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carlyai

Calculating Pump Water Output.

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Pump specifications:

LuckyStar, PC-301EA, 300 W.

 

Jet:

Single Jet PSJ-50

 

TDH = Static ht. + Static lift + Friction loss

 

TDH = 0 + 7.5 m + 4.5 m

 

(The suction pipe length from the footer valve to pump inlet is 7.5m)

 

The friction loss is calculated with 2 pipe joiners and a 90 degree bend.

 

The water table is 2m more than the static lift.

 

Using the pump curve supplied for a single jet, the capacity should be about 22 litres/min.

 

With the pump operating for about 5 mins, I measured the rate to fill a 1 Litre container through a 10 hose, which was 7 secs or approx 9L/min

 

Why aren't I getting a capacity of 22 litres/min?

 

The capacity at the output of the hose does drop of from when I first turn on the pump to when I take the measurement.

 

Sent from my SM-J700F using Tapatalk

 

 

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Try closing a valve on the output to 3/4 open.  You probably won't get full but maybe a little better.

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Try closing a valve on the output to 3/4 open.  You probably won't get full but maybe a little better.
Hi thanks, will do.

Sent from my SM-J700F using Tapatalk

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Your trying to read off the very bottom of the pump curve.

Most pumps work best mid range of the curve. 

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Hi thanks, will do.

Sent from my SM-J700F using Tapatalk

I did that, and a little better. Will check litres/hr later.

I still would like the pump exAPerts to tell me where my theory calcs. are wrong. There's a lot of difference between what I calculate and what I get in L/min.

I have noticed a water leak in a pipe connection when the pump switches off, so will fix that.

Sent from my SM-J700F using Tapatalk

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No expert but my experience with jet pumps finds them finicky.  I think the system needs to be full of water for best output.  If the output stop valve is close to the pump, you can hear the difference from full open to partially closed.  Maybe try closing it until it sounds best.

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25 minutes ago, carlyai said:

I did that, and a little better. Will check litres/hr later.

I still would like the pump exAPerts to tell me where my theory calcs. are wrong. There's a lot of difference between what I calculate and what I get in L/min.

I have noticed a water leak in a pipe connection when the pump switches off, so will fix that.

Sent from my SM-J700F using Tapatalk
 

 

If you've got leaks then you can't expect it to be running at perfect performance, perhaps you also have a leak somewhere else that you can't see that is drawing in some air.

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If you've got leaks then you can't expect it to be running at perfect performance, perhaps you also have a leak somewhere else that you can't see that is drawing in some air.
Yes correct. Will fix it...bit of a job but...leaking where it goes into the jet. I let the offsiders tighten those joints as were a real pain to get tight even with the thread tape.

Sent from my SM-J700F using Tapatalk

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1 minute ago, carlyai said:

Yes correct. Will fix it...bit of a job but...leaking where it goes into the jet. I let the offsiders tighten those joints as were a real pain to get tight even with the thread tape.

Sent from my SM-J700F using Tapatalk
 

 

Absolutely no chance it will work to full capacity with a leak on the jet, you're lucky you got it to work at all!  

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Absolutely no chance it will work to full capacity with a leak on the jet, you're lucky you got it to work at all!  
I didn't notice it as it didn't leak when the pump was on. It leaked when the pump stopped. Just noticed it while doing something else. My back's no good so the guys tightened that joint up and cracked the thread.

Sent from my SM-J700F using Tapatalk

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No expert but my experience with jet pumps finds them finicky.  I think the system needs to be full of water for best output.  If the output stop valve is close to the pump, you can hear the difference from full open to partially closed.  Maybe try closing it until it sounds best.
Hi, yes I've adjusted the valve for best I think.

Sent from my SM-J700F using Tapatalk

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The water table is 2 m more, are you saying the water table is 2m higher the the foot valve. 

How about a quick sketch, solves any misunderstanding. 

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29 minutes ago, Artisi said:

The water table is 2 m more, are you saying the water table is 2m higher the the foot valve. 

How about a quick sketch, solves any misunderstanding. 

I am also confused with the 2m. Is the source capable of delivering 22L/Min was the capacity posted in an earlier thread?

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Note the pipe diam is 30mm , if its smaller it will effect working abilities.

You dont mention a quick return valve in it, maybe (probably) its in the pump. If it is, is it working right?

It prevents from water flowing back in the well again and you ll have air in the pump and piping again.

Pumphouse and piping should be all filled up, no air in or coming in, no cracks in sucktionpiping, which will let air in.

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