90 degree elbow into pump intake

[syntax53]

I spent all day Saturday redoing my plumbing... and now I'm going to have to re-do it all over again. Not necessarily because of the 90 degree elbow into the pump, but because I accidentally used all dwv rated couplers and elbows . I figured all of this out when I went to read the wiring guide for my new pump and saw the notice "do not install a 90 degree eblow directly into pump intake" which led me to research on this site, which led me to have trouble falling asleep thinking about the waste of the day and money. Worst part is I wasted $80 in 2 jandy valves because I glued a 90 degree dwv onto each of them already.

All that aside, how crucial is avoiding the 90 degree elbow into the pump? I say that because I'd have to turn the pump (which I've already drilled into the concrete) and reconfigure my piping plan because I can't fit any sort of straight pipe into the pump how I wanted to lay it out. Pentair 011581 WhisperFlo 1-1/2 HP

 

[JamesW]

A lot depends on the velocity of the water going through the pipe.

Your pump is 2.25 hp, which is big for 2" pvc. For a smaller pump, it wouldn't be an issue.

It will work, but it's not ideal. Having some straight pipe before the inlet is best. If the 90 was 2.5" or 3", it would be better.

Bottom line is that it's not ideal but it will probably work.

I think that the pump is a bit overpowered.

 

[jblizzle]

The dwv fittings are certainly not ideal. But on the suction side they are likely fine. If you decide to change it, you can still use the valve. They are designed to either take a pipe into the valve or use a coupler on the outside of the valve. Just use which ever method you did not the first time. or use a ream bit to drill out the old pipe.

 

[Bama Rambler]

I don't think I'd change it. As said above, it may not be ideal, but it will work and I don't think it'll give you any problems.

 

[mas985]

A 90 connected directly to the impeller inlet could possibly cause cavitation due to the eddies created by the 90. However, in a residential pool pump, there is usually a pump basket between the 90 and the impeller inlet and this will help eliminate any eddies before they reach the impeller inlet so I don't think you have anything to worry about.

 

[syntax53]

Think it would be worth changing to something like this?

 

[mas985]

Worth it how? I don't think it would change performance much if any.

Are there currently any issues? Does the pump work fine with the lines isolated to either the MD or skimmer?

I say if ain't broke, don't fix it.

 

[syntax53]

vs how it is in the picture in the first post, with the 90 directly to the inlet. I haven't connected or turned on the pump yet (brand new). I got as far as I did in that first picture when i realized my mistake with the non-pressure rated fittings and also the warning about the 90 bend. So I'm about to re-do it and wondering if it would be worth turning and re-drilling the pump into the concrete. Though I am drawing up an option that may allow me to leave it in place with at least a few inches of straight pipe after the 90.

 

[mas985]

I got as far as I did in that first picture when i realized my mistake with the non-pressure rated fittings and also the warning about the 90 bend.

Right but what I am saying is that I don't think the 90 is going to matter much and while the DWV fittings are not ideal and weaker than standard schedule 40, I doubt anything catastrophic would happen unless you drop something on the fitting. There are plenty of people on the forum who made the same mistake but chose to live with it without consequence.

I might be inclined to just leave it as is.

But if you choose to make the change, the picture above would work fine. Also, you don't really need to bolt the pump to the concrete. Mine have never been bolted. If you get a lot of vibration, then you may need to bolt it.

 

[SoCalGuy]

As long as you're redoing it, use threaded and o-ringed unions at the pump. It will make your life MUCH easier when it comes to sealing up possible leaks and replacing the pump downstream.

 

[jmastron]

First of all, I second the recommendation to use threaded o-ring unions at the pump, like these: Pump Union for Pentair IntelliFlo Threaded Union 2 MPT x 2 Slip. I was never able to get a regular threaded fitting to seal on my old pump, no matter how much tape and goop I used; the unions with the new pump are much better. And makes it easy to remove the pump for servicing or replacing.

If you want to minimize the changes, it looks like you have room to swing the pipe out a few inches, using 2 45 degree elbows, like this in yellow:



I think even having 4-5 inches of straight pipe before the pump is better than none.