Jan 20, 2009 08:25pm | #9

   Thanks. That's the type of guage I have on now--not a Grainger but it seems to work just fine.  I think I'll run it up to 100 psi and let it sit for a couple days then refill to 100 if it drops and see if stretching or temp. might be the cause of a slight drop.  IF she holds at 100 after that I can put in teh water and cross the fingers.

1. 
   ruffmike | Jan 21, 2009 02:47am | #11

   I kept the 100 lbs of pressure through construction process, it was in slab and staple up. If anyone put a hole in it, we would have known right away.                            Mike

       Small wheel turn by the fire and rod, big wheel turn by the grace of god.