Changing pool piping

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M

milbogo

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Mar 15, 2011
31
Hi guys - I am new to this forum and very new to the pool world - as we have adopted an 55,000 Litre in ground pool with the house we bought - so i have a few questions if I may on this wonderful forum.

I am replacing my pump - and I also need to move it. So I need to change my piping as well - so I will take he opportunity to change piping from 40mm to 50mm (as the new pump I am getting is a DC 3 speed one).

Here are my questions:

1. My skimmer box still has 40mm outlet - is it ok to put a 40mm to 50mm connector here - or will the 40mm on the skimmer cause more friction/bottle neck.
2. My sand filter also has 40mm connectors - it is best to change my sand filter to one that has 50mm connectors as well? or will a 50mm to 40mm reducer be fine here as well. Keep in mind my new pump will be about 12m from the skimmer box.
3. Is it best to have 50mm piping or 40mm piping from the filter back to the pool? I am thinking that 40mm may cause more pressure with the water coming back to the pool - which is better for circulation - especially when using pump at low speed....or is it better to keep it at 50mm for less friction.

My aim is to set up an optium system to reduce running costs - so now is the time to get it right.

Your feedback would be appreciated.

Kind regards,
Mil.
 
Welcome to TFP !! Congrats on becoming a pool owner.

My knowledge in this area is limited, but I wanted to welcome your to the forum. When you get some free time do some reading in pool school.

Since you are a new pool owner your going to need a good test kit like one of the ones we recommend. Take a look at this. pool-school/pool_test_kit_comparison.

Here is another good place to start in pool school. pool-school/pool_water_chemistry

pool-school/types_chlorine_pool

Hope you enjoy the forum !!
 
So - can someone answer this one:
Is it best to have 50mm piping or 40mm piping from the filter back to the pool? I am thinking that 40mm may cause more pressure with the water coming back to the pool - which is better for circulation - especially when using pump at low speed....or is it better to keep it at 50mm for less friction.

Thanks,
Mil
 
Larger pipe is ALWAYS better. There can be a point where it's not enough better to make it worthwhile but larger pipe will always decrease resistance and that's always a good thing.
 
Yup. If you want to increase the velocity of the water when it enters the pool for better circulation, then you can just use smaller eyeballs in the pool (although this adds some head loss and thus lowers the total flow rate some).

It is generally more important to have the larger pipe on the suction side. Not uncommon for basic pools here to have a single 2" suction line with a single 1.5" return line that splits to the jets. Of course it depends on the number of suction sources (floor and skimmer?) and the number of return jets in the pool.

My pool actually only had a single 1.5" suction line from the skimmer, I have since added a second 1.5" suction line from the wall.

Another note, while increasing the pipe size will increase the flow rate up to a point, realize that the more water you are moving, the more electricity it takes. If you are usually running the pump on lower speeds as we recommend, the pipe size may not matter very much anyway.
 
I just drained the dirty water out of my skimmer - and it appears the outlet inside the skimmer is 50mm. I can see a thread on on the 50mm port from the inside. There are two ports on each side also - they are blocked - and those are 40mm. These side ports are higher than the 50mm on the base. Coming out of the skkimmer is a 40mm pipe held with some concrete. So it may be the case it was 50mm - and someone reduced it to 40mm. Is it worth trying to remove the 40mm piplecoming from the skimmer to see if it is infact 50mm - or is it best left alone (I need to remove a little concrete to see). ie - it really doesnt make a difference.

Also - my pump will be at sligtly below the water line - possible on a slight gradient - will I need a check valve? When are check valves required anyway?

Kind regards,
Mil.
 
I would not make the effort to replace a short piece of the smaller pipe.

If pump is bellow the pool, you may want a shut off valve on the suction line so you can open the pump basket. Not a check valve. Same on the return lines, although you could use a check valve, but that adds head loss.
 

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With the way my pool is set on a slight slope - I have the option to:

1. Have the pump below the skimmer outlet
2. Same height as the skimmer outlet
3. Higher than the skimmer outlet
Which is the best option in terms of efficiency for my variable speed pump?

Also - this forum mentions and recommends 2.5 inch pipes - is that an external or internal measurement?
In Australia 40mm and 50mm pipes are the most common - but these are internal measurements. 40mm fittings measure 48mm & 50mm fittings measure 60mm on the OD. So when you guys mention 2.5 inch pipes in this forum - is that our 50mm (60mm) external ones?
 
Your 40mm is our 1½" and your 50mm is our 2". 2½" would be your 65mm.

In the U.S. pipes are designated by NPS (Nominal Pipe Size) loosely measured by the ID, but with the need for the piping to mate fittings the ID varies based on the schedule or thickness.
 
Hi guys,

I have laid down my 50mm pipe layout roughly - can you please advise if this is OK- or I should do something else to optimise the setup before I start pain-staking digging.
This is my last chance to get it right.

Few points:

1. I have the option of having the pump lower than skimmer outlet - is it better to have lower, same height or higher - I can do either of these? (See pic 3 below)
2. Is the length of the last straight pipe before it enters the pump important? I read somewhere that you should have a certain length of straight pipe before it enters the pump. I can make this last length that enters the pump shorter or longer - by changing the pipe length between last two joins (See pic 2 below).
3. Is the distance between connectors important? ie does longer length between connectors cause less friction and more velocity?
4. Sand filter has 40mm fittings.
5. I plan on buying a Viron P320 Variable speed pump.

Any advice on how to optimse this setup before I dig would be greatly appreciated. Since i have spent money and time I would like to get it right. You know the deal - one small thing - can make a difference over the years in cost savings.

Kind regards,
Mil
 

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1) Having the pump about even with the water level is best.
2) Looks like you have a long section of pipe before pump. You only need about a foot or so.
3) Distance between fittings isn't very important unless they're back to back out of plane.
4) & 5) Both of those are fine.
 
Is there a point where its not worth having 2 x 45 elbows together? is how far should they be apart to make it worth while having them - as oppose to just having 1 x 90 degree connector.

Mil
 
jblizzle said:
In the grand scheme, using two 45 is not worth it ... more joints with very little difference in head loss.
Click to expand...

Wow - I am surprised to hear that. There seems to be many views expressing the opposite. Logically - one would think a gradual curve will cause less friction than a 90 degree one. A car can travel faster around a curve - than it can around sharp corner.

However - I trust this forum - and I assume you guys have some hard technical tests that enable you to come to this conclusion - right?
 
There is no real point to minimizing head loss in a few turns when the filter and backwash valve (if you have one) add so much. If you really care, going to larger pipe and fittings well save you more in head loss, but at some point there is no real gain.
 

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