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Poly pipe couplings

2844 Views 3 Replies 2 Participants Last post by  rtoni
I found and replaced what I thought was a bad poly pipe coupling in my water line - using 1 - 1/4" ID poly pipe - rated 75 psi - for my water line - the couplings are also barbed insert 1-1/4" poly. After changing the coupling I seem to still have a small leak - right at the fitting.

I thought maybe the clamps just needed to be tightened - so I did that - still leaking - cranked one down until I actually broke it (then replaced it) and there's still a drip coming from that joint under pressure. The ends of the pipe look clean - no scratches or marks etc.

Same couplings work great on lighter (thin wall) poly but not so good on the heavier 75 psi pipe that I have buried. It's almost like the gear clamps don't tighten down enough.

Isn't this the standard pipe / coupling combo that most others use? What am I doing wrong? Is there a better clamp I should be using? or maybe I should use a stainless steel coupling instead? This is getting a bit frustrating.

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I would recommend red brass barbed fittings...then 2 clamps per barbed end...pulling opposite directions, with the threaded portion 180* opposite each other. To get the pipe on the fitting, heat the end slightly with a small soldering torch. The pipe will become very shiny when it's up to temperature. With the pipe still warm, install your clamps.
thanks RippySkippy - I will give that a try :thumbsup:
ok - couldn't find brass so I used a galvanized coupling instead (still not buried so I can change if necessary) - looks like no more leaks anywhere. All set to test again.

I prime the line and the pump, fire it up, and it pumps like crazy - ran it for 5 minutes straight (hooked up garden hose and just let it run). I have clear braided pvc on the pump fittings so I can see the flow - no air bubbles, etc. All seemed good. I shut off the hose (valve) and the pressure in the bladder tank builds to 40 psi and pump shuts off. So far so good. But almost immediately after the pump stops (at 40 psi) the pressure drops right off to 30 psi - and then holds steady there. Again I check the whole run for leaks - nothing. Pressure holding steady at 30 psi. I open the hose valve - water flows from the tank and pressure starts to drop - just below 20 psi the pump kicks in again. Seems to work exactly as it should (on at @ 20 psi, off @ 40 psi)

So - everything looks fine - except the instant the pump hits 40 psi and shuts off the pressure in the line drops to 30.

I figured maybe air in the line, but it runs, pumps, stops, starts, etc. without so much as a sputter or fart. In the hour or so of playing around I must have stopped and started 20 times and never lost prime. Must have pumped a hundred gallons. Every start the pump immediately ramps up pressure. For sure any air in the line would have been sucked into the pump over that time, no? I just don't see any sign of air.

Can't see any leak anywhere - even at 30 psi. Foot valve maybe?

Changed the foot valve - thought maybe the valve was sluggish or something? not even sure that makes sense? no difference.

Just for fun I spent 10 minutes and put a check valve right next to the pump intake - reprimed the line and fired it up. At 40 psi it shut off and held solid. So I rule out problems at the tank / pump.

So somewhere, somehow in my intake line between tank and foot valve I'm dropping @ 10 psi.

Losing pressure and also losing my sanity.

This run is approx 100 feet of 1 - 1/4" 75psi poly pipe. Could the poly possibly be expanding or stretching enough to cause any noticeable drop in pressure? Could there possible be air trapped in the line even though it primes 1st try and holds prime thru several cycles, gallons, etc.

I don't know where to look.

What am I missing? Any tips appreciated.

Thank you.
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