perplexed about high-flow faucet adapter

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Old 05-12-12, 08:45 AM
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Question perplexed about high-flow faucet adapter

I bought this high-flow 4-way outdoor faucet adapter to replace a standard 4-way adapter that used narrower outlets, thinking that the larger outlets on this model would extend the range of my lawn sprinklers:
Amazon.com: Gilmour Full Flow Poly 4-Way Connector AY4FF Teal/Black: Patio, Lawn & Garden

I was surprised to find that, if anything, the range of my sprinklers decreased slightly with this model. Does that make sense? Does the larger flow of this model result in decreased pressure, and is the range of a lawn sprinkler more dependent upon pressure than upon flow rate?
 
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Old 05-12-12, 10:24 AM
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If you hook a garden hose up and turn on the water, what comes out is full flow. Add a nozzle and as you turn it to add range, you increase the pressure and reduce the flow rate.
If your sprinklers have adjustable nozzles, you can tune them to whatever range (within their limits) that you want.
 
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Old 05-12-12, 10:43 AM
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I suspect that either the original hose bibb or the piping leading to it are the limiting factor, not the four-way adapter.
 
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Old 05-12-12, 11:14 AM
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Furd, nothing leading to the hose bib has changed. I simply swapped out my old 4-way adapter for this one and noticed that after doing so, my sprinkler range didn't increase, but possibly decreased slightly instead.
 
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Old 05-12-12, 12:42 PM
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There are so many variables here.

Well/city water?

Are you running two several things at once?

Something in the home running?

Hose bib open all the way?

What type of sprinkler?

Kink in the hose? Longer length of hose?

Mike NJ
 
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Old 05-12-12, 01:24 PM
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Mike,

It's city water. Impact sprinkler. This one, to be precise:
Amazon.com: Gilmour 196SPB Pattern Master Impulse Sprinkler on Polymer Sled Base: Patio, Lawn & Garden

No other variables are changing. When I was comparing the flow through the original 4-way to the flow through the high-flow 4-way, I used the same conditions, minutes apart. Same hose, same sprinkler, no other water in use in the house. A pure A/B test. The only variable that changed was the 4-way adapter itself.
 
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Old 05-12-12, 01:40 PM
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I guess you have a "truth in advertising" claim to file against the supplier.
Myself, I'd just return the piece of junk.
 
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Old 05-13-12, 08:46 AM
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It is a high flow. Higher flow would mean less psi. Hence the shorter throw of the sprinkler. Less psi means more GPM.

So your sprinkler may be spraying shorter but you are getting say 8 gpm, Your old adapter with a farther throw you may be getting say 5 gpm because higher restriction and higher psi.

Its just how water flow works.

Mike NJ
 
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Old 05-13-12, 11:21 AM
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Sorry, Mike, but no.

Each and every part of the system will have its own resistance to flow. Some will be greater and some will be less. The pressure drop is continuous from supply to point of utilization. Installing a section that allows more flow somewhere between the supply and end will NOT decrease the pressure at the end while increasing the flow.

Envision this: You have a 2-1/2 inch fires hose connected to a hydrant that is directly connected to a 6 inch water main that operating at 60 psi static pressure. (I'm going to make up the numbers rather than do the arithmetic but the concept is valid.) Using a 25 foot hose you can get 50 gallons per minute flow through this hose. Adding another 25 feet of 2-1/2 inch hose (increased resistance to flow) drops that flow rate to maybe 45 gallons per minute, adding a third length drops the flow rate to maybe 35 gallons per minute.

But let's take out that middle section of 2-1/2 inch hose and substitute a piece of 3/4 inch garden hose. Now you will only get about ten gallons per minute (or less) out of the end of the last section of 2-1/2 inch hose. The limiting factor is that small hose in the middle, it makes no difference what size the final stage is if you have excessive resistance to flow in the middle.

Now let us add some pressure gauges to the hoses. A pressure gauge at the hydrant will show 60 psi (the pressure in the water main) while a pressure gauge at the first juncture, between the 2-1/2 inch hose and the 3/4 inch hose will also show 60 psi. However, the pressure gauge at the end of the 3/4 inch hose and juncture with the final 2-1/2 will be considerably lower, maybe 20 psi, maybe even lower and the pressure at the outlet of the last 2-1/2 hose will be zero.


With the sprinkler the the maximum flow is a function of the pressure at the sprinkler and the orifice of the sprinkler. Since the pressure pressure at the sprinkler is a result of the initial pressure minus the pressure drop across the entire system from supply to utilization the pressure at the sprinkler will be less than at the source UNLESS the intervening piping and hoses are so large as to preclude any pressure drop from the finite flow rate as determined by the sprinkler orifice.

What all this means is, if swapping the four-way manifold is the ONLY change being made with less water spray at the sprinkler with the so-called "high flow" manifold compared to the original manifold then it MUST be that the newer manifold has introduced a greater pressure drop in the system and that can ONLY come about because the new manifold has smaller passages.
 
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Old 05-13-12, 02:33 PM
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Hmm, OK. I guess I am thinking in-terms of my well dynamics. At 60 psi I only pump 5 gpm. At 40psi 10 gpm.


I will have to find a link with gpm vs psi.

Irrigation dynamics or some site.

I'll be back....

Mike NJ
 
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Old 05-13-12, 03:07 PM
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Mike, you are absolutely correct with your pump analogy, especially when discussing a centrifugal pump.

I know you know this because you often mention it in regards to fuel gas piping. Installing a smaller pipe somewhere in the run decreases the gas flow no matter how large the pipe after the restriction.
 
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Old 05-13-12, 11:30 PM
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OK.

The OP bought a device that is stated as full flow. It most likley increased the volume at that new adapter compared to the old one, right?

This in turn would lower his pressure hence the sprinkler not shooting as far, but in return he is getting more volume of water, or gpm.

Still trying to find documentation.

Mike NJ
 
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Old 05-14-12, 01:15 AM
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Nope.

Let me try this another way. You have a 1/2 inch nominal pipe with a standard hose bibb on the end. The hose bibb has an effective orifice size of 3/8 inch diameter when wide open. You connect a length of 5/8 inch garden hose to the hose bibb. Use a sprinkler, nozzle or just leave the end of the hose open and you will get a flow X gallons per minute.

Now instead of connecting the hose directly to the valve you insert a six inch long, 1-1/4 inch pipe nipple with bell reducers and garden hose adapters between the valve and the hose. Do you get a greater flow at the end of the hose, less flow or the same flow? If you have a sprinkler on the end of the hose does the pressure at the end of the hose just before the sprinkler increase, decrease or stay the same?

With the entire run being 1/2 inch nominal pipe> 3/8 inch orifice hose bib> 3/4 inch by 3/4 inch female hose adapter> 3/4 inch by 1/1/4 inch bell reducer> 6 inch long 1-1/4 inch nipple> 1-1/4 inch by 3/4 inch bell reducer> 3/4 inch by 3/4 inch male hose adapter> 5/8 inch garden hose + sprinkler where is the point of most resistance?

What is "full flow" and how is it measured? How can you increase flow beyond a point of restriction?
 
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Old 05-14-12, 01:25 AM
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Here's another exercise.

I have two identical positive-displacement pumps coupled to identical motors as per the pump manufacturer's instructions. Both pumps have the same size of suction piping and both are connected to the same tank of water but through separate suction connections so that each pump has the same suction head. Both pumps have a 1 inch discharge port. Pump A has 20 feet of 1 inch discharge piping going back to the water tank and pump B has 20 feet of 2 inch discharge piping back to the tank in the exact same configuration as pump A except for the size change at the pump discharge.

Which pump will have the higher discharge pressure? Which pump will have the greater flow rate? Why? What causes pressure?
 
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Old 05-14-12, 08:45 AM
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Pump A will have a higher pressure at the pump end, but a bigger pressure drop at the end of the pipe run. This is due to friction. You will have a lower gpm also, and this is how irrigation systems are figured.

Pump B Will have less pressure at the pump end and less overall pressure loss overall. Plus more gpm. Less friction.

Now velocity in the pipe? Pipe A would have more velocity.

Mike NJ
 
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Old 05-14-12, 11:02 AM
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Sorry, Mike, but no. I confess it IS a trick question and you obviously skipped over the part where I wrote positive displacement pump. With a positive displacement pump the output volume cannot change but for an infinitesimal amount. That means that the flow will be the same for each pump. The one with the larger pipe MAY draw less horsepower than the one with the smaller pipe and the pressure at the pump discharge port will be lower than the pump with the smaller pipe.

Now, what causes pressure? What is your answer to the previous exercise?
 
 

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