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Will 3/4" FIP fit on 3/4" NPT??

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UmHelp

Member
Joined
Jul 21, 2005
Here is my current setup, look at how the T-Line and the pump connect.

IMG_2173.jpg

Since I have a little bit of money now I was thinking that I could grab a new threaded front to my Iwaki MD-20Z (http://www.customaquatic.com/customaquatic/brandcategory.asp?brandID=IK&catID=wp&offset=15 Part No:WP-IKMD0313 I believe this is the right front i could be wrong though??? Better place to get it???) and then attach the T-Line directly to the pump. For a cleaner look and perhaps better performance.

The T-Line threads are 3/4" FIP (female) and the pumps threads will be 3/4" NPT (male). So my question is will the threads be compatible???

Will 3/4" FIP fit on 3/4" NPT?
 
UmHelp said:
Here is my current setup, look at how the T-Line and the pump connect.
You've probably encountered and solved a number of problems relating to the high flows and pressures of an Iwaki pump. Here's something I use. Use those beige PVC thin wall fittings available at plumbing supply places. You could construct a "stilling well" (decreaces water velocity, but not flow rate) from a 1" tee, some reducers and couplings. This allows the water to slow down in the larger tee and hence more air can escape to the T-line easier. Kind of what you have now though anyway. A 3/4" threaded or barbed connection to the pump can then be used.
 

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Not quite sure what your getting at here?? Would it be better to keep what I have now instead of putting the T-Line on the actual pump?

My T-Line has 5/8" barbed fittings on all 3 parts.
 
Not really sure what he's getting at either... his "solution" looks just like what you have... and doesn't really answer your question.

Also I'm not really sure what problems he's talking about... any proper system will most of the bleed air out quickly.

Seeing as FIP is simply the type of pipe ( stands for Female Iron Pipe) and not a thread standard, the end is probably NPT so the answer is "I think so."
 
UmHelp said:
Not quite sure what your getting at here?? Would it be better to keep what I have now instead of putting the T-Line on the actual pump?

My T-Line has 5/8" barbed fittings on all 3 parts.
Sorry. The point was:
That big fitting is ugly. and takes up a lot of space.
PVC is easier to use.

I'd stay away from screwing fittings onto the pump. It just makes for a bigger part (i. e. pump and fittings) to have to deal with. This is from my own experience. I have the threaded cover on my Iwaki and have to reduce down from the 1" (inlet) and 3/4" (outlet) threads to 3/4' and 1/2 barbs. It's a PITA.
 
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Either way i think that PVC or Brass will make the loop look kinda funky but there really isn't much else you can do about it. It is a sacrifice you have to accept with a bigger pump.

Unless you can find a better fitting, maybe stainless or polished brass, either way it is going to stand out. I don't want a restrictive inlet to my pump, and I believe that even this setup is still a bit restrictive. I believe that with the fitting attached to the pump it may have less restriction, but I could be wrong. I would hate to waste 30 bucks on this new cover and not use it because of different threading.
 
I could be wrong but I fail to see how simply bypassing an inch of tubing by directly screwing the t-fitting into the pump is going to make a bit of difference.

As for PVC or brass fittings, a bit of spray paint works wonders.

That pump head would have to use tapered threads so yes the 3/4" male NPT should screw directly into the female thread.
 
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The barbed fittings have a smaller ID then the tubing so they are a bit restrictive. If you put the T-Line right on the pump you wouldn't have any restriction from that fitting on the inlet. Would it make a huge difference in the system's performance probably not but every little bit counts.
 
The extra fittings don't provide enough resistance to hurt your flow rate all that much. I think what you're worried about is the effect of turbulence at the pump inlet. I don't fully understand it myself, but apparently putting something like an elbow right before the pump can make it cavitate even though the same fitting a foot away would have very little effect. A T would be less of a problem than an elbow, but I'm not sure that putting the T right at the inlet to get rid of the extra coupler wouldn't make things worse. If you try it both ways, let us know. :)
 
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