I'm redoing the suction pipe from a pool pump, and have decided to add a blue pipe union for ease of installment and also for the convenience if i ever have to remove the pump again.

 

I'm gonna use a union as in the picture below. I know they are not high quality, but i guess will be ok for the suction side.

 

Now the question is if there is a difference which way you should mount it.

 

It will be mounted on the horizontal part of the pipe, where one end is short and unmovable, and the other end is about 1.3 meter long, and goes to the pump.

 

So should the inner part that has the wiring on the short end, or doesn't it make a difference?

 

 

 

Makes no difference, just decide what would suit you best if you ever need to remove it. 

From experience, these things don't take misalignment well.

 

Make sure there's enough meat in the pipes both sides so it can be cut out and a new one installed a couple of times, also consider that you may want to replace the pump with one with slightly different pipe locations.

 

But as above, up to you ????

 

For suction / low pressure pipes I've used these in the past, nothing glued. On pressure pipes they do tend to creep.

 

 

Also Global have these which have threaded ends, extra fittings I know but a piece of cake to replace when they start weeping.

 

 

 

1 hour ago, Crossy said:

From experience, these things don't take misalignment well.

 

Make sure there's enough meat in the pipes both sides so it can be cut out and a new one installed a couple of times, also consider that you may want to replace the pump with one with slightly different pipe locations.

 

But as above, up to you ????

 

For suction / low pressure pipes I've used these in the past, nothing glued. On pressure pipes they do tend to creep.

 

 

Yes I am aware of the misalignment issues with the one I have in my OP.

 

I was also looking at the one you suggested, but since no glue involved I was a bit wary of it.

 

Since you have experience with this kind of union, you think for the suction of a pool pump this will be sufficient?

 

The one with the threaded ends you suggest are basically another version as the one I proposed, so will have the same alignment issues I guess

Edited February 9, 20206 yr by Susco

Just now, Susco said:

Since you have experience with this kind of union, you think for the suction of a pool pump this will be sufficient?

 

Cut the pipes so they just don't meet, de-bur the ends. Then take the union apart (or at least loosen it off completely), slide it onto the pipes and ensure it's centred on the joint (if you take it apart make sure you get the plastic washer back in the right place). Then wange the beast up with a couple of big water-pump pliers / stilsons, hand tight isn't enough.

 

The negative pressure from the pump will tend to pull the pipes together, I've not had a suction side one come adrift.

 

2 minutes ago, Crossy said:

 

Cut the pipes so they just don't meet, de-bur the ends. Then take the union apart (or at least loosen it off completely), slide it onto the pipes and ensure it's centred on the joint (if you take it apart make sure you get the plastic washer back in the right place). Then wange the beast up with a couple of big water-pump pliers / stilsons, hand tight isn't enough.

 

The negative pressure from the pump will tend to pull the pipes together, I've not had a suction side one come adrift.

 

Thanks for the advice.

 

When I opened up one of those yesterday, I noticed at each side was a black rubber washer and a thin clear plastic washer.

 

Is the thing clear plastic washer important?

1 minute ago, Susco said:

Is the thing clear plastic washer important?

 

Yeah, it helps reduce the friction when you tighten it, it also stops the rubber getting scrunched up.

 

4 hours ago, Susco said:

Is the thing clear plastic washer important?

+1, don't loose it.

I used such a union for connecting the pipe coming from the well pump.

That's quite a pressure and is tight since 2014 or so.

 

6 hours ago, Crossy said:

For suction / low pressure pipes I've used these in the past, nothing glued. On pressure pipes they do tend to creep.

Very true.

Produced some nice fountains trying to use it for the pipe coming from the well pump

4 hours ago, Crossy said:

 

Cut the pipes so they just don't meet, de-bur the ends. Then take the union apart (or at least loosen it off completely), slide it onto the pipes and ensure it's centred on the joint (if you take it apart make sure you get the plastic washer back in the right place). Then wange the beast up with a couple of big water-pump pliers / stilsons, hand tight isn't enough.

 

The negative pressure from the pump will tend to pull the pipes together, I've not had a suction side one come adrift.

 

I did install, haven't run the pump yet as I want to give the glue some time to dry.

 

Since this is a pipe with several bends it isn't easy to measure the last piece exactly, so there was about 2 cm between the pipes.

 

Is this an acceptable distance?

 

I don't have pliers or stilsons that size so I used a clamp, and this is the furthest I can close it. Would that be ok?

 

I reckon you're good to go, they don't close all the way up anyway. 2cm between the ends is fine.

 

As others have said, great for the suction side, not doo great for the pressure side. I like to use a little Vaseline on the seals, and I just hand tighten the “nuts”.

Well here is the update.

 

No shortage of air bubbles under the pump lid, but I don't see any water leaks.

 

Now here comes the mystery.

 

I switch off the pump, close all the feeding valves and the valve on the output, but air bubble keep arriving under the lid at a steady pace.

 

Many small bubble but every now and then a large bubble. I can clearly see the bubbles come out of the feeding pipe and not from the lid.

 

So with all feeding valves closed, the air must clearly enter somewhere between pump and valves.

 

The bubbles come so fast that in 1 hour there is visible air space under the lid, so the water must have gone somewhere.

 

I have checked the entire length of the pipe with my bare hands, and all valves, I can not find any wet spot.

 

Any suggestions?

 

 

Do not use vaseline as  will help destroy the o ring use silicone grease, tighten the union an ensure the pump lid seal is tight also use silicon areas on seals.

Any leaks on glued joints,

18 minutes ago, sappersrest said:

Do not use vaseline as  will help destroy the o ring use silicone grease, tighten the union an ensure the pump lid seal is tight also use silicon areas on seals.

Any leaks on glued joints,

Like I said, I have gone with my bare hands over the entire pipe from the pump to each of the valves, and I can not find any wet spot.

I have replaced the pump seal already, even switched a lid from another pump, altough when I look in the pump I can clearly see the bubbles enter the strainer from the pipe.

 

I just went checking again, all valves are now closed for 1 1/2 hour, and still bubbles are entering under the lid at a fast pace.

 

If you know the Hayward pumps you will know that the lid bulges, and by now the water has decreased that much that the water doesn't touch the lid anymore.

 

That's an amount of water that can't go unnoticed, so I'm really astonished that I can't find the smallest water drop on any joint.

Edited February 9, 20206 yr by Susco

It's air going in, not water going out (the water that's "not" where the air is, is in the pool).

 

Leaving it to sit overnight with the pump off may reveal a seep but it depends if the leak is under any pressure from the pool water.

 

Otherwise a bit of air in the lid isn't really doing any harm unless it's increasing rapidly.

 

Once it's all stabilised are you getting bubbles from the pool return outlets?

 

1 hour ago, Crossy said:

It's air going in, not water going out (the water that's "not" where the air is, is in the pool).

 

Leaving it to sit overnight with the pump off may reveal a seep but it depends if the leak is under any pressure from the pool water.

 

Otherwise a bit of air in the lid isn't really doing any harm unless it's increasing rapidly.

 

Once it's all stabilised are you getting bubbles from the pool return outlets?

 

I don't see any air in the returns, but it quite a bit of air under the lid when running, to the extend that when the filter cycle ends after 3 hours a very large airbubble sucks into the chlorinator cell.

 

I left pump off all night with all valves closed.

 

When I woke up the water in the strainer was right at the top of the feeding pipe. No bubbles were appearing anymore at that time.

I checked all the piping again with bare hands, as specially at every joint or connection, and could not feel a wet spot anywhere..

 

As you can see from the video and image, it's quite a lot of air.

 

The connector is at the highest level of the piping and connects to 3T that has 3 feeds.

 

I opened the lid and water didn't drain until I opened one of the valves, which indicates the valves close properly and there was still water at the highest point of the piping.

 

 

 

 

 

 

1 hour ago, Crossy said:

It's air going in, not water going out (the water that's "not" where the air is, is in the pool).

 

When pump is off, and all inlet and outlet valves are closed, then the air coming into the strainer at that time is replacing water, since the water level decreases.

 

Or not?

13 hours ago, sappersrest said:

Do not use vaseline as  will help destroy the o ring use silicone grease, tighten the union an ensure the pump lid seal is tight also use silicon areas on seals.

Any leaks on glued joints,

I finally found a drop of water where the pipe is screwed into the pump.

 

There is plenty of Teflon tape on the thread and the fitting is screwed inside until it locked.

 

What is the solution. More or less Teflon tape, or are there fitting available in Thailand designed for the pool pump that will fit better?

We used Loctite 592 thread sealant on air systems. No thread tape.

 

 

There are many others.

Edited February 10, 20206 yr by VocalNeal

The OP opened a new thread same topic in Swimming Pools so this one will close.