In the name of loosing my "head"...

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Guys,

If you want to have a good laugh, read on.

After reading Hydarulic 101, I set to reduce my suction head loss. This happened quite a while ago while I was hot at it.

I did all these is because I was ****** that my PB used 1.5" all around. I found that out from the flowmeter. I am paying for resistance at the 50GPM flow ( best flow I can ever get ) I am having, in other words I should have more flow if 2" pipes are used all around. That's what the pipe calculator showed me.

Due to the nature of the concrete pool, there is no way I can do anything to change the plumbing that is already set in concrete. So my only other method is to modify whatever pipes that are not embedded in concrete and somehow improve it. So I thought...

I don't have any hydraulics background, so the fun is learning by doing....

This is the original set up that came when pool was built.
During normal operation, the TANK valve and the DRAIN valve will always be opened.
There are two spring operated check valves on the suction circuit. One is right before the pump and the other is at the balancing tank suction pipe, at the very end of the pipe.
My test number for the suction is 11.5hg with check valves installed, TANK & DRAIN valves opened.
Without check valves ( i remove the internal parts ) the number is 8hg, TANK & DRAIN valved opened.
So the 2 check valves caused 3.5hg increase, which is equals to 3.9 feet loss of head according to the formula.

 

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So I kept thinking, how do I improve my suction side ?
There is no way I can avoid NOT using a check valve for the balancing tank.
I can avoid the check valve which is right before the pump.

So I called the pool store and asked for a Jandy type gate check valve with a spring which I heard has lowest resistance compared to my in-line plunger type. The pool store said, they do not stock Jandy, everyone wants cheaper in-line ones like the one I am using. I said import from USA for me, I don't care. So after like 2 months, today I got it and its a 2" model from Pentair ( same stuff as jandy..seems so ). I need a 1.5" one, but so what.... I can modify and use it. The only problem is that the Indonesian PVC OD size is not as thick as US ones, so the fitting is very poor when I will use this 2" Jandy. Never mind, small matter.

Back to the plumbing. I told the pool store to send a plumbing guy over and make me a suction manifold using 3" PVC.
My assumption is that, the original set up uses a straight pipe of 1.5" as a common manifold. Since my pool operates 2 suction inlets, the TANK and DRAIN at the same time, it doesn't make sense that a 1.5" pipe is being fed by 2 of 1.5" valves...so I thought. The look of the original plumbing also told me that by position the water being sucked out of the TANK valve will sort of collide with water from DRAIN valve since that is the only way to go.

So I asked for arounded loop for the 3" manifold. Hoping that the effort of suction will be less because there are more area for the water to flow and having a rounded loop means I can have water from left and right, so to speak. I also asked for all 1.5" pipes that can be replace with 2" to be replaced, for filters and so on. I also removed the check valve that is right before the pump and replace it with a 2" valve.

 

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I wanted to laugh looking at the final shape of the 3" looped manifold.
Looks like a baby trampoline without the net...

Not all pipes can be converted to 2". The size of the port at the Hayward cartridge filter is only 1.5"...why ?????? I don't know. So reducers was installed for the Hayward Cartridge.

My 1.5" flowmeter was also removed. I bought a new 2" flowmeter and I have not install it until today.
I accidentally bought a high flow flowmeter for the 2" and the seller does not want it back, even before I use it. I like flowmeter maximum flow not be too much higher than my pump flow. I can get easier reading that way. Looking at the 1.5" and 2" flowmeter, it looks the same. The sensing part of the flowmeter that goes inside the pipe is the same length for 1.5" and 2" model, I suspect they are rated 1.5" and 2" because of possible maximum flow of a given pipe size, not anything to do with pipe size installation compability. I will need to test later. I shall update.

So what happen to my waterflow with the King Kong 3" looped manifold ??
I get 8.5hg reading...WOW, not bad I thought. That is 3 hg improvement with 1 check valve installed at the balancing tank.
3 Hg improvement is 3.4 feet equivalent in head......
But to my amazement I keep getting air bubbles in the pump strainer.
Not so severe but I hate it. I don't want my impeller to be "cooked" by cavitation.
I run a complete check over and over again for minor leak.
I did a pressure test and all are good...

I nearly lost interest here. I was so ****** because I can't find any suction leak.
I gave up and relax a few days to cool off. I am not a very patient person though.

So I surfed and surfed about cavitation bubbles and finally I found out the cause.
The problem is that sudden change in pipe size will cause pressure change in the water.
Going from 1.5" valves to a big 3" pipe and going to 2" pipe after that, pressure changes occured like a venturi effect.
The suspected culprit is the "T" where the 3" pipe gets connected to the 2" valve, the shape of the reducer
should not be the concentric one, I must use an eccentric reducer. However the pipe manucturer does not have such thing. Its all concentratic reducer.[attachment=1:3kdrnbxx]stdcon.gif[/attachment:3kdrnbxx]

 

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So what did I do....throw away the 3" looped manifold...

When I did remove the 3" looped manifold, I discovered that the plumber job was not good. The alignment to the 3 valves are not so good. So my pipes are under stress.

No choice, I got to do this myself from now on. With my pool boy help that is.
I am so used to fixing plumbing on yachts that uses USA type compression fittings and not PVC glue, I then realized it is not that easy to get the "orientation" of a pipe right if rigid pipe and glued fittings are used. It takes carefull planning and practice. Once you insert wrong on a glued connection, you got 10 seconds and the glue will be so sticky, you can't spin the orientation right anymore. Being rigid also does not allow room for error of more than 0.5" when making cut on the PVC pipe.
PVC glue seems like it is able to melt PVC surface, amazing. i neverf give a rat azz in home plumbing ever... it's all paid contractor, now for the love of my pool, I am doing it myself.

I was stuck between choosing another looped manifold of 2" or goes back to original plumbing straight manifold sytle but use 2" pipes all the way to the pump from the 1.5" valves.

At the same time I read the rule of thumb that said :
" Keep a straight pipe at least 10 times the diameter of the pipe when installing a suction pipe".
OK, so how do I do that with the limited space I got ?

So I took my chances. I will use flexible reinforced hose for suction. That way I can create a "simulated" straight suction pipe.
So more time and money down the drain.

This is the final and 3rd manifold revision.
2" pipes all the way and including for the straight line manifold.
Sorry the area is a bit clustered, I am not done mounting the ozone generator properly.

 

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So what do I get for final 3rd revision ?
8Hg without the check valve at the balancing tank.
9hg with the check valve.

If the Jandy check valve can reduce suction effort and I can get 8.5hg. I shall be happy.
I shall update.

What do I learn from all these ?

I realized that all the 1.5" PVC ball valve installed, its China made is not 100% air/water tight !!!!
How do I know that ? I purposely installed an extra 1.5" valve "T " it along the inlet pipe that goes back to the pool.
The idea is, I wanted to measure what is the actual resistance my 1.5" overall plumbing that are already embedded inside the concrete, compared to if I just discharge the water there then with that additional valve 1.5" that has 2 90 degrees turn.

That PVC valve is the same brand as what the entire plumbing uses, so I can interchange the valve module. I realized that it lets out very few drops of water per hour when pump running even when totally shut. When pump is off, due to the height of the sand filter, there is a bit of vacuum, I can hear the micro suction sound. I am only able to find this out because that valve is open ended. I swapped the valve with all other three and all LEAK !!!! OK, 20 milli liters a 14 hours day is what is the leak I get, still it is a leak.

This is another reason I am pi$$ed with my PB. I don't mind spending money for high quality products, in fact that is what I always do if I personally get involved in a purchase. Its always cheaper to do it right in the first try.

Valves are not supposed to be micro leaking.
I can't change them now, the position for the 3 valves are so close to the concrete floor, if I ever mess with them and it breaks, I may be in trouble and have to do some major concrete work. Unless a superior brand can use the same end cap fitting, then I can change it. The end cap of the valves are screwed-on and they are the part that gets glued to the PVC. The valve and check valve are basically modules using the same end cap. Knowing how China products are usually a copy from a popular US or European brand, I may be able to locate one superior make, some day.

This is the sad part living in a developing country. If I do not shop carefully from a good electrical store, I may end up getting circuit breakers which are fake. What a joke.

So is all these efforts and $$ spent worth it ? I said yes.
Its not only the reduction in Hg, its the hands on learning processs.
For every night I spent on my pool looking like a plumbing idiot instead of clubbing wasting my money and getting home dead drunk, its a good thing allrighty...

In my country when you get drunk and get police road block, all you got to do is said that you are drunk and need to go home quick to sleep, and give the cops US$5 while at it, they will tell you, go home mister and drive safe...
This is why drunken driving with fatality is very low here. There is nothing to fear...ha ha ha or to run away from.

 

[SPP]

Got a 2" Pentair ( Jandy ) check valve for the balancing tank. Add some reducer to have it worked on my 1.5" pipe.

Hg dropped to 8.5.. yep. That is good news.