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Kemo

Hose diameter which is best

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Kemo

Just in the process of setting up myself, just a little confused on which type of hose to get as they are different diameters.

anybody shed some light on why / preference etc.

tia

 

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Marko067

The smaller the internal diameter (ID) the slower the flow will be at the brush. 6mm ID hose for example will require considerably more pressure to push the same volume of water through it than 8mm ID hose for a given length.

So if you plan to use 60m of hose on your reel you may be fine with 6mm ID hose. However, if you plan to put 100m or more on your reel you might prefer to use 8mm ID hose.

Of course the bigger the ID of a hose the heavier it will be when pulling it around full of water.

I'm a trolley user myself  and work with relatively short lengths (18 and 25m) so can get away with using 5 or 5.5mm pole hose entirely.

I'm sure you'll get some input shortly from someone experienced with van based systems and reels

The principles are the same though

Edited by Marko067

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Pjj

Most people use 6 mm internal size microbore hose it’s light easy to drag around and works well far better than 8 mm that’s very heavy and difficult to drag round buildings .

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steve garwood

Whether your using 100m or 60m go for 6mm (microbore). 
Using 8mm is like dragging around an anaconda 👍

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Marko067

There you go. You can tell I've never had a van based system 😆

I do remember that when I started with my PF trolley 12 years back, I worked for about a year with just 20m of 8mm ID hose. I never thought about how heavy it was till I switched to pole hose only. I kept thinking my hose had come disconnected it was so light. It was lighter again when I switched to PU pole hose.

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Skxawng

Most pumps will handle 100m of 6mm id Microbore easily. It might only be an issue if you're using one of those cheap mini pumps.

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Chris34

I've got the pure freedom nano trolley and was advised that the 8mm was the only hose you can use to extend it, so I went and ordered a 20 meter extension 8mm hose.  I'm pretty annoyed now that I'm hearing that you can use pole hose, I've only used the 8mm extension once and it's because just like Steve says it's like dragging an anaconda about.  Why would they tell me to use an 8mm and not pole hose?  I don't understand.

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Marko067

I used the standard PF trolley for years in its standard format (Sureflo 100psi pump). I found when I switched to PU pole hose that I couldn’t run it flat out because it kept cycling. It was too powerful. But I still had plenty of flow through 2x 2mm jets. I use a smaller backpack style pump and 2x 100 degree fan jets with at most 25m of hose now, which is more than adequate for my needs and one heck of a lot lighter as I only need to use a 12ah battery to power it as well.

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Chris34
1 hour ago, Marko067 said:

I used the standard PF trolley for years in its standard format (Sureflo 100psi pump). I found when I switched to PU pole hose that I couldn’t run it flat out because it kept cycling. It was too powerful. But I still had plenty of flow through 2x 2mm jets. I use a smaller backpack style pump and 2x 100 degree fan jets with at most 25m of hose now, which is more than adequate for my needs and one heck of a lot lighter as I only need to use a 12ah battery to power it as well.

Sorry I don't understand what you mean by this, what do you mean 'kept cycling'?  Struggling to get my head around it all, to me going from 8mm from machine to pole hose as supplied it works as expected, I can't understand how having a longer pole hose would affect the operation of the pump, I would have thought that a longer 8mm hose would require more pump power as the hose has more space to fill with water, whereas a longer pole hose would be the same power.  

The only thing I can think is a longer pole hose creates a longer bottleneck as it takes longer for the water to flow through the pipe, the bottleneck creates a build up of back pressure causing the pump to cut out, whereas trying to push the water into an 8mm pipe requires less effort as there is more space for the water to flow into, so therefore you could run the pump at higher flow.  

Like if you get an imaginary very long straw and blow into it as hard as you can, well your cheeks would puff out and it would take a while to exhale all the air in your lungs, but at the end of the straw you would be able to feel the force of the air leaving the straw.  if you did the same but used a drain pipe your air in your lungs would exhale in a few seconds so very little resistance, but the air pressure at the end of the drain pipe would be virtually unnoticeable.

So is it the back pressure to the pump that's the problem, or am I completely wrong?  My heads spinning, lol.

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Marko067

Here goes. Lets see if I can get this right

Cycling = switching on and off by itself

 

Explanation: 

There are two main factors that cause the back pressure that the pump has to deal with.

1. The ID of the hose. 
2. The length of the hose.

To illustrate:
If you take a 15cm (6 inches) length of 6mm ID hose and blow through it, it won't take a lot of effort. On the other hand if you try to blow through 20m of the same hose you will find it very hard. This is caused by friction and turbulance in the flow.

If you blow through 15cm of 8mm ID hose it will be easier than the 6mm one. Blowing through 20m of the same hose would not be as hard as the 6mm hose but would still require more effort than the shorter length.

 

You can only ever force a certain amount of water through any hose before something will wear out or break. 

Most pumps are therefore fitted with a pressure switch which is designed to shut the pump off before it gets damaged. If this shuts off the pump before you shut off the water with whatever valve/tap you have fitted in your hose, this is refered to as 'dead ending.' 

If the pump starts switching on and off by itself whilst you are cleaning windows, this means that there is too much back pressure in the hose due to either its ID and or its length. This switching on and off repeatedly is called 'cycling' because a cycle of increasing and decreasing pressure caused by the pump turning on and off is involved.

This can be handled in two ways. Either turning down the flow with a simple electronic controller until the maximum flow that the hose can handle at a given pressure is reached. Or if you have a more advanced controller, calibrating it so that the controller switches off the pump before the maximum pressure the hose can handle is reached.


This all sounds a bit complicated but if you can understand it, it will help you to troubleshoot a malfunctioning system and lead to less time wasted and more time working.

My preference for a trolley with a short hose (25m max) is a simple electronic controller with a smaller lighter pump. A 100psi Sureflo, whilst an excellent pump is overkill for my needs.

Edited by Marko067

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Skxawng

You can adjust the dead end setting on the controller and also the sensitivity of the pressure switch on the pump with a small Allen key. Anticlockwise makes it less sensitive. It's not necessarily a problem if your pump is cycling on and off, it doesn't mean you're putting too much strain on the pump, it just means it needs calibrating for the increased resistance from having a longer hose. Adjust the pressure switch on the pump so it doesn't cut out during normal operation, then adjust your flow controller (if you have one) to cut in just before the pump pressure switch does.

That way, it only uses pump pressure switch as a backup incase the electronic one fails to turn off.

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Marko067

A constantly cycling pump may burn out the pressure switch prematurely and will likely drain a small battery quicker. Worth considering if you are a trolley user. It also sounds horrible if you're working anywhere near it 😬 🥴

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Chris34
3 hours ago, Marko067 said:

Here goes. Lets see if I can get this right

Cycling = switching on and off by itself

 

Explanation: 

There are two main factors that cause the back pressure that the pump has to deal with.

1. The ID of the hose. 
2. The length of the hose.

To illustrate:
If you take a 15cm (6 inches) length of 6mm ID hose and blow through it, it won't take a lot of effort. On the other hand if you try to blow through 20m of the same hose you will find it very hard. This is caused by friction and turbulance in the flow.

If you blow through 15cm of 8mm ID hose it will be easier than the 6mm one. Blowing through 20m of the same hose would not be as hard as the 6mm hose but would still require more effort than the shorter length.

 

You can only ever force a certain amount of water through any hose before something will wear out or break. 

Most pumps are therefore fitted with a pressure switch which is designed to shut the pump off before it gets damaged. If this shuts off the pump before you shut off the water with whatever valve/tap you have fitted in your hose, this is refered to as 'dead ending.' 

If the pump starts switching on and off by itself whilst you are cleaning windows, this means that there is too much back pressure in the hose due to either its ID and or its length. This switching on and off repeatedly is called 'cycling' because a cycle of increasing and decreasing pressure caused by the pump turning on and off is involved.

This can be handled in two ways. Either turning down the flow with a simple electronic controller until the maximum flow that the hose can handle at a given pressure is reached. Or if you have a more advanced controller, calibrating it so that the controller switches off the pump before the maximum pressure the hose can handle is reached.


This all sounds a bit complicated but if you can understand it, it will help you to troubleshoot a malfunctioning system and lead to less time wasted and more time working.

My preference for a trolley with a short hose (25m max) is a simple electronic controller with a smaller lighter pump. A 100psi Sureflo, whilst an excellent pump is overkill for my needs.

That's a great explanation, thanks for taking the time to write that, I really do appreciate it, I get it now.  

Going to order some pole hose and give it a go.  

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spruce
9 hours ago, Part Timer said:

@spruce you've got competition 😀

It's an excellent explanation.  I really like his analogy of blowing through different diameters/lengths of pipe.

Dead ending and calibration seem to be the thing that causes a lot of confusion among window cleaner newbies especially.

My son gets confused and calls flow pressure. Dad, you've got you pressure up too high, that's why you use so much water.

To further confuse, Shurflo pumps are rated at 100 psi and Spring controllers flow regulation is in 100 segments. 

 

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Iron Giant

I left my controller in a state of de since last Friday morning only realised when I went into the back of the van yesterday, fingers crossed all is ok, I'll find out tomorrow 

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Marko067
2 hours ago, spruce said:

It's an excellent explanation.  I really like his analogy of blowing through different diameters/lengths of pipe.

Dead ending and calibration seem to be the thing that causes a lot of confusion among window cleaner newbies especially.

My son gets confused and calls flow pressure. Dad, you've got you pressure up too high, that's why you use so much water.

To further confuse, Shurflo pumps are rated at 100 psi and Spring controllers flow regulation is in 100 segments. 

 

I can’t take credit for the idea. It came from Chris34’s straw.

I’ve done this when I knew the overnight temps were going to drop below zero, albeit with water in the hose. The idea was to blow the water out of the hose so there was nothing in there to freeze. Only took me a moment to realise there was no way I was going to blow it out without hurting myself, even with the 18m hose. Made me realise how tough our pumps are, even the small backpack pumps. 

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