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Wanting more flow rate. What's the issue?


Edward Baskerville

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Hi guys,

Currently running shurflo pump with analogue window cleaning warehouse controller. Had few issues with it but got it calibrated fine to certain flowrate. 

But now I'm wanting to have higher flow rate the controller just won't allow it. So the pressure switch comes on I'm running half inch hose to 6mm down to 5mm pole hose. I hooked up my old reel with 8mm on it and it's much better but I'm reluctant to get rid of my new power up hd reel with 6mm on.

Is there other controllers on the market which will allow me to have higher flow rate with the 6mm on? Pumps about 4 years old same as controller.

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From what you describe, I don't think that will be anything to do with your controller.  Sounds like the smaller bore hose is causing your pump to build up too much pressure hence the pressure switch is cutting in before the controller is doing it.  If you want more flow it sounds like you will need a larger bore hose.

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Battery was fine soon switched to the 8mm it was different but its on battered old reel. I am running like 100m with like 20m pole hose. I have seen lot folk cut lot off their main reel hose with 6mm

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39 minutes ago, Edward Baskerville said:

Hi guys,

Currently running shurflo pump with analogue window cleaning warehouse controller. Had few issues with it but got it calibrated fine to certain flowrate. 

But now I'm wanting to have higher flow rate the controller just won't allow it. So the pressure switch comes on I'm running half inch hose to 6mm down to 5mm pole hose. I hooked up my old reel with 8mm on it and it's much better but I'm reluctant to get rid of my new power up hd reel with 6mm on.

Is there other controllers on the market which will allow me to have higher flow rate with the 6mm on? Pumps about 4 years old same as controller.

Reference controllers the best on the market is Spring Europe Ltd's V16 and I've not ever had any flow issues with them. 

Do you have a possible restriction in your system?

A blocked non return valve 

Blocked filter strainer on the pump or tank

The obvious, twisted hose reel hose or hose joint which is crimped 

Damaged worn out pump diaphragm 

Grossly under charged battery or low voltage which is worth testing 

Worn out pot or controller circuit fault 

Blocked or crimped brush jets or Y connector issues 

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11 hours ago, Edward Baskerville said:

Hi guys,

Currently running shurflo pump with analogue window cleaning warehouse controller. Had few issues with it but got it calibrated fine to certain flowrate. 

But now I'm wanting to have higher flow rate the controller just won't allow it. So the pressure switch comes on I'm running half inch hose to 6mm down to 5mm pole hose. I hooked up my old reel with 8mm on it and it's much better but I'm reluctant to get rid of my new power up hd reel with 6mm on.

Is there other controllers on the market which will allow me to have higher flow rate with the 6mm on? Pumps about 4 years old same as controller.

https://windowcleaningforums.co.uk/topic/16425-ideal-flow-rate-per-minute/?tab=comments#comment-440851

 

Hi guys, I have a 4.5lpm 100psi pump but I’m only getting 1.25lpm at the jets with the controller on 100.

I have 30m of 8mm OD/ 6m ID on the hose reel and 12m of 6mm OD/5mm ID pole hose with 2mm pencil jets.

Why is the lpm so low and what can be done to increase it?

Thanks chaps

my response

We have found that there is a noticeable difference with flow rate though 6mm microbore hose when compared to 8mm minibore, especially this winter. One of the biggest flow reducers is flow turbulence inside a coiled hose.

Microbore is half the 'size' of minibore. You are now adding a length of pole hole which will further restrict flow.

A pump flow rate is given on full pelt with no output restriction. Add restriction and the flow rate drops considerably.

I posted this on another forum 3 years ago. (Copied and pasted.)

 

Another poster on this forum couldn't understand why a difference in 2mm hose size (8mm minibore to 6mm microbore) should make a difference in flow. Doug Atkinson from Daqua posted this in reply

It does -------, makes at least 30% reduction in flow
 

Take a look at this; Added; Sorry this link no longer exists.

http://www.flourmilling.co.uk/water.html

I realise its steel pipe but I see the flow rate difference between 6mm and 8mm bore steel pipe is considerable. At 4 bar the flow through 6mm pipe is 0.022 litres per second. The 8mm pipe its  0.056 litres per sec at the same pressure. So a 6mm tube will only allow fractionally less than 1/2 the volume of water at 4 bar. Our hose coiled up around a hose reel will probably reduce those figures a bit more.

Hot water will have a higher (or is it lower) viscosity (less dense) so will flow better through a smaller diamt hose. So most hot water users happily use microbore hose.


http://www.frca.co.uk/Documents/100308 Physics of flowLR.pdf

Interesting read these 7 pages.

Look at the difference between Laminar flow and Turbulent flow. Once fluid in a tube reaches a certain speed it become turbulent. Once it becomes turbulent it requires 4 times the amount of pressure to double the flow rate. Fluid through hose coiled on hose reels won't be laminar in flow but turbulent.

To calculate the area of a circle the formula is

A = π r2

A 6mm id hose is fractionally more than half the size of an 8mm hose.
A 3mm jet is a little more than twice the size of a 2mm jet.
A 1mm jet is about 1/4 of the size of a 2mm jet.

 

Pole hose is 2/3rds the size of micrbore. Many years ago Aquadapter (now Exceed Innovations) did an experiment to see if pole hose would be a better alternative to hose reel hose. Nothing came of it. I wasn't sure if this was a sales ploy to sell more pole hose or if it was a genuine experiment.

Edited by spruce
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@Edward Baskerville.

https://windowcleaningforums.co.uk/topic/23475-pressure-problem/?tab=comments#comment-350792

At 88psi a 15mm straight steel pipe will support a water flow of nearly 17lpm. An 8mm (minibore sized hose) pipe will support a flow of 4.26lpm at 88psi and 6mm pipe (minibore size) will only support 1.68lpm at 88psi. Of course the longer the hose the slower the flow of water through it.

The other point to understand is that water can flow freely through a straight pipe with a smooth inside water fairly quickly. But there comes a point when it starts to become turbulent due to friction. It starts at the sides and this turbulence interrupts the follow and creates a restriction. This can be overcome to a certain extent by increasing the pressure but that uses more energy and probably self defeating.

Replace that smooth pipe with coiled plastic reinforced hose and you will get turbulence much sooner.

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Ok so I rang window cleaning warehouse about the controller and they said I could bypass the pressure switch. But he did mention that the de light could come on to stop the pump and the flowrate won't increase and it only works at the flow rate given. Today I went to my colleagues house and tried his pump and controller which doesn't have calibration and it came through the reel fine. No pressure switch activating etc. I literally thought even with his pump on and controller the pressure switch would still kick in because of the 6mm hose. But obviously wasn't the case. I'm wondering if the controller is actually faulty... when clearly you can get more flowrate.

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Just a thought. To determine if it's a controller or pump fault, assuming that it's not a connector/strainer/inlet problem, then you can run the pump directly off your leisure battery (Via a fuse) as that will run the pump at full speed. If you still have same issue then maybe the pump is worn and not providing the flow rate it should. Alternatively are you sure your pressure switch is set correctly as they are adjustable! 

By the sound of your post it sounds like your analogue controller has dead end detection which is designed to protect the pump when the flow is stopped (univalve, tap, etc). So you can bypass the pressure switch to see if that fixes the issue. If bypassing the pressure switch works then I would guess it's either the pressure switch set wrong or the pressure switch is failing.

Hope that gives you some clues.

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37 minutes ago, ched999uk said:

Just a thought. To determine if it's a controller or pump fault, assuming that it's not a connector/strainer/inlet problem, then you can run the pump directly off your leisure battery (Via a fuse) as that will run the pump at full speed. If you still have same issue then maybe the pump is worn and not providing the flow rate it should. Alternatively are you sure your pressure switch is set correctly as they are adjustable! 

By the sound of your post it sounds like your analogue controller has dead end detection which is designed to protect the pump when the flow is stopped (univalve, tap, etc). So you can bypass the pressure switch to see if that fixes the issue. If bypassing the pressure switch works then I would guess it's either the pressure switch set wrong or the pressure switch is failing.

Hope that gives you some clues.

I did try my mates pressure switch and swapped it over and it did the same thing. So I thought id try my mates pump and controller to see if was my hose that was causing the problem. But it was fine. I was wondering whether to buy new controller try it on this pump and see if it still kicks in then maybe if it does. It's the pump that's the issue?

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Your diaphragm in the pump is probably wearing out after 4 years. After that time pumps do lose some power it’s only when you put on a new one you will see the immediate difference.

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6 minutes ago, doug atkinson said:

Your diaphragm in the pump is probably wearing out after 4 years. After that time pumps do lose some power it’s only when you put on a new one you will see the immediate difference.

So are you saying if I put new pump in its most likely my controller will allow me to up my flow rate?

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Very simplistically, put 12v directly onto the pump with a fuse. If you get full flow it's controller if not it's pump. 

Edited by ched999uk
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So when I do this I'm assuming the flow rate I'm getting through the brush head to determine that? As you can flush the pump through max no problem when disconnected from the reel.. it just seems to be struggling I guess when going through the reel

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7 minutes ago, Edward Baskerville said:

So are you saying if I put new pump in its most likely my controller will allow me to up my flow rate?

Try your mates pump with your Controller and if it improves you know it’s the pump. What model pump do you have

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7 minutes ago, doug atkinson said:

Try your mates pump with your Controller and if it improves you know it’s the pump. What model pump do you have

Shurflo pump. I'm not sure if he will let me disconnect it all now but I could ask.

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A new Shurflo pump's pressure switch is set to activate at 100psi. If the pressure switch is activating then the pressure at deactivation is 100psi, unless the adjuster screw has been adjusted.

One of our pumps is 15 years old and still running well. The other is 14 years old and is also fine.

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2 hours ago, Edward Baskerville said:

So are you saying if I put new pump in its most likely my controller will allow me to up my flow rate?

As Doug mentioned, if your pump is tired and old or the diaphragm is worn then it's ability is less

Simple analogy

It's like trying to drink through a straw with a hole in it

New pump theoretically problem solved 

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32 minutes ago, Apw1210 said:

As Doug mentioned, if your pump is tired and old or the diaphragm is worn then it's ability is less

Simple analogy

It's like trying to drink through a straw with a hole in it

New pump theoretically problem solved 

Ordered new pump and I'll let you know how I get on

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