Connecting poly to jet pump

[Jmartin9199]

Replacing a horizontal twin pipe jet pump using plastic barbed fittings. Would I be better off threading the fittings into the pump and then heating the pipe to connect or insert the fittings into the pipe with a rubber mallet without heating and then thread the fittings to the pump (clamping afterwards in both cases)? Thanks.

 

[LLigetfa]

I would avoid using plastic barb fittings. They are prone to deformation that can create a suction leak.

 

[Sponsor]

 

[Valveman]

Yeah into the pump use metal barb fittings. Plastic ones will get hot and leak.

 

[Jmartin9199]

Yeah into the pump use metal barb fittings. Plastic ones will get hot and leak.

How do they get hot with all that water running through them?

 

[Valveman]

As long as water is running through them they don't get hot. But a stuck pressure switch, a suction leak, low water level, or many other things can cause a lack of flow and plastic fittings will melt and make the problem even worse.

 

[Jmartin9199]

As long as water is running through them they don't get hot. But a stuck pressure switch, a suction leak, low water level, or many other things can cause a lack of flow and plastic fittings will melt and make the problem even worse.

Something I was curious about..If I had a vacuum leak on the suction side at the pump connection would I most likely have water leaking there when the pump is idle?

 

[LLigetfa]

If I had a vacuum leak on the suction side at the pump connection would I most likely have water leaking there when the pump is idle?

No, not necessarily. Consider a perfect vacuum as being around 14 PSI of external (atmospheric) pressure. A plastic fitting can deform (shrink) under vacuum causing the leak but expand under pressure, sealing it from leaking pressure. Also, air molecules are smaller than water molecules so can fit through smaller spaces.

 

[Seaweeds]

I use a lot of poly and dip the end into hot water to soften it up. Safest way to do that. Fitting can screw on first (best) or after insertion. Just don't tighten the clamp yet so fitting can rotate inside poly while tightening.

 

[Jmartin9199]

I use a lot of poly and dip the end into hot water to soften it up. Safest way to do that. Fitting can screw on first (best) or after insertion. Just don't tighten the clamp yet so fitting can rotate inside poly while tightening.

My pipes come out of the ground at a 45 so can't really dip in hot water. I plan to heat both at the same time by blowing hair dryers inside the end of each pipe (2 minutes seems good in my experimenting) and then having someone push the end of the pump to insert fittings while I hold the pipes stiff. If that doesn't work I'll insert the fittings into the pipes first. Look good?

 

[LLigetfa]

I suppose a hair dryer would be slow but would do in a pinch. I use a heat gun if in a location that has easy access to power otherwise I use a propane torch. You can tell when the poly is getting too hot as it gets a surface shine on it and/or the burrs on the cut edge start to round off.

In tight spaces I insert the barb first and then thread it into the port afterwards. Wait for the poly to cool some before tightening the jubilee clamps. It should be cool enough after you're done tightening the threads

 

[Jmartin9199]

I suppose a hair dryer would be slow but would do in a pinch. I use a heat gun if in a location that has easy access to power otherwise I use a propane torch. You can tell when the poly is getting too hot as it gets a surface shine on it and/or the burrs on the cut edge start to round off.

In tight spaces I insert the barb first and then thread it into the port afterwards. Wait for the poly to cool some before tightening the jubilee clamps. It should be cool enough after you're done tightening the threads

I ended up heating both pipes at the same time for 2 minutes with two hair dryers on low. With an assistant I was able to get the pipes fully seated but it required a bit of effort. If I did it again that way I would heat for 3 minutes.